byMarc S. Novick1,

Robert E. Gresswell2, and Sherri Johnson3

1OSU, Department of Fisheries & Wildlife, 2USGS-NRMSC, and 3USFS-PNL

Factors Influencing the Distribution of Coastal Cutthroat Trout in a

Cascade Mountain Stream

byMarc S. Novick1,

Robert E. Gresswell2, and Sherri Johnson3

1OSU, Department of Fisheries & Wildlife, 2USGS-NRMSC, and 3USFS-PNL

Factors Influencing the Distribution of Coastal Cutthroat Trout in a

Cascade Mountain Stream

Study Background

• Small streams represent majority of stream length in forested areas

• Need to identify habitat

• Dynamic, heterogeneous environments

Study Background

• Look at temporal stability of spatial patterns (Gresswell et al. 2005 In press)

• Spatial scale of variation in fish abundance is uncertain requires multi-scale approach (unit, micro=common)

• Bottom-up vs. top-down approach

0 2,100 4,2001,050 Meters

±

Located in the Umpqua River Basin

OREGON

Roseburg

N

Research QuestionsResearch Questions1) Do relative abundance patterns of coastal cutthroat trout persist across seasons?

2) How do habitat variables influence relative abundance patterns?

3) What are the effects of seasonal stream discharge on movement and activity levels of coastal cutthroat trout?

Study DesignStudy Design

•Electrofishing census of watershed

• Identification of study sections

• Seasonal habitat surveys

• Stationary and mobile half-duplex PIT-tag technology (13 month, bimonthly)

0 1,000 2,000500 Meters

±

Low

High

Summer 2003 ElectrofishingSouth Fork Hinkle Creek

N

52 3

10

9

761 4

16

11

817

18

15

12

14

19

13

±

±

Sou th Fork Hinkle Creek

Tributary 2 Tr ibutary 3

Abundance

HighLow

0 250 500125 Meters

Monitored Habitat PatchesRange 30-320 m300 m

Monitoring Habitat PatchesMonitoring Habitat Patches

HighHigh

LowLowHighHigh

Fish TaggingFish Tagging

Number Tagged= 320 (study section)Number Tagged= 320 (study section)

Fork Length= 122 mm (100Fork Length= 122 mm (100--190 mm)190 mm)

Tag:BodyTag:Body Weight= 3% (<1Weight= 3% (<1--7%)7%)

Stationary Antenna ResultsStationary Antenna Results•Recording data 91% of the time(average of all antennas 10/13/03 to 10/15/04)

• Antenna Efficiency= 90%(measured w/test tag, not related to stage height)

• Mean Maximum Read Range= 25 cm(single-sided, not related to wattage or stage height)

• Detection Efficiency= 88%(percent fish detected by mobile and stationary antennas)

Research QuestionsResearch Questions

1) Do relative abundance patterns of coastal cutthroat trout persist across seasons?

Survey

Num

ber

of f

ish

0 2 4 6 8 10

0

5

10

15

20

Seasonal Persistence

High abundance

Low abundance

Mainstem

Seasonal Persistence

Survey

Num

ber

of f

ish

0

5

10

15

20

0 2 4 6 8 10

High abundance

Low abundance

Tributaries

Num

ber o

f fis

h/se

ctio

n

Section 4 Section 5 Section 6 Section 7 Section 9 Section 10

0

5

10

15

20

25

30

35

01

23

45

6 01

23

45

6 01

23

45

601

23

45

601

23

45

601

23

45

6

Num

ber o

f fis

h/se

ctio

n

Section 4 Section 5 Section 6 Section 7 Section 9 Section 10

0

5

10

15

20

25

30

35

01

23

45

601

23

45

6 01

23

45

601

23

45

6 01

23

45

601

23

45

601

23

45

601

23

45

601

23

45

601

23

45

601

23

45

601

23

45

6

Individual DynamicsMainstem High

New fish

Previously detected

Individual DynamicsMainstem Low

0

5

10

15

20

25

30

35

Sect. 1 Sect. 2 Sect. 3 Sect. 8 Sect. 11 Sect. 12

0123456 0123456 0123456012345601234560123456

Sect. 16

0123456

Num

ber o

f fis

h/se

ctio

n

0

5

10

15

20

25

30

35

Sect. 1 Sect. 2 Sect. 3 Sect. 8 Sect. 11 Sect. 12

01234560123456 01234560123456 01234560123456012345601234560123456012345601234560123456

Sect. 16

01234560123456

Num

ber o

f fis

h/se

ctio

n

New fish

Previously detected

Research QuestionsResearch Questions

2) How do habitat variables influence relative abundance patterns?

Seasonal Habitat UsePe

rcen

t of

Det

ection

s

Fall Winter Spring Summer0

20

40

60

80

100

120

CascadeRifflePool

Mobile Surveys

Pool Formation

Mainstem Tributaries

Boulder Bedrock LWD Root

67%50%

Significance of Boulders

Number of Boulders

Fish

Abu

ndan

ce

y = 0.1279x + 0.2626R2 = 0.84

05

101520253035

0 100 200 300

Research QuestionsResearch Questions

3) What are the effects of seasonal stream discharge on movement and activity levels of coastal cutthroat trout?

Dave Leer 2003

0

2

4

6

8

10

12

14

16

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Mea

n nu

mbe

r of

fis

h or

Wat

er T

(ºC)

Mea

n st

ream

dis

char

ge (m

3s-

1 )

2003 2004

Seasonal Overview Discharge Water Temp. Fish

Seasonal Stream Discharge

0

10

20

30

40

50

60

70

Mea

n Daily D

isch

arge

(cf

s) 1.2 yr event

Fall Winter Spring Summer

Movement Discharge Relationship

Discharge (m3/s)

Num

ber

of F

ish

Det

ecte

d

Spring

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.40

10

20

30

40

50

y = 0.35^ (-6.26x)

R2 = 0.57

N = 614 detections (68 fish)

Summary •Fish abundance more stable in MS than Tribs

•Movement in proportion to stream discharge, resilient to discharge extremes

•High/low relative abundance patterns persisted in MS, but individuals dynamic

• Fish abundance depends on habitat complexity and temporal stability

Doug BatemanDoug Bateman

Mike HeckMike HeckDave Dave HockmanHockman--WertWert

Aaron BergerAaron BergerDave LeerDave Leer

Vince Vince TranquilliTranquilliWarren LeechWarren Leech

Doug BatemanDoug Bateman

Mike HeckMike HeckDave Dave HockmanHockman--WertWert

Dave LeerDave Leer

Vince Vince TranquilliTranquilliWarren LeechWarren Leech

Aaron BergerAaron Berger

Nicolas Nicolas ZegreZegreNicolas Nicolas ZegreZegre

AcknowledgementsAcknowledgements

Watershed Research CooperativeWatershed Research Cooperative

Questions ?Questions ?

Bank Full Event

Distance (m)

Perc

ent

of F

ish

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60 70 80 90 100

110

410

Upstream DownstreamNo Movement

N= 59 fish