Biological Services Program

L~ ary

NcLional Wetlands Resea rch CenterU S Fi3h and Wildlife Service7 ~raquo Cajundome BoulevardLafayette La 70506

FWSOBSmiddot82105FEBRUARY 1982

HABITAT SUITABILITY INDEX MODELSCUTTHROAT TROUT

-

~ ~

~ - bull bullbullbulle ~ - ~ _ ~~ bull ~ ~~ bullbull

_ gth and Wildlife Service

~ Department of the InteriorSK36 1 uS4n o 82shy105

The Biological Services Program was established within the US Fis hand Wild life Service to supply scientific information and methodolog ies onkey environmental issues that impact fish and wi ldli fe reso urces and theirsupporting ecosystems The mission of the program is as follows

bull To strengthen the Fish and Wi ldl i fe Service i n its role asa primary source of information on national f ish and wildshylife resources particularly in respect to environmentalimpact assessment

bull To gather analyze and present info rmation that wi ll aiddecisionmakers in the identification and re solut ion ofproble ms associated with major changes in land and wateruse

bull To provide bet ter ecological informat ion and eval uat ionfor Department of the Interior development programs suchas those relating to energy developme nt

Informat i on developed by the Biol ogi cal Ser vices Program is i nt endedfor use in the planning and decis ionma ki ng process to prevent or mi nimizethe impact of development on f i sh and wi ldli fe Research activ ities andtec hnical assistance services are based on an analysis of t he issues adetermina tion of t he decisionmakers involved and the i r i nformati on needsand an evaluat ion of the state of t he art to iden ti fy i nformation Hapsand to determine pr iorit ies This is a st ra t egy t hat wi l l ensure t hatthe products produced and di sseminated are t ime ly and useful

Proj ect s -have been initiated i n t he following areas coal ext ract ionand convers ion power plants geot hermal mi neral and oil shal e developshymen t wat er reso urce analysis i ncl udi ng stream alterations and west ernwater allocation coastal ecosystems and Outer Con tinent al Shelf devel opshyment and systems invento ry inc l uding Na ti onal Wetl and Inventoryhabitat classi f i cation and analysi s and informat i on transfer

The Biological Servi ces Program cons ists of the Off i ce of Bi ol ogi calSer vi ces in Washingt on DC wh i ch i s res po nsi ble for overal l planning andma nagement National Teams whi ch provide the Programs cent ral scien tifi c Iand tec hnical expertise and arrange for contract i ng bi ol o9ica l servicesstudies with states universities consulting firms and othe r s Regiona lStaffs who provide a link to problems at the operating leve l and staffs atcertain Fish and Wil dli fe Ser vice resear ch fa cili t i es wh o conduct i n-houseresearch studi es

FWSOBS-82105February 1982

HABITAT SUITABILITY INDEX MODELS CUTTHROAT TROUT

by

Terry Hickman a

andRobert F Raleigh

Habitat Evaluation Procedures GroupWestern Energy and Land Use Team

US Fish and Wildlife ServiceDrake Creekside Building One

2625 Redwing RoadFort Collins Colorado 80526

Western Energy and Land Use TeamOffice of Biological Services

Fish and Wildlife ServiceUS Department of the Interior

Washington DC 20240

aCurrent address US Fish and Wildlife Service Endangered Species Office1311 Federal BUilding 125 S State Street Salt Lake City Utah 84138

This report should be cited as

Hickman T and R F Raleigh 1982 Habitat suitability index modelsCutthroat trout USD Fish and Wildlife Service FWSOBS-8210538 pp

i i

PREFACE

The habitat use information and Habitat Suitability Index (HSI) modelspresented in this document are an aid for impact assessment and habitat manshyagement activities Literature concerning a species habitat requirements andpreferences is reviewed and then synthesized into HSI models which are scaledto produce an index hetween 0 (unsuitable habitat) and 1 (optimal habitat)Assumptions used to transform habitat use information into these mathematicalmodels are noted and guidelines for model application are described Anymodels found in the literature which may also be used to calculate an HSI arecited and simplified HSI models based on what the authors believe to be themost important habitat characteristics for this species are presented

Use of the models presented in this publication for impact assessmentrequires the setting of clear study objectives and may require modification ofthe models to meet those objectives Methods for reducing model complexityand recommended measurement techniques for model variables are presented inAppendix A

The HSI models presented herein are complex hypotheses of species-habitatrelationships not statements of proven cause and effect relationshipsResults of mode~erformance tests when available are referenced howevermodels that have demonstrated reliability in specific situations may proveunreliable in others For this reason the FWS encourages model users toconvey comments and suggestions that may help us increase the utility andeffectiveness of this habitat-based approach to fish and wildlife planningPlease send comments to

Habitat Evaluation Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife Service2625 Redwing RoadFt Co 11 ins CO 80526

iii

CONTENTS

PREFACE iiiACKNOWLEDGEMENTS vi

HABITAT USE INFORMATION 1Genera 1 1Age Growth and Food 1Reproduct ion 2Anadromy 2Specifi c Habitat Requi rements 3

HABITAT SUITABILITY INDEX (HSI) MODELS 7Model Applicability 7Model Description - Riverine 9Suitability Index (SI) Graphs for

Model Variables 10Riverine Model 22Lacustrine Model 26Interpreting Model Outputs 27

ADDITIONAL HABITAT MODELS 31Modell 31Model 2 31Model 3 31Model 4 32

REFERENCES CITED 32

v

ACKNOWLEDGMENTS

We are indebted to Ron Anderson and Dave Meyer for their aid with earlyliterature reviews and development work of sUitability index graphs and narrashytive sections of the cutthroat trout summary The manuscript was reviewed byRobert Behnke Norman Benson Jim Mullen and James Johnston Their reviewcontributions are gratefully acknowledged but the authors accept fullresponsibility for the contents of the summary Word processing was providedby Dora Ibarra and Carolyn Gulzow The cover of this document was illustratedby Jennifer Shoemaker

vi

CUTTHROAT TROUT (Salmo clarki)

HABITAT USE INFORMATION

General

Cutthroat trout Salmo clarki are a polytypic species consisting ofseveral geographically distinct forms with a broad distribution and a greatamount of genetic diversity (Hickman 1978 Behnke 1979) Behnke (1979)recognized 13 extant subspecies Coastal cutthroat (S c clarki) in coastalstreams from Prince William Sound Alaska to the Eel Rlver in Californiamountain cutthroat (~ ~ alpestris) in upper Columbia and F~Dser Riverdrainages of British Columbia west slope cutthroat (S c lewisi) in theupper Columbia Salmon Clearwater South Saskatchewan and upper Missouridrainages of Montana and Idaho an undescribed subspecies in the Alvord basinOregon Lahonton cutthroat (S c henshawi) Pauite cutthroat (S cseleniris) and an undescribed- subspecies in the Humboldt River drafnage ofthe Lahontan basin of Nevada and California Yellowstone cutthroat (S cbouvieri) in the Yellowstone drainage of Wyoming and Montana and the SnakeRiver drainage of Wyoming Idaho and Nevada an undescribed subspecies (finespotted) in the upper Snake River Wyoming Bonneville cutthroat (S c utah)in the Bonneville basin in Utah Nevada Idaho and Wyoming Colorado Rivercutthroat (~ ~ pleuriticus) in the Colorado River drainage in Wyoming UtahNew Mexico and Colorado greenback cutthroat (S c stomias) in the SouthPlatte and Arkansas River systems and Rio Grande cutthroat (~ ~ virginalis)in the Rio Grande River drainage of Colorado and New Mexico Many of these 13subspecies are included on Federal or State endangered or threatened specieslists

Temperature and chemical preferences migration and other ecological andlife history attributes vary among cutthroat subspecies (Behnke 1979) Differshyences in growth rate (Carlander 1969 Scott and Crossman 1973 Behnke 1979)and food preferences have also been reported (Trojnar and Behnke 1974) betweensome subspecies

Age Growth and Food

Most male cutthroat trout mature at ages II to III whereas femalesusually mature a year later (Irving 1954 Drummond and McKinney 1965 Johnstonand Mercer 1977) In Washington streams that contain anadromous populationsof cutthroat which predomi nant ly smo 1t at age I I 1ess than 15 of thecutthroat returning to the river for the first time are sexually mature females(Mercer and Johnston 1978) The maximum life expectancy for coastal cutthroatis about 10 years (Johnston and Mercer 1976) whereas the maximum reported agefor interior cutthroat is 7 years (Behnke 1979) Size at maturity will varydepending on environmental conditions Cutthroat mature at a smaller size insmall headwater streams (Behnke and Zarn 1976)

Trout are opportunistic feeders (Behnke and Zarn 1976) but their dietconsists mainly of aquatic insects (Allen 1969 Carlander 1969 Baxter andSimon 1970 Scott and Crossman 1973 Griffith 1974) Other foods such aszooplankton (McAfee 1966 Carlander 1969 Trojnar and Behnke 1974) terrestrial

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

The Biological Services Program was established within the US Fis hand Wild life Service to supply scientific information and methodolog ies onkey environmental issues that impact fish and wi ldli fe reso urces and theirsupporting ecosystems The mission of the program is as follows

bull To strengthen the Fish and Wi ldl i fe Service i n its role asa primary source of information on national f ish and wildshylife resources particularly in respect to environmentalimpact assessment

bull To gather analyze and present info rmation that wi ll aiddecisionmakers in the identification and re solut ion ofproble ms associated with major changes in land and wateruse

bull To provide bet ter ecological informat ion and eval uat ionfor Department of the Interior development programs suchas those relating to energy developme nt

Informat i on developed by the Biol ogi cal Ser vices Program is i nt endedfor use in the planning and decis ionma ki ng process to prevent or mi nimizethe impact of development on f i sh and wi ldli fe Research activ ities andtec hnical assistance services are based on an analysis of t he issues adetermina tion of t he decisionmakers involved and the i r i nformati on needsand an evaluat ion of the state of t he art to iden ti fy i nformation Hapsand to determine pr iorit ies This is a st ra t egy t hat wi l l ensure t hatthe products produced and di sseminated are t ime ly and useful

Proj ect s -have been initiated i n t he following areas coal ext ract ionand convers ion power plants geot hermal mi neral and oil shal e developshymen t wat er reso urce analysis i ncl udi ng stream alterations and west ernwater allocation coastal ecosystems and Outer Con tinent al Shelf devel opshyment and systems invento ry inc l uding Na ti onal Wetl and Inventoryhabitat classi f i cation and analysi s and informat i on transfer

The Biological Servi ces Program cons ists of the Off i ce of Bi ol ogi calSer vi ces in Washingt on DC wh i ch i s res po nsi ble for overal l planning andma nagement National Teams whi ch provide the Programs cent ral scien tifi c Iand tec hnical expertise and arrange for contract i ng bi ol o9ica l servicesstudies with states universities consulting firms and othe r s Regiona lStaffs who provide a link to problems at the operating leve l and staffs atcertain Fish and Wil dli fe Ser vice resear ch fa cili t i es wh o conduct i n-houseresearch studi es

FWSOBS-82105February 1982

HABITAT SUITABILITY INDEX MODELS CUTTHROAT TROUT

by

Terry Hickman a

andRobert F Raleigh

Habitat Evaluation Procedures GroupWestern Energy and Land Use Team

US Fish and Wildlife ServiceDrake Creekside Building One

2625 Redwing RoadFort Collins Colorado 80526

Western Energy and Land Use TeamOffice of Biological Services

Fish and Wildlife ServiceUS Department of the Interior

Washington DC 20240

aCurrent address US Fish and Wildlife Service Endangered Species Office1311 Federal BUilding 125 S State Street Salt Lake City Utah 84138

This report should be cited as

Hickman T and R F Raleigh 1982 Habitat suitability index modelsCutthroat trout USD Fish and Wildlife Service FWSOBS-8210538 pp

i i

PREFACE

The habitat use information and Habitat Suitability Index (HSI) modelspresented in this document are an aid for impact assessment and habitat manshyagement activities Literature concerning a species habitat requirements andpreferences is reviewed and then synthesized into HSI models which are scaledto produce an index hetween 0 (unsuitable habitat) and 1 (optimal habitat)Assumptions used to transform habitat use information into these mathematicalmodels are noted and guidelines for model application are described Anymodels found in the literature which may also be used to calculate an HSI arecited and simplified HSI models based on what the authors believe to be themost important habitat characteristics for this species are presented

Use of the models presented in this publication for impact assessmentrequires the setting of clear study objectives and may require modification ofthe models to meet those objectives Methods for reducing model complexityand recommended measurement techniques for model variables are presented inAppendix A

The HSI models presented herein are complex hypotheses of species-habitatrelationships not statements of proven cause and effect relationshipsResults of mode~erformance tests when available are referenced howevermodels that have demonstrated reliability in specific situations may proveunreliable in others For this reason the FWS encourages model users toconvey comments and suggestions that may help us increase the utility andeffectiveness of this habitat-based approach to fish and wildlife planningPlease send comments to

Habitat Evaluation Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife Service2625 Redwing RoadFt Co 11 ins CO 80526

iii

CONTENTS

PREFACE iiiACKNOWLEDGEMENTS vi

HABITAT USE INFORMATION 1Genera 1 1Age Growth and Food 1Reproduct ion 2Anadromy 2Specifi c Habitat Requi rements 3

HABITAT SUITABILITY INDEX (HSI) MODELS 7Model Applicability 7Model Description - Riverine 9Suitability Index (SI) Graphs for

Model Variables 10Riverine Model 22Lacustrine Model 26Interpreting Model Outputs 27

ADDITIONAL HABITAT MODELS 31Modell 31Model 2 31Model 3 31Model 4 32

REFERENCES CITED 32

v

ACKNOWLEDGMENTS

We are indebted to Ron Anderson and Dave Meyer for their aid with earlyliterature reviews and development work of sUitability index graphs and narrashytive sections of the cutthroat trout summary The manuscript was reviewed byRobert Behnke Norman Benson Jim Mullen and James Johnston Their reviewcontributions are gratefully acknowledged but the authors accept fullresponsibility for the contents of the summary Word processing was providedby Dora Ibarra and Carolyn Gulzow The cover of this document was illustratedby Jennifer Shoemaker

vi

CUTTHROAT TROUT (Salmo clarki)

HABITAT USE INFORMATION

General

Cutthroat trout Salmo clarki are a polytypic species consisting ofseveral geographically distinct forms with a broad distribution and a greatamount of genetic diversity (Hickman 1978 Behnke 1979) Behnke (1979)recognized 13 extant subspecies Coastal cutthroat (S c clarki) in coastalstreams from Prince William Sound Alaska to the Eel Rlver in Californiamountain cutthroat (~ ~ alpestris) in upper Columbia and F~Dser Riverdrainages of British Columbia west slope cutthroat (S c lewisi) in theupper Columbia Salmon Clearwater South Saskatchewan and upper Missouridrainages of Montana and Idaho an undescribed subspecies in the Alvord basinOregon Lahonton cutthroat (S c henshawi) Pauite cutthroat (S cseleniris) and an undescribed- subspecies in the Humboldt River drafnage ofthe Lahontan basin of Nevada and California Yellowstone cutthroat (S cbouvieri) in the Yellowstone drainage of Wyoming and Montana and the SnakeRiver drainage of Wyoming Idaho and Nevada an undescribed subspecies (finespotted) in the upper Snake River Wyoming Bonneville cutthroat (S c utah)in the Bonneville basin in Utah Nevada Idaho and Wyoming Colorado Rivercutthroat (~ ~ pleuriticus) in the Colorado River drainage in Wyoming UtahNew Mexico and Colorado greenback cutthroat (S c stomias) in the SouthPlatte and Arkansas River systems and Rio Grande cutthroat (~ ~ virginalis)in the Rio Grande River drainage of Colorado and New Mexico Many of these 13subspecies are included on Federal or State endangered or threatened specieslists

Temperature and chemical preferences migration and other ecological andlife history attributes vary among cutthroat subspecies (Behnke 1979) Differshyences in growth rate (Carlander 1969 Scott and Crossman 1973 Behnke 1979)and food preferences have also been reported (Trojnar and Behnke 1974) betweensome subspecies

Age Growth and Food

Most male cutthroat trout mature at ages II to III whereas femalesusually mature a year later (Irving 1954 Drummond and McKinney 1965 Johnstonand Mercer 1977) In Washington streams that contain anadromous populationsof cutthroat which predomi nant ly smo 1t at age I I 1ess than 15 of thecutthroat returning to the river for the first time are sexually mature females(Mercer and Johnston 1978) The maximum life expectancy for coastal cutthroatis about 10 years (Johnston and Mercer 1976) whereas the maximum reported agefor interior cutthroat is 7 years (Behnke 1979) Size at maturity will varydepending on environmental conditions Cutthroat mature at a smaller size insmall headwater streams (Behnke and Zarn 1976)

Trout are opportunistic feeders (Behnke and Zarn 1976) but their dietconsists mainly of aquatic insects (Allen 1969 Carlander 1969 Baxter andSimon 1970 Scott and Crossman 1973 Griffith 1974) Other foods such aszooplankton (McAfee 1966 Carlander 1969 Trojnar and Behnke 1974) terrestrial

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

FWSOBS-82105February 1982

HABITAT SUITABILITY INDEX MODELS CUTTHROAT TROUT

by

Terry Hickman a

andRobert F Raleigh

Habitat Evaluation Procedures GroupWestern Energy and Land Use Team

US Fish and Wildlife ServiceDrake Creekside Building One

2625 Redwing RoadFort Collins Colorado 80526

Western Energy and Land Use TeamOffice of Biological Services

Fish and Wildlife ServiceUS Department of the Interior

Washington DC 20240

aCurrent address US Fish and Wildlife Service Endangered Species Office1311 Federal BUilding 125 S State Street Salt Lake City Utah 84138

This report should be cited as

Hickman T and R F Raleigh 1982 Habitat suitability index modelsCutthroat trout USD Fish and Wildlife Service FWSOBS-8210538 pp

i i

PREFACE

The habitat use information and Habitat Suitability Index (HSI) modelspresented in this document are an aid for impact assessment and habitat manshyagement activities Literature concerning a species habitat requirements andpreferences is reviewed and then synthesized into HSI models which are scaledto produce an index hetween 0 (unsuitable habitat) and 1 (optimal habitat)Assumptions used to transform habitat use information into these mathematicalmodels are noted and guidelines for model application are described Anymodels found in the literature which may also be used to calculate an HSI arecited and simplified HSI models based on what the authors believe to be themost important habitat characteristics for this species are presented

Use of the models presented in this publication for impact assessmentrequires the setting of clear study objectives and may require modification ofthe models to meet those objectives Methods for reducing model complexityand recommended measurement techniques for model variables are presented inAppendix A

The HSI models presented herein are complex hypotheses of species-habitatrelationships not statements of proven cause and effect relationshipsResults of mode~erformance tests when available are referenced howevermodels that have demonstrated reliability in specific situations may proveunreliable in others For this reason the FWS encourages model users toconvey comments and suggestions that may help us increase the utility andeffectiveness of this habitat-based approach to fish and wildlife planningPlease send comments to

Habitat Evaluation Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife Service2625 Redwing RoadFt Co 11 ins CO 80526

iii

CONTENTS

PREFACE iiiACKNOWLEDGEMENTS vi

HABITAT USE INFORMATION 1Genera 1 1Age Growth and Food 1Reproduct ion 2Anadromy 2Specifi c Habitat Requi rements 3

HABITAT SUITABILITY INDEX (HSI) MODELS 7Model Applicability 7Model Description - Riverine 9Suitability Index (SI) Graphs for

Model Variables 10Riverine Model 22Lacustrine Model 26Interpreting Model Outputs 27

ADDITIONAL HABITAT MODELS 31Modell 31Model 2 31Model 3 31Model 4 32

REFERENCES CITED 32

v

ACKNOWLEDGMENTS

We are indebted to Ron Anderson and Dave Meyer for their aid with earlyliterature reviews and development work of sUitability index graphs and narrashytive sections of the cutthroat trout summary The manuscript was reviewed byRobert Behnke Norman Benson Jim Mullen and James Johnston Their reviewcontributions are gratefully acknowledged but the authors accept fullresponsibility for the contents of the summary Word processing was providedby Dora Ibarra and Carolyn Gulzow The cover of this document was illustratedby Jennifer Shoemaker

vi

CUTTHROAT TROUT (Salmo clarki)

HABITAT USE INFORMATION

General

Cutthroat trout Salmo clarki are a polytypic species consisting ofseveral geographically distinct forms with a broad distribution and a greatamount of genetic diversity (Hickman 1978 Behnke 1979) Behnke (1979)recognized 13 extant subspecies Coastal cutthroat (S c clarki) in coastalstreams from Prince William Sound Alaska to the Eel Rlver in Californiamountain cutthroat (~ ~ alpestris) in upper Columbia and F~Dser Riverdrainages of British Columbia west slope cutthroat (S c lewisi) in theupper Columbia Salmon Clearwater South Saskatchewan and upper Missouridrainages of Montana and Idaho an undescribed subspecies in the Alvord basinOregon Lahonton cutthroat (S c henshawi) Pauite cutthroat (S cseleniris) and an undescribed- subspecies in the Humboldt River drafnage ofthe Lahontan basin of Nevada and California Yellowstone cutthroat (S cbouvieri) in the Yellowstone drainage of Wyoming and Montana and the SnakeRiver drainage of Wyoming Idaho and Nevada an undescribed subspecies (finespotted) in the upper Snake River Wyoming Bonneville cutthroat (S c utah)in the Bonneville basin in Utah Nevada Idaho and Wyoming Colorado Rivercutthroat (~ ~ pleuriticus) in the Colorado River drainage in Wyoming UtahNew Mexico and Colorado greenback cutthroat (S c stomias) in the SouthPlatte and Arkansas River systems and Rio Grande cutthroat (~ ~ virginalis)in the Rio Grande River drainage of Colorado and New Mexico Many of these 13subspecies are included on Federal or State endangered or threatened specieslists

Temperature and chemical preferences migration and other ecological andlife history attributes vary among cutthroat subspecies (Behnke 1979) Differshyences in growth rate (Carlander 1969 Scott and Crossman 1973 Behnke 1979)and food preferences have also been reported (Trojnar and Behnke 1974) betweensome subspecies

Age Growth and Food

Most male cutthroat trout mature at ages II to III whereas femalesusually mature a year later (Irving 1954 Drummond and McKinney 1965 Johnstonand Mercer 1977) In Washington streams that contain anadromous populationsof cutthroat which predomi nant ly smo 1t at age I I 1ess than 15 of thecutthroat returning to the river for the first time are sexually mature females(Mercer and Johnston 1978) The maximum life expectancy for coastal cutthroatis about 10 years (Johnston and Mercer 1976) whereas the maximum reported agefor interior cutthroat is 7 years (Behnke 1979) Size at maturity will varydepending on environmental conditions Cutthroat mature at a smaller size insmall headwater streams (Behnke and Zarn 1976)

Trout are opportunistic feeders (Behnke and Zarn 1976) but their dietconsists mainly of aquatic insects (Allen 1969 Carlander 1969 Baxter andSimon 1970 Scott and Crossman 1973 Griffith 1974) Other foods such aszooplankton (McAfee 1966 Carlander 1969 Trojnar and Behnke 1974) terrestrial

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

This report should be cited as

Hickman T and R F Raleigh 1982 Habitat suitability index modelsCutthroat trout USD Fish and Wildlife Service FWSOBS-8210538 pp

i i

PREFACE

The habitat use information and Habitat Suitability Index (HSI) modelspresented in this document are an aid for impact assessment and habitat manshyagement activities Literature concerning a species habitat requirements andpreferences is reviewed and then synthesized into HSI models which are scaledto produce an index hetween 0 (unsuitable habitat) and 1 (optimal habitat)Assumptions used to transform habitat use information into these mathematicalmodels are noted and guidelines for model application are described Anymodels found in the literature which may also be used to calculate an HSI arecited and simplified HSI models based on what the authors believe to be themost important habitat characteristics for this species are presented

Use of the models presented in this publication for impact assessmentrequires the setting of clear study objectives and may require modification ofthe models to meet those objectives Methods for reducing model complexityand recommended measurement techniques for model variables are presented inAppendix A

The HSI models presented herein are complex hypotheses of species-habitatrelationships not statements of proven cause and effect relationshipsResults of mode~erformance tests when available are referenced howevermodels that have demonstrated reliability in specific situations may proveunreliable in others For this reason the FWS encourages model users toconvey comments and suggestions that may help us increase the utility andeffectiveness of this habitat-based approach to fish and wildlife planningPlease send comments to

Habitat Evaluation Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife Service2625 Redwing RoadFt Co 11 ins CO 80526

iii

CONTENTS

PREFACE iiiACKNOWLEDGEMENTS vi

HABITAT USE INFORMATION 1Genera 1 1Age Growth and Food 1Reproduct ion 2Anadromy 2Specifi c Habitat Requi rements 3

HABITAT SUITABILITY INDEX (HSI) MODELS 7Model Applicability 7Model Description - Riverine 9Suitability Index (SI) Graphs for

Model Variables 10Riverine Model 22Lacustrine Model 26Interpreting Model Outputs 27

ADDITIONAL HABITAT MODELS 31Modell 31Model 2 31Model 3 31Model 4 32

REFERENCES CITED 32

v

ACKNOWLEDGMENTS

We are indebted to Ron Anderson and Dave Meyer for their aid with earlyliterature reviews and development work of sUitability index graphs and narrashytive sections of the cutthroat trout summary The manuscript was reviewed byRobert Behnke Norman Benson Jim Mullen and James Johnston Their reviewcontributions are gratefully acknowledged but the authors accept fullresponsibility for the contents of the summary Word processing was providedby Dora Ibarra and Carolyn Gulzow The cover of this document was illustratedby Jennifer Shoemaker

vi

CUTTHROAT TROUT (Salmo clarki)

HABITAT USE INFORMATION

General

Cutthroat trout Salmo clarki are a polytypic species consisting ofseveral geographically distinct forms with a broad distribution and a greatamount of genetic diversity (Hickman 1978 Behnke 1979) Behnke (1979)recognized 13 extant subspecies Coastal cutthroat (S c clarki) in coastalstreams from Prince William Sound Alaska to the Eel Rlver in Californiamountain cutthroat (~ ~ alpestris) in upper Columbia and F~Dser Riverdrainages of British Columbia west slope cutthroat (S c lewisi) in theupper Columbia Salmon Clearwater South Saskatchewan and upper Missouridrainages of Montana and Idaho an undescribed subspecies in the Alvord basinOregon Lahonton cutthroat (S c henshawi) Pauite cutthroat (S cseleniris) and an undescribed- subspecies in the Humboldt River drafnage ofthe Lahontan basin of Nevada and California Yellowstone cutthroat (S cbouvieri) in the Yellowstone drainage of Wyoming and Montana and the SnakeRiver drainage of Wyoming Idaho and Nevada an undescribed subspecies (finespotted) in the upper Snake River Wyoming Bonneville cutthroat (S c utah)in the Bonneville basin in Utah Nevada Idaho and Wyoming Colorado Rivercutthroat (~ ~ pleuriticus) in the Colorado River drainage in Wyoming UtahNew Mexico and Colorado greenback cutthroat (S c stomias) in the SouthPlatte and Arkansas River systems and Rio Grande cutthroat (~ ~ virginalis)in the Rio Grande River drainage of Colorado and New Mexico Many of these 13subspecies are included on Federal or State endangered or threatened specieslists

Temperature and chemical preferences migration and other ecological andlife history attributes vary among cutthroat subspecies (Behnke 1979) Differshyences in growth rate (Carlander 1969 Scott and Crossman 1973 Behnke 1979)and food preferences have also been reported (Trojnar and Behnke 1974) betweensome subspecies

Age Growth and Food

Most male cutthroat trout mature at ages II to III whereas femalesusually mature a year later (Irving 1954 Drummond and McKinney 1965 Johnstonand Mercer 1977) In Washington streams that contain anadromous populationsof cutthroat which predomi nant ly smo 1t at age I I 1ess than 15 of thecutthroat returning to the river for the first time are sexually mature females(Mercer and Johnston 1978) The maximum life expectancy for coastal cutthroatis about 10 years (Johnston and Mercer 1976) whereas the maximum reported agefor interior cutthroat is 7 years (Behnke 1979) Size at maturity will varydepending on environmental conditions Cutthroat mature at a smaller size insmall headwater streams (Behnke and Zarn 1976)

Trout are opportunistic feeders (Behnke and Zarn 1976) but their dietconsists mainly of aquatic insects (Allen 1969 Carlander 1969 Baxter andSimon 1970 Scott and Crossman 1973 Griffith 1974) Other foods such aszooplankton (McAfee 1966 Carlander 1969 Trojnar and Behnke 1974) terrestrial

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

PREFACE

The habitat use information and Habitat Suitability Index (HSI) modelspresented in this document are an aid for impact assessment and habitat manshyagement activities Literature concerning a species habitat requirements andpreferences is reviewed and then synthesized into HSI models which are scaledto produce an index hetween 0 (unsuitable habitat) and 1 (optimal habitat)Assumptions used to transform habitat use information into these mathematicalmodels are noted and guidelines for model application are described Anymodels found in the literature which may also be used to calculate an HSI arecited and simplified HSI models based on what the authors believe to be themost important habitat characteristics for this species are presented

Use of the models presented in this publication for impact assessmentrequires the setting of clear study objectives and may require modification ofthe models to meet those objectives Methods for reducing model complexityand recommended measurement techniques for model variables are presented inAppendix A

The HSI models presented herein are complex hypotheses of species-habitatrelationships not statements of proven cause and effect relationshipsResults of mode~erformance tests when available are referenced howevermodels that have demonstrated reliability in specific situations may proveunreliable in others For this reason the FWS encourages model users toconvey comments and suggestions that may help us increase the utility andeffectiveness of this habitat-based approach to fish and wildlife planningPlease send comments to

Habitat Evaluation Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife Service2625 Redwing RoadFt Co 11 ins CO 80526

iii

CONTENTS

PREFACE iiiACKNOWLEDGEMENTS vi

HABITAT USE INFORMATION 1Genera 1 1Age Growth and Food 1Reproduct ion 2Anadromy 2Specifi c Habitat Requi rements 3

HABITAT SUITABILITY INDEX (HSI) MODELS 7Model Applicability 7Model Description - Riverine 9Suitability Index (SI) Graphs for

Model Variables 10Riverine Model 22Lacustrine Model 26Interpreting Model Outputs 27

ADDITIONAL HABITAT MODELS 31Modell 31Model 2 31Model 3 31Model 4 32

REFERENCES CITED 32

v

ACKNOWLEDGMENTS

We are indebted to Ron Anderson and Dave Meyer for their aid with earlyliterature reviews and development work of sUitability index graphs and narrashytive sections of the cutthroat trout summary The manuscript was reviewed byRobert Behnke Norman Benson Jim Mullen and James Johnston Their reviewcontributions are gratefully acknowledged but the authors accept fullresponsibility for the contents of the summary Word processing was providedby Dora Ibarra and Carolyn Gulzow The cover of this document was illustratedby Jennifer Shoemaker

vi

CUTTHROAT TROUT (Salmo clarki)

HABITAT USE INFORMATION

General

Cutthroat trout Salmo clarki are a polytypic species consisting ofseveral geographically distinct forms with a broad distribution and a greatamount of genetic diversity (Hickman 1978 Behnke 1979) Behnke (1979)recognized 13 extant subspecies Coastal cutthroat (S c clarki) in coastalstreams from Prince William Sound Alaska to the Eel Rlver in Californiamountain cutthroat (~ ~ alpestris) in upper Columbia and F~Dser Riverdrainages of British Columbia west slope cutthroat (S c lewisi) in theupper Columbia Salmon Clearwater South Saskatchewan and upper Missouridrainages of Montana and Idaho an undescribed subspecies in the Alvord basinOregon Lahonton cutthroat (S c henshawi) Pauite cutthroat (S cseleniris) and an undescribed- subspecies in the Humboldt River drafnage ofthe Lahontan basin of Nevada and California Yellowstone cutthroat (S cbouvieri) in the Yellowstone drainage of Wyoming and Montana and the SnakeRiver drainage of Wyoming Idaho and Nevada an undescribed subspecies (finespotted) in the upper Snake River Wyoming Bonneville cutthroat (S c utah)in the Bonneville basin in Utah Nevada Idaho and Wyoming Colorado Rivercutthroat (~ ~ pleuriticus) in the Colorado River drainage in Wyoming UtahNew Mexico and Colorado greenback cutthroat (S c stomias) in the SouthPlatte and Arkansas River systems and Rio Grande cutthroat (~ ~ virginalis)in the Rio Grande River drainage of Colorado and New Mexico Many of these 13subspecies are included on Federal or State endangered or threatened specieslists

Temperature and chemical preferences migration and other ecological andlife history attributes vary among cutthroat subspecies (Behnke 1979) Differshyences in growth rate (Carlander 1969 Scott and Crossman 1973 Behnke 1979)and food preferences have also been reported (Trojnar and Behnke 1974) betweensome subspecies

Age Growth and Food

Most male cutthroat trout mature at ages II to III whereas femalesusually mature a year later (Irving 1954 Drummond and McKinney 1965 Johnstonand Mercer 1977) In Washington streams that contain anadromous populationsof cutthroat which predomi nant ly smo 1t at age I I 1ess than 15 of thecutthroat returning to the river for the first time are sexually mature females(Mercer and Johnston 1978) The maximum life expectancy for coastal cutthroatis about 10 years (Johnston and Mercer 1976) whereas the maximum reported agefor interior cutthroat is 7 years (Behnke 1979) Size at maturity will varydepending on environmental conditions Cutthroat mature at a smaller size insmall headwater streams (Behnke and Zarn 1976)

Trout are opportunistic feeders (Behnke and Zarn 1976) but their dietconsists mainly of aquatic insects (Allen 1969 Carlander 1969 Baxter andSimon 1970 Scott and Crossman 1973 Griffith 1974) Other foods such aszooplankton (McAfee 1966 Carlander 1969 Trojnar and Behnke 1974) terrestrial

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

CONTENTS

PREFACE iiiACKNOWLEDGEMENTS vi

HABITAT USE INFORMATION 1Genera 1 1Age Growth and Food 1Reproduct ion 2Anadromy 2Specifi c Habitat Requi rements 3

HABITAT SUITABILITY INDEX (HSI) MODELS 7Model Applicability 7Model Description - Riverine 9Suitability Index (SI) Graphs for

Model Variables 10Riverine Model 22Lacustrine Model 26Interpreting Model Outputs 27

ADDITIONAL HABITAT MODELS 31Modell 31Model 2 31Model 3 31Model 4 32

REFERENCES CITED 32

v

ACKNOWLEDGMENTS

We are indebted to Ron Anderson and Dave Meyer for their aid with earlyliterature reviews and development work of sUitability index graphs and narrashytive sections of the cutthroat trout summary The manuscript was reviewed byRobert Behnke Norman Benson Jim Mullen and James Johnston Their reviewcontributions are gratefully acknowledged but the authors accept fullresponsibility for the contents of the summary Word processing was providedby Dora Ibarra and Carolyn Gulzow The cover of this document was illustratedby Jennifer Shoemaker

vi

CUTTHROAT TROUT (Salmo clarki)

HABITAT USE INFORMATION

General

Cutthroat trout Salmo clarki are a polytypic species consisting ofseveral geographically distinct forms with a broad distribution and a greatamount of genetic diversity (Hickman 1978 Behnke 1979) Behnke (1979)recognized 13 extant subspecies Coastal cutthroat (S c clarki) in coastalstreams from Prince William Sound Alaska to the Eel Rlver in Californiamountain cutthroat (~ ~ alpestris) in upper Columbia and F~Dser Riverdrainages of British Columbia west slope cutthroat (S c lewisi) in theupper Columbia Salmon Clearwater South Saskatchewan and upper Missouridrainages of Montana and Idaho an undescribed subspecies in the Alvord basinOregon Lahonton cutthroat (S c henshawi) Pauite cutthroat (S cseleniris) and an undescribed- subspecies in the Humboldt River drafnage ofthe Lahontan basin of Nevada and California Yellowstone cutthroat (S cbouvieri) in the Yellowstone drainage of Wyoming and Montana and the SnakeRiver drainage of Wyoming Idaho and Nevada an undescribed subspecies (finespotted) in the upper Snake River Wyoming Bonneville cutthroat (S c utah)in the Bonneville basin in Utah Nevada Idaho and Wyoming Colorado Rivercutthroat (~ ~ pleuriticus) in the Colorado River drainage in Wyoming UtahNew Mexico and Colorado greenback cutthroat (S c stomias) in the SouthPlatte and Arkansas River systems and Rio Grande cutthroat (~ ~ virginalis)in the Rio Grande River drainage of Colorado and New Mexico Many of these 13subspecies are included on Federal or State endangered or threatened specieslists

Temperature and chemical preferences migration and other ecological andlife history attributes vary among cutthroat subspecies (Behnke 1979) Differshyences in growth rate (Carlander 1969 Scott and Crossman 1973 Behnke 1979)and food preferences have also been reported (Trojnar and Behnke 1974) betweensome subspecies

Age Growth and Food

Most male cutthroat trout mature at ages II to III whereas femalesusually mature a year later (Irving 1954 Drummond and McKinney 1965 Johnstonand Mercer 1977) In Washington streams that contain anadromous populationsof cutthroat which predomi nant ly smo 1t at age I I 1ess than 15 of thecutthroat returning to the river for the first time are sexually mature females(Mercer and Johnston 1978) The maximum life expectancy for coastal cutthroatis about 10 years (Johnston and Mercer 1976) whereas the maximum reported agefor interior cutthroat is 7 years (Behnke 1979) Size at maturity will varydepending on environmental conditions Cutthroat mature at a smaller size insmall headwater streams (Behnke and Zarn 1976)

Trout are opportunistic feeders (Behnke and Zarn 1976) but their dietconsists mainly of aquatic insects (Allen 1969 Carlander 1969 Baxter andSimon 1970 Scott and Crossman 1973 Griffith 1974) Other foods such aszooplankton (McAfee 1966 Carlander 1969 Trojnar and Behnke 1974) terrestrial

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

ACKNOWLEDGMENTS

We are indebted to Ron Anderson and Dave Meyer for their aid with earlyliterature reviews and development work of sUitability index graphs and narrashytive sections of the cutthroat trout summary The manuscript was reviewed byRobert Behnke Norman Benson Jim Mullen and James Johnston Their reviewcontributions are gratefully acknowledged but the authors accept fullresponsibility for the contents of the summary Word processing was providedby Dora Ibarra and Carolyn Gulzow The cover of this document was illustratedby Jennifer Shoemaker

vi

CUTTHROAT TROUT (Salmo clarki)

HABITAT USE INFORMATION

General

Cutthroat trout Salmo clarki are a polytypic species consisting ofseveral geographically distinct forms with a broad distribution and a greatamount of genetic diversity (Hickman 1978 Behnke 1979) Behnke (1979)recognized 13 extant subspecies Coastal cutthroat (S c clarki) in coastalstreams from Prince William Sound Alaska to the Eel Rlver in Californiamountain cutthroat (~ ~ alpestris) in upper Columbia and F~Dser Riverdrainages of British Columbia west slope cutthroat (S c lewisi) in theupper Columbia Salmon Clearwater South Saskatchewan and upper Missouridrainages of Montana and Idaho an undescribed subspecies in the Alvord basinOregon Lahonton cutthroat (S c henshawi) Pauite cutthroat (S cseleniris) and an undescribed- subspecies in the Humboldt River drafnage ofthe Lahontan basin of Nevada and California Yellowstone cutthroat (S cbouvieri) in the Yellowstone drainage of Wyoming and Montana and the SnakeRiver drainage of Wyoming Idaho and Nevada an undescribed subspecies (finespotted) in the upper Snake River Wyoming Bonneville cutthroat (S c utah)in the Bonneville basin in Utah Nevada Idaho and Wyoming Colorado Rivercutthroat (~ ~ pleuriticus) in the Colorado River drainage in Wyoming UtahNew Mexico and Colorado greenback cutthroat (S c stomias) in the SouthPlatte and Arkansas River systems and Rio Grande cutthroat (~ ~ virginalis)in the Rio Grande River drainage of Colorado and New Mexico Many of these 13subspecies are included on Federal or State endangered or threatened specieslists

Temperature and chemical preferences migration and other ecological andlife history attributes vary among cutthroat subspecies (Behnke 1979) Differshyences in growth rate (Carlander 1969 Scott and Crossman 1973 Behnke 1979)and food preferences have also been reported (Trojnar and Behnke 1974) betweensome subspecies

Age Growth and Food

Most male cutthroat trout mature at ages II to III whereas femalesusually mature a year later (Irving 1954 Drummond and McKinney 1965 Johnstonand Mercer 1977) In Washington streams that contain anadromous populationsof cutthroat which predomi nant ly smo 1t at age I I 1ess than 15 of thecutthroat returning to the river for the first time are sexually mature females(Mercer and Johnston 1978) The maximum life expectancy for coastal cutthroatis about 10 years (Johnston and Mercer 1976) whereas the maximum reported agefor interior cutthroat is 7 years (Behnke 1979) Size at maturity will varydepending on environmental conditions Cutthroat mature at a smaller size insmall headwater streams (Behnke and Zarn 1976)

Trout are opportunistic feeders (Behnke and Zarn 1976) but their dietconsists mainly of aquatic insects (Allen 1969 Carlander 1969 Baxter andSimon 1970 Scott and Crossman 1973 Griffith 1974) Other foods such aszooplankton (McAfee 1966 Carlander 1969 Trojnar and Behnke 1974) terrestrial

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

CUTTHROAT TROUT (Salmo clarki)

HABITAT USE INFORMATION

General

Cutthroat trout Salmo clarki are a polytypic species consisting ofseveral geographically distinct forms with a broad distribution and a greatamount of genetic diversity (Hickman 1978 Behnke 1979) Behnke (1979)recognized 13 extant subspecies Coastal cutthroat (S c clarki) in coastalstreams from Prince William Sound Alaska to the Eel Rlver in Californiamountain cutthroat (~ ~ alpestris) in upper Columbia and F~Dser Riverdrainages of British Columbia west slope cutthroat (S c lewisi) in theupper Columbia Salmon Clearwater South Saskatchewan and upper Missouridrainages of Montana and Idaho an undescribed subspecies in the Alvord basinOregon Lahonton cutthroat (S c henshawi) Pauite cutthroat (S cseleniris) and an undescribed- subspecies in the Humboldt River drafnage ofthe Lahontan basin of Nevada and California Yellowstone cutthroat (S cbouvieri) in the Yellowstone drainage of Wyoming and Montana and the SnakeRiver drainage of Wyoming Idaho and Nevada an undescribed subspecies (finespotted) in the upper Snake River Wyoming Bonneville cutthroat (S c utah)in the Bonneville basin in Utah Nevada Idaho and Wyoming Colorado Rivercutthroat (~ ~ pleuriticus) in the Colorado River drainage in Wyoming UtahNew Mexico and Colorado greenback cutthroat (S c stomias) in the SouthPlatte and Arkansas River systems and Rio Grande cutthroat (~ ~ virginalis)in the Rio Grande River drainage of Colorado and New Mexico Many of these 13subspecies are included on Federal or State endangered or threatened specieslists

Temperature and chemical preferences migration and other ecological andlife history attributes vary among cutthroat subspecies (Behnke 1979) Differshyences in growth rate (Carlander 1969 Scott and Crossman 1973 Behnke 1979)and food preferences have also been reported (Trojnar and Behnke 1974) betweensome subspecies

Age Growth and Food

Most male cutthroat trout mature at ages II to III whereas femalesusually mature a year later (Irving 1954 Drummond and McKinney 1965 Johnstonand Mercer 1977) In Washington streams that contain anadromous populationsof cutthroat which predomi nant ly smo 1t at age I I 1ess than 15 of thecutthroat returning to the river for the first time are sexually mature females(Mercer and Johnston 1978) The maximum life expectancy for coastal cutthroatis about 10 years (Johnston and Mercer 1976) whereas the maximum reported agefor interior cutthroat is 7 years (Behnke 1979) Size at maturity will varydepending on environmental conditions Cutthroat mature at a smaller size insmall headwater streams (Behnke and Zarn 1976)

Trout are opportunistic feeders (Behnke and Zarn 1976) but their dietconsists mainly of aquatic insects (Allen 1969 Carlander 1969 Baxter andSimon 1970 Scott and Crossman 1973 Griffith 1974) Other foods such aszooplankton (McAfee 1966 Carlander 1969 Trojnar and Behnke 1974) terrestrial

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

insects (Carlander 1969 Trojnar and Behnke 1974 Hickman 1977) and fish(Carlander 1969) are locally or seasonally important Cutthroat trout usuallybecome more piscivorous as they increase in size (McAfee 1966 Carlander 1969Baxter and Simon 1970)

Reproduction

Cutthroat trout are stream spawners The fertilized ova are deposited inredds constructed primarily by the female in the stream gravels (Smith 19411947) Spawning begins in spring as early as February (Behnke 1979) but canoccur as late as August in colder areas (Juday 1907 Fleener 1951) The timeof spawning depends on water temperature runoff (Lea 1968) ice melt (Calhoun1944) elevation and latitude (Behnke and Zarn 1976)

Anadromy

Coastal cutthroat are the most abundant of the thirteen recognizedcutthroat subspecies and consist of both resident and anadromous populationsBoth populations are usually found in the same watershed The resident populashytions are frequently but not always segregated from the anadromous stock bysome barrier to anadromy Although resident and anadromous populations havebeen reported to occur in sympatry in streams and lakes more information isneeded to determine if gene flow between populations is absent (Johnston1979)

Anadromous coastal cutthroat spend less time in saltwater than steelheadtrout or salmon Although some cutthroat overwinter in saltwater most returnto freshwater after 3 to 8 months (Johnston 1979) During this period insaltwater the cutthroat stay close to shore and are rarely found at depthsgreater than 3 m Preferred habitats in saltwater are gravel beaches vegetatedabove the high tide mark and gravel spits created by tidal currents Cutthroatare rarely found in saltwater in areas with silt mud or solid rock substrateAnadromous cutthroat utilize cover during upstream migration from saltwater

Coastal cutthroat initially smolt at age II III or IV Some smolt atage I whereas others may not migrate to salt water until age VI (Jones 19741975 1976) In Washington the smallest cutthroat entering salt water weighfrom 25 to 45 gms and are 120 to 170 mm long Physiological adaptation tosalt water appears to be related to size rather than age (Johnston and Mercer1976)

In Washington and Oregon smolt movement to salt water begins in Marchpeaks in mid-May and is completed by mid-June (Johnston and Mercer 1976) InAlaska migration begins in April (Armstrong 1971 Jones 1974 1975 1976)peaks at the end of May but may continue into August Most seaward migrationsoccur at night Re-entry into fresh water in Washington and Oregon begins inJuly peaks in September and October and 1asts until the end of October(Giger 1972 Johnston and Mercer 1976) In smaller coastal streams re-entrybegins in October peaks in December and January and continues into MarchMigrations into small stream-lake systems in Alaska begin as early as mid-Maypeak in September and last until October (Armstrong 1971 Jones 1974 19751976)

2

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

Specific Habitat Requirements

Optimal cutthroat trout riverine habitat is characterized by clear coldwater a silt free rocky substrate in riffle-run areas an approximately 11pool-riffle ratio with areas of slow deep water well vegetated stream banksabundant instream cover and relatively stable water flow temperature regimesand stream banks (Ra1ei gh and Duff 1981) Cutthroat trout tend to occupyheadwater stream areas especially when other trout species are present in thesame river system (Glova and Mason 1976)

Optimal lacustrine habitat is characterized by clear cold deep lakesthat are typically oligotrophic butparticularly in reservoir habitatsrequire tributary streams with graveltion to occur

may vary in size and chemical qualityCutthroat trout are stream spawners andsubstrate in riffle areas for reproduc-

Trout literature does not clearly distinguish between feeding stationsescape cover and winter cover requirements Prime requisites for optimalfeeding stations appear to be low water velocity and access to a plentifulfood supply eg energy accretion at a low energy cost Water depth is notclearly defined as a selection factor and overhead cover is preferred but notessential Escape cover however must be nearby (Raleigh and Duff 1981)The feeding stations of dominant adult trout will include overhead cover whenavailable The feeding stations of subdominant adults and juveniles howevermay not always include overhead cover

Cover is recognized as one of the essential components of trout streamsBoussu (1954) was able to increase the number and weight of trout in streamsections by adding artificial brush cover and to decrease numbers and weightby removing brush cover and undercut banks Lewis (1969) reported that theamount of cover was important in determining the number of trout in sectionsof a Montana stream Cover for adult trout consists of areas of obscurestream bottom in areas of water ~ 15 cm deep with a low velocity ofs 15 cmsec (Wesche 1980) Wesche (1980) reported that in larger streamsthe abundance of trout ~ 15 cm in length increased with depth most were atdepths of at least 15 to 45 cm Cover is provided by overhanging vegetationsubmerged vegetation undercut banks instream objects such as debris pileslogs large rocks and pool depth or surface turbulence (Giger 1973) A coverarea of ~ 25 of the total stream area will provide adequate cover for adulttrout a cover area of ~ 15 is adequate for juveniles The main use ofsummer cover is probably for predator avoidance and resting In wintersalmonids occupy different habitat areas than in the summer (Hartman 1965Everest 1969 Bustard and Narver 1975a)

In some streams the major factor limiting salmonid densities may be theamount of adequate overwintering habitat rather than summer rearing habitat(Bustard and Narver 1975a) Winter hiding behavior in salmonids is triggeredby low temperatures (Chapman and Bjornn 1969 Everest 1969 Bustard and Narver1975ab) Cutthroat trout were found under boulders log jams upturnedroots and debris when temperatures neared 4 to 8deg C depending on velocity(Bustard and Narver 1975a) Everest (1969) found juvenile rainbows 15 to30 cm deep in the substrate which was often covered by 5 to 10 cm of anchor

3

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

ice Lewis (1969) reported that during winter adult rainbow trout tended tomove into deeper wa t er (class 1 pools) Bjornn (1971) indicated that downshystream movement during or preceding winter did not occur if sufficient wintercover was locally available Trout move to winter cover to avoid physicaldamage from ice scouring (Hartman 1965 Chapman and Bjornn 1969) and toconserve energy (Chapman and Bjornn 1969 Everest 1969)

Headwater trout streams are relatively unproductive Most energy inputsto the stream are in the form of allochthonous materials such as terrestrialvegetation and terrestrial insects (Idyll 1942 Chapman 1966 Hunt 1975)Aquatic invertebrates are most abundant and diverse in riffle areas withrubble substrate and on submerged aquatic vegetation (Hynes 1970) Howeveroptimal substrate for maintenance of a diverse invertebrate population consistsof a mosaic of gravel rubble and boulders with rubble being dominant Theinvertebrate fauna is much more abundant and diverse in riffles than in pools(Hynes 1970) but a ratio of about 11 of pool to riffle area (about 40 to 60pool area) appears to provide an optimal mix of trout food producing andrearing areas In riffle areas the presence of fines (gt 10) reduces theproduction of invertebrate fauna (based on Cordone and Kelly 1961 Crouse eta1 1981)

Canopy cover is important in maintaining shade for stream temperaturecontrol and in providing allochthonous materials to the stream Too muchshade however can restrict primary productivity in a stream Stream tempershyatures can be increased or decreased by controlling the amount of shadeAbout 50 to 75 mid-day shade appears optimal for most small trout streams(Anonymous 1979) Shading becomes less important as stream gradient and sizeincreases In addition a well vegetated riparian area helps to controlwatershed erosion In most cases a buffer strip about 30 m deep 80 of whichis either well vegetated or has stable rocky stream banks will provide adeshyquate erosion control and maintain undercut stream banks characteristic ofgood trout habitat The presence of fines in riffle-run areas can adverselyaffect embryo survival food production and cover for juveniles

There is a definite relationship between the annual flow regime and thequality of trout habitat The most critical period is typically the base flow(lowest flows of late summer to winter) A base flow ~ 50 of the averageannual daily flow is considered excellent a base flow of 25 to 50 is considshyered fair and a base flow of lt 25 is considered poor for maintaining qualitytrout habitat (adapted from Binns and Eiserman 1979 Wesche 1980)

Of 66 streams sampled in British Columbia those containing cutthroattrout had a pH of 60 to 88 (Hartman and Gill 1968) Thirteen streams inWyoming containing populations of Colorado River cutthroat trout had pH levelsof 71 to 83 (Binns 1977) Sekulich (1974) reported that the pH in threereservoirs containing cutthroat trout ranged from 78 to 85 Platts (1974)analyzed three streams in Idaho with cutthroat trout where the pH ranged from73 to 79 and total dissolved solids ranged from 41 to 63 mgl Some isolatedpopulations of cutthroat trout in the Great Basin area have developed a uniquetolerance for high pH alkalinity total dissolved solids and temperatureconditions The Lahontan basin cutthroat trout persist in Pyramid and WalkerLakes Nevada where total dissolved solids exceed 5000 mgl and 10000 mglrespectively (Behnke and Zarn 1976) The largest cutthroat trout ever recordedcame from Pyramid Lake which has a pH range between 90 and 95 The Lahontan

4

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

basin cutthroat also lives in alkaline waters such as Walker Lake Nevada(alkalinity of 2900 mgl) These conditions are probably lethal to othercutthroat trouts (Behnke and Zarn 1976) Precise pH tolerance and optimalranges for cutthroat trout are not well documented Most cutthroat populationscan probably tolerate a pH range of 5 to 95 with an optimal range of 65 to8 The Lahontan basin cutthroat appear to have developed a tolerance tohigher pH conditions with regional pH tolerance and optimal ranges of 5 to 10and 65 to 85 respectively

Bachmann (1958) reported that at turbidities above 35 ppm cutthroattrout stopped feeding and moved to cover Turbidities of less than 25 JTU andtotal dissolved solids from 38 to 544 rngl characterized 13 Wyoming streamscontaining cutthroat trout (Binns 1977)

Adult Dissolved oxygen requirements vary with species age prioracclimation temperature water velocity activity level and concentration ofsubstances in the water (McKee and Wolf 1963) As temperature increases thedissolved oxygen saturation level in the water decreases while the dissolvedoxygen requirements for the fish increases As a result an increase intemperature resulting in a decrease in dissolved oxygen can be detrimental tothe fish Optimal oxygen levels for cutthroat trout are not well documentedbut appear to be gt 7 mgl at temperatures ~ 15deg C and ~ 9 mgl at temperaturesgt 15deg C Doudoroff and Shumway (1970) demonstrated that swimming speed andgrowth rates for salmonids declined with decreasing dissolved oxygen levelsAt temperatures ~ 15deg C cutthroat trout generally avoid water with dissolvedoxygen levels of less than 5 mgl (Trojnar 1972 Sekulich 1974)

Cutthroat trout usually do not persist in waters where maximum temperashytures consistently exceed 22deg C although they may be able to withstand briefperiods of water temperature as high as 26deg C if considerable nightime coolingtakes place (Behnke and Zarn 1976) The Humboldt River cutthroat trout in theLahontan basin however occupy waters where temperatures may reach a summermaximum of 25deg C (Behnke 1979) Needham and Jones (1959) reported cutthroattrout actively feeding at 0deg C Bell (1973) reported a preferred temperaturerange of 9 to 12deg C for cutthroat trout Dwyer and Kramer (1975) reported thegreatest scope for activity in cutthroat trout occurred at 15deg C when testedat 5deg C increments We assume that scope for activity is a better measure ofoptimal temperature than temperature preference tests and have selected12-15deg C as an optimal temperature range for cutthroat trout

Focal point velocities for adult cutthroat trout on territorial stationsin Idaho streams were primarily between 10 and 14 emsec with a maximum of22 emsec (Griffith 1972)

Embryo Incubation time varies inversely with temperature Eggs usuallyhatch within 28 to 40 days (Cope 1957) but may take as long as 49 days (Scottand Cr-o s smau 1973) Bell (1973) reported that cutthroat trout spawning tempershyatures ranged from 6 to 17deg C The optimal temperature for embryo incubationis approximately 10deg C (Snyder and Tanner 1960) Calhoun (1966) reportedincreased mortalities of rainbow embryos at temperatures lt 7deg C and normaldevelopment at temperatures s 12deg C Hooper (1973) and Thompson (1972)reported spawning velocities ranging from 31 to 92 emsec while Hunter (1973)reported the range as 11 to 40 emsec Average water column velocities forembryo development apparently range from 11 to 92 emsec We assume that

5

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

optimal velocities range from 30 to 60 emsec The combined effects oftemperature dissolved oxygen levels water velocity and gravel permeabilityare important for successful incubation (Coble 1961) In a 30 sand and 70gravel mixture only 28 of implanted steel head embryos hatched of the 28that hatched only 74 emerged (Bjornn 1969 Phillips et al 1975) We assumethat these same results would be true for the closely related cutthroat troutWe further assume that optimal spawning gravel conditions include ~ 5 finesand that ~ 30 fines will cause low survival of embryos and emerging yolk-sacfry Suitable incubation substrate is gravel 03 to 8 em in diameter (Duff1980) Optimal substrate size will depend on size of spawners but we assumeit will average 15 to 60 em in diameter Doudoroff and Shumway (1970)reported that salmonids incubated at low dissolved oxygen levels were weak andsmall with slower development and more abnormalities Dissolved oxygenrequirements for cutthroat trout embryos are probably similar to the requireshyments for adults

Fry Cutthroat trout remain in the gravel for about two weeks afterhatching (Scott and Crossman 1973) and emerge 45 to 75 days after egg fertilishyzation depending on water temperature (Calhoun 1944 Lea 1968) When movingfrom natal gravels to rearing areas cutthroat trout fry exhibit threedistinctly different genetically controlled patterns 1) downstream to alarger river or lake 2) upstream from an outlet river to a lake or 3) localdispersion within a common spawning and rearing area to areas of low velocityand cover (Raleigh and Chapman 1971) Fry of lake resident fish may eithermove into the 1ake from nata 1 streams duri ng the fi rst growi ng season oroverwinter in the spawning stream and move into the lake during subsequentgrowing seasons (Raleigh 1971 Raleigh and Chapman 1971) Salmo clarki lewisiaverage two growing seasons but may spend 1 to 4 years in ~stream beforemigrating to the lake (Roscoe 1974)

Fry residing in streams prefer shallower water and slower velocities thanother life stages (Miller 1957 Horner and Bjornn 1976) Fry utilize velocshyities of less than 30 emsec but less than 80 emsec are preferred (Griffith1972 Horner and Bjornn 1976) Fry survival decreases with increased velocityafter optimal velocity has been reached (Bulkley and Benson 1962 Drummond andMcKinney 1965) A pool area of 40 to 60 of the total stream area is assumedto provide optimal fry habitat Cover in the form of aquatic vegetationdebris piles and the interstitial spaces between rocks is critical Griffith(1972) states that younger trout live in shallower water and stay closer toescape cover than do older trout Few fry are found more than 1 m from coverAs the young cutthroat grow they move to deeper faster water Everest(1969) suggested that one reason for this movement was the need for coverwhich is provided by increased water depth surface turbulence and largersubstrate

Trout fry usually overwinter in shallow areas of low velocity near thestream margin with rubble being the principle cover (Bustard and Narver1975a) Optimal size of substrate used as winter cover by steelhead fry andsmall juveniles ranges from 10 to 40 em in diameter (Hartman 1965 Everest1969) An area of substrate of this size class (10-40 em) of ~ 10 of thetotal habitat will probably provide adequate cover for cutthroat fry and smalljuveniles The use of smaller diameter rocks (gravel) for winter cover mayresult in increased mortality due to greater shifting of the substrate (Bustard

6

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

and Narver 1975a) The presence of fi nes (~ 10) in the ri ffl a-r-un areasimpairs the value of the area as cover for fry and small juveniles

Juvenile Juvenile cutthroat trout in streams are most often found inwater depths of 45 to 75 em and velocities of 25 to 50 emsec (Nickelsonunpublished data) Griffith (1972) reported focal point velocities forjuvenile cutthroat in Idaho of between 10 and 12 emsec with a maximumvelocity of 22 emsec Metabolic rates are highest between 11 and 21deg C withan apparent optimal temperature of 15deg C (Dwyer and Kramer 1975)

Bustard and Narver (1975b) demonstrated that juvenile cutthroat troutused rubble and overhanging banks as cover The juveniles also showed apreference for clean as opposed to silted rubble for cover Common types ofcover for juvenile trout are upturned roots logs debris piles overhangingbanks and small boulders (Bustard and Narver 1975a) Young salmonids occupydifferent habitats in winter than in summer with log jams and rubble importantas winter cover Wesche (1980) observed that larger cutthroat trout (gt 15 emlong) tended to use streamside cover (overhanging banks and vegetation) moreoften than instream substrate objects while juveniles (= 15 em) preferredinstream substrate cover

HABITAT SUITABILITY INDEX (HSI) MODELS

Figure 1 depicts the theoretical relationships among model variablescomponents and HSI for the cutthroat trout model

Model Applicability

GeographiC area The following model is applicable over the entire rangeof cutthroat trout distribution Where differences in habitat requirementshave been identified for different races of cutthroat trout suitability indexgraphs have been constructed to reflect these differences For this reasoncare must be excercised in use of the individual graphs and equations

Season The model rates the freshwater habitat of cutthroat trout forall seasons of the year

Cover types The model is applicable to freshwater riverine or lacustrinehabitats

Minimum habitat area Minimum habitat area is the mlnlmum area of continshyuous habitat that is required for a species to live and reproduce Sincecutthroat can move considerable distances to spawn or locate suitable summeror winter rearing habitat no attempt has been made to define a minimum habitatsize for the species

Verification level An acceptable level of performance for this cutthroattrout model is for it to produce an index between 0 and 1 that the authors andother biologists familiar with cutthroat trout ecology believe is positivelycorrelated with the carrying capacity of the habitat Model verificationconsisted of testing the model outputs from sample data sets developed by theauthors to simulate high medium and low quality cutthroat trout habitat

7

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

Habitat variables

Average thalweg depth (V~)

Model components

~~ adult cover (V 6A) -----~-_==~ Adult

~~ pools (VIa)

Pool class (VIS)

~6 juveni 1e cover

~~ p00 1s (VI a) ----------------=~J uvenil e

Pool class (VIS)

~~ substrate size (V8)~FrY

pools (VIa) --~ ------------~HSI

riffle fines (V16B)

Ave max temp (V z )

Ave min O (V3 )

Water velocity (Vs ) ---shy

Ave gravel SiZ~

~~ fines (VI6A)

Max temperature (VI)

Base flow (VI4)

Dominate substrate (V9 )

vegetation (VII)

vegetation (erosion) (VIZ)

riffle fines (VI6B)---~

_-===~Embry 0

Variables that affect all life stages

Figure 1 Diagram illustrating the relationships among modelvariab1es components and HSI

8

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

Model Description - Riverine

The riverine HSI model consists of five components adult (CA) Juvenile

(CJ) Fry (CF) Embryo (CE) and Other (CO) Each 1ife stage component conshy

tains variables specifically related to that component The component Co

contains variables related to water quality and food supply that affect alllife stages of cutthroat trout

The model utilizes a modified limiting factor procedure This procedureassumes that model variables and components with suitability indices in theaverage to good range gt 04 to lt 10 can be compensated for by higher suitshyability indices of other related model variables and components Howevervariables and components with suitabilities ~ 04 cannot be compensated forand thus become limiting factors on habitat suitability

Adult component Variable V6 percentage of instream cover is included

because standing crops of adult trout have been shown to be correlated withthe amount of cover available Percentage of pools (VI O) is included because

pool s provide cover and resting areas for adult trout Variable VlD al so

quantifies the amount of pool habitat that is needed Variable VIS pool

class is included because pools differ in the amount and quality of escapecover winter cover and resting areas that they provi de Average thalwegdepth (V4 ) is included because average water depth affects the amount and

quality of pools and instream cover available to adult trout and migratoryaccess to spawning and rearing areas

Juvenile component Variables V6 percentage of instream cover VIO

percentage of pools and VIS pool class are included in the juvenile component

for the same reasons listed above for the adult component Juvenile cutthroattrout use these essential stream features for escape cover winter cover andresting areas

Fry component Variable Va substrate size class is included because

trout fry utilize substrate as escape cover and winter cover Variable VIO

percent pools is included because fry use the shallow slow water areas ofpools and backwaters as resting and feeding stations Variable VI6 fines

is included because the percent fines affects the ability of the fry to utilizethe rubble substrate for cover

Embryo component It is assumed that habitat suitability for troutembryos depends primarily on water temperature V2 dissolved oxygen content

V3 water velocity Vs spawning gravel size V7 and percent fines VI 6Water velocity Vs gravel size V7 and percent fines VI 6 are interrelated

factors that have been shown to effect the transport of dissolved oxygen tothe embryo and the removal of the waste products of metabolism from the embryo

9

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

These functions have been shown to be vital to the survival of trout embryosIn addition the presence of too many fines in the redds will block movementof the fry from the incubating gravels to the stream

Other component This component contains model variables for two subcomshyponents water quality and food supply that affect all life stages Thesubcomponent water quality contains four variables maximum temperature (Vi)

minimum dissolved oxygen (VJ ) pH (V1 J ) and base flow (V1 4 ) All four varishy

ables have been demonstrated to affect the growth and survival of all 1ifestages except embryo whose water quality requirements are included with theembryo component The subcomponent food supply contains three variablessubstrate size (V9 ) percent vegetation (Vii) and percent fines (V1 6 )

Dominant substrate type (V9 ) is included because the abundance of aquatic

insects an important food item for cutthroat trout is correlated with subshystrate type Variable V1 6 percent fines in riffle-run and spawning areas is

included because the presence of excessive fines in riffle-run areas willreduce the production of aquatic insects Variable Vii is included because

allochthonous materials are an important source of nutrients to cold unshyproductive trout streams The waterflow of all streams fluctuate on an annualseasonal cycle It has been demonstrated that a correlation exists betweenthe average annual daily streamflow and the annual low base flow period inmaintaining desirable stream habitat features for all life stages VariableV1 4 is included to quantify the relationship between annual water flow fluctua-

tions and trout habitat suitability

Variables ViZ and Vi are optional variables to be used only when needed

and appropriate Percentage of streamside vegetation ViZ is an important

means of controlling soil erosion a major source of fines in streams Varishyable Vi percentage of mid-day shade is included because studies have shown

that the amount of shade can affect water temperature and photosynthesis instreams Variables ViZ and Vi are used primarily for streams$ 50 m wide

with temperature photosynthesis or erosion problems or when changes in theriparian vegetation are part of a potential project plan

Suitability Index (SI) Graphs for Model Variables

This section contains suitability index graphs for 17 model variablesEquations and instructions for combining groups of variable SI scores intocomponent scores and component scores into cutthroat trout HS1 scores areincluded

The graphs were constructed by quantifying information on the effect ofeach habitat variable on the growth survival or biomass of cutthroat troutThe curves were built on the assumption that increments of growth survivalor biomass originally plotted on the y-axis of the graph could be directlyconverted into an index of suitability from 0 to 10 for the species 0 indishycates unsuitable conditions and 10 indicates optimal conditions Graph trendlines represent the authors best estimate of suitability for the various

10

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

levels of each variable presented The graphs have been reviewed by biologistsfamiliar with the ecology of the species but obviously some degree of SIvariability exists The user is encouraged to vary the shape of the graphswhen existing regional information indicates that the variable suitabilityrelationship is different

The habitat measurements and SI graph construction are based on thepremise that it is the extreme rather than the average values of a variablethat most often limit the carrying capacity of a habitat Thus measurementof extreme conditions eg maximum temperatures and minimum dissolved oxygenlevels are often the data used with the graphs to derive the SI values forthe model The letters Rand L in the habitat column identify variables usedto evaluate riverine (R) or lacustrine (L) habitats

Habitat

RL

Variable

Average maximum watertemperature (OC) duringthe warmest period ofthe year (adultjuvenile and fry)

For lacustrine habitatsuse temperature stratanearest ootimal indissolved oxygen zonesof gt 3 mglA = GeneralB = Lahontan Basin

Suitability Graph

1 0 -+----~_IIt_~-+gtltQ)

0

oS 08gt

+-gt 060ro~ 04l

()

02

R Average maximum watertemperature (OC) duringembryo development

11

gtltQ)

-g 08

gt+-gt 06--

lltn

02

10

10

20 30

20

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

RL Average mlnlmumdissolved oxygen(mgl) during thelate growing seasonlow water period andduring embryo developshyment (adult juvenilefry and embryo)

For lacustrine habitatsuse the dissolved oxygenreadings in temperaturezones nearest to optimalwhere dissolved oxygenis gt 3 mgl

A = $ 15deg CB = gt 15deg C

10

xOJ 08-0s

~06-r-

0 04nl~

02U1

3 6

mgl

9

R Average thalweg depth(em) during the lategrowing season lowwater period

A = $ 5 m stream widthB = gt 5 m stream width

10

~ 08-0s

gt 06~r-

~ 04nl~

~ 02

15 30

em

45 60

R Average ve1oe ity(emsec) over spawningareas during embryodevelopment

10

x~ 08s

~ 06r-

0 04nl~r-

~ 02

12

25 50

emsec

75 100

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

R (V6 ) Percent cover 10during the lategrowing season xlow water period OJ 08

-0

at depths ~ 15 em c~

and velocities ~ 06lt 15 emsecJ = Juveniles 04A = Adults 0

l1l+gt

J 02V1

10 20 30 40

R (V7) Average size of sub- 10strate between 03-8 em diameter in xspawning areas OJ 08-0

preferably during the c~

spawning period~ 06

To derive an average04value for use with graph 0

l1l

V7 include areas con- +gt--J 02taining the best spawning V1

substrate sampled untilall potential spawningsites are included or 5 10unt i 1 the sample containsan area equal to 5 of the emtotal cutthroat habitatbeing evaluated

R (Va) Percent substrate size 10class (10-40 em) usedfor winter and escape x

OJ 08cover by fry and small -0c

juveniles ~

gt06+-

0 04l1l+gtJ 02V1

5 10 15 20

13

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

- f-

-

-

-

R (V 9 ) Dominant (~ 50) 10substrate type inriffle-run areas for x

food production ~ 08s

A) Rubble or small ~ 06boulders or aquatic --

vegetation in spri ng --

~ 04areas dominant with ~

limited amounts of --=l

gravel 1a rge () 02boulders or bedrock

B) Rubble gravelboulders and finesoccur in approximatelyequal amounts or gravelis domi nant Aquaticvegetation mayor maynot be present

C) Fines bedrock orlarge boulders aredominant Rubbleand gravel areinsignificant (s 25)

A B C

R Percent pools duringthe late growingseason low waterperiod

1 0 +-o-amp~_ -~ +x~ 08s

~ 06-shy---0 04res~

~ 02

14

25 50

75 100

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

R (V 11) Average percent vege- 10tat ion (trees shrubsand grasses-forbs) x

ltlJ 08along the streambank 0s

during the summer for

allochthonous input b 06Vegetation Index =2 ( shrubs) + 15

0 04( grasses) + ( trees) ro+-

+ 0 ( bareground) l 02Vl

(For streams ~ 50 m wide)

100 200 300

R (V 1 2 ) Average percent rooted 10(Optional) vegetation and stable

rocky ground cover along xthe streambank during the ltlJ 080summer (erosion control) s

gt 06+-

040

ro+--r-

l 02Vl

25 50 75 100

RL (V 1 3 ) Annual maximal or 10minimal pH Use themeasurement with thelowest 51 value x 08ltlJ

0s

For lacustrine habitats

gt 06measure pH in the zone +-

of the best combination

of dissolved oxygen and 0 04rotemperature +-

02l

A General Vl=B = Lahontan Basin

5 6 7 8 9 10

pH

15

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

R Average annual baseflow regime during thelate summer or winterlow flow period as apercentage of the

average annual dailyflow

10

lt

~ 08s

~06

~ 04-j-)

l

Vl 02

R Pool class rating duringthe late growing seasonlow flow period Therating is based on the of the area containingpools of 3 classes asdescribed below

A) ~ 30 of the areais comprised of1st-class pools

B) ~ 10-lt 30 1stshyclass pools or~ 50 2nd-classpools

C) lt 10 1st-classpools and lt 502nd-class pools

(See pool class desshycriptions below)

10

lt~ 08s

gt06-j-)

0 04ro

-j-)

~ 02

A

25 50

B

75

C

100

A) First-class pool Large and deep Pool depth and size are suffishycient to provide a low velocity resting area for several adulttrout More than 30 of the pool bottom is obscure due to depthsurface turbulence or the presence of structures eg logsdebris piles boulders or overhanging banks and vegetation Orthe greatest pool depth is ~ 15 m in streams s 5 m wide or z 2 mdeep in streamsgt 5 mwide

16

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

B) Second-class pool Moderate size and depth Pool depth and sizeare sufficient to provide a low velocity resting area for a fewadult trout From 5 to 30 of the bottom is obscure due to surfaceturbul ence depth or the presence of structures Typi ca 1 secondclass pools are large eddies behind boulders and low velocitymoderately deep areas beneath overhanging banks and vegetation

C) Third-class pool Small or shallow or both Pool depth and sizeare sufficient to provide a low velocity resting area for one tovery few adult trout Cover if present is in the form of shadesurface turbulence or very limited structure Typical third-classpools are wide shallow pool areas of streams or small eddies behindboulders Virtually the entire bottom area is discernable

R (V 1 6 ) Percent fin es laquo 3 mm) 10in ri ffl e-run and inspawning areas during

xOJ

08summer flows -0average s

A Spawninggt 06= +-

B Riffle-run --=

0 04ro+-

l() 02

15 30

45 60

R (V1 7 ) Percent of stream area 10

(Optional) shaded between 1000 and x1400 hrs (for streams OJ

08-0

s 50 m wide) Do not s

use on cold laquo18degC) gt06unproductive streams +-

--

--0 04ro+---

l() 02

25 50

75 100

References to sources of data and the assumptions used to construct theabove suitability index graphs for cutthroat trout HSI models are presented inTable 1

17

Table 1 Data sources for cutthroat trout suitability indices

Variable and source

Needham and Jones 1959Bell 1973Behnke and Zarn 1976Behnke 1979Dwyer and Kramer 1975

Snyder and Tanner 1960Bell 1973Calhoun 1966

Doudoroff and Shumway 1970Trojnar 1972Sekulich 1974

Delisle and Eliason 1961Estimated by authors

Thompson 1972Hooper 1973Hunter 1973

Assumption

Average maximal daily water temperashytures have a greater effect on troutgrowth and survival than minimaltemperatures The maximal temperashyture related with the greatest scopefor activity is optimum

The average maximal daily water temshyperature during the embryo developshyment period related to the highestsurvival and normal development ofthe embryo is optimum Thosetemperatures that reduce survivalare suboptimum

The average minimal daily dissolvedoxygen level during embryo developmentand the late growing season that isrelated to the greatest growth andsurvival of cutthroat trout and troutembryos is optimal Those that reducesurvival and growth are suboptimum

The average thalweg depths thatprovide the best combination ofpools instream cover and instreammovement of adult trout is optimum

The average velocities over spawningareas affect the suitability withwhich dissolved oxygen and wasteproducts are carried to and fromthe developing embryos Averagevelocities which result in thehighest survival of embryos areoptimum Those that result inreduced survival are suboptimum

18

Variable and source

Boussu 1954Elser 1968Lewis 1969

Bjornn 1969Phillips et al 1975Duff 1980

Table 1 (continued)

Assumption

Trout standing crops are correlatedwith the amount of usable coverpresent Usable cover is associatedwith water ~ 15 em deep and velocities~ 15 emsec These conditions areassociated more with pool than riffleconditions The best ratio of habitatconditions is about 50 pool to 50riffle areas Not all of a pool IS areaprovides usable cover Thus it isassumed that optimal cover conditionsfor trout streams can be reached atlt 50 of the total area

The average size of spawning gravelthat is correlated with the best waterexchange rates proper redd constructshyion and highest fry survival isassumed to be optimum for average sizedcutthroat trout The percentage oftotal spawning area needed to support agood trout population was calculatedfrom the following assumptions

1 Excellent riverine trout habitatwill support about 500 kghectare

2 Spawners comprise about 80 ofthe weight of the population500 kg x 80 = 400 kg ofspawners

3 Cutthroat adults average about02 kg each400 kg _02 kg - 2000 adult spawners

4 There are two adults per redd2000 = 1 000 pairs

2

5 Each redd covers ~ 05 m2

1000 x 05 = 500 m2 per hectare

6 There are 10000 m2 per hectare

105~~0 = 5 of total area

19

Variable and source

Table 1 (continued)

Assumption

Hartman 1965Everest 1969Bustard and Narver 1975a b

Pennak and Van Gerpen 1947Hynes 1970Binns and Eiserman 1979

Needham 1940Elser 1968Hunt 1971Horner and Bjornn 1976

Idyll 1942Delisle and Eliason 1961Chapman 1966Hunt 1975

Anonymous 1979Raleigh and Duff 1981

Hartman and Gi 11 1968Platts 1974Sekulich 1974Behnke and Zarn 1976Binns 1977

Binns 1979Adapted from Duff and

Cooper 1976

The substrate size range selectedfor escape and winter cover by cutshythroat fry and small juveniles isassumed to be optimum

The dominant substrate type containingthe greatest numbers of aquatic insectsis assumed to be optimum for insectproduction

The percent pools during late summerlow flows that is associated with thegreatest trout abundance is optimum

The average percent vegetation alongthe streambank is related to theamount of allochthanous materialsdeposited annually in the streamShrubs are the best source ofallochthanous materials followed bygrasses and forbs and then treesThe vegetational index is a reasonableapproximation of optimal and suboptimalconditions for most trout streamhabitats

The average percent rooted vegetationand rocky ground cover that providesadequate erosion control to the streamis optimum

The average annual maximal or minimalpH levels related to high survival oftrout are optimum

Flow variations affect the amount andquality of pools instream cover andwater quality Average annual baseflows associated with the higheststanding crops are optimum

20

Variable and source

V1 5 Lewis 1969Raleigh (in press)

V1 6 Bjornn 1969Cordone and KellyPl atts 1974McCuddi n 1977Crouse et al 1981

V17 Sabean 1976 1977Anonymous 1979

1961

Table 1 (concluded)

Assumption

Pool classes associated with thehighest standing crops of trout areoptimum

The percent fines associated with thehighest standing crops of food organismsembryos and fry in each designated areais optimum

The percent of stream area shaded thatis associated with optimal water temshyperatures and photosynthesis rates isoptimum

The above references include data from studies on related salmonid speciesThis information has been selectively used to supplement verify or completedata gaps on the habitat requirements of cutthroat trout

21

Riverine Model

This model uses a life stage approach with five components adultjuvenile fry embryo and other

Case 1

Case 2 12where V6 is ~ (V lD x ViS)

If V4 or (V i Dx Vis) 1 2 is ~ 04 in either equation then CA = the lowest

factor score

Juvenile (CJ)

or if any variable is ~ 04 then CJ = the lowest variable score

or if Vi Dor (V s x V1 6 ) 1 2 is ~ 04 then CF = the lowest factor score

22

Steps

A A potential spawning site is an ~ 05 m2 area of gravel 03-80 cm insize covered by flowing water ~ 15 cm deep At each spawning sitesampled record

1 The average water velocity over the site2 The average size of all gravel 03-80 cm3 The percentage of fines lt 03 cm in the gravel and4 The total area in m2 of each site

B Derive a spawning site suitability index (V ) for each site by combiningVs V7 and V1 6 values for each site s

C Derive a weighted average (V s ) for all sites included in the sample

Select the best V scores until all sites are included or untilsa total spawning area equal to but not exceeding 5 of the totalcutthroat trout habitat has been included whichever comes first

nVs I A= i=l 1

total

where

V Sl

habitat area 005 (output cannotgt 10)

Ai = the area of each spawning site in m2 but I A cannot

exceed 5 of the total cutthroat habitat 1

V Sl

= the individual SI scores from the best spawning areasuntil all spawning sites have been included or untilSl ls from an area equal to 5 of the total cutthroathabitat being evaluated has been included whicheveroccurs first

D Derive CE

CE = the lowest score of V2 V3 or Vs

23

Other (CO)

(V g x VI6) 1 2 + VII

2

12

where N = the number of variables within the parentheses Notethat variables VI 2 and VI 7 are optional and therefore

may be omitted (see page 18)

HSI determination HSI scores may be derived for a single life stage acombination of two or more life stages or all life stages combined In allcases except for the embryo component (CE) an HSI is obtained by combining

one or more life stage component scores with the other component (CO) score

1 Equal Component Value Method The equal component value method assumesthat each component exerts equal influence in determining HSI Thismethod should be used to determine HSI unless information exists thatindividual components should be weighted differently ComponentsCA CJ CF CE and Co

or if any component is ~ 04 then HSI = the lowest component valueor if CA is lt the equation value then HSI = CA

where N = the number of components in the equation

Solve the equation for the number of components to be included in theevaluation There will be a minimum of two one or more life stagecomponents and the component (CO) unless only the embryo life stage

(CE) is being evaluated then HSI = CEo

2 Unequal Component Value Method This method also uses a life stageapproach with five components adult (CA) juvenile (CJ ) fry (CF)embryo (CE) and other (CO) However the Co component is divided into

two subcomponents food (COF) and water quality (COQ) It is assumed that

the COF subcomponent can either increase or decrease the suitability of

24

the habitat by its effect on growth at each life stage except embryo TheCOQ subcomponent is assumed to exert an influence equal to the combined

influence of all other model components in determining habitat suitabilityThe method also assumes that water quality is excellent COQ = 1 When

COQ is lt 1 HSI is decreased In addition when a basis for weighting

exists model component and subcomponent weights can be increased bymultiplying each index value by multipliersgt 1 Model weightingprocedures must be documented

Components and subcomponents CA CJ CF CE COF and COQ

Steps

A Calculate the subcomponents (COF and COQ) of Co

(V V )1 2 V9 x 16 + 11

COF = 2

or if any variable is ~ 04 then COQ = the value of the lowestvariable

B Calculate HSI by either the noncompensatory or the compensatory option

Noncompensatory option This option assumes that degraded waterquality conditions cannot be compensated for by good physical habitatconditions This assumption is most likely true for small streams(~ 5 m wide) and for persistent degraded water quality conditions

or if any component is ~ 04 then HSI = the lowest componentvalue x COQ

where N = the number of components and subcomponents inside theparentheses or if the model components or subcomponentshave unequal weights then N = I of weights selected

25

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Variable and source

Boussu 1954Elser 1968Lewis 1969

Bjornn 1969Phillips et al 1975Duff 1980

Table 1 (continued)

Assumption

Trout standing crops are correlatedwith the amount of usable coverpresent Usable cover is associatedwith water ~ 15 em deep and velocities~ 15 emsec These conditions areassociated more with pool than riffleconditions The best ratio of habitatconditions is about 50 pool to 50riffle areas Not all of a pool IS areaprovides usable cover Thus it isassumed that optimal cover conditionsfor trout streams can be reached atlt 50 of the total area

The average size of spawning gravelthat is correlated with the best waterexchange rates proper redd constructshyion and highest fry survival isassumed to be optimum for average sizedcutthroat trout The percentage oftotal spawning area needed to support agood trout population was calculatedfrom the following assumptions

1 Excellent riverine trout habitatwill support about 500 kghectare

2 Spawners comprise about 80 ofthe weight of the population500 kg x 80 = 400 kg ofspawners

3 Cutthroat adults average about02 kg each400 kg _02 kg - 2000 adult spawners

4 There are two adults per redd2000 = 1 000 pairs

2

5 Each redd covers ~ 05 m2

1000 x 05 = 500 m2 per hectare

6 There are 10000 m2 per hectare

105~~0 = 5 of total area

19

Variable and source

Table 1 (continued)

Assumption

Hartman 1965Everest 1969Bustard and Narver 1975a b

Pennak and Van Gerpen 1947Hynes 1970Binns and Eiserman 1979

Needham 1940Elser 1968Hunt 1971Horner and Bjornn 1976

Idyll 1942Delisle and Eliason 1961Chapman 1966Hunt 1975

Anonymous 1979Raleigh and Duff 1981

Hartman and Gi 11 1968Platts 1974Sekulich 1974Behnke and Zarn 1976Binns 1977

Binns 1979Adapted from Duff and

Cooper 1976

The substrate size range selectedfor escape and winter cover by cutshythroat fry and small juveniles isassumed to be optimum

The dominant substrate type containingthe greatest numbers of aquatic insectsis assumed to be optimum for insectproduction

The percent pools during late summerlow flows that is associated with thegreatest trout abundance is optimum

The average percent vegetation alongthe streambank is related to theamount of allochthanous materialsdeposited annually in the streamShrubs are the best source ofallochthanous materials followed bygrasses and forbs and then treesThe vegetational index is a reasonableapproximation of optimal and suboptimalconditions for most trout streamhabitats

The average percent rooted vegetationand rocky ground cover that providesadequate erosion control to the streamis optimum

The average annual maximal or minimalpH levels related to high survival oftrout are optimum

Flow variations affect the amount andquality of pools instream cover andwater quality Average annual baseflows associated with the higheststanding crops are optimum

20

Variable and source

V1 5 Lewis 1969Raleigh (in press)

V1 6 Bjornn 1969Cordone and KellyPl atts 1974McCuddi n 1977Crouse et al 1981

V17 Sabean 1976 1977Anonymous 1979

1961

Table 1 (concluded)

Assumption

Pool classes associated with thehighest standing crops of trout areoptimum

The percent fines associated with thehighest standing crops of food organismsembryos and fry in each designated areais optimum

The percent of stream area shaded thatis associated with optimal water temshyperatures and photosynthesis rates isoptimum

The above references include data from studies on related salmonid speciesThis information has been selectively used to supplement verify or completedata gaps on the habitat requirements of cutthroat trout

21

Riverine Model

This model uses a life stage approach with five components adultjuvenile fry embryo and other

Case 1

Case 2 12where V6 is ~ (V lD x ViS)

If V4 or (V i Dx Vis) 1 2 is ~ 04 in either equation then CA = the lowest

factor score

Juvenile (CJ)

or if any variable is ~ 04 then CJ = the lowest variable score

or if Vi Dor (V s x V1 6 ) 1 2 is ~ 04 then CF = the lowest factor score

22

Steps

A A potential spawning site is an ~ 05 m2 area of gravel 03-80 cm insize covered by flowing water ~ 15 cm deep At each spawning sitesampled record

1 The average water velocity over the site2 The average size of all gravel 03-80 cm3 The percentage of fines lt 03 cm in the gravel and4 The total area in m2 of each site

B Derive a spawning site suitability index (V ) for each site by combiningVs V7 and V1 6 values for each site s

C Derive a weighted average (V s ) for all sites included in the sample

Select the best V scores until all sites are included or untilsa total spawning area equal to but not exceeding 5 of the totalcutthroat trout habitat has been included whichever comes first

nVs I A= i=l 1

total

where

V Sl

habitat area 005 (output cannotgt 10)

Ai = the area of each spawning site in m2 but I A cannot

exceed 5 of the total cutthroat habitat 1

V Sl

= the individual SI scores from the best spawning areasuntil all spawning sites have been included or untilSl ls from an area equal to 5 of the total cutthroathabitat being evaluated has been included whicheveroccurs first

D Derive CE

CE = the lowest score of V2 V3 or Vs

23

Other (CO)

(V g x VI6) 1 2 + VII

2

12

where N = the number of variables within the parentheses Notethat variables VI 2 and VI 7 are optional and therefore

may be omitted (see page 18)

HSI determination HSI scores may be derived for a single life stage acombination of two or more life stages or all life stages combined In allcases except for the embryo component (CE) an HSI is obtained by combining

one or more life stage component scores with the other component (CO) score

1 Equal Component Value Method The equal component value method assumesthat each component exerts equal influence in determining HSI Thismethod should be used to determine HSI unless information exists thatindividual components should be weighted differently ComponentsCA CJ CF CE and Co

or if any component is ~ 04 then HSI = the lowest component valueor if CA is lt the equation value then HSI = CA

where N = the number of components in the equation

Solve the equation for the number of components to be included in theevaluation There will be a minimum of two one or more life stagecomponents and the component (CO) unless only the embryo life stage

(CE) is being evaluated then HSI = CEo

2 Unequal Component Value Method This method also uses a life stageapproach with five components adult (CA) juvenile (CJ ) fry (CF)embryo (CE) and other (CO) However the Co component is divided into

two subcomponents food (COF) and water quality (COQ) It is assumed that

the COF subcomponent can either increase or decrease the suitability of

24

the habitat by its effect on growth at each life stage except embryo TheCOQ subcomponent is assumed to exert an influence equal to the combined

influence of all other model components in determining habitat suitabilityThe method also assumes that water quality is excellent COQ = 1 When

COQ is lt 1 HSI is decreased In addition when a basis for weighting

exists model component and subcomponent weights can be increased bymultiplying each index value by multipliersgt 1 Model weightingprocedures must be documented

Components and subcomponents CA CJ CF CE COF and COQ

Steps

A Calculate the subcomponents (COF and COQ) of Co

(V V )1 2 V9 x 16 + 11

COF = 2

or if any variable is ~ 04 then COQ = the value of the lowestvariable

B Calculate HSI by either the noncompensatory or the compensatory option

Noncompensatory option This option assumes that degraded waterquality conditions cannot be compensated for by good physical habitatconditions This assumption is most likely true for small streams(~ 5 m wide) and for persistent degraded water quality conditions

or if any component is ~ 04 then HSI = the lowest componentvalue x COQ

where N = the number of components and subcomponents inside theparentheses or if the model components or subcomponentshave unequal weights then N = I of weights selected

25

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Variable and source

Table 1 (continued)

Assumption

Hartman 1965Everest 1969Bustard and Narver 1975a b

Pennak and Van Gerpen 1947Hynes 1970Binns and Eiserman 1979

Needham 1940Elser 1968Hunt 1971Horner and Bjornn 1976

Idyll 1942Delisle and Eliason 1961Chapman 1966Hunt 1975

Anonymous 1979Raleigh and Duff 1981

Hartman and Gi 11 1968Platts 1974Sekulich 1974Behnke and Zarn 1976Binns 1977

Binns 1979Adapted from Duff and

Cooper 1976

The substrate size range selectedfor escape and winter cover by cutshythroat fry and small juveniles isassumed to be optimum

The dominant substrate type containingthe greatest numbers of aquatic insectsis assumed to be optimum for insectproduction

The percent pools during late summerlow flows that is associated with thegreatest trout abundance is optimum

The average percent vegetation alongthe streambank is related to theamount of allochthanous materialsdeposited annually in the streamShrubs are the best source ofallochthanous materials followed bygrasses and forbs and then treesThe vegetational index is a reasonableapproximation of optimal and suboptimalconditions for most trout streamhabitats

The average percent rooted vegetationand rocky ground cover that providesadequate erosion control to the streamis optimum

The average annual maximal or minimalpH levels related to high survival oftrout are optimum

Flow variations affect the amount andquality of pools instream cover andwater quality Average annual baseflows associated with the higheststanding crops are optimum

20

Variable and source

V1 5 Lewis 1969Raleigh (in press)

V1 6 Bjornn 1969Cordone and KellyPl atts 1974McCuddi n 1977Crouse et al 1981

V17 Sabean 1976 1977Anonymous 1979

1961

Table 1 (concluded)

Assumption

Pool classes associated with thehighest standing crops of trout areoptimum

The percent fines associated with thehighest standing crops of food organismsembryos and fry in each designated areais optimum

The percent of stream area shaded thatis associated with optimal water temshyperatures and photosynthesis rates isoptimum

The above references include data from studies on related salmonid speciesThis information has been selectively used to supplement verify or completedata gaps on the habitat requirements of cutthroat trout

21

Riverine Model

This model uses a life stage approach with five components adultjuvenile fry embryo and other

Case 1

Case 2 12where V6 is ~ (V lD x ViS)

If V4 or (V i Dx Vis) 1 2 is ~ 04 in either equation then CA = the lowest

factor score

Juvenile (CJ)

or if any variable is ~ 04 then CJ = the lowest variable score

or if Vi Dor (V s x V1 6 ) 1 2 is ~ 04 then CF = the lowest factor score

22

Steps

A A potential spawning site is an ~ 05 m2 area of gravel 03-80 cm insize covered by flowing water ~ 15 cm deep At each spawning sitesampled record

1 The average water velocity over the site2 The average size of all gravel 03-80 cm3 The percentage of fines lt 03 cm in the gravel and4 The total area in m2 of each site

B Derive a spawning site suitability index (V ) for each site by combiningVs V7 and V1 6 values for each site s

C Derive a weighted average (V s ) for all sites included in the sample

Select the best V scores until all sites are included or untilsa total spawning area equal to but not exceeding 5 of the totalcutthroat trout habitat has been included whichever comes first

nVs I A= i=l 1

total

where

V Sl

habitat area 005 (output cannotgt 10)

Ai = the area of each spawning site in m2 but I A cannot

exceed 5 of the total cutthroat habitat 1

V Sl

= the individual SI scores from the best spawning areasuntil all spawning sites have been included or untilSl ls from an area equal to 5 of the total cutthroathabitat being evaluated has been included whicheveroccurs first

D Derive CE

CE = the lowest score of V2 V3 or Vs

23

Other (CO)

(V g x VI6) 1 2 + VII

2

12

where N = the number of variables within the parentheses Notethat variables VI 2 and VI 7 are optional and therefore

may be omitted (see page 18)

HSI determination HSI scores may be derived for a single life stage acombination of two or more life stages or all life stages combined In allcases except for the embryo component (CE) an HSI is obtained by combining

one or more life stage component scores with the other component (CO) score

1 Equal Component Value Method The equal component value method assumesthat each component exerts equal influence in determining HSI Thismethod should be used to determine HSI unless information exists thatindividual components should be weighted differently ComponentsCA CJ CF CE and Co

or if any component is ~ 04 then HSI = the lowest component valueor if CA is lt the equation value then HSI = CA

where N = the number of components in the equation

Solve the equation for the number of components to be included in theevaluation There will be a minimum of two one or more life stagecomponents and the component (CO) unless only the embryo life stage

(CE) is being evaluated then HSI = CEo

2 Unequal Component Value Method This method also uses a life stageapproach with five components adult (CA) juvenile (CJ ) fry (CF)embryo (CE) and other (CO) However the Co component is divided into

two subcomponents food (COF) and water quality (COQ) It is assumed that

the COF subcomponent can either increase or decrease the suitability of

24

the habitat by its effect on growth at each life stage except embryo TheCOQ subcomponent is assumed to exert an influence equal to the combined

influence of all other model components in determining habitat suitabilityThe method also assumes that water quality is excellent COQ = 1 When

COQ is lt 1 HSI is decreased In addition when a basis for weighting

exists model component and subcomponent weights can be increased bymultiplying each index value by multipliersgt 1 Model weightingprocedures must be documented

Components and subcomponents CA CJ CF CE COF and COQ

Steps

A Calculate the subcomponents (COF and COQ) of Co

(V V )1 2 V9 x 16 + 11

COF = 2

or if any variable is ~ 04 then COQ = the value of the lowestvariable

B Calculate HSI by either the noncompensatory or the compensatory option

Noncompensatory option This option assumes that degraded waterquality conditions cannot be compensated for by good physical habitatconditions This assumption is most likely true for small streams(~ 5 m wide) and for persistent degraded water quality conditions

or if any component is ~ 04 then HSI = the lowest componentvalue x COQ

where N = the number of components and subcomponents inside theparentheses or if the model components or subcomponentshave unequal weights then N = I of weights selected

25

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Variable and source

V1 5 Lewis 1969Raleigh (in press)

V1 6 Bjornn 1969Cordone and KellyPl atts 1974McCuddi n 1977Crouse et al 1981

V17 Sabean 1976 1977Anonymous 1979

1961

Table 1 (concluded)

Assumption

Pool classes associated with thehighest standing crops of trout areoptimum

The percent fines associated with thehighest standing crops of food organismsembryos and fry in each designated areais optimum

The percent of stream area shaded thatis associated with optimal water temshyperatures and photosynthesis rates isoptimum

The above references include data from studies on related salmonid speciesThis information has been selectively used to supplement verify or completedata gaps on the habitat requirements of cutthroat trout

21

Riverine Model

This model uses a life stage approach with five components adultjuvenile fry embryo and other

Case 1

Case 2 12where V6 is ~ (V lD x ViS)

If V4 or (V i Dx Vis) 1 2 is ~ 04 in either equation then CA = the lowest

factor score

Juvenile (CJ)

or if any variable is ~ 04 then CJ = the lowest variable score

or if Vi Dor (V s x V1 6 ) 1 2 is ~ 04 then CF = the lowest factor score

22

Steps

A A potential spawning site is an ~ 05 m2 area of gravel 03-80 cm insize covered by flowing water ~ 15 cm deep At each spawning sitesampled record

1 The average water velocity over the site2 The average size of all gravel 03-80 cm3 The percentage of fines lt 03 cm in the gravel and4 The total area in m2 of each site

B Derive a spawning site suitability index (V ) for each site by combiningVs V7 and V1 6 values for each site s

C Derive a weighted average (V s ) for all sites included in the sample

Select the best V scores until all sites are included or untilsa total spawning area equal to but not exceeding 5 of the totalcutthroat trout habitat has been included whichever comes first

nVs I A= i=l 1

total

where

V Sl

habitat area 005 (output cannotgt 10)

Ai = the area of each spawning site in m2 but I A cannot

exceed 5 of the total cutthroat habitat 1

V Sl

= the individual SI scores from the best spawning areasuntil all spawning sites have been included or untilSl ls from an area equal to 5 of the total cutthroathabitat being evaluated has been included whicheveroccurs first

D Derive CE

CE = the lowest score of V2 V3 or Vs

23

Other (CO)

(V g x VI6) 1 2 + VII

2

12

where N = the number of variables within the parentheses Notethat variables VI 2 and VI 7 are optional and therefore

may be omitted (see page 18)

HSI determination HSI scores may be derived for a single life stage acombination of two or more life stages or all life stages combined In allcases except for the embryo component (CE) an HSI is obtained by combining

one or more life stage component scores with the other component (CO) score

1 Equal Component Value Method The equal component value method assumesthat each component exerts equal influence in determining HSI Thismethod should be used to determine HSI unless information exists thatindividual components should be weighted differently ComponentsCA CJ CF CE and Co

or if any component is ~ 04 then HSI = the lowest component valueor if CA is lt the equation value then HSI = CA

where N = the number of components in the equation

Solve the equation for the number of components to be included in theevaluation There will be a minimum of two one or more life stagecomponents and the component (CO) unless only the embryo life stage

(CE) is being evaluated then HSI = CEo

2 Unequal Component Value Method This method also uses a life stageapproach with five components adult (CA) juvenile (CJ ) fry (CF)embryo (CE) and other (CO) However the Co component is divided into

two subcomponents food (COF) and water quality (COQ) It is assumed that

the COF subcomponent can either increase or decrease the suitability of

24

the habitat by its effect on growth at each life stage except embryo TheCOQ subcomponent is assumed to exert an influence equal to the combined

influence of all other model components in determining habitat suitabilityThe method also assumes that water quality is excellent COQ = 1 When

COQ is lt 1 HSI is decreased In addition when a basis for weighting

exists model component and subcomponent weights can be increased bymultiplying each index value by multipliersgt 1 Model weightingprocedures must be documented

Components and subcomponents CA CJ CF CE COF and COQ

Steps

A Calculate the subcomponents (COF and COQ) of Co

(V V )1 2 V9 x 16 + 11

COF = 2

or if any variable is ~ 04 then COQ = the value of the lowestvariable

B Calculate HSI by either the noncompensatory or the compensatory option

Noncompensatory option This option assumes that degraded waterquality conditions cannot be compensated for by good physical habitatconditions This assumption is most likely true for small streams(~ 5 m wide) and for persistent degraded water quality conditions

or if any component is ~ 04 then HSI = the lowest componentvalue x COQ

where N = the number of components and subcomponents inside theparentheses or if the model components or subcomponentshave unequal weights then N = I of weights selected

25

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Riverine Model

This model uses a life stage approach with five components adultjuvenile fry embryo and other

Case 1

Case 2 12where V6 is ~ (V lD x ViS)

If V4 or (V i Dx Vis) 1 2 is ~ 04 in either equation then CA = the lowest

factor score

Juvenile (CJ)

or if any variable is ~ 04 then CJ = the lowest variable score

or if Vi Dor (V s x V1 6 ) 1 2 is ~ 04 then CF = the lowest factor score

22

Steps

A A potential spawning site is an ~ 05 m2 area of gravel 03-80 cm insize covered by flowing water ~ 15 cm deep At each spawning sitesampled record

1 The average water velocity over the site2 The average size of all gravel 03-80 cm3 The percentage of fines lt 03 cm in the gravel and4 The total area in m2 of each site

B Derive a spawning site suitability index (V ) for each site by combiningVs V7 and V1 6 values for each site s

C Derive a weighted average (V s ) for all sites included in the sample

Select the best V scores until all sites are included or untilsa total spawning area equal to but not exceeding 5 of the totalcutthroat trout habitat has been included whichever comes first

nVs I A= i=l 1

total

where

V Sl

habitat area 005 (output cannotgt 10)

Ai = the area of each spawning site in m2 but I A cannot

exceed 5 of the total cutthroat habitat 1

V Sl

= the individual SI scores from the best spawning areasuntil all spawning sites have been included or untilSl ls from an area equal to 5 of the total cutthroathabitat being evaluated has been included whicheveroccurs first

D Derive CE

CE = the lowest score of V2 V3 or Vs

23

Other (CO)

(V g x VI6) 1 2 + VII

2

12

where N = the number of variables within the parentheses Notethat variables VI 2 and VI 7 are optional and therefore

may be omitted (see page 18)

HSI determination HSI scores may be derived for a single life stage acombination of two or more life stages or all life stages combined In allcases except for the embryo component (CE) an HSI is obtained by combining

one or more life stage component scores with the other component (CO) score

1 Equal Component Value Method The equal component value method assumesthat each component exerts equal influence in determining HSI Thismethod should be used to determine HSI unless information exists thatindividual components should be weighted differently ComponentsCA CJ CF CE and Co

or if any component is ~ 04 then HSI = the lowest component valueor if CA is lt the equation value then HSI = CA

where N = the number of components in the equation

Solve the equation for the number of components to be included in theevaluation There will be a minimum of two one or more life stagecomponents and the component (CO) unless only the embryo life stage

(CE) is being evaluated then HSI = CEo

2 Unequal Component Value Method This method also uses a life stageapproach with five components adult (CA) juvenile (CJ ) fry (CF)embryo (CE) and other (CO) However the Co component is divided into

two subcomponents food (COF) and water quality (COQ) It is assumed that

the COF subcomponent can either increase or decrease the suitability of

24

the habitat by its effect on growth at each life stage except embryo TheCOQ subcomponent is assumed to exert an influence equal to the combined

influence of all other model components in determining habitat suitabilityThe method also assumes that water quality is excellent COQ = 1 When

COQ is lt 1 HSI is decreased In addition when a basis for weighting

exists model component and subcomponent weights can be increased bymultiplying each index value by multipliersgt 1 Model weightingprocedures must be documented

Components and subcomponents CA CJ CF CE COF and COQ

Steps

A Calculate the subcomponents (COF and COQ) of Co

(V V )1 2 V9 x 16 + 11

COF = 2

or if any variable is ~ 04 then COQ = the value of the lowestvariable

B Calculate HSI by either the noncompensatory or the compensatory option

Noncompensatory option This option assumes that degraded waterquality conditions cannot be compensated for by good physical habitatconditions This assumption is most likely true for small streams(~ 5 m wide) and for persistent degraded water quality conditions

or if any component is ~ 04 then HSI = the lowest componentvalue x COQ

where N = the number of components and subcomponents inside theparentheses or if the model components or subcomponentshave unequal weights then N = I of weights selected

25

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Steps

A A potential spawning site is an ~ 05 m2 area of gravel 03-80 cm insize covered by flowing water ~ 15 cm deep At each spawning sitesampled record

1 The average water velocity over the site2 The average size of all gravel 03-80 cm3 The percentage of fines lt 03 cm in the gravel and4 The total area in m2 of each site

B Derive a spawning site suitability index (V ) for each site by combiningVs V7 and V1 6 values for each site s

C Derive a weighted average (V s ) for all sites included in the sample

Select the best V scores until all sites are included or untilsa total spawning area equal to but not exceeding 5 of the totalcutthroat trout habitat has been included whichever comes first

nVs I A= i=l 1

total

where

V Sl

habitat area 005 (output cannotgt 10)

Ai = the area of each spawning site in m2 but I A cannot

exceed 5 of the total cutthroat habitat 1

V Sl

= the individual SI scores from the best spawning areasuntil all spawning sites have been included or untilSl ls from an area equal to 5 of the total cutthroathabitat being evaluated has been included whicheveroccurs first

D Derive CE

CE = the lowest score of V2 V3 or Vs

23

Other (CO)

(V g x VI6) 1 2 + VII

2

12

where N = the number of variables within the parentheses Notethat variables VI 2 and VI 7 are optional and therefore

may be omitted (see page 18)

HSI determination HSI scores may be derived for a single life stage acombination of two or more life stages or all life stages combined In allcases except for the embryo component (CE) an HSI is obtained by combining

one or more life stage component scores with the other component (CO) score

1 Equal Component Value Method The equal component value method assumesthat each component exerts equal influence in determining HSI Thismethod should be used to determine HSI unless information exists thatindividual components should be weighted differently ComponentsCA CJ CF CE and Co

or if any component is ~ 04 then HSI = the lowest component valueor if CA is lt the equation value then HSI = CA

where N = the number of components in the equation

Solve the equation for the number of components to be included in theevaluation There will be a minimum of two one or more life stagecomponents and the component (CO) unless only the embryo life stage

(CE) is being evaluated then HSI = CEo

2 Unequal Component Value Method This method also uses a life stageapproach with five components adult (CA) juvenile (CJ ) fry (CF)embryo (CE) and other (CO) However the Co component is divided into

two subcomponents food (COF) and water quality (COQ) It is assumed that

the COF subcomponent can either increase or decrease the suitability of

24

the habitat by its effect on growth at each life stage except embryo TheCOQ subcomponent is assumed to exert an influence equal to the combined

influence of all other model components in determining habitat suitabilityThe method also assumes that water quality is excellent COQ = 1 When

COQ is lt 1 HSI is decreased In addition when a basis for weighting

exists model component and subcomponent weights can be increased bymultiplying each index value by multipliersgt 1 Model weightingprocedures must be documented

Components and subcomponents CA CJ CF CE COF and COQ

Steps

A Calculate the subcomponents (COF and COQ) of Co

(V V )1 2 V9 x 16 + 11

COF = 2

or if any variable is ~ 04 then COQ = the value of the lowestvariable

B Calculate HSI by either the noncompensatory or the compensatory option

Noncompensatory option This option assumes that degraded waterquality conditions cannot be compensated for by good physical habitatconditions This assumption is most likely true for small streams(~ 5 m wide) and for persistent degraded water quality conditions

or if any component is ~ 04 then HSI = the lowest componentvalue x COQ

where N = the number of components and subcomponents inside theparentheses or if the model components or subcomponentshave unequal weights then N = I of weights selected

25

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Other (CO)

(V g x VI6) 1 2 + VII

2

12

where N = the number of variables within the parentheses Notethat variables VI 2 and VI 7 are optional and therefore

may be omitted (see page 18)

HSI determination HSI scores may be derived for a single life stage acombination of two or more life stages or all life stages combined In allcases except for the embryo component (CE) an HSI is obtained by combining

one or more life stage component scores with the other component (CO) score

1 Equal Component Value Method The equal component value method assumesthat each component exerts equal influence in determining HSI Thismethod should be used to determine HSI unless information exists thatindividual components should be weighted differently ComponentsCA CJ CF CE and Co

or if any component is ~ 04 then HSI = the lowest component valueor if CA is lt the equation value then HSI = CA

where N = the number of components in the equation

Solve the equation for the number of components to be included in theevaluation There will be a minimum of two one or more life stagecomponents and the component (CO) unless only the embryo life stage

(CE) is being evaluated then HSI = CEo

2 Unequal Component Value Method This method also uses a life stageapproach with five components adult (CA) juvenile (CJ ) fry (CF)embryo (CE) and other (CO) However the Co component is divided into

two subcomponents food (COF) and water quality (COQ) It is assumed that

the COF subcomponent can either increase or decrease the suitability of

24

the habitat by its effect on growth at each life stage except embryo TheCOQ subcomponent is assumed to exert an influence equal to the combined

influence of all other model components in determining habitat suitabilityThe method also assumes that water quality is excellent COQ = 1 When

COQ is lt 1 HSI is decreased In addition when a basis for weighting

exists model component and subcomponent weights can be increased bymultiplying each index value by multipliersgt 1 Model weightingprocedures must be documented

Components and subcomponents CA CJ CF CE COF and COQ

Steps

A Calculate the subcomponents (COF and COQ) of Co

(V V )1 2 V9 x 16 + 11

COF = 2

or if any variable is ~ 04 then COQ = the value of the lowestvariable

B Calculate HSI by either the noncompensatory or the compensatory option

Noncompensatory option This option assumes that degraded waterquality conditions cannot be compensated for by good physical habitatconditions This assumption is most likely true for small streams(~ 5 m wide) and for persistent degraded water quality conditions

or if any component is ~ 04 then HSI = the lowest componentvalue x COQ

where N = the number of components and subcomponents inside theparentheses or if the model components or subcomponentshave unequal weights then N = I of weights selected

25

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

the habitat by its effect on growth at each life stage except embryo TheCOQ subcomponent is assumed to exert an influence equal to the combined

influence of all other model components in determining habitat suitabilityThe method also assumes that water quality is excellent COQ = 1 When

COQ is lt 1 HSI is decreased In addition when a basis for weighting

exists model component and subcomponent weights can be increased bymultiplying each index value by multipliersgt 1 Model weightingprocedures must be documented

Components and subcomponents CA CJ CF CE COF and COQ

Steps

A Calculate the subcomponents (COF and COQ) of Co

(V V )1 2 V9 x 16 + 11

COF = 2

or if any variable is ~ 04 then COQ = the value of the lowestvariable

B Calculate HSI by either the noncompensatory or the compensatory option

Noncompensatory option This option assumes that degraded waterquality conditions cannot be compensated for by good physical habitatconditions This assumption is most likely true for small streams(~ 5 m wide) and for persistent degraded water quality conditions

or if any component is ~ 04 then HSI = the lowest componentvalue x COQ

where N = the number of components and subcomponents inside theparentheses or if the model components or subcomponentshave unequal weights then N = I of weights selected

25

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

If only the embryo component is being evaluated then H5I = CE x COQ

Compensatory option This method assumes that moderately degradedwater quality conditions can be partially compensated for by goodphysical habitat conditions This assumption is useful for largerivers (~ 50 m wide) and for temporary or short term poor waterquality conditions

1) H5I = (CA

x CJ

x CF

x CE

x COF)1N

or if CA is ~ 04 then H5I = CA

where N = the number of components and subcomponents in theequation or if the model components or subcomposhynents have unequal weights then N = I of weightsselected

2) If COQ is lt H5I then H5I = H5I x [1- (H5I - COQ)] if not

H5I = H5I

3) If only the embryo component is being evaluated follow theprocedure in step 2 substituting CE for H5I

Lacustrine Model

The following model is available to evaluate cutthroat trout lacustrinehabitat The lacustrine model consists of two components water quality andreproduction

Water Quality (CWQ)

or if the 51 scores for VI or V3 are ~ 04 then CWQ = the lowest 51score for VI or V3 bull

Note Lacustrine cutthroat require a tributary stream for spawning andembryo development If the embryo life stage habitat is to be included inthe evaluation use the embryo component steps and equations in the riverinemodel above except that the area of spawning gravel needed is only about 1of the total surface area of the lacustrine habitat

26

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

nVs L A V

= i=l 1 Sl

total habitat area 001 (output cannotgt 10)

HSI determination

HSI

If only the lacustrine habitat is evaluated then HSI = CWO

Interpreting Model Outputs

Model HSI scores for individual life stages composite life stages or forthe species are a relative indicator of habitat suitability for the evaluationelement The HSI models in their present form are not intended to consisshytently predict standing crops of fishes throughout the United States Standingcrop limiting factors such as interspecific competition predation diseasewater nutrient levels and length of growing season are not included in theaquatic HSI models The models contain physical habitat variables importantin maintaining viable populations of cutthroat trout If the model iscorrectly structured a high HSI score for a habitat would indicate nearoptimal regional conditions for cutthroat trout for those factors included inthe model intermediate HSI scores would indicate average habitat conditionsand low HSI scores would indicate poor habitat conditions An HSI of 0 doesnot always mean that the species is not present An HSI of 0 means that thehabitat is very poor and the species will be scarce or absent

Cutthroat trout tend to occupy riverine habitats with very few other fishspecies present They are usually competitively excluded by other troutspecies Thus factors of disease interspecific competition and predationusually will have little effect on the model When the cutthroat trout modelis applied to cutthroat trout streams with similar water quality and length ofgrowing season it should be possible to calibrate the model output to reflectsize of standing crops within some reasonable confidence limits This possishybility however has not been tested with the present model

Sample data sets selected by the authors to represent high intermediateand low habitat suitabilities are given in Table 2 along with the 5I Is andH5I Is generated by the cutthroat trout riverine model The model outputscalculated from the sample data sets (Tables 3 and 4) reflect what the authorsbelieve carrying capacity trends would be in riverine habitats with the listedcharacteristics thus the model meets the specified acceptance level

27

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Table 2 Sample data sets using the riverine cutthroat trout HS1 model

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Max temperature(OC) V1 14 10 15 10 16 10

Max temperature( 0C) V2 12 10 15 066 17 04

Min dissolved O2

(mgl) V3 9 10 7 073 6 042

Ave depth (cm) V4 25 09 18 06 18 06

Ave velocity(cms) Vs 30 10 25 07 20 057

cover V6 20 A 095 10 A 065 10 A 065J 1 0 J 092 J 092

Ave gravel size(cm) V7 4 10 3 10 25 10

Dam substratesize (cm) Vs 15 10 8 07 8 07

Dam substrateclass V9 A 10 B 06 B 06

pools V10 55 10 15 065 10 046

Allochvegetation Vll 225 10 175 10 200 10

bank vegetation V12 95 10 50 06 40 05

Max pH V13 71 10 72 10 72 10

Ann base flow V14 37 08 30 06 25 05

Pool class V15 A 10 B 06 C 03

fines (A) V16 5 10 20 05 20 05

0 fines (B) V16 15 09 30 06 30 060

0 shade V17 60 10 60 10 60 100

28

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Table 3 Average value method

Data set 1 Data set 2 Data set 3

Variable Data SI Data SI Data SI

Component

CA 095 062 037

CJ 1 00 077 037

CF 097 065 055

CE 1 00 066 040

Co 096 078 040

Species HSI 098 070 037

29

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Table 4 Average value probability method

Data set 1 Data set 2 Data set 3

Variable Data 51 Data 51 Data SI

Component

CA 095 062 037

CJ 10 077 037

CF 097 065 055

CE 1 00 066 040

COF 097 080 080

COQ 096 080 067

Species HS1

Noncompensatory 094 056 025Compensatory 096 070 037

30

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

ADDITIONAL HABITAT MODELS

Mode 1 1

Optimal riverine cutthroat trout habitat is characterized by

1 Clear cold water with an average maximum summer temperature of lt 22deg C

2 An approximate 11 pool-riffle ratio

3 Well vegetated stable stream banks

4 ~ 25 of stream area providing cover

5 Relatively stable water flow regime lt 50 annual fluctuation fromaverage annual daily flow

6 Relatively stable summer temperature regime averaging about13deg C plusmn 4deg C and

7 A relatively silt free rocky substrate in riffle-run areas

Model 2

HSI = number of attributes present7

A riverine trout habitat model by Binns and Eiserman (1979) Transposethe model output of pounds per acre to an index of 0-1

HSI = model output of pounds per acreregional optimal pounds per acre

Model 3

Optimal lacustrine cutthroat habitat is characterized by

1 Clear cold water with an average summer midepilimnion temperatureof lt 22deg C

2 A midepilimnion pH of 65 to 85

3 Dissolved oxygen content of epilimnion of ~ 8 mgl and

31

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

4 Access to riverine spawning tributaries

Model 4

HSI = number of attributes present4

A low effort system for predicting habitat suitability of planned coolwater and cold water reservoirs as habitat for individual fish species byMcConnell et al (1982)

REFERENCES CITED

Allen K R 1969 Limitations on production in salmonid populations instreams Pages 3-18 in T G Northcote ed Symposium on salmon andtrout in streams H-R MacMillian lecture series in fisheries UnivBritish Columbia Vancouver

Anonymous 1979 Managing riparian ecosystems (zones) for fish and wildlifein eastern Oregon and eastern Washington Prepared by the RiparianHabitat Subcommittee of the OregonWashington Interagency Wildl Comm44 pp

Armstrong R H 1971 Age food and migration of sea-run cutthroat troutSalmo clarki at Eva ia ke southeastern Alaska Trans Am Fish Soc1OO( 2) 302-306

Bachmann R W 1958 The ecology of four north Idaho trout streams withreference to the influence of forest road construction MS ThesisUniv of Idaho Moscow Id 97 pp

Baxter G T and J R Simon 1970 Wyoming fishes Wyoming Game FishDept Bull 4 168pp

Behnke R J 1979 Monograph of the native trouts of the genus Salmo ofwestern North America Rep prepared for US Fish and Wildl-servRegion 6 Denver Colo 215 pp

Behnke R J and M Zarn 1976 Bi 01 ogy and management of threatened andendangered western trout US For Servo General Tech Rep RM-2845 pp

Bell M C 1973 Fisheries handbook of engineering requirements and biolog-ical criteria US Army Corps Eng North Pacific Div ContractDACW57-68-C-0086 92 pp

Binns N A 1977 Present status of indigenous populations of cutthroattrout Salmo clarki in southwestern Wyoming Wyoming Game Fish DeptFish T~Bull 2 58 pp

32

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

1979 A habitat quality index for Wyoming trout streamsWyoming Game Fish Dept Fish Res Rep 2 75 pp

Binns N A and F M Eiserman 1979 Quantification of fluvial trouthabitat in Wyoming Trans Am Fish Soc 108215-228

Bjornn T C 1969 Embryo survival and emergence studiesDept Salmon and Steelhead Invest Proj F49-R-7 Job 5Rep 11 pp

Idaho Fish GameAnn Completion

1971 Trout and salmon movements in two Idaho streams asrelated to temperature food streamflow cover and population densityTrans Am Fish Soc 100(3)423-438

Boussu M F 1954 Relationship between trout populations and cover on asmall stream J Wildl Manage 18(2)229-239

Bulkley R V and N G Benson 1962 Predicting year-class abundance ofYellowstone Lake cutthroat trout US Fish Wildl Res Rep 59 21 pp

Bustard D R and D W Narver 1975a Aspects of the winter ecology ofjuvenile coho salmon (Oncorhynchus kisutch) and steel head trout (Salmogairdneri) J Fish Res Board Can 32(3)667-680 --

1975b Preferences of juveni 1e coho salmon (Oncorhynchuskisutch) and cutthroat trout (Salmo clarki) relative to simulated alterashytion of winter habitat J Fis~s Board Can 32(3)681-687

Calhoun A J 1944 The food of the black-spotted trout in two SierraNevada lakes Calif Fish Game 30(2)80-85

1966 Inland fisheries management Calif Fish Game 546 pp

Carlander K D 1969 Handbook of freshwater fishery biology Vol 1Iowa State Univ Press Ames Iowa 752 pp

Chapman D W 1966 The relative contributions of aquatic and terrestrialprimary producers to the trophic relations of stream organisms Pages116-130 in K W Cummins C A Tryon and R T Hartman (eds)Organism~ubstrate relationships in streams Univ Pittsburgh PymatuningLab Ecol Special Publ 4 Edwards Brothers Inc Ann Arbor Mich

Chapman D W and T C Bjornn 1969 Distribution of salmonids in streamswith special reference to food and feeding Pages 153-176 in T GNorthcote (ed) Symposium on salmon and trout in streams- H RMacMillan lecture series in fisheries Univ British Columbia Vancouver

Coble D W 1961 Influence of water exchange and dissolved oxygen in reddson survival of steelhead trout embryos Trans Am Fish Soc90(3)469-474

33

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Cope O B 1957 The choice of spawning sites by cutthroat trout ProcUtah Acad Sci Arts and Letters 3473-79

Cordone A J and D W Kelly 1961 The influence of inorganic sedimenton the aquatic life of streams Calif Fish Game 47(2)189-228

Crouse M R C A Callahan K W Malueg and S E Dominguez 1981Effects of fine sediments on growth of juvenile coho salmon in laboratorystreams Trans Am Fish Soc 110(2)281-286

Delisle G E and B E Eliason 1961 Stream flows required to maintaintrout populations in the Middle Fork Feather River Canyon Calif DeptFish Game Water Pr-o i Branch Rep 2 19 pp

Doudoroff P and D L Shumway 1970 Dissolved oxygen requirements offreshwater fishes FAO Fish Tech Paper 86 Rome 291 pp

Drummond R A and T D McKinney 1965 Predicting the recruitment ofcutthroat trout fry in Trappers Lake Colorado Trans Am Fish Soc94(4)389-393

Duff D AUtah1977

1980 Livestock grazing impacts on aquatic habitat in Big CreekPresented to Livestock and Wildlife Fisheries Workshop May 3-5Reno Nev US Bur Land Manage Utah State Office 36 pp

Duff D A and JCooper 1976 Techniques for conducting stream habitatsurveys on National Resource Lands USDI Bur Land Manage Tech Note283 72 pp

Dwyer P D and R H Kramer 1975 The influence of temperature on scopefor activity in cutthroat trout Salmo clarki Trans Am Fish Soc104(3)552-554

Elser A A 1968habitat zones97(4)389-397

Fish populations of a trout stream in relation to majorand c han ne 1 aItera t ion s Tran s Am Fish Soc

Everest F H 1969 Habitat selection and spatial interaction of juvenilechinook salmon and steelhead trout in two Idaho streams PhDDissertation Univ Idaho Moscow Id 77 pp

Fleener G C 1951 Life history of the cutthroat trout Salmo clarki inLogan River Utah Trans Am Fish Soc 81(2)235-248

Giger R D 1972 Ecology and management of coastal cutthroat trout inOregon Oregon Game Comm Corvallis Oreg Fish Res Rep 6 61 pp

1973 Streamflow requirements of salmonids AFS-62-1Oregon Wildl Comm Portland Oreg 117 pp

Glova G J and J C Mason 1976 Interactive ecology of juvenile salmonand trout in streams Tobard Fish Res Station Manuscript Rep 1391Tobard Can 24 pp

34

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Griffith J S 1972 Comparative behavior and habitat utilization of brooktrout (Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in northern Idaho J Fish Res Board Can 29(3)265-273

1974 Utilization of invertebrate drift by brook trout(Salvelinus fontinalis) and cutthroat trout (Salmo clarki) in smallstreams in Idaho Trans Am Fish Soc 103(3)440-447

Hartman G F 1965 The role of behavior in the ecology and interaction ofunderyearling coho salmon (Oncorhynchus kisutch) and steel head trout(Salmo gairdneri) J Fish Res Board Can 22(4)1035-1081

Hartman G F and C A Gill 1968 Distributions of juvenile steelheadand cutthroat trout (Salmo gairdneri and~ clarki clarki) within streamsin southwestern British Columbia J Fish Res Board Can 25(1)33-48

Hickman T J 1977 Studies on relict populations of Snake Valley cutthroattrout in western Utah 1976 Prepared for USDI Bur Land Manage Sa ItLake City Utah 41 pp

1978 Systematic study of the native trout of the BonnevilleBasin MS Thesis Colorado State Univ Ft Collins Colo 122 pp

Hooper D Recology97 pp

1973 Evaluation of the effects of flows on trout streamDept Eng Res Pac Gas and Electric Co Emeryville Calif

Horner N and T C Bjornn 1976 Survival behavior and density of troutand salmon fry in streams Univ of Idaho For Wildl and Exp StnContract 56 Prog Rep 1975 38 pp

Hunt R L 1971 Responses of a brook trout population to habitat develop-ment in Lawrence Creek Dept Nat Res Tech Bull 48 Madison Wise35 pp

1975 Food relations and behavior of salmonid fishes137-151 in A D Hasler (ed) Coupling of land and water systemsStudiesVol 10 Springer Verlag

PagesEco1

Hunter J W 1973 A discussion of game fish in the State of Washington asrelated to water requirements Rep by Fish Manage Div WashingtonState Dept Game to Washington State Dept Ecol 66 pp

Hynes H B N 1970 The ecology of running waters Univ Toronto PressCanada 555 pp

Idyll C 1942 Food of rainbow cutthroat and brown trout in the CowichanRiver System British Columbia J Fish Res Board Can 5448-458

Irving R B 1954 Ecology of the cutthroat trout in Henrys Lake IdahoTrans Am Fish Soc 84(2)275-296

35

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Johnston J M 1979 Coastal cutthroat (Salmo clarki clarki) WashingtonState Game Dept Olympia Wash Fish ~Rep 29 pp

Johnston J M and S P Mercer 1976 Sea-run cutthroat in saltwaterpens broodstock development and extended juvenile rearing (with a lifehistory compendium) Washington State Game Dept Olympia Wash FishRes Rep AFS-57-1 92 pp

1977 Sea-run cutthroat brood stock development and evaluationof a new enhancement technique Washington State Game Dept OlympiaWash Fish Res Rep 26 pp

Jones D E 1974 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress Rep AFS42 1973-1974

1975 Life history of sea-run cutthroat trout in southeastAlaska Alaska Dept Fish Game Progress R~p AFS42 1974-1975

1976 Stee 1head and sea-run cutthroat trout 1i fe hi storystudy in southeast Alaska Alaska Dept Fish Game Progress Rep AFS-421975-1976

Juday C 1907 Notes on Lake Tahoe its trout and trout fishing BullUS Bur Sport Fish 26133-146

Lea R N 1968 Ecology of the Lahontan cutthroat trout Salmo clarkihenshawi in Independence Lake California MA Thesis Univ CalifBerkeley Calif 95 pp

Lewis S La trout34 pp

1969 Physical factors influencing fish populations in pools ofstream MS Thesis Montana State Univ Missoula Mont

McAfee W R 1966 Lahontan cutthroat trout Pages 225-231 in A Calhoun(ed) Inland fisheries management Calif Dept Fish Game-

McConnell W J E P Bergersen and K L Williamson 1982 Habitatsuitability index models A low effort system for planned coolwater andcoldwater reservoirs USDl Fish Wildl Serv FWSOBS-82l0347 pp

McCuddin M E 1977 Survival of salmon and trout embryos and fry in gravelshysand mixtures MS Thesis Univ Idaho Moscow Id 33 pp

McKee J E and H W Wolf 1963 Water quality criteriaQuality Control Board Publ 3A Sacramento Calif 548 pp

State Water

Mercer S P and J M Johnston 1978 Sea-run cutthroat Development andevaluation of a new enhancement technique Washington State Game DeptOlympia Wash Fish Res Rep 24 pp

Miller R B 1957 Permanence and size of home territory in stream-dwellingcutthroat trout J Fish Res Board Can 14(5)687-691

36

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Needham P R 1940 Trout streams Comstock Publ Co Inc Ithaca NewYork 233 pp

Needham P R and A C Jones 1959 Flow temperature solar radiationand ice in relation to activities of fishes in Sagehen Creek CaliforniaEcology 40(3)465-474

Nickelson T E Oregon Dept Fish Game Res Sect Corvallis Oreg Unpubldata

Pennak R W and E D Van Gerpen 1947 Bottom fauna production andphysical nature of the substrate in a northern Colorado trout streamEcology 28(1)42-48

Phillips R W R L Lantz E W Chaire and J R Moring 1975 Someeffects of gravel mixtures on emergence of coho salmon and steelheadtrout fry Trans Am Fi~h Soc 104(3)461-466

Platts W S 1974 Geomorphic and aquatic conditions influencing salmonidsand stream classification with application to ecosystem classificationUS For Serv SEAM Publ Billings Mont 199 pp

Raleigh R F 1971 Innate control of migrations of salmon and trout fryfrom natal gravels to rearing areas Ecology 52(2)291-297

Raleigh R F and D W Chapmantions of cutthroat trout fry

1971 Genetic control in lakeward migrashyTrans Am Fish Soc 100(1)33-40

Ra 1e i gh R F and D A Duff 1981 Trout stream habi tat improvementecology and management Pages 67-77 in W King (ed) Proc of WildTrout Symposium II Yellowstone Natl Park Wyom Sept 24-25 1979

Raleigh R F T J Hickman K L Nelson and O E Maughan (in press)Riverine habitat evaluation procedures for rainbow trout Proceedings ofthe trout stream improvement workshop Asheville N C November 1980

Roscoe J W 1974 Systematics of the westslope cutthroat trout MSThesis Colorado State Univ Ft Collins Colo 74 pp

Sabean B 1976 The effects of shade removal on stream temperature in NovaScotia Nova Scotia Dept Lands and For Cat 76-1~8-100 32 pp

1977 The effects of shade remova 1 on stream temperature inNova Scotia Nova Scotia Dept Lands and For Cat 77-135-150 31 pp

Scott W B and E J Crossman 1973 Freshwater fishes of Canada FishRes Board Can Bull 184 966 pp

Sekulich P T 1974 Role of the Snake River cutthroat trout (Salmo clarkisubsp) in fishery management MS Thesis Colorado State Univ FtCollins Colo 102 pp

37

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

Smith O R 1941 The spawning habits of cutthroat and eastern brook troutsTrans Am Fish Soc 65(4)461-471

1947 Returns from natural spawning of cutthroat trout andeastern brook trout Trans Am Fish Soc 74281-296 (1944)

Snyder G R and H A Tanner 1960 Cutthroat trout reproduction in theinlets to Trappers Lake Color~do Fish Game Tech Bull 7 85 pp

Thompson K 1972 Determining stream flow for fish life Pages 31-50 inProc Instream Flow Requirement Workshop Pac Northwest River Bas-shyComm Vancouver Wash

Trojnar J R 1972cutthroat trout59 pp

Ecological evaluation of two sympatric strains ofMS Thesis Colorado State Univ Ft Collins Colo

Trojnar J R and R J Behnke 1974 Management implications of ecologicalsegregation between two introduced populations of cutthroat trout in asmall Colorado lake Trans Am Fish Soc 103(3)423-430

Wesche T A 1980 The WRRI trout cover rating method development andapplication Water Resources Research Institute Laramie Wy WaterResources Ser 78 46 pp

38

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

50272 -101

REPORT ~~MENTATON ll-FWSioBSmiddot-821053 Recipients Accession No

4 Titte and Subtitle

_ Habitat Suitability Index Models Cutthroat troutFebruarv 1982

7 Author(s)

Terry J Hickman and Robert F Raleigha Performing Oanizatlon RePt- No

9 Performing Oraanization Name and Address Ha bi ta t Eva 1uati on Procedures GroupWestern Energy and Land Use TeamUS Fish and Wildlife ServiceDrake Creekside Building One2625 Redwing RoadFort Collins Colorado 80526

10 ProjectTaskWorlc Unit No

11 Contract(C) or Grant(Gl No

(C)

laquon

12 Sponsoring Organization Name and Address Western Energy and Land Use TeamOffice of Biological ServicesFish and Widlife ServiceUS Department of InteriorWashinaton DC 20240

13 Type of Report amp Period Covered

14

15 Supplementary Notes

middot18 Abstract (Limit 200 words)

Cutthroat trout (Salmo clarki) characteristics are described including distributionage growth food reproduction and anadromy A detailed literature review of specifichabitat requirements is also included 17 habitat variables are then evaluated andquantified in suitability index graphs These data are subsequently synthesized intoHabitat Suitability Index (HSI) models for the cutthroat trout

This is one in a series of publications developed to provide information on the habitatrequirements of selected fish and wildlife species HSI models are designed to provideinformation for use in impatt assessment and habitat management activities The HSItechnique is a corollary to the US Fish and Wildlife Services Habitat EvaluationProcedures

17 Oocument Analysis a Oescriptors

Habi tabil ityFishes

b IdentlfiersOl)en-Ended Terms

IndexHabitatHabitat SuitabilityCutthroat troutSalmo clarkit c COSATI FieldGroup

18 Availability Statement

Unlimited 19 Security Class (This Report)

UnclassifiedI 20 Security Class (This Pagel

Unclassified

1

21_ No of Pag

I 38

(s ANSI-z3918l See Instructions 01 Reverse

US GOVERNMENT PRINTING OFFICE 1982-578middot127189 REGION NO8

OPTIONAL FORM 272 (4-77)(Formerly NTIS-35lDepartment of Commerce

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

bull

bullbullbull __ J~

middot 0 -

Hawaiian Islands (gt

-(( Headq uarters Division of BiologicalServices Wasnington DC

x Eastern Energy anO Land Use TeamLeetown WV

Nationa l Coastal Ecosystems TeamSli dell LA

bull Western Energy and Land Use TeamFt Coll ins CO

bull Locat ions of Regional Off ices

REGION 1Regional DirectorUS Fish and Wildlife ServiceLloyd Five Hundred Building Suite 1692500 NE Multnomah StreetPortland Oregon 97232

REGION 4Regional DirectorUS Fish and Wildlife ServiceRichard B Russell Building75 Spring Street SWAtlanta Georgia 30303

IJ- - - ----

6 1r-- - -~-

L JI - ~- --I I

1- - -I Il_I 2 -~--

-_J

REGION 2Regional DirectorUS Fish and Wildlife ServicePO Box 1306Albuquerque New Mexico 87 103

REGION 5Regional DirectorUS Fish and Wildlife ServiceOne Gateway Cente rNewton Corner Massachusetts 02158

REGION 7Regional DirectorUS Fish and Wildlife ServicelOll E Tudor RoadAnchorage Alaska 99503

- ~

REGION 3Regional DirectorUS Fish and WildlifeServiceFederal Building Fort SnellingTwin Cities Minnesota 551 J I

REGION 6Regional DirectorUS Fish and Wildli fe ServicePO Box 25486Denver Federal CenterDenver Colorado 8022 5

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration

usFISH WILDLIFE

fgtERVICE

DEPARTMENT OF THE INTERIOR hi]usFISH ANDWILDLIFESERVICE ~

-r rw T

As the Nat ions pri ncipal conservation agency the Department of the Interior has responshysibility for most of our nationally owned public lands and natural resources This includesfostering the wisest use of our land and water resources protecting our fish and wildlifepreserving th amp environmental and cultural values of our national parks and historical placesand providing for the enjoyment of life through outdoor recreation The Department asshysesses our energy and mineral resources and works to assure that t heir development is inthe best interests of all our people The Department also has a major respons ibility forAmerican Indian reservation communit ies and for people who live in island territories underUS adm inist ration