Research Summary on Potential Mariculture Species for the Gulf Of

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ResearchSummary on Potential Mariculture Speciesfor the Gulf of Mexico D. A. Davis, C. R. Arnold and G. J. Holt. The University of Texas at Austin Marine Science Institute Fisheriesand Mariculture Laboratory 750 Channel View Drive Port Aransas TX 78373

Abstract The Gulf of Mexico is one of the US's most economically productive marinehabitats supporting a wide variety of industriesincluding a highly productivefishery. In 1996, Texaslandings of marinespecies were valued at 9.5 million dollars and included a diverse group of fish species ranging from highlypelagic to reef fish. Giventhe establishedfishing infrastructure, diverseselection of nativespecies and relativelywarm waters,the Gulf of Mexicoprovides an excellentopportunity for mariculturedevelopment. To supporta commercialmariculture industry, the targetspecies must be bio- logicallycompatible with the cultureconditions, have a controllablerepro- ductivecycle, and larvaldevelopment suitable for the massculture of juveniles. Additionally,suitable markets must be identifiablethat will support the price structurenecessary for a commercialoperation. Our laboratory hasbeen evaluating and developing native fish speciessuch as Florida pompano,various snappers, groupers, drums, jacks and the cobiaas maricul- turespecies. This paper is a briefoverview of researchat the Universityof Texasat Austin, MarineScience Institute, Fisheries and MaricultureLabo- ratorywith emphasison speciesof potentialcommercial interest. Examples of controlledmaturation, larval development and growth rateswill be discussed.Growth ratesand culturepotential for variousgulf speciessuch as Floridapompano, grey snapper,yellowtail snapper, ling and greateramberjack are presented.

Introduction Oceanfishing, the largestsource of fish production,is producingabout 90 million metric tons annuallyand can no longersustain the over fishing andpollution pressures man has placed on it Willinskyand Champ, 1993!. 121 At the sametime, the world'sdemand for seafoodis rapidlyincreasing and is expectedto reach110 to 120 milliontons bv the year2010. In response to this demandaquaculture has developedinto the fastestgrowing food productionsystem in theworld and is expectedto produce39 milliontons by 2010 FAO1996!. As the world'ssecond largest importing nation of fisheriesproducts, the continued expansion of U.S.seafood production will diversifyagriculture, reduce the nation'sbalance of trade,relieve fishing pressureson nativespecies, diversify the supplyof productsfor seafood processing,provide fry andfingerlings for conservationprojects, and pro- videhigh quality seafood grown under conditions that controlthe useof antibiotics,steroids and other additivesused elsewhere. The SoutheastRegion of the United States Texasto North Carolina, Puerto Rico and the U.S. Virgin Islands!supports a diversefishing and processingindustry that was valued in 1994at about1 billiondollars NOAA 1996!.Associated with the wild fisheries.are established processing and distributionchannels for a widevariety of species.With an establishedinfra- structurefor seafoodprocessing and suitable coastal and oceanic sites for maricultureoperations, this area has considerable potential for the contin- ueddevelopment of commercialmariculture operations. Althoughcommercial shrimp and fish farmingoperations have experi- encedsome difficulties, mariculture operations are slowlybecoming established.In Texas,the reddrum, Sciaenops ocel latus, and pacific white shrimp Penaeusuannamei are the primarymariculture species. Each contributing about3 millionpounds to localproduction. This production is relatively small,yet it hasallowed the expansionof infrastructural support such as feed mills and hatcheries. In addition to a small but establishedmariculture industry, Texas has an active marine enhancementprogram. This program was established,in part,due to decliningstocks of reddrum in the 1970's.The enhancement programhas specialized in the spawningand rearing of sciaenidspecies suchas red drum Sciaenopsocellatus! and spottedseatrout Cynoscion nebulosus!.Utilizing spawning technologies developed by Arnoldet al. 979, 1988!and extensive pond larval rearing techniques, this program hasbeen extremelysuccessful. It has developedinto an activemarine enhancementprogram that includesthree hatcheries capable of producing 30 million red drum and 5 million seatrout fingerlings anually. Theseexamples of maricultureand stock enhancement operations clearly demonstratethat commercialoperations and large scalehatcheries are vi- ableentities in the UnitedStates. In additionto the well establishedproduc- tion technologyfor the reddrum there are a widevariety of nativespecies 122 occupyinga variety of habitatsthat could be developedfor commercial production.In fact, severalspecies that are nativeto US coastalwaters, suchas the greateramberjack and cobia are being commercially cultured in other countries.Hence, it couldbe arguedthat it is not a lackof technical knowledge,but a lackof marketincentives as well asregulatory hurdles that haskept the maricultureindustry from growingat a paceequal to that seen in the world market. As the demand for high quality fisheries products con- tinues to increase, the incentives to expand mariculture operations in the US will continueto grow. If maricultureexpansion is to be encouraged,it is essentialthat we developculture techniques for nativespecies and adapt thesetechniques to meet our socialand economicconstraints. The useof nativespecies will not only avoidthe introductionof non nativespecies, but it will also supportthe developmentof techniquesthat can be appliedto both maricultureand remediationprojects to enhanceboth sport and commercial fisheries. One of the primary goals of the The Universityof Texasat Austin, Marine Science Institute, Fisheriesand Mariculture Laboratory FAML! is to facilitatethe developmentof sustainablemariculture through research and education.This programapplies a multi-disciplinaryapproach to the study of naturalhistory combined with laboratorydeterminations of physiological and environmentalrequirements as well as the developmentof production technologies.The objective of thispaper is to summarizeobservations and research results that have been obtained at FAML for native speciesin the areas of maturation/reproduction, larval rearing and grow out.

Maturation/reproduction The FAML has a long history in the field of maturation/reproduction wherescientists have successfully spawned a numberof marinespecies of commercial and scientific interest Table 1!. We currently have 12 spawningtanks that range in sizefrom 10,000to 30,000I forlarge fish -50 kg! and 10 spawningtanks 400 I! for smallerfish andcrustaceans. Each maturationtank is anindependent closed recirculation system consisting of culturetank, settling area, biological filter and air lift pump.All of the fish specieswe currentlywork with arepelagic spawners. Consequently, once spawningis initiatedwe simplycollect the eggsin a 250micron filter bag connectedto the effluentdrain leadingfrom the culturetank to the biological filter. The fertilizedeggs are then quantifiedand utilizedfor research purposes. Fish,like manyother species, exhibit rhythmic physiological and behav- ioralpatterns generally known as bio-rhythms. Fish reproduction maturation, mating,and spawning! is oftenrhythmic and strongly correlated with 123

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Larval Rearing Currentproduction technology for marinefish larvae requires the use of livefeeds that can be expensiveand unreliable. Consequently, a major fo- cusof our researchis to eliminatethe live food requirementfor marinefish larvae.Efficient use of artificialdiets by marinefish larvaewill haveimpor- tantimplications for the economicviability of aquaculture.We have devel- opedtest tanks with a closed,recirculating design to evaluatenutrients and physicalrequirements of artificial diets Holt,1993!. Previous to thedevel- opmentof thissystem, feeding artificial diets was difficult because of rapid 125

15 1051/13/25 06/17 9/9 12/22/245/19 8/11 11/31/26 4/20 7/13 10/5 12/28 92 93 94 Temperature C! ~ Numberof spawns

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Fig.1. Exampleof spawningdata, averaged over 14-day intervals, from yellowtail snapper.Number of spawnsrepresents the total numberof spawnthat were re- corded over each interval. 126 deteriorationof water quality.An addedbenefit gained by this closedcul- turesystem is the abilityto rigorouslycontrol temperature and salinity. A feedingprotocol was developed for reddrum larvae based on combininga commercialmicroparticulate diet with liverotifers in the testtanks. In five feedingtrials growth and survival were measured on larvaereared on a combination of live and artificial food for one to five days before being weaned to artificial diets. Results in each trial were compared to control larvae reared on the traditional diet of live rotifers and brine shrimp. The bestresults were feeding a combinationof liveand artificial food for five daysand then completely discontinuing live prey. This meant that 8 dayold larvaecould be weaning,greatly reducing the needfor live food.Survival andgrowth rates of larvaefed this combinationwere as goodas larvae rearedsolely on liveprev Holt,1993!. Both groups metamorphosed to the juvenilestage at lessthan one month. Survival rates of the earlyweaned fish was a remarkable 60/o from egg to juvenile. Successfulweaning of reddrum from live food after 7 daysallowed us for the first time to evaluatespecific nutrient requirementsof larvae.We havedeveloped a semi-purifieddiet to evaluatenutrient requirements for weekold larvae.Microparticulate, semi-purified diets formulated with vary- inglevels of totallipid from 13-28/oof thedry weight were fed to larvalred drum. The resultsindicate that 18"/olipid in the diet producedthe best growthin termsof lengthand any lower percentage lipid was associated withpoor performance on stresstests Brinkmeyer and Holt, 1995!. Growth of larvaewas depressedwhen offereddiets with very low .2'/o! or very high.0! levelsof n-3!highly unsaturate fatty acids HUFA!. We found an optimumvalue for theratio of twoimportant n-3! HUFA DHA/EPA>2.5! in the diet as measuredby increasein length,weight and protein content Brinkmeyerand Holt, in press!.Research designed to evaluateoptimal sources phospholipids vs triglycerides!of HUFAand their effecton lipid requirements is underway. We havelearned some things about the nutrition of weanedlarvae but we havenot solvedthe first feedingproblem. Live food is still criticalfor the first weekof feeding.Currently, we are investigatingthe role of endog- enousand exogenous digestive enzymes on ratesof digestionand growth duringdevelopment of thedigestive system. Our goal is to eliminatethe live foodrequirement for larvaeperhaps through additions of digestiveenzymes directlyinto thediets or throughthe incorporationof selectedmicrobes to enhance the utilization of nutrients in artificial diets. Thelarvae of somefish species, e.g. red drum, can be successfully reared usingextensive pond production techniques. However, many other marine 127 speciesrequire a morecarefully controlled environment. Based on ourlabo- ratoryscale red drum production protocol, the growout of larvaeon a large scalehas beendemonstrated and we are currentlyoptimizing our production protocol.Through the useof an intensivesemi-closed recirculating systemand minimal reliance on livefeeds, the productionof juvenilefish canbe carriedout yearround. Once additional species are spawned and eggsare made available, the protocols developed for reddrum will be adapted for the mass production of other marine species. Species of interest The Gulf of Mexicosupports a diversegroup of fish speciesthat inhabit a varietyof habitatsranging from freshwaterto openocean conditions. Atlanticcoastal migratory pelagic fishes e.g. cobia, and dolphin!, reef fish e.g. snappersand jacks!and pompanosrepresent an importantresource of potentialmariculture species for cageand closed system culture where "oceanic conditions" can be maintained. Cobia and dolphin sport fisheries producemore than 90"/0 of thetotal annual yield of Atlanticcoastal pelagic species NOAA 1991! and are a componentof a keyrecreational fishery. Additionally,there are over 100 reef fishesimportant to commercialor sportfishermen for whichmarkets are established,having an estimated docksidevalue of $48 million NOAA 1991!. Concernhas been expressed overthe futureof manyof our marinefish stocks which are vulnerable to overfishingowing to variousfactors such as long lives,ease of capture, largebody size and delayed reproduction NOAA 1991!. Fish stocks which havebeen characterized as over-utilizedwould benefit from reducedfishing pressuresand/or remediation projects. Consequently, thedevelopment of biologicaldata required for the commercialculture of marinefish would benefit both the fisheries and the mariculture industry. Twospecies of reeffish, the greateramberjack Seriola dumerili! and yellowtail snapper Ocyunus chrysurus!, as well as the pelagiccobia Rachycentroncanadum! and the Horida pompano Trachinotus carolinus!, arehighly-prized recreational species supporting key recreational and com- mercialfisheries for whichfishing pressures have been increasing and stocks arethought to be low. Thesespecies also have characteristics that make them suitablecandidates for cultureand hencewarrant continued research. Thesnapper family consists of approximately100 species that are found throughoutthe worldin tropicaland subtropical areas. Because of their wideacceptance as an excellent food fish as well as declines in commercial fisheries,there is considerableinterest in culturingvarious snapper species. In factseveral species are commercially cultured in Asia.Although literature is scarce,information on spawningand raising several species of snapper 128 e.g.Lutjanus argentimaculQtus! isavailable. When considering species of thisfamily one must recognize that in generalthe larvae are relatively small and hencedifficult to raise.Although, considerable effort hasbeen invested in the developmentof larvalrearing techniques for snappers,success has been limited and techniquesare considerablybehind those developed for other marinespecies. Additionally in the wild, juvenileshave relatively slow growthrates. Manooch 987! hassummarized the growth rates of a numberof snapperspecies. Four species that are currently being evaluated for theirculture potential in theUS are the yellowtail Ocyurus chrysurus!, red LutjQnuscQmpechanus!, grey Lutjanus griseus! and mutton snapper LutjQnusanQlis!. Based on predictivegrowth equations these species will onlyreach 200-300 g intwo years in thewild. Despite there slow growth in the wild, resultsunder culture conditions indicate an improvementin growth rates.Utilizing semi-closed recirculating systems, we haveraised yellow tail snapperto 489gin 767day that is similar to theresults obtained by Thouard et al 990! usingcage culture techniques in Tahitii.Similarly, wild juvenile greysnapper approximately 3g initialweight! raised in ourlaboratory have reached500g after two yearsof culture.Despite improvements in growth ratesunder culture conditions, a twoto threeyear production period will be requiredto producea 0.5 to 1 kg fish. The developmentof a supplyof juvenilesis one of the factorsrestricting thedevelopment of culturetechniques for snapper.Several of thesnapper specieshave been spawned either using hormone induction or environ- mentalmanipulations. Previously, we have spawned both the yellowtail and redsnapper and are currently working on the developmentof techniques for the greysnapper. The yellowtail snapper appear to bea relativelyeasy speciesto workwith in the maturationlaboratory and we havehad very goodresults. Additionally, we havehad some success with raisingthe larvaeand haveclosed the life cyclefor this species.With the first generation of laboratoryreared yellowtail snapper initiating spawning this year,we havea uniqueopportunity to developlarval rearing techniques for thisim- portant snapper species. Anotherspecies of potentialinterest is the greateramberjack. Life history, abundanceand ecological data for amberjackare restrictedto rela- tivelyfew publications concerning: anatomy of the digestivetract Grauet aL 1992!,descriptions of foods Manoochand Haimovici 1983!, evalua- tion of geneticvariability as determinedby mitochondrialDNA variation Richardsonand Gold 1993! and tagging studies Mather 1962; Moe 1966!. Thedevelopment of larvaeunder culture conditions utilizing hormone in- ducedspawning for this specieshave been described by Japanesescientists 129 Tachiharaet al. 1993!, thus,confirming that larvaland juvenile production is technicallyfeasible. Unlike the snapperspecies, the growthrates are very impressive.Juveniles captured from the wild and raisedat FAMLhave reached2 kgin approximatelyone year. As with manyof the marinefish this specieshas also been cultured using wild seedstock! in cageswith goodsuccess. Consequently, once maturation and larval rearing techniques aredeveloped commercial culture for thisspecies could develop relatively quickly. Becauseof its acceptanceas an excellentfood fish, high marketprice averagecommercial value of $6.6/kg!, adaptabilityto intensiveculture systems,ready acceptance of artificialfeeds and relatively fast growth rate, the Floridapompano has been considered a suitablecandidate species for commercialculture Wiliamset al., 1985!. Most researchin captivityhas been conductedin cagesor pond polyculturessystems utilizing wild juveniles Tatum,1972; Gomezand Scelzo,1982; Gomezand Larez, 1983!. Althoughfeed conversion efficiencies are very poor in thisspecies gener- allyaround 50/o!, they have a goodgrowth rate and readily adapt to culture conditions.Based on growthrates at our laboratory1g juveniles collected from the wild can reach0.8 kg in a year.Although, this specieslooks very promisingfor commercialculture, maturation and larval rearing techniques will need to be developed. Thefinal species that we feelhas considerable culture potential is the lingor cobia.Although data on thecobia are extremely limited and gener- allyrestricted to ecologicaldata Dittyand Shaw 1992; Joseph et al. 1964; Dawson1971; Richards 1967! and a reporton preliminarytechniques for raisinglarvae from eggs captured from the wild Hasslerand Rainville 1975!, thisspecies has excellent culture potential. The eggs from this species are relativelylarge .25 mmin diameter!and the larvaeare relatively large at hatch mm!. Basedon the work of Hasslerand Rainville975!, the developmentof larvalrearing techniques should be verysimilar to those that havebeen developed for the red drum and other marinespecies. Con- sequently,once maturation technologies are developed, larval rearing tech- niquesshould be relativelyeasy to implement.Additionally, the juveniles growat extremelyfast growth rates and are relatively hardy. Juveniles .5 to 1g initialweights! collected from the wild havereached 4.5 kg in one year.This extremely fast growth rate, high quality flesh and tolerance of moderateto poorwater quality conditions make this one of themost prom- isingculture species that we haveevaluated. 130 Summary With the exceptionof salmonids,the maricultureindustry has been slow to developin the UnitedStates. This is probablydue to a varietyof factors that when combined have inhibited the development of this industry. De- spitethese difficulties the mariculture industry has been expanding it, adapt- ing to US socialand economic constraints, identifying native species with commercialpotential and slowly expanding. As longas seafood prices continueto rise,mariculture operation will continueto expand.With expanded supportfor researchand technology transfer programs coupled with gov- ernmentsponsored incentive programs for commercialoperations, the U.S. couldquickly develop mariculture into a highlycompetitive industry.

Literature Cited Arnold, C.R. 1988. Controlledyear-round spawning of the red drum Sciaenops ocellatus!in captivity.Contributions in MarineScience, Supplement to Vol. 30:65-70. Arnold,C.R., W. H. Bailey,T. D. Williams,A. Johnsonand J. L. Lasswell.1979. Laboratoryspawning and larvalrearing of red drumand southern flounder. Proceedingsof the Annual Conference of S. E.Association of Fishand Wildlife Agencies. 31:437-440. Brinkmeyer,R.L. andG.J. Holt. 1995.Response of reddrum larvae to graded levelsof menhadenoil semipurifiedmicroparticulate diets. ProgressiueFish- Culturist 57!: 30-36. Brinkmeyer,R.L. and G.J. Holt. in press!Highly unsaturated fatty acids in dietsof red drum Sciaenopsocellatus! larvae. Aquaculture. Dawson,C.E. 1971. Occurrence and description of prejuvenileand early juvenile Gulf of Mexico cobia, Rachycentron canadum. Copeia 1:65-71. Dittv,J.G. and R.F. Shaw. 1992. Larval development, distribution, and ecology of cobiaRachycentron canadum Family: Rachycentridae! in the northern Gulf of Mexico. Fishery Bulletin 90:668-677. Gomez,A. andM. Scelzo. 1982. Polyculture experiments of pompano, T. carolinus, andspotted red shrimp,P. brasiliensis,in concreteponds, Margarita Island, Venezuela.Journal of World Mariculture Society. 13:146-153. GomezA. and LarezF., 1983. Crecimientode pampanosTrachinotus goodei, T. Falcat us, T. carolinus alimentados con dicta scca GSCA en la islade Margarita, Venezuela.Bol. Inst. Oceanogr.De Venez.Univ. Oriente,22:21-28. Grau,A.S., M. Crespo,C. Sarasqueteand M.L. Gonzales De Canales. 1992. The digestivetract of the amberjackSeriola dumerili, Risso: a lightand scanning electronmicroscope study. Journal of FishBiology 41:287-303. Hassler,W.W. and R.P. Rainville. 1975. Techniques for hatchingand rearing cobia, Ranchycentroncanadum, through larval and juvenile stages. University of North CarolinaSea Grant CollegeProgram., UNC-SG-75-30, Raleigh. Holt, G.J. 1993. Feedinglarval red drumon microparticulatediets in a closed recirculatingwater system.Journal of the World AquacultureSociety 24!: 225-230. Joseph,E.B., J.J. Norcross and W.H. Massmann. 1964. Spawning of thecobia, Rachycentroncanadum, in theChesapeake Bay area, with observations of juvenilespecimens. Chesapeake Science 5-2!:67-71. Manooch,C.S. III andM. Haimovici.1983. Foods of greateramberjack, Seriola dumerili,and almaco jack, Seriola rivoliana Pisces:Carangidae!, from the SouthAtlantic Bight. The Journal of theElisha Mitchell Scientific Society 99: 1- 9. Mather,F.J. 1962. Progress report, Cooperative game fish tagging program. Woods Hole OceanographyInstitute. November 9. Moe,M.A. Jr. 1966.Tagging fishes in Floridaoffshore waters. Technical Series No. 49. pp. 1-40.Florida Board of ConservationMarine Laboratory. St. Petersburg Florida. National Oceanicand AtmosphericAdministration NOAA! 1996. Our Living Oceans. The Economic Status of U.S. Fisheries, 1996. NationalOceanic and AtmosphericAdministration NOAA! TechnicalMemoran- dum.1991. Our Living Oceans. The First Annual Report on theStatus of U.S. LivingMarine Resources. NMFS-F/SPO-1. pp. 1-123.U.S. Department of Commerce. Richards,C.E. 1967. Age, growthand fecundityof the Cobia.Rachycentron canadum,from Chesapeake Bay and Adjacent Mid-Atlantic Waters. Transac- tions of the American FisheriesSociety. 96:343-350. Richardson,L.R. and J.R. Gold. 1993. Mitochondrial DNA variation in redgrouper Epinephelusmorio! and greater amberjack Seriola dumerili! from the Gulf of Mexico. ICES Journal of Marine Science 50:53-62. Tachihara,K., R. Ebisuand Y. Tukashima.1993. Spawning, eggs, larvae and juve- nilesof thepurplish amberjack, Seriola dumerili. Nippon Suisan Gakkaishi 59: 1470-1488. Tatum,W., 1972. Comparativegrowth, mortality and efficiencyof pompano Trachinotuscarolinus! receiving a dietof groundindustrial fish with those receivinga dietof troutchow. !. Proc.World Mar. Soc., 3:65-69. Thouard,E. P. Soletchnik, and J.-P. Marion. 1990. Selection of finfish species for aquaculturedevelopment in Martinique F.W.I.!. InAdvances inTropical Aquac- ulture.Tahiti. Feb. 20 March4, 1989. AQUACOP.IFREMER. Actes de Collogue 9 pp 499-510. Thomas,P., C.R. Arnold and G.J. Holt. 1995. Sciaenid fishes. In BroodstockMan- agementand Egg and Larval Quality N. Bromageand R.J. Roberts, eds!. 6: 118-137. Blackwell Scientific Publishers. Williams,S., Lovell, R. and Hawke, J.P. 1985. Value of MenhadenOil in Dietsof FloridaPompano. Prog. Fish-Cult. 47 !: 159-165. Willinsky,M.D. and M.A. Champ. 1993. Offshore fish farming: Reversing the "oceanic dustbowl."Sea Technology August 1993!:21-26.

133 Hawaii Qffshore Potential

Fig. 1. Hawaii'sbeneficial characteristics for of shoremanculture. of an offshore mariculture industry in Hawaii. The agencies involved include the Universitv of Hawaii Sea Grant Program, the State of Hawaii's AquacultureDevelopment Program, and the Oceanic Institute. Hawaii maintains stablewater temperaturesyear raund ranging from 24-27"C. the watersare oligotrophicand its infrastructureis in place.The stateis strate- gicallylocated between markets in Asia and the U.S. Figure1!,

Hawaiian Fisheries Development The Institute has been developing comprehensive technologies through the Hawaiian Fisheries Development Program I-IFD! utilizing representa- tive speciesfrom a varietyof ecologicalniches. The HFD programis funded by the NationalOceanic and AtmosphericAdministration NOAA! through the National Marine FisheriesService NMFS! far the commercial development of technologv for stock enhancement and farm production purposes, The technologyserves as a modelfor standardized,yet flexibleprotocols for the collection and quarantine of broodstock, maturation and spawning af broodstock, and intensive hatchery and grow oui. Species that have been successfullycultured at the institute include striped mullet mugt! cepha!us Edaet al, 1990:Liu andKelly. 1994a!, milkfish Chanoschonos- Lee, 1986: Lee et al., 1986, Liu and Kellv, 1994b!, rnahimahi Coryphaena 134

hippurus Kim et al., 1993!, pacific threadfin polydactyfus sexji is- Ostrowski et al.,1996! and the bluefin trevally Caranx mefampygus!.

Quarantine and Growout Fish species collected from the wild are placed into a rigorous quarantine program before thev are allowed in growout areas at the Institute. The new fish are fresh water dipped to rid them of any external parasites and then placed into quarantine tanks for 4 weeks. These tanks consist of low volume 000l!, high water exchange rates 0+ turnover/day!, and are isolated from maturation. hatchery, and growout areas. If problems occur during quarantine, different. treatments are administered depending on the disease/parasite prognosis. These treatments include fresh water baths, tank exchanges,formalin baths, and Oxytetracylcine treatments. The fish are initially fed a diet consisting of squid. krill and smelt and are later weaned onto a dry 5.0 mm pellet Moore Clarke Marine Grower ! consisting of 50 percent protein and 14 percent lipid. Before growout, the fish are tested for tolerances to anesthetics such as MS222 and 2-Phenoxvethanol. Toler- ances have been determined at 80-90ppm of MS 222 for both bluefin trevally and amberjack. After quarantine the fish are transferred to growout tanks and fed to satiation twice per day on the drv pellet and are measured and weiqhed monthly for growth performance, Survival rates and feed con- versions are also calculated,

Pit Tagging Once the fish near maturity. they are anesthetized and tagged for broodstock. Data acquisition is necessaryfor a long term breeding program and is facilitated through the use of a pit tag. The pit taq 4 mm long! has a 14 digit binary code and can be scanned up to 17.5mm intra-musculature. The tag is inserted into the left dorsal musculature at a 45-degree angle with a modified. spring loaded. syringe and data is retrieved via a Biomark -Avid Power Tracker 2 scanner Figure 2!, The pit tag identifies individual fish and allows for the collection of biological data regarding their size, length, sex, growth and maturity.

Broodstock Management Proper rnanagerneni.is the key to strong healthy broodstock. Feeding a complete diet percent total body weight of fish/day! consisting of fish, crustacean.cephalopod and vitamins will enhance the growth and development of the broodstock. Maintaining a clean tank with high water quality is essential, This can be accomplished by periodic cleaning with a brush of algae and scum and maintaining adequate water exchanges for the amount 135

i ig. 2. Waterproofscanner pit tag 4 rnm!.arNf pit tag syringe. of fish in the l.ank.Disease prevention through close observation and strict operatingprocedures i.e. not handlingbroodstock with a netfrom quarantine!, will decreasethe risk of diseasewithin a culture system. Knowing your fish through behavioralobservations is very important. Problemscan be divertedby carefullyobserving feed amounts and swimmingpatterns. No- ticing theseproblems early on will reducedisease outbreaks and decrease the recovery time of the fish.

Maturation Broodstock fish are scanned once a month and examined for growth and maturation. The fish are corralled with a PVC crowder and netted with a perforated,plastic net and placedinto a 150 1 bathof MS 222 90 ppm!, The fish are then scannedwith the Power Tracker for identification, weighed, measured,and cannulatedfor gonadaldevelopment. Cannulation is facilitated with the use of a 26 cm long polyethylene tube. The inside diameter is 0.8 mm and the outside diameter is 1.52 mm, The cannula is placed into the urogenitalpore at an HO angle,between 1-2.5 cm deep Figure3!. The other endof the cannulais gentlysucked upon to extracteggs/semen from the fish. Semen extracted from a male it is placed onto a slide with a drop of seawaterand examined under a microscope for motility. Eggs collected from a femaleare placedinto a testtube with 5 percentformalin and later checkedin the laboratoryfor development.The eggsare stagedfor devel- 136opmentFig.3.Cannulation under a microscopeofa andamberjack fertilization kg! with rate a is calculated.8 tube. The greater devel- polyethylene opment of oo cvtes from a pre-vitellogenic through a cortical vesical both immature! stage to a vitellogenic mature! egg are important as to when the fish mav spawn, An important aspect of our current broodstock research involvesthe determination of critical oo cyte diameters. The critical oo cyte diameter is the minimum size an egg will respond to a hormone implant or injection.

Spawning Once the spawning season has been established, an egg collector is placed outside the tank to extract floating, fertilized eggs. The collector is built from a 55 gallon plastic barrel and with a 200 micron mesh bag sus- pended within. Surface water from the tank is skimmed and directedthrough the mesh bag and barrel outside the tank. Spawning generally takes place at night so collectors are set late in the afternoon and eggs collected the following morning. Several ways that 01 induces maturation is through photo period and temperature manipulation and hormone implant/injection. Protocol regarding the use of chronic releasing cholesterol pellets has been establishedat the Institute. The chronic releasing cholesterol pellet is made in the laboratory 00 micrograms each! from combining LHRH-a, cholesterol and co- coa butter in a mortar and pestle. The mixture is pressedinto a plastic grid, 137

Fig. 4. The btuefin trevally Caranx melarnpygus!. dried in an incubator, and then a hammer and nail is used to punch the pellets out, The finished produci.can than be implanted into the fish through a 3 cm incision made with a scapula! along the right dorsal musculature. The pellet is inserted with a special syringe approximately 2 cm deep. The cholesterol pellet will slowlv releaseLHRH-a for approximately 5-6 months and promote maturation, increase egg production and extend the spawning season of the fish. The bluefin trevally has been successfullyspawned year round at OI, Spawning has been natural and induced with most spawns occurring from May through September Figure 4j.

Species Potential The characteristics of a good offshore species includes: 1. An established mass culture technique for consistent year round production of fry. In order for an offshoreproject to be economicallyfeasible, cages must be stocked with thousands of fish for return on investment. It is essential that seed stock be produced or purchased in large amounts for year round stocking purposes, 2, Rapid growth rates ! 0.5 kg/year! and reliable feed conversionsof 2:1 or less. 3. Adaptability to the rigorous offshore environment, A fish that can with stand currents greater than 2 knots and seasgreater than 3 meters. 4. A species that is hardy. that can handle crowding, and is resistant to disease and parasites. 5, Marketability, A fish that is widely acceptable and can be sold for a profit. 138

Bluefin Trevally Egg Production 16.0, 1995 1996 3 997 14.0

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6,0

2.0 0.0lJ S k J M M J S k J M M J S hRnnth Fig. b. Year round egg production of the biuefin trevaiiy.

Blue Fin Trevally Caranx melampygusis in the family Carangidae Figure 4!, It is a strong swimming predator fish that frequents open ocean drop offs and reefs. They are especiallyprized by fisherman for their spectacularfighting ability Hoover 1993! and have been caught at 10 kg from the wild. Developmen- tal work through the HFD program indicates the trevally to exhibit excellent offshore qualities. The trevally can be readily collected, domesticated. and trained onto a commercial diet. They can be cultured to .5 kg in 11 months at densitiesof 20 kg/ms on shore.Maturity of broodstockoccurs between 1.5-2.0 kg. The broodstock can be spawned vear round naturallv and/or induced! resulting in a constant production of eggsfor a hatchery Figure 5!. Larvae culture has been successfulon a research level but problems exist concerning first feed items on a commercial level. Currently. new feed studies are commencing at the institute to resolve these issues.New feed items such as copepods. trochaphores. and various larvae enrichments are being examined.

Greater Arrrberjack Preliminary researchat the Institute with the amberjack has been prom- ising and indicates potential qualities for offshore culture, Captive juveniles collected from the wild 0mrn! have taken to a dry feed within 36 hours and have grown to 2.8 kg in one vear with a feed conversion of 1.2. This specie can obtain weights of over 50 kg in the wild Figure 6!, The amberjack has been considered an excellent aquaculture candidate because of 139

Fig, 6, The greater amberjack Seriota dumeriii! their rapid growth rates, Garcia et al. 1993; Greco et al. 1993; Porrello et al. 1993!. their ability to adapt to confinements Micale et al. 1993!, high commercial value Greco et al. 1993; Porrello et al, 1993!, and tolerance to handling Greco et al, 1993!. Serio!a dumerifi are cultured intensively on land as well as in seacagesin the Mediterranean Greco et al, 1993; Garcia Gomez 1993; Grau et al. 1993!, Japan Masuma et al. 1990; Tachihara et al. 1993!, and Hong Kong Wang 1995!, Vitellogenic eggs .2mrn! have been observed in captive broodstock at 6 kg, Mariculture facilities in the Mediterranean have been unsuccessfulin larval development Grau t et al. 1996!. However, in Japan, fertilized eggs have been produced with intra-muscular hormonal injections Tachihara et al. 1993; Masuma et al. 1990!. The bulk of amberjack seedstock comes from the wild Grau, et al. 1996: Garcia et al. 1993! and market size is 1 1.2 kg in 9 months Grau et al. 1996!. In 1994, Hong Kong exported an estimated 10 million juvenilesto Japan which they cultured from wild caught fry Wong 1995!. In the Mediterranean, one of the major stumbling blocks is hatchery production Grau et al. 1996!. This is a major bottleneck for most marine finfish production Figure 7! and needs immediate research and attention before an offshore industry can be successful. Markets for the amberjack are excellent in Japan, Mexico, Mediterra- nean countries and, Statesbordering the Gulf of Mexico, In Hawaii, captive fisheries do not exist due to the potential problems associatedwith worms and ciguatera. If amberjack were produced from a hatchery and raised on a commercial diet. these problems could essentiallybe eliminated,

Conclusion This is an overview of the Oceanic Institute's approach to broodstock husbandry. maturation and spawning for the hatchery development of marine fish species.The intent is to produce a protocol for the rapid develop-

141

semihumeda. Bol. Inst. Exp. Oceanogr., !: 347-360. Grau,A., G Gonzalez,E. Pastor,E. Layousand S. Crespo.1993. Histopathologi- calobservations of wild amberjack,Seriola dumerili from the SpanishMediter- ranean area. FROM-DISCOVERY-TO- Grau,A., S. Crespo,F. Riera,S. Pouand M.C. Sarasquete.1996. Oogenesisin the amberjackSeriola dumerili Risso, 1810: An histological,histochemical and ultra- structuralstudy of oocytedevelopment. Scientia Marina 60 -3!:391-406. Greco,S., D. Caridi,S. Cammarotoand L. Genovese.1993. Preliminarystudies on artificialfeeding of amberjackfingerlings. Production,-Environment-and-Quality. Ghent-BelgiumEuropean-Aquaculture-Soc. no.18, pp. 247-254. Hoover,J.P. 1993. Hawaii's Fishes. Mutual Publishing, Honolulu, Hawaii. USA. 82pp. Kim, B.G., A.C. Ostrowski,and C. Brownell.1993. Reviewof hatcherydesign and techniquesused at the OceanicInstitute for intensiveculture of the mahimahi Coryphaenahippurus! on a commercialscale. TML ConferenceProceedings 3:179 190. FinfishHatchery in Asia'91. Cheng-ShengLee, Mao-Sen Su, and I ChiuLiao, eds.!. Tungkang Marine Laboratory, TFRI, Taiwan and The Oceanic Institute, Hawaii, USA. Lee,C.-S., M.S. Gordonand W.O. Watanabe Eds.!. 1986. Aquacultureof the milkfish Chanoschanos!: state of the art. The OceanicInstitute, Honolulu, Hawaii. USA. 88pp. Lee,C.-S. 1986. Environmentalfactors in milkfishreproduction. In: C.-S.Lee, I.C. Liao editors!Reproduction and cultureof the milkfish.Proceedings for a work- shopheld at theTungkang Marine Laboratory, taiwan. April 22-24. Pp. 99-104. The Oceanic Institute, Honolulu, Hawaii. USA. Liu, K.K.M. andC.D. Kelly editors!.1994a. The OceanicInstitute Hatchery Manual Serious:Milkfish Chanos chanos!. The Oceanic Institute, Honolulu, Hawaii. USA. 284pp. Liu, K.K.M. and C.D. Kelly Eds!.1994b. The OceanicInstitute Hatchery Manual Serious:Striped Mullet Mugi/ cephalus!.The OceanicInstitute, Honolulu, Ha- waii. USA. 88pp. Masuma,S., M. Kanematuand K. Teruya.1990. Embyronicand morphologicalde- velopmentof larvaeand juveniles of the amberjack,Seriola dumerili. Japanese Journal of Ichthyology. 37 !: 164-169. Micale,V. L. Genovese,S. Grecoand F. Perdichizzi.1993. Aspectsof the reproduc- tivebiology of theamberjack, Seriola dumerili Risso 1810!. FROM-DISCOVERY- TO-COMMERCIALIZATION. Carrillo,-M.; Dahle,-L.; Morales,-J.;Sorgeloos,-P.; Svennevig,-N.;Wyban,-J.-eds. Oostende-Belgium European-Aquaculture-Soc. no.19, p.413. Ostrowski,A.C., T. Iwai, S. Monahan,S. Unger,D. Dagdagan,P. Murakawa,A. Schivell,and C. Pigao.1996. Nursery production technology for Pacificthreadfin Polydactylussexfilis!. Aquaculture 139: 19-29. Porrello,S. F. Andaloro,P. Vivonaand G. Marino. 1993. Rearingtrial of Seriola dumeriliin a floatingcage. Production,-Environment-and-Quality. Ghent-Belgium European-Aquaculture-Soc.no.18, pp. 299-308. Wong,P. S. 1995.The production economics and marketing aspects of marinefin- fish culturein Asia. In Main, K. L. and C. Rosenfeld editors!, Culture of High- ValueMarine Fishesin Asia and the United States.The OceanicInstitute, Makapuu Point, HI, pp. 259-268.

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]oining Forceswith Industry James McVey AquacultureProgram Leader National Sea Grant Office Silver Spring, Maryland and Granvil Treece Aquaculture Specialist Texas Sea Grant College Program Bryan, Texas Participantsfrom around the world assembled in Corpus Christi, Texas May10-15, 1998 for the 3rdInternational Open Ocean Aquaculture Con- ference.The conferencewas sponsoredby the Sea Grant Programsin Texas,Hawaii, Louisiana, New Hampshire and Virginia, the NationalSea Grant Office, the NationalCoastal Resources Research and Development Institute,and Mr. Red Ewald.Pre-conference tours took participantsto a shorelinefinfish hatchery, a finfishresearch facility, a stateaquarium and to offshoreplatforms, loading docks and other support facilities with potential for supportingopen oceanaquaculture. Summariesand updatesof open oceanaquaculture projects were pro- videdby presenters who have been working in variousparts of theworld, includingthe Atlantic Ocean off the Northeastern United States, The Gulf of Mexico,Ireland, Canada, New Zealand, Australia and the Philippines. Mostreports were very positive. Gilbert Normand, the Secretary of State fromCanada, spoke of strongsupport in hiscountry for theoffshore aquac- ultureindustry, and stated that a reportaddressing how Canadawill pro- ceedwith the industry will be completed within two years. He indicatedthat he wouldlike to seereductions in rulesand regulations, simplification of permittingand development of the industry similar to agriculture.Other governmentalrepresentatives from the United States presented the status andfuture directions of theirdepartmental agencies and programs in rela- tion to offshore aquaculture. Sincethe majortheme of the conferencecentered on offshoreplatforms,the merits and problems with usingplatforms in theGulf of Mexico and other U.S. waters for aquaculturewere discussed.Our summaryin laymen'sterms is: withouta changein currentlaws, the realstumbling blockto their useappears to be the U.S. MineralsManagement Service 144 MMS!requirements on liability and bondingfor accidentand leaseaban- donment.MMS requires100 percentassurance that eachstructure will be removed once its use is terminated. Even though an aquaculture venture groupmay obtain a bondto assumeresponsibility, MMS still looks to the originalpetroleum company/owner for final assurance.Therefore, the pe- troleumcompanies are hesitantto releasethe platformsto venturegroups if they continueto be held responsiblefor the platform. MMS statesthat a SuretyBond, US Treasuryor ZeroCoupon Bond, will work.Apparently thosebonds stage payments based upon production.Other ways that an oil companycan release liability are to turn rigsover to the "Rigsto Reefs" program' or to havea Federalagency take over the liability.A Department of Commerce DOC! member said that he wouldcheck into the viabilityof the DOC assumingliability for one platformas a pilot for a multi-useeffort weather sensors, aquaculture, etc.!. There are presentlytwo projectsin the Gulf of Mexicooff Texas.One has recentlyreceived a U.S.Army Corpspermit and is proposingto grow fish in proximity to a platform, but the petroleumcompany has not re- leasedthe platform.The other projectis beingconducted with a petroleum companyand finfish have already been stocked at the platform.Results of a pastproject by an oil companywere discussed in detail,and the conclu- sionswere: 1! it appearedto be too expensive,but economicsare yet unproven;2! therewas no liabilityrelief under current law; 3! operationsand engineeringare unproven;and 4! to starta newindustry requires new regulations. Onespeaker discussed the costsassociated with offshoreaquaculture and indicatedthat a minimumproduction level of 200 tons of finfish per yearmust be reachedfor the ventureto appearworthwhile and havea hatchery,with an estimate of 100tons annually being the break-even point. It wasstated that a minimumproduction of 18.5 kg of fish per cubicmeter mustbe grownand a salesprice of $US10/kgmust be obtained.Produc- tion in Japanhas reached 45.5 kg persquare meter with flounderculture. Thespeaker stated that the minimumcapital investment for a hatcheryto supportan offshore project would require $US 1.5 million. That same project would have a $US 2 million annual operating cost.

'The Rigsto Reefprogram exists in Texasand involveseither dropping drilling platformsin placeor movingthem and dropping them into statewater locationsidentified by the TexasParks and Wildlife Department. The sunken platformsbecome fish attractionsdevices of interestto recreationalfishermen fed.] 145 Anotherspeaker suggested that an entireoffshore project would cost $US7.5 million,with a startupcost of $US2 millionfor the base,$1.1 millionfor thehatchery, and $2.5 millionfor theoffshore operation. Such a venturewas estimated to employ20 to 25 people,and to havea US$1 million/yearpayroll and US$2.2 million/year operational costs. Two large boatswould be requiredto meetthe needsof sucha project. Jointoperations petroleum and fish production! were not recommended becauseof spacelimitations on productionplatforms. It wassuggested that thebest depth for aquacultureis 35 to 70 m, andthere were approximately 800 platformsin the Gulfwithin that optimumdepth range. A full-time crew of three to four wouldbe neededon eachplatform. There shouldbe sufficientcapacity to storea fourto sevenday supply of feed.A 15 to 20 ton cranefor handlingbulk feed containers and cleaning equipment would berequired, and the use of videomonitors and sonar was recommended to cut the cost of diving and safety/insurance requirements. It was estimatedthat 2.5 to 5 percentof the feed usedis wasted,and that a significantdispersion area is requiredfor wastes.It wasalso estimatedthat a processingplant must process 5,000 tonsannual to be eco- nomicallyviable. Currently, the U.S. Environmental Protection Agency will not allowprocessing in the ExclusiveEconomic Zone EEZ!,and probably will not allow it in state waters. The finfish cultureparticipants from countriesother than the US sug- gestedthat the platformscarry too muchbaggage with them,and current technologieshave developed such that the structures are not necessaryfor offshoreaquaculture. Ireland uses large Bridgestone-type cages that are left alonefor up to 50 dayswhen the weather is badand they have withstood wavesup to 15 m in height.Moveable cage systems were discussed as optionsto facilitatethe movement of fishfarms into offshoreexposed waters.Using bioeconomic-modeling techniques, new and improvedcages arebeing developed. An adaptationof the SeaStation tm!system, a free- floating,self-propelled system, was tested at the Massachusetts Institute of Technology.The motivatingfactors were: vast unexploited areas of the EEZ,limitations of currentcage technologies, concerns over environmental impactsof nearshoresites, concerns over environmental impacts of fixed fish farms,costs and arearequirements of anchorsystems, and costof harvest and delivery of conventional cages. A well-knowncage manufacturer reported on cagedesigns that have evolvedfor severalapplications, including a gravitycage system and a high currentand exposed water environment cage system or SeaStation tm!sea cagesystem. Commercial tests of theSea Station tm!sea cage system were 146 employedon threeworking farms: one farm growing summer flounder in LongIsland Sound and two farmsgrowing milkfish offshore in the Philip- pines.Apparently, the cages worked very well with production described in a single3,000 cubic meter cage being at least255 tons of milkfishper year. One innovativeand progressiveFilipino farmer has grown shrimpin a Sea Station tm! with milkfish. Sociologicaland environmental issues were discussed. An offshoreaquac- ultureproject off the NortheasternUnited States offers hope of reviving fisheriesproduction in NewEngland. Some countries such as Ireland have coastalcommunities that have been revivedthrough the developmentof offshoreaquaculture. They have streamlined the permitting process for open oceanranching and only have a smallnumber of permittingagencies, with a short turn-aroundtime permit applications.Offshore aquaculturehas developedinto a $US80million per year industry there, with most compa- niesproducing 5 tonsor moreannually. Having scientific information avail- ablethrough monitoring and measurement was critical to changingpercep- tions.The systemshave actually increased crab and lobsterpopulations near facilities. Securingtenure is veryimportant to the successof privateaquaculture in the coastalzone. One speakeradvised starting at the marketand work- ingbackward and said the species selected should have a profitmargin that allowsfor mistakes.The site is chosento makeyou a low-costproducer. The mostimportant thing on the farm relatesto personnel.It takesthe humanmanagement on a dailybasis to makeit work.You must have humil- ity andbe willing to changeif youwant to survive.You must develop a farmingproduction plan with a sensitivityanalysis to succeed.As invest- mentin rearingvolume goes up thereis lessprofit. You shouldchoose speciesand products where you have technical or naturalresource advan- tage.Operate directly with the end user, and patent your product. You are onlyas good as your transportation cost. One finfish hatchery researcher statedthat, in general,the slowergrowing finfish species have shown the highestfeasibility for aquaculture. Most of the researchersat the meetingshared the opinion that what is necessarynow to implementa workablehatchery for offshoresupport is money.The biological research has been accomplished in many instances, butthere has not been adequate funding for a commercialscale hatchery to supportoffshore aquaculture in the United States. Japan's new $100 million fish hatcherywas cited as an exampleof the necessarysupport in another country. Larvalproduction is wheremost bottlenecks occur, and biologists have 147 the mosttrouble with massfingerling production. Maturation and spawning arethe keysto developingnew species, and they can be donewith hormonal induction using pituitary extracts. Onespeaker listed the dolphinor Mahimahi CoryphaenQhippurus!, greateramberjack Seriola dumerili!, yellowtail amberjack S.lalancfi!, Pacific yellowtail S. mazatlana!, yellowfin tuna Thunnus albacQres!, bluefin tuna Thunnusthynnus!, pompano Trachinotus carolinus!, southern flounder PQralichthyslethostigmQ!, Gulf flounder P. Qlbigutta!, mutton snapper LutjanusQnalis!, red snapper L. cQmpechanus!,gray or mangrovesnap- per L. griseus!,yellowtail snapper Ocyuruschrysurus!, groupers Epinephelusspp.!, and red drum Sciaenops ocellatus! asbeing among the nativeand exotic candidate species with potentialfor commercialaquacul- turedevelopment in offshore systems in the Gulf of Mexico.A summaryof speciesresearch from Texas indicated that red drum is established but the marketprice is onlymoderate; pompano has good potential because of highmarket value; greater amberjack has good potential and is established elsewhere,but the marketvalue is low;Ling or Cobiahas excellent potential with moderatemarket value and is beinggrown in large pondsin Tai- wanwhere they collect the eggs, but spawning has not beenobtained elsewhere;snappers have moderate culture potential with a moderatemarket price,but the growth rate is slow and the food conversion ratio is poor; and the muttonsnapper may be the bestsnapper candidate for offshorecul- ture. Grouperand the common snook have been assessed for culturein Florida; summerflounder, winter flounder,witch flounder,cod, haddock,oysters, scallops,urchins, and macrophytic algae are being assessed off NewEn- gland;while development of the bluefin trevally Caranx melampygus! and greateramberjack are being undertaken in Hawaii.

For moredetailed information on the feasibilityof offshoremariculture, see "Feasi- bilityStudy OffshoreMariculture," A Report of WaldemarInternational Inc. to U.S.Department ofCommerce, NOAA/NMFS, under award NA77FL0150, 1998.