Hybrid Ihms Fingerlings

ObseIva6ons on Pond Froduetion ofHybrid Ihms FingerlingsJanus W. Kahrs

On June 10' 1981 y 40' 000 hybrid bass finger 1 ingswere stocked into a 1-acre pond at our Osage Beachfacility. The fingerlings were 38 to 50 mm inlength and weighed approximately 1.5 grams. A flowof 15 gpm of aerated spring water flowed through thepond until harvest.

The fish were fed twice daily using a mixtureof crumbled floating trout feed �8X protein!. Thefish fed voraciously at all water levels from thesurface to the bottom. When the electric golf cartor pick-up truck used in feeding operations camenear the pond the fish would rapidly congregate inthe area where they were normally fed.

The fish were sampled throughout the summer andwere sold when necessary to meet commitments.

On August 17th, 7, 000 fingerlings were harvest-ed for delivery to customers. These fish averaged127 mm total length TL! but no weights were tak-en. Survival was high and no disease problems wereencountered. During the last week in August 1981 asix-inch rain occurred during a 2-hour period. Thecreek that lies adjacent to the fingerling pond roseto the highest level I had seen in nearly 30 yearsand completely flooded the pond. containing the hy-brid bass ~ Some fish were recovered from the orig-inal pond and adjacent ponds, but many made theirway to the Lake of the Ozarks which lies less thanone-quarter mile downstream.

In June 1982, the same pond was stocked with22,000 fingerling hybrid bass 25 to 50 mm TL ~ Peri-odic harvests of some fish were made until the pondwas completely harvested in early September 1982.Survival rates were not estimated and lengths and

In. tensive Culture 91Intensive Culture90

are the sensitivity to rapid fluctuations in waterquality and outbreaks of stress related disease, thedependence on mechanical devices, a need to supplyall the nutritional requi.rements in the absence ofnatural foods, the need for alarm and backup systemsand a requirement for experienced personnel.Nevertheless, the added risk is often justified bythe increase in production capacity, where harvestdensities can be three levels of magnitude greaterthan traditional pond production levels.

The striped bass is an excellent species forintensive culture. It is adaptable to controlledenvironments, exhibits rapid growth rates incaptivity, accepts artificial feeds, has broadphysiological tolerances and has a high marketvalue. Intensive culture methods have been appliedto all developmental stages of striped bass, fromlarvae to mature adult. Historically, eggs havebeen incubated in McDonald hatching jars andresulting larvae and fry reared in aquaria andtroughs Bayless 1972; Bonn 1976!. Traditional pondculture methods are still commonly used during thenursery period when fry are reared to fingerling.However, in recent years a variety of intensiveculture systems have been tested for rearingfingerlings and for the production of advancedfingerlings and food fish under controlled cultureconditions. These intensice culture systems includefloating cages, tanks, raceways, and silos. Thefollowing is a review of some of the significantaccomplishments made in the continued effort todevelop intensive culture techniques for stripedbass.

INTENSIVE CULTURE OF FRY

Dennis Wildlife Center,South Carolina Wildlife and

Marine Resources Department,Bonneau, South Carolina

Bayless 1972; Bayless and Harrell pers. comm.!

In the late 1960s striped bass culture techniqueswere refined at the Moncks Corner Hatchery. Theculture sequence was modified to include a 7 � to15-day period of rearing fry in 303 � 1 fiberglasscoated wood troughs prior to stocking in ponds. Frywere fed brine shrimp nauplii as an initial foodsource to increase their strength and developmentprior to their release in ponds. This methodallowed for some control during the critical firstfew days of feeding, and has often been found toincrease the subsequent survival of striped bassreared in ponds. Troughs are now traditionally usedto hold fr y at several hatcheries prior to pondstocking. Fry are often stocked in troughs at 200fry/I and fed trout starter mash and ground fish at1OX of their body weight per day.

Fish Culture Development Center,U.S. Fish and Wildlife Service,

Tishomingo. Oklahoma Inslee 1977!

Between 1972 and 1974, investigators in Oklahomatested t.he use of 1 � m3 cages floating in tanks andponds as an alternative to the fuse o aquaria forrearing larvae until swim-up Th e cages wereconstructed of wood frames covered with saranscreen. Following 5 days of culture theu ure, t e cages were

rge an the fry were allowed to escape into

in tanks equipped with wooden paddle agitators andafter 3

fingerlings reared in ponds stocked with frwere initial

oc e wit ry that

twice the survially held in saran cages was 35.7X Ia most

e survival rate of aquaria-reared fry �8X!

larval rearing were the difficulty of stocking theenvironmental conditions. Nevertheless, it wasdemonstrated th at larvae cultured in cages prior topond release required less care and manpower thanaquaria methods.

Intensive Culture93

Intensive Culture92

Texas Parks and Wildlife Department,Fisheries Research Station,

Palacios, Texas Colura et al. 1976; Hysmith pers. comm.!

Research was conducted on the culture of stripedbass larvae by intensive methods involving the useof circular tanks. Larvae were reared from day 3 today 10 in 0.4-, 2.5-, or 6.8-m3 tanks. The tankswere operated as a closed system, at a temperatureof 19 C and a salinity of 6-8 ppt. Prior tostocking in brackish water ponds fry were fed brineshrimp nauplii . This study showed that fry could beP roduced by intensive tank culture methods in aclosed system at law salinities.

INTENSIVE CULTURE OF FINGERLINGS

The rearing of fry to 2.5- ta 5.0-cm fingerlingstraditionally involves stocking 5-day � o y� ld fr

roduced in aquaria into earthen ponds of aboabout 0.5pro uce

h in size at densities of 250,000/ha. ey eed bon zoop alankton populations which are enhanced y

fertilization and supplemented with arti icia ee s Bonn 1976!. Survival of fry grown by extensivepond culture methods is usually less than 20X atharvest after 30-50 days. Over the past 20 yearsconsiderable effort has been made to improvesurvival rates during this critical stage ofdevelopment. These efforts include several attemptsto utilize intensive culture techniques.

North Carolina State Fish HatcheryWeldon, North Carolina

Tatum et al. 1965!.The first recorded efforts to culture fingerlings

by intensive methods were conducted at Weldon in theearly 1960s. Culture experiments were conducted in20-m3 concrete pools stocked with 2-day-old larvaeat densities of 0.5/I and 2.5/l. They were fed livezooplankton for 3 weeks and trout starter meal afterthe second week. Sixteen weeks of culture resultedin the production of 6- to 13-cm fingerlings with an

85X survival rate. This study showed that fry couldbe cultured successfully in outdoor concrete poolsand would readily consume artificial feed.

Edenton National Fish HatcheryU.S, Fash and Wxldlzfe Serv>ce,

Edenton, North Carolina Anderson 1966; Wirtanen and Ray 1971;

Atstupenas pers. comm.!Since the early 1960s, the Edenton Hatchery has

been one of the primary sites for the production offingerlings in ponds. The first recorded attempt torear fingerlings for enhancement purposes, asapposed to stocking sac-fry, was at the EdentonHatchery in 1964 Anderson 1966! . Sac-fry obtainedfrom the Weldon Hatchery were grown in 450 1 troughssupplied with 21'C aerated well water at a rate of5.7 lpm. The fry were fed emulsified shrimp tentimes a day. After 15 days in the troughs mortalityin the first group was greater than 75X. It wasconcluded that emulsified shrimp was not an adaquatediet for an extended culture period.

A second group of fry were grown in the troughsfor on1.y 5 days prior to stocking in a pond.Subsequently, 30,000 fingerlings weighing 4-5 g eachwere harvested from the pand after 83 days. Fromthis study researchers concluded that stocking pondswith older fry resulted in greater survival tafingerling size and that providing the appropriat efeed was the most critical factor .

Routine operations at the Edenton Hatcheryinvolve stocking fry in late Nay, and 5-cmfingerlings weighing 0.45 g are harvested after 35days in early July. Some fingerlings are graded andrestocked for production of advanced fingerlings andothers grown to maturity in an effort to develop acaptive broodstock.

Despite the relatively successful pond cultureoperations at Edenton some research there hasinvolved the development of alternative culturetechniques to increase survival rates. In 19640.6-g fry were stocked in indoor concrete holding

95Intensive CultureIntensive Culture94

tanks at a density of 4 g/l. The tanks weresupplied with 18'C well water at a rate thatproduced three water changes per hour. The fry werefed commercial trout feed at a rate of 5X bodyweight per day. There were considerable diseaseproblems caused by Flexibacter columnaris,attributed to the relatively high stocking density.

Other studies on the intensive culture offingerlings were conducted in two 45.4 m3 outdoorfiberglass raceways. Fry weighing 1.4 g werestocked at two densities, 0.5 g/1 and 1.0 g/1. Bothraceways were supplied with 24- C well water at arate of 208 lpm. The first raceway received 13,810fry and yielded 5,715 fingerlings at 7.5 g eachafter 140 days �1.4X survival!. The second racewayreceived 29,795 fry and yielded 10,159 fingerlingsat 1 1.1 g each after 187 days �4.1X survival!. Theresults of the raceway experiment showed thatfingerlings could be cultured in intensive systemsfrom a relatively high stocking density of 2.76kg/m3 with a survival percentage nearly twice thatachieved in ponds. In addition, this researchrevealed the advantage of raceways for the controlof predat.ion and treatment of disease.

Lower Fisheries Research UnitDepartment of Fisheries and Applied Aquaculture

Auburn University, Auburn, Alabama Kelley 1967; Shell 1972;

Snow 1977, 1979; Braid 1981!A study similar to the one conducted at Edenton

was performed at the Agricultural Experiment Stationof Auburn University in 1967 Kelley 1967!.Fourteen 98-1 stainless steel troughs were eachstocked with 100 15- to 35-mm fry. Each trough hada flow of 2.6 lpm of filtered water and fry were fedfloating Purina Trout Chow and beef liver at 10Xbody ~eight per day. After 16 weeks of culture,fingerlings with an average size of 70.6 mm wereproduced with only 14.7X mortality. The lengthattained by a similar group reared in ponds was only54.9 mm. The results from this study showed that

fingerlings could be reared in intensive culturesystems when fed an adequate amount of apprnpriat.efeed.

Similar studies conducted at Auburn Universityfrom 1971-1973 assessed the value of extendedculture of larvae in NcDonald hatching jars priorto stocking fry in troughs for intensive productionof fingerlings Shell 1972!. Larvae were stocked in7.6-1 and 22.7-1 jars at densities of 10,000 and30,000, respectively. There were considerableproblems with infestation by fungus that resulted intotal mortality in the 22.7 � l jars and only 0.02Xsurvival in the smaller 7.6-1 jars. In subsequentattempts 29 � day-old fry were stocked into aluminumtroughs that received 17.8'C stream water adjustedto a salinity of 5 ppt. The fry were fed brineshrimp nauplii every 3 hours and dry feed every 15minutes. Again the results were discouraging, witha mortality of 97X resulting from cannibalism andunknown causes. At that time i.t was concluded thatdelayed stocking of fry increased survival rates tofingerling size, however due to the high mortalityrates of fry in hatching jars and troughs, thisproved to be of little advantage.

The importance of diet was apparent from thefirst two studies. Therefore, in 1974 a series ofexperiments were conducted to determine a suitablediet for fry in intensive culture. Severalcombinations of brine shrimp with commercial troutfeeds were tested Braid 1981!. Later studies atAuburn University in 1976 and 1977 investigatedalternative methods for the intensive culture of fry Snow 1977 and 1979!, In 1976 a closed recirculatedculture system was tested. Although thispreliminary trial was successful, when the fry werestocked in brackish water ponds at the Claude PeteetNariculture Center, Gulf Shores, Alabama, more thanhalf the resulting fingerlings showed signs ofscoliosis. This was attributed to possible vitamindeficiencies in the feed.

Continuing work in 1976 concerned the evaluationof tank culture systems. In one experiment five2.4-m3 circular plastic pools were supplied with


water at 25'C that was pre-treated with organic orinorganic fertilizer to stimulate the growth ofnatural food organisms. Attempts to stock 4-day-oldfry resulted in total mortality. However, when16-day-old fry were stocked, 23.1X survived tofingerling stage, compared to 21.2X for similargroups cultured in ponds. This st.udy indicated thattank culture methods were suitable for advanced fry.

An additional study conducted in 1976 tested853-1 cages constructed of saran screen andsuspended in 1. 5-m3 concrete tanks. Fry were fedbrine shrimp nauplii five times per day. After 15days, survival was only 22.6X due t.o high rates ofcannibalism. It was believed that brine shrimpnauplii might not provide all the nutritionalrequirements of older fry. In 1977 investigationsw ere initiated to identify an alternative to brineshrimp nauplii, since this feed was in short supp y1

and relatively expensive. Again, saran cages wereused in the 1.5-m3 tanks. Two sizes of cages weretested, with volumes of 0.5 and 7.5 m3. A thirdsystem consisted of two circular fiberglass tanks,1.5 and 2.4 m in diameter and volumes of 1.3 and 3. .4

m3, respectively. The study involved the testing ofseveral artificial dry feeds in combination withnatural food organisms grown in adjacent ponds. Theresults demonstrated that zooplankton could becultured in ponds and transferred to intensive fryculture systems as needed.

Virginia Institute of Marine SciencesGloucester Point, Virginia

Kerby and Joseph 1978!Concurrent with the tank culture studies

conducted at Auburn University, similar systems werebe'ng investigated at the VIMS Laboratory, Initialej.ngattempts at tank culture of 900,000 larvae resulte din 4,000 fingerlings, giving only a 0. 4X survival.Subsequent studies conducted in 1970 were moresuccessful. Two series of experiments wereconducted to compare the growth and survival ofstriped bass and striped bass x white perch hybrids

cultured in intensive systems . Two 1.300-1fiberglass tanks were supplied with 24*C well waterat a rate of four exchanges per day. Fry were fedPurina Trout Chow twice per day, The first trialswere conducted for 332 days, yielding 203 � g stripedbass fingerlings with a survival of 46X, and 171-ghybrids with 82X survival. The second trials wereconducted for 331 days, during which time thestriped bass attained an average size of 174 g with38X survival, and the hybrids reached 196 g with 87Xsurvival. This study demonstrated that hybrids wereclearly more hardy than striped bass. In addition,it was determined that hybrids could be grown to aharvest density of 32 kg/m3 in tanks supplied withconstant aeration.

University of Rhode IslandGraduate School of Oceanography

Kingston, Rhode Island Rhodes and Merriner 1973; Rogers 1974!

Studies at the University of Rhode Island weredesigned to test the use of inexpensive wading poolsas alternatives to more permanent concrete orfiberglass tanks. Experiments were conducted in 3 mdiameter by 0.6 m deep vinyl lined pools. They wereoperated as semi-closed systems supplied withrecirculated, filtered water and received 95 lpd ofmake-up water from a well source that was adjustedto 4.7-5 6 ppt salinity. The 3.4-m3 pools were eachstocked with 100,000 fry and fed brine shrimpnauplii. When the fingerlings were between 42 and67 days of age they were fed Tetra-Min flakes.Older fingerlings were fed trout pellets.

The initial objective was to produce yearlings,however the researchers concluded that this systemwas best suited for fingerling production. Theyestimated that between 15,000-20,000 fingerlings20-25 mm in length could be produced in a singlepool. The study also showed that vinyl pools werean inexpensive closed system that could be easilysetup near the spawning grounds.

Intensive CultureIntensive Culture 9998

Gulf Coast Research LaboratoryOcean Springs, Mississippi

Nicholson 1973; McIlwain 1976, 1978!Probably the most extensive work on the

development of intensive culture methods forproduction of fingerlings has occurred at the GulfCoast Research Laboratory. Work began in 1969 tostock a North Atlantic Coast strain of striped bass,as part of an effort to establish an anadromousreproducing population of sea-run striped bass alongthe Gul.f Coast.

The culture system developed at this laboratorywas comprised of ten banks of five circularfiberglass tanks 2,4 m diameter by 1.2 m deep, witha capacity of 3.9 m3. Four tanks in each modulewere used for culture and the remaining one was usedan up � flow filter.

The circular culture tanks are equipped with acentral stand pipe drain and a venturi pipe withopenings covered with nytex to retain larvae andfry. Aeration consists of a circular loop aroundthe base of the venturi pipe that produces a bubblecurtain of air that helps fry from becoming impingedon the drain screen. Water at 23'C is supplied froma well, pre � treated through pressure sand filters,and used to exchange one volume of the filter tankdaily. The up � flow filters have perforatedcorrugated fiberglass at the bottom that functionsas a deflector panel which is covered with 20 cm ofclam shell followed by 18 cm of foam rubber . Fryhave been stocked in this system at densitiesranging from 3-9 fry/liter. The fry are generallyfed brine shrimp nauplii from day 5, and brineshrimp nauplii plus wild zooplankton from a 0 1-hapond after day 10. Commercial trout feeds aresupplied by automatic feeders after 15 days.Automatic feeders have also been developed for thebrine shrimp and zooplankton Nicholson pers comm.!

In a study conducted in 1974, 1-day-old fry werestocked at 8.9 fry/1, producing 45.l-mm fingerlingsin 60 days with only 0.73X survival McIlwain 1976!.The extremely high mortality rates were caused by F.columnaris, which was difficult to control in the

filtration pond. A subsequent study conducted in1976 compared the growth of fry obtained fromVirginia with those from South Carolina. Whenstocked at densities of 3.3 fry/1, the group~ fromVirginia produced 12-33 mm fingerlings in 27 days,with 38X survival and a growth rate of 0.64 mm/day.The group from South Carolina did not. attain thissize until after 38 days, showing a slower growthrate of 0.49 mm/day. However, they did haveslightly greater survival �0X!.

The major cause of mortality in this system wasdetermined to be cannibalism, which became intenseafter the fingerlings exceeded 20 rnm in length.This research also determined that food supply was amajor limiting factor in the intensive culture ofstriped bass fingerlings. To avoid these problems,researchers routinely graded the fish and increasedthe size and quantity of the pelleted feed. Growthand survival of striped bass in low salinity waterwas reported to be greater than that of fishcultured in fresh water . In addition, striped basssurvival increased as the technicians became moreexperienced.

Texas Instruments, Inc.Consolidated Edison Company

Verplanck, New York Annual Reports for 1973 to 1976,

Overview 1973-1975!A 5-year study was conducted between 1973 and

1977 to determine the feasibility of operating ahatchery for the release of striped bass fingerlingsinto the Hudson River to mitigate power plantentrainment of eggs and larvae. The objective wasto refine intensive culture methods for fingerlingproduction and to rear 20,000 7.6 � to 12.7 � cmfingerlings for mark-recapture studies. A pilothatchery was constructed for the production oflarvae. Some larvae were sent ta hatcheries atDurant and Medicine Park, Oklahoma, for productionof advanced fingerlings by conventional pond culturemethods. Most of the intensive culture experimentswere conducted in cooperation with Auburn

Intensive Culture100 Intensive Culture 101

University, Southern Illinois University, and theGulf Coast Research Laboratory.

Results of work in 1973 showed that larval

mortality was reduced when they were cultured at asalinit.y of 2 ppt after 17 days of age rather thanin freshwater . Some problems resulting from the

have been reduced by use of brackish water in larvalculture. Studies in 1974 determined a need tosupply adequate quantities of brine shrimp nauplii�00-500 nauplii per larva per day!, until the fishbecame 20 � mrn fingerlings. They also revealed theimportance of feeding nauplii in combination withdry flake food during a 2-week weaning period andthe need for grading to reduce cannibalism afterfingerlings attain a size of 40 mm.

Initial experiments on intensive cultureconducted at the Verplanck Laboratory utilized 3.6and 4.6 m diameter vinyl-lined pools supplied withquarry water at 13-17 C at a rate of 11.3 lpmadjusted. to 2 ppt salinity. Fry reared in aquariafor 28 days to a size of 12 � 16 mm were stocked inthe pools and fed 60 nauplii per larva per day every3 hours. After 60 days of age this rate wasincreased to 250 nauplii per fry and supplementedwith Tetra-Min dispensed from automatic feeders.After 118 days of culture over 6,000 51 � mmfingerlings were produced, however only 6X survived.Some abnormalities were noticed which wereattributed to the lack of swimbladder inflation,which caused the fish to swim vertically.

In 1975, studies were conducted in 6.4-rn3stainless steel tanks 3.7 rn in diameter . The tankswere equipped with perforated brass cylinder draincollars over the stand pipe and nylon mesh lift � netliners 30 crn deep. Water was introd.uced at thesurface by a spray bar and aeration provided by abubble collar around the central stand pipe drain.Water flow through the system was 8- to 10-lpm,which produced a peripheral circular velocity of 2cm/sec. Ten-day-old fry were stocked at densitiesof 25,000 and 37,000 per tank and fed 60 nauplii perlarva per day at 3 hour intervals. This ration was

later increased to 300-400 nauplii per larva per dayand supplemented with artificial feed. This studyproduced 7.6- to 12.7-cm fingerlings that weremarked with color-coded wire magnetic nose tags andfin � clipped prior to release into the Hudson River.

These studies demonstrated the use of a circularcurrent to aid schooling behavior, facilitatefeeding and reduce cannibalism among fingerlings.Also, they showed the importance of a transitionalweaning period ta dry feeds and the need forgrading. The researchers concluded that a dualprocedure of culture was preferable, consisting ofproduction of fingerlings in ponds and advancedfingerlings in tanks.

Southern Illinois UniversityFisheries Research Laboratory

Gorham, Illinois Lewis and Heidinger 1976, 1981!

Cooperative studies with Texas Instruments, Inc.on intensive fingerling production were conducted atSouthern Illinois University for 3 years, 1974-1976.Subsequent studies were supported by a sub-contractto UMA Engineers, Inc. from Consolidated EdisonCompany. In 1974, three rearing systems weretested: 3 m diameter circular pools, 3 m longaluminum raceways, and 1.8 rn diameter fiberglasstanks. The study was designed to test various waterflow patterns, i.e. circular, linear, downward, andupflow. Larvae were fed nauplii on a 24 hourschedule in subdued light from day 5 through day 30and maintained at 14 � 17'C. They were fed 250nauplii/day until 14 days old and after 20 days oldthey were fed 500 nauplii/day. Training to dryfeeds began from day 12-17 with Tetra-Min and groundsalmon starter dispensed from automatic feeders, atwhich time water temperature was increased to 25'C.By 30 days of age fry were completely weaned ontosalmon starter feed, which was fed 12 � 16 times perday. When less than 40 days old they were fed lOXbody weight per day over 10 feedings, and then thefeeding rate was reduced to 5X per day forsubsequent rearing. Particle size is a critical


factor at this stage. Larvae were stocked at 100/1at 1 or 5 days old, to avoid handling shock to themore sensitive 2- to 4-day-old larvae. Fry wereshown to have exponential growth for the first 80days of culture, giving an average growth rate of 2mm/day. Fry were grown to 51 mm fingerling in 55days and 120 mm fingerlings in 95 days. Survivalwas 46X to 5- to 10-cm fingerling size, althoughnearly half of the fingerlings did not inflate theirswimbladder. This phenomenon is commonly observedin intensive culture, but also occurs in pond rearedfingerlings at a much lower level �-55X!.

The study of water flow patterns showed a needfor an upflow current during the initial 5 days ofdevelopment, when the larvae have limited swimmingability and have not yet initiated swimbladderinflation for bouyancy control. To meet this need,a unique upflow larval rearing unit. was designed.It consisted of a 550-1 box constructed of marineplywood. Water was introduced at the bottom of thebox and passed through an aluminum plate diffuserpositioned 10 cm off the bottom and perforated with100 3 � mm holes. At the top there was an ll cm highpyramid shaped larval retention screen constructedof 0.5 mm stainless steel scree~ which was angled 60degrees inward. The overflow drain had a swiveljoint that allowed for adjustment of water level andfor draining through the screen or periodic drainingabove the screen level to remove any surface film.The larval retention screen had 10,000 cm2 surfacearea, and the water velocity was kept below 0.16mm/sec to avoid impingment of larvae on the drainscreen.

Fry were reared in the upflow system until 10days old and approximately 6 cm in length. At thattime they were transferred to circular productiontanks for subsequent growth. It was necessary totransfer larvae before day 12 since the upflow tankswere unfavorable to swimbladder inflation. A bankof 34 insulated, circular tanks was constructed,each of which were 1.8 m in diameter with a volumeof 2.0 m3. Each tank was equipped with a centralstandpipe with bottom drain slots and fitted with a

drain screen collar constructed of rectangular meshmetal bars. Both units were operated as closed,recirculating systems with 2 � 5X make-up water addeddaily. They were supplied with 14'C well water at arate of 26 lpm. The recirculation rate was 7.6 ipmduring the initial period from 0-5 days old, andthen increased to 26.5 lpm thereafter. The circulart.anks had a water turn-over rate of four exchangesper day at a flow rate of 11- to 19 � lpm. Circularflow was kept at. a minimum for the first 4 weeks ofcu1.ture, and then the angle of the water supply waschanged to provide a circular velocity of less than2 cm/sec. Associated culture system componentsconsisted of a plunge basin aspirator and rotaryblower aeration system, a sedimentation basin, anupflow biofilter filled with 1 cm styrene beads andsupplied with injected oxygen, pressure sandfilters, and ultraviolet sterilization. Flow ratethrough the filtration syst.em was maintained above1..4 1pm per kilogram of fish for lg or smaller fishand was reduced to 0.7 lpm per kilogram for largerfish.

T his work has shown the critical need to satisfth e nutritional requirement~ of fry and fingerlingsreared in intensive systems. They demonstrated theneed to provide an upflow current during initialdevelopment to reduce mortality in 2- to 4-day-oldlarvae and the subsequent need for a reduced currentto accommodate swimbladder inflation. The primarysource of mortality in later stages cannibalism!was limited by periodic grading, and furtherdiscouraged by providing a continuous food supply.Other critical factors identified were thedeleterious effects of light on feeding, the needfor effective aeration and filtration, and thedifficulty of isolating the culture system from thebiofilters during disease treatments.

Continuing work at the Gulf Coast ResearchLaboratory and at Southern I1.linois University hasdemonstrated the biological and technicalfeasibility of intensive culture methods forproduction of striped bass fingerlings. Otherinvestigators are now attempting to refine thesemethods.


University of MarylandCenter for Environmental and Estuarine Studies

Horn Point, Maryland Krantz 1982 pers. comm!

Investigators at the University of Marylandattempted to utilize large oyster hatchery conicaltanks for striped bass fingerling production in theoff-season. Sources of supply of seawater andfreshwater provided a continuous flow of brackishwater to the facility. Hater entered the bottom ofthe cones and was maintained at 0.5-2 ppt salinityuntil eggs water hardened, which reduced problemswith floating eggs and disease. At first feeding,5-day-old fry were transferred to oyster troughs andsalinity increased to 3-5 ppt. After thefingerlings attained a size of 2.5 cm they wereconverted to full strength seawater, 33 ppt .

Other organizations that are planning to conductresearch on the production of striped bassfingerlings in intensive culture systems are.'

NMFS Galveston Laboratory, TexasMoncks Corner Hatchery, South CarolinaNatchitoches Hatchery, LouisianaBaltimore Gas and Electric Company, MarylandConsolidated Edison Company, New YorkUniversity of Minnesota, Minneapolis

INTENSIVE CULTURE OF ADVANCED FINGERLINGS

Initial efforts to produce fingerlings of 2.5- to5-cm by intensive culture methods generally resultedin survival rates lower than 10X; survival ofstriped bass from extensive pond culture averagedabout 20X. It was not until the raid 1970s thatsurvival rates for fingerlings reared in intensiveculture systems increased to levels exceeding twice�6X! those achieved in ponds McIlwain 1976; Lewisand Heidinger 1976!. Even greater success has beenachieved in the culture of advanced fingerlings.

Alabama Department of Conservationand Natural Resources

Dauphin Island, Alabama Swingle 1970, 1972; Powell 1971, 1973!

The focus of this research was to evaluate the

use of cylindrical cages floating in brackish waterfor the production of advanced fingerlings. Thecages were 0.9 m diaraeter by 1.2 m deep, having avolume of 800-1. They were constructed of woodframes covered with either 0.6 or 1.3 cm meshvinyl � coated galvanized hardware cloth that wascovered with fiberglass window screen. The cageswere equipped with styrofoam floats and a feedingring.

Experiments conducted in 1969 evaluated threestocking densities of 143, 200 and 400 fish per800-l tank. Fish were stocked at 1.7 g and fed 5Xof body weight per day over six feedings. After 2months of culture, 12-g fingerlings were harvested.Continued studies in 1970 showed that fry could begrown to 15 � to 25-cm fingerlings in 5 months on adiet of Purina Trout Chow, with a feed conversion of3.7-4..5:1 Swingle 1972!. Survival of fingerlingsafter attaining IO g was 83.5X. Investigatorsconcluded that floating cage systems were bestsuited for production of advanced fingerlings from10 g fingerlings. Problems encountered with thismethod of culture were fouling of the cage withh dy rozoans and mechanical rupture of the cage inrough weather.

Subsequent studies conducted in 1971 and 1972were designed to determine the appropriate diet andstocking density for fingerlings reared in cages.In experiments on diet and feeding regime, eight1.3� � cm mesh cages were stocked at a density of 30fry per 800 I, The cages were suspended in brackishwater at 19 ppt salinity, and fish were fed PurinaTrout Chow or a ground fish plus soybean meal dietat 10X body weight per day during two to fourfeedings. After 3 months of culture the group fedthe trout diet was superior . Fingerlings attainedan average weight of 126.1 g, giving a growth rateof 0.98 g/day, survival of 97.4X and a feedconversion of 2.1:1.

A similar experiment conducted in 1972 evaluatedthree stocking densities of 100, 200, and 300 fryper 800 1, Six 1.3-cm mesh cages were stocked with136-g fingerlings, two at each of the three


densities, and fish were fed Purina Trout Chow at. 3Xht er da . After 60 days of culture at

the highest stocking density, the harvest ensi ywas 69.6 kg/800 1 �.09kg/1!, survival was 99X, and

lin s attained anfeed conversion was 2.4:1. Finger ingsaverage size of 226.8 g.

ure ofThese studies demonstrated that cage culture ostriped bass fingerlings in brackish water wasfeasible. The researchers concluded that the majorlimiting factor for culture of striped bass inmarine enviroenvironments was bacterial diseases,primarily caused by pseudomonads.

A para e s11 1 study on the culture of fingerlings ini ed with2.9-m3 circular fiberglass tanks, equippe wi

venturi drains and micro-pore diffusers forsimilarly good results. The tanks

thewere supplied with water at a rate of 76 lpm and t efry were fed Purina Trout Chow. One tank wasstocke witd 'th 102 9.6-g fingerlings that attained an

da s with 94,-1Xaverage weight of 79.9 g in 93 days, witsurv'vival and a food conversion of 2.f 2.0:1, Their

growth rate of 0.87 g/day was comparable to that offish in the most productive cage. The circularraceway design was equally productive as thefl ting cage. Labor required for fee ing anoa ing cag

nlmaintenance o isf f'sh in t.he circular raceway was o y

25X of that required to maintain fish in thefloating cage.

Fish Farming Experimental StationBureau of Sport Fisheries and Wildlife

Stuttgart, Arkansas Allen 1974!

The success with intensive tank culture methodsd dditional work on the refinement of

ththese systems. At the Stutt.gart Laboratory botcircular tanks and raceways were tested. Sixcircular tanks were constructed of fiberglass withvolumes o f 1.6 m3. In addition, three rectangularaluminum raceways with volumes f 4.25 3of 4.25 m3 were

tested. Each tank was supplied with water of22-24'C at a rate of 30 1pm. Fry were fed floatingtrout feed with a 40X protein content, five timesper day. At the completion of the study 1,136

fingerlings were produced with an average weight of55.5 g, compared to 11.6 g for fry reared in ponds.

In a parallel experiment, 118 fry with an averageweight of 11.7 g were stocked in raceways receivingwater of 29'C at a rate of 60 lpm, They were fedtrout feed and floating catfish feed having a 30Xprotein content. At the end of the summer growingseason this system produced 86 advanced fingerlings�.7X survival! with an average weight of 178 g anda feed conversion ratio of 2.2:1. The projectedgrowth rate of yearlings suggest that they wouldhave exceeded 500 g by the end of the second summer.

Central Valley's HatcheryCalifornia Department of Fish and Game

Elk Grove, California Cochran pers. comm.!

The production of striped bass fingerlings wasinitiated at one of California's warmwater fishhatcheries in 1972. This facility was originallyconstructed in 1938 for the culture of smallmouthbass Therefore, it was equipped with fingerlingproduction ponds to which troughs and concreteraceways were added in 1973. After 4-8 weeks ofpond culture, the resulting 23-mm �.2 g!fingerlings were stocked at a density of 6,000 per300-1 t.rough. The troughs were supplied with wellwater passed through a reservoir pond where it wasaerated and heated to about 24'C. The fingerlingswere fed moist and dry salmon diets and gradedfrequently to reduce cannibalism. Fingerlings weregrown in the troughs for 10-14 days to an averagesize of 0.8 g after which the density is reduced to3,000 fingerlings per trough. Fingerlings weretransferred in July from the rearing troughs to12.9-m3 outdoor concrete raceways and stocked at adensity of 6 kg/m3 for final grow-out to yearlings.The raceways were supplied with well water at 20'Cwhich was aerated by an aspirator. The fingerlingswere fed commercial salmon feed at 3X body weightover three feedings per day. Yearlings wereharvested in April at an average weight of 252 g perfish. Advanced fingerling mortalities in thissystem were usually minimal. The approximately

Intensive Culture 109Intensive Culture108

150,000 yearlings produced each year were used forstocking several freshwater reservoirs in Californiaand coastal areas of Southern California. Plans toincrease the enhancement efforts in San FranciscoBay and the Sacramento-San Joaquin Delta willrequire that annual production at this hatchery bedoubled over the next 3 years.

Southeastern Fish Cultural LaboratoryU.S. Fish and Wildlife Service

Narion, Alabama Parker 1979a, 1979b, pers. comm.!

Considerable research has been conducted at theUSFW Laboratory at Narion, Alabama, on high densitypond culture of channel catfish in ponds equippedwith air-lift pumps. Small ponds of 0.02 to 0.01 hawere found to be easily managed and could supportstanding crop of approximately 10,000 kg/ha ofchannel catfish. Preliminary studies suggest -thatthe maximum standing crop for striped bass may besignificantly increased in ponds with airlift pumps.Current studies in cooperation with the Edenton andNatchitoches Hatcheries indicate that both thestanding crop �2-77 kg/ha! and the survival rate�5-66X! of hybrid fingerlings reared in aeratedponds will more than double levels achieved. byconventional pond culture methods �6-49 kg/ha and10-46X survival! .

Another area of research at this facilityconcerns the use of high-density silo culturetechniques for production. of fingerlings or foodfish and for holding domestic broodstock. Twosubsurface semi-closed silos were installed in awater reuse system in 1978. The silos were 3 m dia.by 6 m deep with concave bottoms and a capacity of42.0 m3. Aeration and current patterns weremaintained by internal airlift pumps. Therecirculation rate was 2,100 lpm, which resulted ina turnover of the water every 20 minutes, or threetimes per hour. The waste water was removed fromthe silo through a 15 cm diameter drain in thebottom, which was connected to an external airliftriser. Nake � up water was added at the top of the..T.

silo at. a rate of 3 1 m whi107 h. exc ange per day. Waste w

pm, w ich was approximately a

volumes per day �50 lpm!. Thetrian ula

ese units weregu ar shaped boxes havin 62 m

on a series of corrg m2 of surface area

'es o corrugated fiberglass platespositioned at a 45 or 60 de ree an le

acilitates removal of particles with arate greater than 3 cm/minan cm min. The average settling

o particulate waste from stri/

removed about 90X of hcm min, and the late sp separators

o the settleable solids.F p ' y clarifiers the water entered aFrom the rimar c

our stage rotating biological contact 'R C

returned t hpm. e remainder ofof the water was

1 400 2o t e culture silos.os. The RBC contained

m of surface area on 2 m irotated at 2 r m.

m diameter discs thata rpm. The hydraulic load for

to 733 litersiters/m2 but has been increased

iters/m2 of filter substrate.t sedth h

particles with seroug a secondar ciay arifier to remove

wi settling rates greater than 0.8cm/min and was then returned to the silos.

Striped bass, stri ed bca is ave been grown in this system. Dissolved

excoxygen became limiting when the 1 d

ceded 1360 kg of channel catfish. In 'e oa per silo

1 'd o 'lib n wi e required for fish densigreater than 32 k /m3 �lb/ft3

Subsurface silos have the benef'thermal

e ene its of providin1 stabilization and low head differences

between the culture tank and the filtrationcomponents. Unfartunatel , they, latter feature also

s i i icult to drain and harvest fish fthe silos. Harvestin h

is romves ing as been accomplished with a

i t screen from the bottom band a 3 � m di

o om, y chemical treatmenta � m iameter by 3 � m dee netp

e easi y and considerable cannibalism haseen observed with fingerling fish.

0 ' ' ' y em has been covered withOne silo in this s stome and used to vover-winter ~Tile ie ~s. The silos

a

Intensive Culture

have been equipped with automatic feeders and anelectrical grid system has been used to replace themechanical screen at the bottom of the tank.

Gallatin Steam PlantTennessee Valley Authority

Gallatin, Tennessee Collins et al. 1982; Schweinforth pers. comm.!Studies by TVA at the Gallatin facility have

focused on the use of thermal effluent forhigh-density culture of channel catfish in concreteraceways. In 1981 a preliminary experiment wasconducted on the potential for hybrid striped bassculture in this system. A 4.4-m3 section of one ofthe 17.4-m3 raceways was stocked with 385 hybridsaveraging 3.1 g and 5 cm in length. Thermaleffluent was supplied at a rate of 387 lpm whichresulted in a turnover every 16 minutes. The wateraveraged 26.7'C and was aerated by the injection ofliquid oxygen. The fingerlings were fed a 36Xprotein floating catfish feed and a 45X proteinsinking trout feed over four daily feedings. After117 days, 336 advanced fingerlings were harvestedwith an average weight of 127 g, length of 20.8 cm,growth rate of 0.95 g/day, survival of 87.3X, foodconversion of 1.94:1, and harvest densiry of 9kg/m3.

Results from this study indicated that hybridstriped bass preferred the 45X protein sinkingpellet. when compared to the 30X protein floatingpellet. Some problems due to crowding and F.columnaris were observed. This study showed thatthe growth rate of hybrid striped bass cultured inthermal effluent was accelerated., yet, feedconversion remained favorable.

INTENSIVE CUI.TURE OF FOOD FISH

Marine Protein CorporationHomestead, Florida

Stevens 1979 pers. comm.!Extensive culture of striped bass to a marketable

size of 0.5-1.0 kg in intensive systems was first

Intensive CultureLII

attempted in 1973 in a cf .l.aci ity built b M

a commercial pilot productiony arine Protein Corporation. Fry

were cultured in 208-1 drums and 1.2-1..9-m3horizontal raceways. Over 300 000 f'

d d f hsize fish

e rom t ese s stems.y . Fingerlings and marketsize is were grown in six silos of var in h

a justed to provide 5.7 Ipm for each k of f' hg o is iny . The silos were stocked with 244,000fingerlings of 5 � 17.8 cm. Of the remainin

kg were grown to advsings, ,000 were sold for stockin d 4 536'ng an

cm! under contraco advanced fingerlings size �5 4 � 28act with Texas Instruments, Inc. formark-recapture studies in the H

the fingerlings stocked in the six silos,� m food fish were produced.

cann'bal' , dro ems encountered included mort 1'ta i ies caused by

pesticide contamination fi ism, isease ande water su 1pp y. These systems were both lab d0

capital intensive, and re u' a or an've, an required considerable amounts

s stemso energy. After 3 years of investig t' hga ion t ese

the imy s proved to be uneconomic 1, Ha , owever, withe improved technology available tod

favorable m k a e to ay and moree market conditions, this method of culture

may now be feasible.

New York Ocean Science I boratoryMontauk I ng Island New York

Valenti 1976!At the NYOSL in 1974, floating ca e cult

ges were cubical, having a volumevin 1-co . m3. They were constructed of 16

y � oated galvanized wire with 2.5 gauge

mesh. The initial stud a . x 1.3 cm

stockin densitiu y was conducted to evaluat

k g ' es. The fingerlings were fed e

Fin erl'Central Soya Trout. feed at 8X b y.a ody weight per day.

-unt 'ingerlings stocked in June had 94Xa survival rate-un il February, when unseasonsonally cold temperaturesi e 5 of the fish. Survivin fing ingerlings were

-1 indoor pools at 16 C.

28-50/m3 grew to 383-420 g, with feed conversions fconversions of

Intensive CultureIntensive Culture112

1,4-1.8:1. The rate of growth was shown to be afunct.ion o s oc ' . ef t cking density. At harvest the

was 19 k /m3. Investigators conclude dstanding crop was g mthat . � . g0.25-0.5 k marketable size fish c.ould be grownin one year.

re uire lessFloating cages were demonstrated to r qspace an powerd r than did intensive systems

previous y tes e1 t d. However, new problems wereintroduced related to the high maintenance o cagh t frequently became fouled with marine organisms,

and also the difficulty of harvesting with'th a hoist

from a floating platform.

Center for Harine StudiesSan Diego State University

San Diego, California Van 01st and Carlberg 1978; Van 01st et al. 1979!

In 1970 Sea Grant began to support research atSDSU on the growth rate of crustaceans annd finfish

cultured at elevated temperatures in the thermale uen sffl t from coastal power plants. Preliminarywor onk striped bass culture was conducte inat the Encina Power Plant. of San Diego as

the SouthernElectric Company, under funding from eCalifornia Edison Company. These studies wereperformed in conjunction with a program of t eCalifornia Department of Fish and Game to releaseyear ing s rip1' triped bass in coastal estuaries in hopesof developing an anadromous population of stripersin Southern California. Advanced fingerlings ofabout 30 g were cu ltured in ambient temperature andthermal effluent seawater. Results showed thatstriped bass could be acclimated to full strengthseawater and grown at. elevated temperatures.

1977 at the SDSUA second study was conducted inA uaculture Laboratory located at the ScrippsI t'tution of Oceanography. Advance i g

quacu urd fin erlingsns i

eked at awith an average weight of 91.5 g were stoc erate of 4.2 kg/1 into three 1.1-m3 circularfiberglass tan s. m ik A b'ent temperature seawater witha mean of 16'C and a range of 12-21'C was suppliedto each tank at a rate of 12 lpm. In one year thefingerlings were grown to a weight o g

length of 35 cm. Survival was 100X, with an averagegrowth rate of 1.7 g/day, a harvest density of 27.5kg/1, and a feed conversion of about 2:1. Therelatively low standing crop at harvest resultedfrom the relatively low initial stocking density.

Based on the favorable results of these twopreliminary studies, an experiment was conducted in1978 to evaluate growth and survival at differenttemperatures and feeding levels . Ad.vancedfingerlings with an average weight of 38.2 g werestocked in ten 760-1 rectangular fiberglass racewaysat densities of 2.5 g/1. The raceways were equippedwith a center divider and air-lifts along thedivider and around the perimeter to provide aerationand a circular current. Four raceways were suppliedwith mixed thermal effluent and ambient temperatureseawater at 24 C, four at 22 C and two at ambient18*C. Fingerlings in two of the four raceways at22 C were fed 1.5X body weight per day, all othersreceived 3X body weight per day of Purina floatingTrout Chow. After 4 months the highest specificgrowth rate �.6X per day! and feed conversion ratio�.2:1! were recorded for fish cultured at thehighest temperature, 24 C. For fish reared at 18 Cgrowth rates was 0.98X per day and feed conversionwas 2.6:1 whereas fish reared 22'C grew at 1.3X perday and had a feed conversion of 2.4:1. The effectof lower feeding levels �.5X per day! resulted in aslower growth rate, 1.0X per day.

A related study conducted in 1979 involved theevaluation of floating cages in Southern Californiabays for the culture of advanced fingerlings priorto release for enhancement of the marinerecreational fishery. Wood frame walkways supportedby styrofoam floats were used to suspend 20-m3 meshknotless nylon cages. Approximately 1,000 70-gfingerlings were stocked into cages in San Diego andMission Bays. Previous studies demonstrated that70-g fingerlings could be grown to 1.0 kg in lessthan a year. The need to vaccinate fingerlingsprior to culture in full-strength seawater wasdemonstrated by the considerable mortalitiesattributed to Vibrio infection.

115Intensive Culture

Intensr.ve Culture114

Mercer Generating Statr.onPublic Service Electric annd Gas Company

Trenton, New Jersey Guerra and Godfriaux 1978;

Ebl d Godfriaux pers. comm.!e anaterr stud. on the use of a freshwa e

78 b researchers at Trenton State o ege u19 yrPSE&G Company. Three rearingcontract from the

attempts were in at.rials were at emptern ted. The first ad a 246 � m3 pond. The

with 4 000 advanced fingerlings'ned earthen raceway an a

raceway was stocked with , a vain len th, at a density oK ' d h h 1

p d turn over everacewa was supplie wi

rate that produce one u6 0nd was stocked with

'n s in both systems vereof the same size. Fingerlings in o

species thaeason to augmeng t their culture ofthe warm summer s

w trout during the cool season. ue oi � wn of both condenser units osimultaneous shut-down o o c

dro ed toower lant, culture temperatures roppees of the Delaware River. Thisbi �t p ares o t.

ift resulted in an in essudden thermal shif e ' snd less than o

stri ed bass survive

anks with rounded corners.fiberglass tan sw s 25.6'C and the ow rah fl rate was 20 lpm.temperature was 25.6

of IOX body weightrout ellets were fed at a rate oe , ' bl mortality was caused byer day. Considera e mo

bpe

ozoan diseases, as well as yal and prot inni alism. The investigators conc u e

re at this location wasstra.ped bass culture at t ~sile due to the susceptiblity o s runfeasibi e ue

d in the Delaware River.to pathogens commonly foun in

Multi � Aquaculture SystemsAmagansett, New York Va].enti pers. comm !

the rior study at the Ocean ScienceLaboratory stimulated the interest o ev

commercial striped bass cage culture operation onLong Island. In the late 1970s MAS constructedtwenty-two 45 4-m3 vinyl-lined circular pools. Aseawater well supplies water at 10'C and 26 pptsalinity at a rate of 117 lpm to each pool. Inaddition, several floating 41-m3 cages wereconstructed. The cages were stocked with 60 day oldfingerlings at a density of 100,000 per cage and fedground trash fish three times per day. Bay waterhad a salinity of about 28 ppt and a temperature of20'C in the summer . Fingerlings grew from 0.5 g toabout 75 grams from late April to November. Eachcage produced approximately 907 kg of advancedfingerlings with an 80'. survival. The fingerlingswere then stocked for overwintering in the pools ata density of 5,000 fish per pool. Little growthoccured at the low winter temperatures. Thefollowing spring the fingerlings were restocked intothe cages. In December, 907 kg of 220- to 340-gfood fish were harvested from each cage and these18- to 20-month-old striped bass were marketed at aprice of $4.00 per pound.

The problems encountered with this productionmethod have included fouling of the nets in thesummer nets had to be brushed every few days!tearing of the nets by predators, and slow growthof the fish due to low winter temperatures.

DOMSEA Farms Inc.Marine Resources Research Institute

Charleston, South Carolina Williams 1981; Williams, Lindberg,

and Sandifer pers. comm.!Similar cage culture experiments were conducted

in 1978 and 1979 at the Stono River Marina in SouthCarolina. Two 13.6-m3 cages were constructed fromwood frames supported by styrofoam floats from ~hicheither 0.6 or 1.9 cm mesh knotless nylon nets weresuspended. Temperature in the bay averaged 28'C butvaried between 7 � 31 C, and salinity had a mean of 22ppt with a range of 11 � 28 ppt. Fingerlings were fedcommercial salmon feed and ground trash fish at 5Xbody weight once per day.


The initia stu y1 stud resulted in over 78X mortalityure due to thein the first 40 days of culture, due to t e

t of the fingerlings to successfully ma eh f' h to elleted feedthe transit ion from fresh is o p

red with Vibrio diseaseProblems also were encountere wiand cannibalism. y r'H brids appeared ta be less

d attemptaffected than striped ba . h ass. In the secon a

hybrids were vaccinated fof r Vibrio and e acombined diet of fish and pellets. Two cages were

1 070 40-day-old fingerlings weighingX h h f h1.7 g each. Survival was 74.6 w en e

380 d s old and they averaged 5 g.23 . The growtaycro of 12rate was . g1 37 /day, with a st.anding crop

k / 3 and a feed conversion og mducted in 1979 in w ich' hA third experiment was conducte

eked with 900 3 g fingerlings atthree cages were stocked wifish/m3. Survival was 88 w en eX h the

fish were 380 days old and they averag gs 0.81 /day, a standing crop a

f 211 T '1ok /m3 and a feed conversion of . : . efeed conversion was attributegrowth rate and lower ee con ' e

to limited food at the lower feeding leve o1-2X/day in this experiment.

Problems encountered were g,a ain related to4b' f ling requiring the net toto be changed everyio ou i

b blue crabs.wee s, ak nd damage to nets caused y� ize stri ed bassThis study showed that a pan � size 'p

d be roduced from April to December, andf cold winter watermarketed prior to the onset of co

temperatures.

Aurora Field StationNorth Carolina State University

Aurora, North Carolina Woods 1981; Kerby 1982 pers. comm.!

In 1980 preliminary studies werewere conducted to

valuate high-density pond cu lture. Fingerlingss a own to 351 g in 13 months,stacked at. 20 g were grown to g

of 4 88693X and a standing crop owith a sur ival of

kg/ha. ro/ . P blems encountered were cause y an istress and bird predation.

fStudies in 1981 evaluated poo ls and cages or useFour 1.6 � m3 circular tanksin striped bass cult.ure. Four

were constructed from 122-cm corrugated galvanizedmetal used for grain silas, and were fitted withvinyl pool liners, The pools were equipped with acentral stand pipe drain and airlifts forcirculation. Well water was supplied at a rate of60 1pm. Fingerlings were fed 40X protein troutfeed. The pools were stocked with 53-g hybrids atdensities of 0.9, 3.2, and 4.5 kg/m3. At harvestfish in the high density tanks averaged 275 g with astanding crop of 3.9 kg/m3, and 74X survival.

A parallel study conducted in nine cages stackedat 100, 150, or 200 fish/m3 gave similar results.Upon harvest the high stocking density cagesproduced 310 g fish at a standing crop of 59.7kg/m3, and 74X survival.

Problems encountered in this study were F.columnaris disease, cannibalism, low dissolvedoxygen levels, high maintenance requirements, andlack of contral over temperature flucuations.Nevertheless, this study did demonstrate that amarketable size hybrid striped bass could beproduced in 15-18 months when cultured at highdensity.

Aq"atic Systems IncorporateSan Diego California

Van 01st et al. 1980, 1981; Carlberg et al. 1981!The principals of ASI, while at SDSU, directed

the research previously described on the use ofthermal effluent in the intensive culture of stripedbass Van 01st and Carlberg 1978, 1979! . Based anthe success of these studies they began a program in1980 to develop a commercial striped bass cultureoperation.

Although the results from the earlier grow-outexperiments vere encouraging, these studies dependedupon obtaining fingerlings from the state hatchery.Since there vas na commercial source of fingerlings,the first step was to begin development of anindependent supply of larvae and fingerlings. Basedon previous success with the culture of crustaceanand finfish larvae under controlled environmentalconditions, efforts were focused on the modification

Intensive Cult:ure118 Intensive Culture 119

of these systems for rearing striped bass. Thedevelopment of intensive fingerling culturetechniques was a cooperative effort between ASI, theUniversity of California at Davis, and theDepartment of Fish and Game.

The first study involved the use of fiberglasscylindrical tanks with conical bottoms and volumesof 375 l. The units were designed as rec.irculatedclosed systems to facilitat.e environmental control.Water temperat.ure was maintained at 16-19 C,salinity at 10-12 ppt, and ammonia levels controlledby filtration and water exchange. The tanks had acommon central standpi.pe drain and water circulationapparatus that provided an upflow current. A draincollar covered with Nytex screen retained the larvaeand their food supply while an aeration ringproduced a bubble curtain that kept the screen fromclogging. Larvae were fed nauplii and moist salmondiet. Initial results were successful, withsurvival exceeding 90X from hatch to 10 � day-old fry.Observed mortalities were caused by cannibalism andstarvat.ion resulting from under feeding. Upflawcirculation allowed for control over thedistribution of larvae and nauplii, and facilitatedcleaning and maint.enance. This culture unit. wasdemonstrated to be useful for hatching eggs, rearinglarvae to initial feeding, and for the weaning offry to artificial diets with a minimum of labor .

Refinement of the design and operation of thetank was continued in 1981. New tanks werefabricated that had an improved shape, color, andsize, but incorporated the water upflow and screendesign of the earlier prototype. These tanks, whichare still in use by ASI, are an ogive shape with aparabolic bottom. They also have a white bottom taassist observation from above by the culturist. Theogive unit has a volume of 100 1 and can hold100,000 eggs for hatching and development prior tofeeding. Fry were fed hatched, de-capsulated, brineshrimp nauplii to reduce the time consuming effortrequired for separating cyst shells from hatchednauplii, and to eliminat.e problems associated withingestion of unhatched cysts. Nauplii were movedto the ogive tank from a holding reservoir by a

metering pump at 15 minute intervals 24 hours a day.Later stages of fry were continuously fed moistsalmon diets by use of automatic feeders. Work in1981 showed that a flow rat.e of 7.6 1pm providedsufficient flushing, that acclimation to a salinityof 10 ppt, 12 hours after hatch, significantlyreduced mortality, and that gentle aeration, dimlight, and delayed feeding may contribute toincreased survival and normal inflation of theswinbladder.

A prototype modular spawning system wasf habricated and used in field spawning operations inCalifornia, Oregon, and Louisiana. From thisprogram, three separate strains of striped bass havebeen maintained and grown to 2-8 kg for use asdomestic broodstock. Related studies anout-of-season spawning are in progress with theseand other captive adults.

The evaluation of using thermal effluent seawaterfor striped bass culture was continued in 1981. Acooperative study with SDSU and San Diego Gas 5Electric was designed to refine methods for use inf uture commercial mariculture operations. The workwas conducted at the Encina Power Plant of SDGRE.Experiments were conducted on the effects oftemperature, salinity, stocking density, feeding1 evel, and vaccination on the growth and survival ofstriped bass. Approximately 6,000 advancedfingerlings weighing an average of 40 g were used inthese studies.

Results from these experiments showed thatspecific growth rates of 4.58X/day were achievableat temperatures of 24 � 28 C and reduced to 2.98K/dayat 20'C. Salanities of 0, 20, and 33 ppt had nosignificant effect on growth or survival. Neithertemperature nor salinity significantly affected feedconversion.

In the Vibrio immunization experiment, 20-gfingerlings exhibited antibody agglutinationreactions within 3 weeks of vaccination. urger30 � g fingerlings showed an immune response by theeighth week.

The study on stacking density compared four


levels: 8, 16, 24, and 32 kg/m3. Results showedthat growth and feed conversion were reduced at thehighest density tested. However, yield was alsogreatest at the highest stocking density.

Studies at ASI's laboratory in San Diego and at.its pond culture facility in Central California havebeen conducted under commercial operationconditions. Research on intensive culture systemswas conducted in a series of 946-1 circularfiberglass tanks, operated as semi � closed systemswith a recirculation rate of 19 lpm, and a turn � overrate of about half the tank volume daily. Amajority of the tanks were 2.7-4.2 m3 in volume andoperated as closed systems. The systems wereequipped with inclined plate separators, high ratesand filters, and bio-trickle filters. With thesefiltration components, culture densities of 40 kg/m3were routinely maintained. Most fingerlings andlarger fish were fed commercial trout feeds, Astudy that compared floating to sinking pelletsshowed no significant differences on growth betweengroups. Other experimental feeds are currentlybeing tested on several life stages. Some resultshave shown that although maximum growth was near26'C, optimum temperature for both growth and feedconversion was closer to 24'C. Preliminary workwith striped bass x white bass hybrids has shownthat under optimum conditions hybrid fingerlingsgrew at a rate of 5.3X/day, which was nearly twicethat of striped bass. Hybrids maintained feedconversion efficiencies �.3:1! equal to or betterthat found for striped bass. Hybrids also had anincreased resistance to stress induced diseases.Generally it has been found that a one-poundmarketable hybrid can be grown in 9-12 months,compared to 12-15 months for striped bass.

Mortality for striped bass and hybrid fingerlingslarger than 2.5 cm is generally less than 2X peryear, except during periods involving handling ormechanical failures. Cannibalism is a problem withfry, but not with fingerlings if they are well fed.Most significant disease � related mortalities havebeen the result of infections by Aeromonas,

Pseudomonas and F. columnaris bacteria. Fungusinfestations and bacterial attacks of Vibrio haveb een controlled with KMn04 and vaccinations,respectively.

F uture plans of ASI involve the development ofintensive commercial production facilities at siteswhere thermal effluent or geothermal warmwater isavailable. These systems will consist of a seriesof large circular tanks, equipped with oxygeninjection and sophisticated filtration for removalof suspended solids and arrrmonia,

CONCLUSIONS

Intensive culture of striped bass on a commercialscale requires considerable capital for constructionand operation at an economical level. Majorconstraints to implementation of the developedtechnology are the lack of suitable sites anddifficulty in obtaining financing.

The future development of intensive culturesystems for striped bass will depend upon solvingthree major limiting factors. First, additionalresearch is needed on the development of domesticbroodstock to facilitate a year � round supply offingerlings of a strain that is well adjusted toculture conditions, Second, increased production offingerlings by intensive methods will requireimproved diet formulation, and better control ofcannibalism and swimbladder inflation. Third,techniques and procedures must be developed toreduce handling stress and to control infectiousdiseases,

The biological and technological feasibility ofintensive striped bass culture has been proven.What is now needed is to derrronstrate that theoperation of a commercial � scale facility will beeconomically viable. There is good evidence that astriped bass culture industry will soon bedeveloped.


REFERENCES

Anon. 1974-1978. Feasibility of Culturing andStocking Hudson River Striped Bass. Ann. Reportsfor 1973 � 1977. Texas Instruments Inc . ScienceServices Division, Dallas, Texas.

Anon. 1977. Feasibility of Culturing and StockingHudson River Striped Bass. An Overview, 1973 � 1975.Texas Instruments Inc. Science Services Division,

Dallas, Texas. 8lp.

Allen, K.O. 1974. Notes on the Culture of StripedBass in Tanks and Small Raceways. Frog.Fish Cult.36�!:60-61.

Anderson, J.C. 1966. Production of Striped BassFingerlings, Prog. Fish Cult. 28�!:162-164.

Bailey, W.M. 1974. An Evaluation of Striped BassIntroductions in the Southern United States. Proc,Ann. Conf. S.E. Assoc. Fish and game Comm. 28:54-68.

Bayless, J.D. 1972. Artificial Propagation andHybridization of Striped Bass, Morone saxatilis Walbaum!. South Carolina Wildlife and MarineResources Department. 135p.

Bonn, E.W. ed.!. 1976. Guidelines for StripedBass Culture. Striped Bass Culture. Striped BassCommittee, So. Div., Amer, Fish Soc. 103p.

Braid, M.R. and E.W. Shell. 1981. Incidence ofCannibalism among Striped Bass Fry in an IntensiveCulture System, Frog. Fish Cult, 43�!:210-212.

Braschler,Techniques Walbaum!.Game Comm.

E.W. 1974. Development of Pond Culturefor Striped Bass Morone saxatilisProc, Ann. Conf. S.E, Assoc. Fish and

28:44 � 48.

Carlberg, J.M., J.C, Van 01st, M.J. Massingill, T.A.Hovanec, M.D. Cochran, and S.I . Doroshev. 1981.Intensive Culture of Striped Bass Larvae at CentralValleys Hatchery. Progress Report to the CaliforniaDepartment of Fish and Game. 15p

Collins, C.M., C.Le Burtom, and R.L. Schweinforth.1981. Raceway Culture of Striped Bass x White BassFingerlings Utilizing Power Plant Waste Heat.Fourth ann. Proc. Catfish Farmers of America,pp .39 � 40.

Colura, R.Lss B.T. Hysmith and R.F. Stevens . 1976.Fingerling Production of Striped Bass, Moronesaxatiiis, Spotted Seatrout, ~C oacion nebulosus,and Red Drum, ~Sciaeno s oceilatus in SaltwaterPonds. Proc. World Mariculture Society 7r79-92.

Guerra, C.R. and B.L. Godfriaux. 1978. Power PlantWaste Heat Utilization in Aquaculture. SecondAnnual Report. Public Service Electric and GasCompany. pp.23-24 and 76 � 90.

Inslee, T.D. 1977. Holding Striped Bass Larvae inCages Until Swim-up. Proc. Ann. Conf. S.E. Assoc.Fish and Wildlife Agencies 31:422-424.

Kelley, J.R. Jr. 1967. Preliminary Report onMethods for Rearing Striped Bass, Roccus saxatilis Walbaum!, Fingerlings. Proc . Ann. Conf . S .E.Assoc. Game and Fish Comm. 20:341-356.

Kerby, J .H. and E.B. Joseph. 1978. Growth andSurvival of Striped Bass and Striped Bass x WhitePerch Hybrids. Poc. Ann . Conf. S.E. Assoc . Fish andWildlife Agencies 32 715-726.

Kerby, J .Hw s L.C . Woods, III, and M.T. Huish. 1982.A Review of Methods, Advances and ProblemsAssociated with Culture of the Striped Bass and ItsHybrids. 64p. in prep!.


Krantz, G.E. 1982. Current Mid-Atlantic. FishCulture Operations. Striped Bass Culture at theUniversity of Haryland. Proc. 4th Ann. MarylandAquaculture Conf. unpublished!.

Lewis, W.M. and R.C. Heidinger. 1976. Striped BassRearing Experiments 1976. Southern IllinoisUniversity. 197p.

Lewis, W.M. and R.C. Heidinger. 1981. Tank Cultureof Striped Bass Production Manual. Illinois StripedBass Project. I.D.C. F-26-R. Southern IllinoisUniversity. 115p.

McIlwain, T.D. 1976. Closed Circulating System forStriped Bass Production. Proc. World MaricultureSociety 7: 523-534.

McIlwain, T.D. 1978. Rearing and. Stocking StripedBass � Mississippi Gulf Coast. Ann. Frog. Report onProject AFCS-6-18/2. Gulf Coast ResearchLaboratory. 102p.

McIlwain, T.D. 1980. Striped Bass RestorationProgram � Mississippi Gulf Coast . Ann, Prog. Reporton Project AFCS � 7 � 1. Gulf Coast ResearchLaboratory. 88p.

Nicholson, L.C. 1973. Culture of Striped Bass Morone saxatilis! in Raceways under ControlledConditions. Proc . Ann. Conf. S.W. Assoc. of StateGame and Fish Comm. 1973.

Parker, N.C. 1979a. Striped Bass Culture inContinuously Aerated Ponds. Proc. Ann. Conf. S.E.Assoc. Fish and Wildlife Agencies 33:353-360.

Parker, N.C. 1979b. An Air-operated Fish CultureSystem with Water-Reuse and Subsurface Silos.Bio. � Eng. Sym. Fish. Cult. 13p.

Powell, M.R. 1971. Striped Bass, Horone saxatilis,

Production to Establish Commercial Stocks in AlabamaEstuaries. Ann. Prog. Report on Project AFC � 3 � 2.Alabama Department of Conservation & NaturalResources. 26p .

Powell, M.R. 1973. Cage and Raceway Culture ofStriped Bass in Brackish Water in Alabama. Proc.Ann. Conf. S.E. Assoc. Game and Fish Comm.26:3I45-356.

Rhodes, W. and J.V. Merriner. 1973. A PreliminaryReport on Closed System Rearing of Striped Bass SacFry to Finger ling Size. Prog. Fish Cult.35�!:199-201.

Rogers, B.A. 1974. Growin.g Striped Bass inCaptivity. Haritimes 18�!:1-3.

Shell, E.W. 1972. Effects of Increased WaterHardness, Source of Fry, and Age at Stocking onSurvival and Growth of Striped Bass Fry in Ponds.Ann. Frog. Report for Project AFC-4, Segment 2.Auburn University. 31p.

Snow, J.R. 1977. Feasibility of Increasing theYield of Striped Bass Fingerlings Through Use ofIntensive Culture Methods. Ann. Prog. Report forProject AFC-9-1, Segment 1. Auburn University.27p.

Snow, J.R. 1979. Feasibility of Increasing TheYield of Striped Bass Fingerlings Through Use ofIntensive Culture Methods. Ann. Prog. Report forProject AFC-9-2, Segment 2. Auburn University.46p.

Stevens, R.F. 1966. Hormone-Induced Spawning ofStriped Bass for Reservoir Stocking. Frog. FishCult. 218 l!:19-28.

Stevens, R.F. 1979. Striped Bass Culture in theUnited States. The Comm. Fish Farmer & AquacultureNews. 5�!:10-14.

127Intensive CultureIntensive Culture

Swingle, W.E. 1972. Alabamas Marine Cage CultureStudies. Proc. World Mariculture Society 3:75-81.

Swingle, W.E. 1970. Experiments in the Culture ofMarine Species in Floating Baskets. Ann. Prog.Report an Project 2-86-R-l. Alabama Department ofConservation. 26p.

Tatum, B.L., J.D. Bayless, E.G. McCoy, and W.B.Smith. 1965. Preliminary Experiments in theArtificial Propagation of Striped Bass, Roccussaxatilis, Proc . Ann. Conf . S.E, Assoc . Game andFish Comm. 19:374-389.

Valenti, R.J., J. Aldred, and J. Liebell. 1976 .Experimental Marine Cage Culture of Striped Bass inNorthern Waters. Proc. World Mariculture Society7:99-108.

Van 01st, J.C. and J.M. Carlberg. 1978. BeneficialUse of Thermal Effluent in Aquaculture. FinalReport for Phase III. Research Contract No. U2585907. Research and Development Department,Southern California Edison Company. pp.494-518.

Van 01st, J.C., R.M. Ford, J.M. Carlberg, and W.R.Schmitt. 1979. Re-establishment of AnadromousFishes in Southern California. Ann. Report forProject No. R/F � 42. Univ. of Calif. Sea GrantCollege Prog. 3p.

Van 01st, J.C., J.M. Carlberg, M.J. Massingill, T.A.Hovanec, M.D. Cochran, and S.I. Doroshev. 1980.Methods for Intensive Culture of Striped Bass Larvaeat Central Valleys Hatchery. Prog. Report to theCalif. Dept. of Fish and Game. 17p.

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Woods, L.C., III, J.H. Kerby, M.T, Huish, and G.M.Gafford. 1981. Circular Tank for Intensive Cultureof Hybrid Striped Bass. Prog. Fish Cult.43�!:199 � 200.

High Density Culture of White Bass xSteeped Bass Fingerlings in Race~~Using Power Plant Heated ENuentJohn G. Woiwode and Era R. Adelman

Culture of the striped bass I white bass hybrids andthe reciprocal cross, is currently generating agreat deal of interest in various state game andfish agencies, federal organizations and privateenterprises due to the success of hybridization, thehybrids value as a sport and table fish, its fastergrowth rate than the parent species for the first 18months, and its adaptability to intensive culture Stevens 1964, 1983; Bishop 1967; Logan 1967; Collins,Burton and Schweinforth l982b; Woods et al, 1983!.

The culturing of a relatively small number ofhybrids at Gallatin during 1981 and the interestshown by private industry stimulated further cultureinvestigations.

MKTHODS

The Gallatin Waste Heat Aquaculture Facility islocated on the bank of TVA's Gallatin Steam Plantdischarge canal near Gallatin, Tennessee. The powerplant uses once-through cooling with an average A T

0of approximately 12 F.

Five 3 x 8 x 1 ft wire3mesh floating cagessuspended in three 614 ft �0 x 4 x 4 ft outsidedimensions! concrete raceways were stocked onMay 19, 1982 with 21,560 hybrids weighing 1,691fish/lb. A water flow rate of approximately 100 gpm complete exchange every 45 minutes! was maintainedduring cage culture. Sub-samples from two of the 14oxygenated plastic bags were taken prior to stockingto determine the number of fish stocked. Fish verekept in cages for 20 days. A 38 percent proteinsinking trout ration was pulveri.zed and hand fed adlibitum four times daily at the beginning of the

Power Plant Culture130 Power Plant Culture 131

culture period. Feeding frequency was increased tonine times daily after it was apparent that the fishwould feed more often. Trout ration was replacedwith a 50 percent protein trout starter ration size2! because of the inconvenience of preparing the 38percent protein ration in a blender, gradual decreasein feeding activity, daily mortalities and cannibal-i srrl

Four 614 ft concrete raceways were stocked fromcages on June 7 through June 12 with 9,210 hybrids.Three raceways were stocked at 2.6 fish/ft �,535fish/raceway! and the remaining raceway at 5.1fish/ft �, 070 fish! Table 1!. Each raceway gasdivided into two separate culture units �07 ft ! bya wire mesh divider. A flow rate of 300 gpm com-plete exchange every 16 minutes! was maintained ineach of the raceways. Fish averaged 361/lb atstocking. A 40 percen.t protein sinking trout ration size 4! was hand fed ad libitum four times dailyinitially and gradually decreased to twice dailyafter the hybrids approached four inches in totallength. On July 5 a 37.5 percent protein floatingtrout ration was fed with the sinking ration. Thisfeeding system continued until September 1 when thehybrids were switched exclusively to the floatingration.

Daily minimum and maximum water temperatures wererecorded from a Heath Kit Digital Weather Computer.Dissolved oxygen levels were measured with a YellowSprings Instrument Dissolved Oxygen Meter and recordeddaily.

Total alkalinity, carbon dioxide, pH, total andun-ionized ammonia and nitrite levels were taken andrecorded weekly in raceways using a Hach PortableWater Quality Kit.

Disease identification was performed on-site wi.ththe exception of bacterial diseases. Suspectedcases were coTrfirmed by the Fish Farming ExperimentalStation, Stuttgart, Arkansas. The following methodsfor disease treatment were used in administeringchemicals to raceways: �! static with aeration;�! flush; �! oral.

Hybrids in each raceway section were sampled

periodically throughout the study. Fish were

determine growth rates and general cond't' f hi ion o t e

Fish in ca es andg raceways were harvested manuallwith dip nets and a wire me h d

ua y

d's crow er. Feeding was

iscontinued for two days prior to harvesting toallow accurate measurement of fish production.

Results and Discussion

Hybrids were harvestrvested from raceways on September 16.A total of 5,773 fish weighing 658 lb were removedfrom the four raceways.

Average length and weight, food conversion andreatment 2survival are presented in Table 2. T

high stocking density! contained 321 Ib at harvestcompared to Treatment I low stocking densit ! which

g . Average length and weight weresi y w ic

quite similar for both treatments. Treatment 2 hadmore efficient food conversion 1.70,n,, compared to2.16 in Treatment l. Survival wa h dwas en anced inTreatment 2, 84.6R, compared to 68.7/ for Treatmentl. Data also indicate that length d i han we g t growthrates were similar between treatments Fig. I!.

No difference in production on or water quality wasapparent between upper and lowerwer raceway sectionswithin each treatment. Past work at Gallatin withchannel catf'e ca ish culture at densities up to 10 lb/ftshowed a decline in production t d howar t e racewaydischarge due to progressively d te eriorating waterquality Collins et al. 1982a!. Th h'I us, t e culturesystem s carrying capacity for hybrid bass is ap-parently much greater than th t kie s oc ng degsitiestested in this study maximum of 0.5 lb/ft ! . Theimproved food conversion and h hig er survival inTreatment 2 indicat ed that fish were more ef ficientat the hi h densitg y. The above observations demon-

for much hr. hstrated that hybrid bass culture has hu ure as t e potentialor much higher densities than were realized in this

study.

Periodic sampling from June 22 to Au ust 18 wasconducted by a graduate student assigned to the

Power Plant Culture Power Plant Culture 133132

Table l. Raceway stocking of white bass K stripedbass � per raceway average.

3.0

Weight ib/1, OOOTreatment No. fish No,/ft lb Fish/1b fish

393 2.55.1 S.O2 0

Table 2. Total number and weight, average size, foodconversion and survival of white bass Xstriped bass in raceways- � by treatment.

Total Average AverageNo. Weight Weight Length Food Percent

Treatment Harvested lb! lh! in! Conversion Survival9-158-4 8-18

SA18'LE DATE6-22 6-29 7 13

1,039 112.0 0.11 6.0 2.16 6$.7

2e 655

1,570

3,140

2.6 5,0 314 3.2

321.0 0.12 6 2 l. 70 84.6

5

4'I

Figure 1. Length and weight of white bass K stripedbass by sampling.

Power Plant Culture 135Power Plant Culture134

project to evaluate growth parameters as partialrequirement for a thesis. During sampling, extremecare was exercised to keep stress at a minimum;however, more than 45 percent of the recorded mor-talities in raceways occurred within three daysfollowing sampling.

Fish were fed four times daily after stocking incages. It was apparent after several days that morefrequent feedings were required due to fish feedingintensity and observed cannibalism. A marked de-crease in mortality was noted after increasing thefeeding rate to nine times daily and changing feedfrom 35 percent protein sinking trout ration to 50percent protein trout starter ration. An automaticfeeder Falls 1980! was installed over one cage toobserve fish feeding activity with a continuouslyavailable food supply. Nearly all food offered byhand and automatic feeder was consumed with negligi-ble waste, It would probably be beneficial to thefish and culturist alike to utilize automatic 'feedersdue to increased growth rate, greater availability offood, likely decrease in cannibalism and decreasedlabor costs.

Food size was increased and feeding frequencydecreased as fish increased in size. When thehybrids reached four inches in total length, afloating pellet was offered periodically to evaluateacceptance. Larger fish immediately utilized thefloating pellet. Size 4 sinking ration continued tobe fed as a supplement, but the hybrids fed moreagressively on floating feed. After September I fishwere switched totally to a floating ration.

Hybrids fed intensely at all temperatures through-out the study. The reciprocal hybrids cultured atGallatin in 1981 responded in a like manner Collins,et al. 1982b!. Woiwode and Adelman �983! found thathybrid white K striped bass grew at temperatures from51.8 to 95 F and had an optimum growth temperature of87.8 F,

High density culture of hybrid bass provides anideal environment for opportunistic pathogens. Ex-ternal parasite infestations encountered during thestudy period included T ' h h, Costia, ~Eist lis,

Chilodonella and Trichodina. The most abundant and

successfully controlled with one of two standardchemical treatments; �! 85 ppm formalin flush for60 minutes, or �! 2.5 ppm potassium permanganateflush for 60 minutes. Prior to each treatment fishwere subjected to a 2 percent salt NaC1! staticwater bath for 30 minutes. This procedure was usedto remove the excess mucus exposing parasites to thetreatment chemical.

Two bacterial pathogens were identified: �!columnaris and �! Aeromonas ~hdro hila. Externalcolumnaris was a frequent but controllable problemusing the aforementioned potassium permanganatetreatment. Systemic infections of columnarisoccurred twice in combination with Aeromonas~hdro hila B.oth were treated with the recommendedlevel of Terramycin mixed in feed 85g activeingredient/100 lb! for 10 days with limited or nosuccess. Furacin was tested in subsequent bioassaystudies for control of columnaris and Aeromonas~h dro hila infections sing two types of treatment,Furacin was mixed with feed at a rate of 83g activeingredient/100 lb and fed for seven days. Reductionin palatability eliminated this method as an ef-fective treatment. Furacin was also tested as a 20ppm static water bath for 60 minutes. Neithercolumnaris nor Aeromonas ~h dro hila were eliminatedbut effective control was established with twotreatments on successive days.

Two problems related to the cult~re environmentwere responsible for a greater part of the studyysmortali.ty than any of the mentioned pathogens: �!gas bubble disease and �! cannibalism.

Gas bubble disease GBD! can be caused by super-saturation of atmospheric gases mainly nitrogen! inheated effluent through changes in temperatureand/or atmospheric pressure during the condensercooling process D'Aoust and Clark 1980!. Obviousclinical signs of GBD popeye, fin and subcutaneousbubbles, gas emboli in gills, etc.! began to appearin the second week of cage culture. Approximately40 percent of the mortality during the cage culture

136 Power Plant CulturePower Plant Culture 137

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0 0 0IIIIo

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phase can be attributed to GBD. Aerating incomingwater Fig. 2! successfully degassed culture waterto the point that GBD was practically eliminated.

Cannibalism was evident throughout the study indaily observations and stomach analysis, but mainlyduring the first month of culture. As previouslydiscussed, feeding frequency and protein level infeed were increased, which improved growth per-formance, satisfied appetite and reduced cannibalism.After the hybrids were stocked in raceways, observa-bl instances of cannibalism dropped, especially ine 'ncreasedthe high density groups as evidenced by an increasesurvival rate. Overall, from stocking to harvest,62 percent of the total number stocked were unac-counted for. This discrepancy may be attributed tocannibalism and/or subsampling error prior tostocking. The degree of cannibalism that occurredwas impossible to quantify.

Cannibalism is an inherent risk in intensiveculture of carnivorous fish. However, it is apparentfrom the data presented that several managementpractices can reduce the incidence of cannibalism.Particularly important in the fry and small finger-ling stages is constant availability of a highquality palatable food. Automatic feeders would be

advantage during this growth phase. Periodic1grading and removal of larger individuals wou d

presreserve greater size uniformity. Comparison ofsurvival between the two stocking densities indicatedthat higher densities suppressed cannibalism ~

Water quality parameters shown in Table 3 wereevaluated weekly, with the exception of temperatureand dissolved oxygen, which were monitored daily.

Minimum and maximum water temperatures are OFpreseresented in Fig. 3 showing an average A T of 50and average daily temperature of 79 F for the pro-duction period. It was noted that hybrid bassperformed weIl at all temperatures.

Average weekly dissolved oxygen levels remainedwithin 0.5 ppm of saturation and averaged 7.5 ppm inboth treatments.

Seasonal high, low and average water qualityvalues for alkalinity, carbon dioxide, pH, total

Power Platjt Culture138 Power Plant Culture 139

1.000

CfllaJ

IEK

58

j

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Figure 2. Weekly total mortality white bass X stripedbass � May 19 to September 16.

IDl

ID

OlCvCVCV

IXI

CLVJE/J

IVICv

I ct!

IDC4~ h

4jY

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8 8

Power Plant Culture 141Power Plant Culture140

REFERENCES

CONCLUSIONS

-i d ramonia and nitr ites Table 3!ammonia, un-ionize aramoniwere we wi in11 'th' limits required for hybrid bass

t onculture. Stocking density had very little impacwater quality a ong e1 the length of the raceway ineither treatment.

White assWh b s X striped bass fingerlings can be0.5cultu ed at high densities at least

lb/ft ! without affecting performance.Production parameters were enhan 'gced at hi h

stocking densities.

2. Coramercially available trout diets sustainedacceptable growth.

1Samp zng as1 h an adverse affect on survivaand production.

4. Fish performed well at a variety of tempera-tures.

5. Diseases cas can be controlled using chemo-therapeutic agents.

6. Cannibalism can be supressed with highstocking densities. Periodic grading and theuse of autoraatic feeders should also bebenef icia1.

7. Water quality indicated that hybrids can becultured at higher stocking densities thanthose tested.

8. Economic potential is great.

This study was made possible by the Tennessee ValleyAuthority TVA! and Jaraes W. Kahrs, OsageCatfisheries, Inc.

BISHOP, R. D. 1967. Evaluation of the striped bass,Recess saaatilis, acd white bass, R. ~chr sc s,hybrids after two years. Proc. Ann. Conf. S.E.Assoc. Game and Fish Commissioners. 21.245-254.

COLLINS, C. M., G. L. BURTON and R. L, SCHWEINFORTH1982a. Intensive culture of channel catfish inraceways utilizing power plant waste heat. Proc.Ann. CFA Research Workshop. 4:37-38.

Raceway culture of striped bas Xwhite bass fingerlings utilizing power plant wasteheat. Proc. Ann. CFA Research Workshop. 4 r39-40.

D'AOUST, B. G. and M. J. R. CLARK. 1980. Analysis ofsupersaturated air in natural waters and reservoirs.Trans. Amer. Fish. Soc. 109�!:708-724a

FALI.S, W. W. 1980. Economical, automatic, dry � foodf ish feeder. Prog. Fish-Cult. 42 �!: 240.

LOGAN, H. J . 1967. Comparison of growth and survivalrates of striped bass and striped bass X white basshybrids under controlled environments. Proc. Ann.Conf. S.E. Assoc. Game and Fish Coaanissioners.21:260 � 263.

STEVENS, R. E. 1964. A final report on the use ofhorraones to ovulate striped bass, Roccus saxatilisWalbaum. Proc, Ann, Conf. S,E. Assoc. Game and FishCommissioners. 18:525-538.

1983, Historical overview of striped bassculture and managemen.t. Presented at the StripedBass and Striped Bass Hybrid Conf., Annapolis, MD,January 14, 1983. 19 pp.

WOIWODE, J. G. and I. R. ADELMAN. 1983. Growth,food conversion efficiency, and survival of the

Power Plant Culture142

hybrid white X striped bass as a function of tempera-ture. Presented at the Striped Bass and StripedBass Hybrid Conf., Annapolis, HD, January 14,1983. 10 pp.

WOODS III, L. C., J. H. KERBY and M. T. HUISH. 1983.Estuarine cage culture of hybrid striped bass.Abstracts World Hariculture Soc. Tech. Sessions,Aq. '83, Washington, D. C., January 9-13, 1983. 80.

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