bait shrimp culture

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The live bait shrimp industry inthe southeastern U.S. is dependenton three shrimp species: theAtlantic white shrimp (Litopenaeussetiferus), the Gulf brown shrimp(Farfantepenaeus aztecus) and theGulf pink shrimp (F. duorarum).All three species occur along thesouthern and eastern U.S. coastsfrom Texas through NorthCarolina. The live bait shrimpindustry within this extensivecoastal region is mostly a capturefishery. Juvenile shrimp within asize range of 150- to 60-count

shrimp (3.0- to 7.5-g) are harvestedfrom inshore waters with trawlinggear. Recently, farm-raised, livebait shrimp were introduced as analternative to wild-caught shrimp.

Bait shrimp market

The wild product is highly season-al and the supply rarely meetsdemand, especially during the

peak demand period of Marchthrough September.

Shrimp are sold as both a live and

a frozen product, with live shrimpcommanding a premium price.The dockside (ex-vessel) price

wholesalers pay to boat captainsfor live bait shrimp ranges from$2.75 to $4.00 per pound. The

wholesale price bait retailers payranges from $7.50 to $14.00 per

pound. This wholesale price

includes delivery from the shrimpboat to the retail bait shop and soit varies with the distancesinvolved. Retailers who own theirown shrimp boats may charge fish-ermen as little as $7.00 per pound;in general, fishermen pay $10 to$16 per pound for live bait shrimp(Fig. 1).

Live hauling bait shrimp

Wild-caught bait shrimp are trans-ported to market in oxygenatedholding tanks at densities of 1 to

2 pounds per gallon of water.Mortality rates can be 25 to 50 per-cent within 24 hours of delivery.

However, live-haul trials of farm-

raised, live bait shrimp showedthat commercial volumes (200 to500 pounds per shipment) couldbe successfully transported toretail bait shops with more than95 percent survival 24 hours afterdelivery.

Seed supply

The main impediment to baitshrimp aquaculture has been thelack of consistent supplies of dis-ease-free postlarvae (PL). Withoutthem, both researchers and com-

mercial aquaculturists have reliedon two methods of obtaining PL.

VIPRApril 2007

SRAC Publication No. 1201

1 Mote Marine Laboratory Shrimp ResearchProgram, Sarasota, Florida.

Bait Shrimp Culture

Ryan L. Gandy1

Figure 1. The most valuable consumers of live bait shrimp.


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plied with a combination of freshsquid, adult enrichedArtemia andbloodworms fed on a wet-weightbasis (20 percent of body weight

per day, bw/d). Dry maturationdiets are added to reduce the costof fresh food.

Once acclimated to the maturationsystem, females are unilaterallyablateda process in which oneeyestalk is removed to induce mat-uration. Ovarian developmentensues within 72 hours and matingand spawning begin thereafter.Broodstock ranging from 25 to 35 ghave a reproductive capacity of100,000 to 250,000 eggs per spawnand can spawn every 3 to 7 days.

Fertilized eggs will hatch within 24hours of fertilization at 28 C(82.4 F). The nauplii are allowedto remain in hatching tanks until

they metamorphose into the last

Method I - sourcing wild, mated,gravid females

This method entails leasing coastalshrimp boats during the full moonsof spring and early summer totrawl the spawning grounds formated, gravid (egg-bearing) females(Fig. 2). Once gravid females are

caught, they are either spawned inindividual tanks onboard the vesselor transported to land-basedspawning tanks. Each gravidfemale is kept in an individual tankfor 12 to 36 hours under dark con-ditions, at a temperature of about28 C (82.4 F), and at a salinity of30 to 35 ppt. After spawning, thefemale is removed from the tankand the fertilized eggs hatch within24 hours.

Sourcing wild, mated, gravidfemales is a cost-effective tech-

nique for acquiring fertilized eggs,but it is not a reliable year-round

production method. There also is ahigh risk of acquiring shrimpinfected with viral pathogens that

will jeopardize the biosecurity andsustainability of the farm.

Method II hatchery

Developing and operating a biose-cure hatchery is both capital andlabor intensive. However, a biose-cure hatchery ensures a sufficient

year-round supply of PL for com-mercial operations. Healthy brood-stock must be developed and main-tained in a disease-free hatchery.The quantity of viral pathogen-freebroodstock is limited. Researchersat the Mote Marine Laboratory inSarasota, Florida, the WaddellMariculture Center in Bluffton,South Carolina, and the TexasAgricultural Experiment Station inCorpus Christi, Texas, are isolatingand developing high-healthbroodstock populations of the

Atlantic white shrimp and Gulfpink shrimp.

High-health broodstock are devel-oped through a process of quaran-tine and routine population testingusing histological examination anda polymerase chain reaction (PCR)technique. Continuous screening ofbroodstock and offspring withthese diagnostic tools detectsorganisms with specific pathogensso they can be eliminated from

these populations. Once a high-health wild population has beenisolated, it is induced to spawnand its offspring are tested forknown viral pathogens. Once theoffspring are determined to beclean, they are moved to a biose-cure grow-out facility where theyare raised to broodstock size. The

broodstock are then reproduced inmaturation facilities and their off-spring are used to supply farmers

with PL.

The maturation and reproductionof broodstock occur in a climate-controlled maturation system(27 C, 80.6 F) with 14-hour lightand 10-hour dark photoperiods(Fig. 3). Broodstock are kept in10.5- to 16.4-m2 (12-ft to 15-ftdiameter) maturation tanks at den-sities of six shrimp per m2. During

maturation, broodstock are sup-

Figure 2. Sourcing gravid females at night onboard a shrimp boat.

Figure 3. Maturation system.


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naupliar stage (N5). During thenaupliar stages, no feed is providedas nauplii feed on their yolk sacs.Nauplii (N5) are then collected andtransferred to larval-rearing tanksmaintained at 28 to 29 C (82.4 to84.2 F) where they are fed marinealgae (Chaetoceros gracilis and

Isochrysis galbana), live, newly

hatchedArtemia nauplii, and drylarval and postlarval diets, depend-ing on the stage of developmentand the dietary needs of that stage.

Shrimp larvae go through six larvalstages over a 9-day period in thelarval-rearing tank before theymetamorphose to a postlarval (PL1)stage. The entire larval cycle fromN5 until the shipment of the PL8-13lasts 17 to 22 days, depending onthe age of the PL requested by thefarm. In general, farmers request

PL8 - PL13 for stocking productionsystems.

Shipping post-larvae

Post-larvae are removed from lar-val-rearing tanks and concentratedfor counting, packing and ship-

ping. Shrimp PL are shipped atdensities of 1,000 to 2,000 per L in

polyethylene bags containing sea-water (30 to 35 ppt) that is saturat-ed with oxygen and cooled to18 C (64.4 F) before packing.The bags are usually packed in

insulated foam coolers to maintaintemperature during shipping. Somefarmers save on the high cost offreight by transporting high densi-ties of PL (more than 1 million) inlive-haul trucks with oxygenatedtanks.

Acclimation

When a PL is at least 8 days old(PL8), it is sufficiently robust tohandle the stress of transport andacclimation. The culture system

must be more than 15 ppt salinityand warmer than 20 C (68 F) forthe acclimation to proceed.Acclimation is accomplished insmall, temporary tanks near the

pond (direct stocking) or in a nurs-ery tank (a temporary tank forholding animals before they arereleased into the grow-out system).During acclimation, the density ofshrimp is more than 500 per L.Pure oxygen is provided to thetanks and bags during acclimation.

As a general rule, the acclimationtemperature is changed by 1 C(1.8 F) every 15 minutes until itmatches the culture system tem-

perature. Once temperature isadjusted, salinity can be changedby 1 ppt every 15 minutes until itmatches the culture tank salinity.If the pond has less than 15 ppt

salinity and/or a temperature ofless than 20 C (68 F), it isadvisable to use a nursery phaseand stock older, heartier juvenileslater on.

Zero exchangeintensive nurseries

Intensive nurseries (1,000 to50,000 PL/m2) with biomasscapacities of 2 to 4 kg/m2 operatedunder zero exchange have becomean important tool for shrimp

farmers. Zero exchange nurserysystems can have survivals ofmore than 80 percent and a har-vest biomass of 1 to 7 kg/m2,depending on the skill of themanagement and the investmentin capital infrastructure (filtersand oxygenation). Basic systemsconsist of a green house enclo-sure; a 20- to 60-mil, high-density,

polyethylene (HDPE) liner; a sandor bead filter; a regenerativeblower for aeration; a propane orelectric heat source; and oxygen

injection for large biomasses(more than 2.5 kg/m2) and emer-gencies. With increased experi-ence and capital expenditure,

farmers may increase productiondensities to more than 2.5 kg/m2.

Intensive nurseries increase grow-out survival by allowing farmers tostock larger shrimp (0.25 to 1.0 g)into grow-out systems. In the tem-

perate climate of the southeasternU.S., greenhouse-enclosed nurs-eries are used to give shrimp ahead start in early fall (Fig. 4). Ahead start nursery is an effective

way to increase the number ofcrops each year and have bettercontrol over production by stock-ing known quantities of heartier

juveniles. In regions where earlyspring temperatures are coolerthan 20 C (68 F), greenhousenurseries are essential so that thecrop can be held until water in thegrow-out system warms up.

Nursery management

Nursery culture water is main-tained at a temperature of 28 to29 C (82.4 to 84.2 F), a dissolvedoxygen level of 5 to 7 mg/L, a pHof 7.5 to 8.5, and a Secchi depth of25 to 30 cm. Ten to 14 days beforePL arrive from a hatchery, the cul-ture tanks are filled with seawater(20 to 35 ppt). Then the water issterilized with sodium hypochlo-rite (household bleach at 10 ppm)to prevent the introduction of

pathogens from incoming waters.

The treated culture water isallowed to sit for 24 hours withoutaeration to prevent a rapid reduc-tion of chlorine. During this period

Figure 4. Intensive greenhouse nursery at Mote Marine Laboratory.


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the chlorine concentration willremain above 1 ppm to provide thenecessary disinfection level. After24 hours, the water is heavily aer-ated to remove residual chlorine, a

process that takes 3 to 5 daysdepending on temperature andorganic load. The dechlorinatedculture water is then fertilized and

inoculated with algae.The raceway water is fertilized

with inorganic fertilizer (5 mg/Lurea, 0.5 mg/L triple super phos-

phate and 1 mg/L sodium metasili-cate). Water from an adjacent race-

way with a healthy algal bloom isgenerally used to inoculate the newraceway with algae. Moderate aera-tion is maintained in the racewaysas the algal bloom develops overthe next 7 days to a Secchi readingof approximately 25 to 30 cm. It is

important to check pH as thebloom develops. The high pH(higher than 8.75) created by thealgal bloom can be a problem for

young PL. To counteract it, carbondioxide from a compressed CO2cylinder is added to the culture

water with an air stone to decreasethe pH to 8.0 before PL arestocked. Nursery aeration is thenreduced to a minimum and PL areacclimated and stocked in the nurs-ery system.

Nursery feeds

A diet of newly hatchedArtemia(five nauplii/L/day) and dry post-larval feed (50% protein) is fed at10 to 25 percent of the total body

weight per day (bw/d) for the first5 days after stocking. Then thefeed rate is reduced to 7.5 percentbw/d and the feed is changed to a40% protein crumble #0 feed. Thecrumble size is gradually increased(0, 1, 2, 3 and 4) as the shrimpgrow. Shrimp feed is provided at7.5 percent bw/d for days 6

through 14, then reduced to 6 per-cent bw/d for the remainder of theculture period.

Nursery growth rate

Under intensive nursery culture,native shrimp have grown from aPL10 to 0.5 g in 50 to 60 days.Supplemental oxygen and periodicfiltration (using a sand or bead fil-ter) are necessary to complete the

nursery cycle as the biomassincreases to more than 2.5 kg/m2.

Nursery harvesting

Nurseries should be equipped witha harvest basin and constructed todrain fully. Harvest begins in theearly morning when the nursery isdrain-harvested into a harvestbasin. Shrimp are removed fromthe harvest basin with collectionnets and transferred to hanging bal-ances for group weights. Duringthe weighing process, a periodicsub-sample of the population is

weighed and counted to determinethe average weight of the popula-tion. The average weight and totalbiomass are used to determine totalshrimp harvested and the survivalin the raceways

Total shrimp harvested = Total biomass

weighed Average weightSurvival rate = (Total shrimp harvested

Number of shrimp stocked) x 100 %

The shrimp are rapidly weighedand placed in hauling tanksequipped with oxygen injection fortransportation to the pond.

Intensive pond production

For optimum production, pondwater should have a temperature of28 to 29 C (82.4 to 84.2 F), asalinity of 20 to 30 ppt, a dissolved

oxygen level higher than 5 mg/L, a

pH higher than 7.5, and a Secchidepth of 25 to 30 cm. Ponds maybe disinfected with 10 ppm chlo-rine upon filling to kill viral vec-tors and pathogens that may beintroduced from wild sources.However, this may not be econom-ically feasible, given the cost ofchlorine and size of the operation.

Whether or not a pond is dechlori-nated, incoming water shouldalways be filtered with 200-micronsocks.

Ponds are filled and fertilized with200 pounds per acre of cottonseedmeal 5 to 7 days before stocking.Culture water from an established

pond is transferred into the newpond to inoculate it and expeditethe algal bloom. The algal bloomshould be well established (25 to30 cm Secchi depth) when shrimp

are stocked.Once in the ponds, shrimp are feda 30 to 35% protein feed at rates of3 to 6 percent bw/d. Feed trays areused to prevent overfeeding. The

water must be aerated at a rate of10 to 18 hp per acre (Fig. 5). Thegeneral pond culture period for90-count shrimp (5.0 g) is 90 days.Ponds stocked with 0.5-g shrimp ata density of 200 per m2 can growat a rate of 0.5 g per week, have70 percent survival, and produceup to 7,000 kg/ha (6,160 lbs/ac) of

market size (5.0-g) live bait shrimp.

Figure 5. Intensive pond production at the Texas Agricultural ExperimentStation in Corpus Christi, Texas.


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Pond harvesting

Shrimp are harvested in the earlymorning when the temperature islow. A seine can be used to manu-ally harvest the pond, though thismethod is labor intensive. Anothermethod uses a hydraulic fish

pump attached to the harvest

basin to drain-harvest the pond.Harvested shrimp are rapidlyweighed in small batches (lessthan 35 pounds each) before beingloaded into a hauling truck. Thehauling truck is equipped withoxygen injection to maintain satu-rated oxygen conditions (morethan 10 mg/L) during transport.The temperature is also lowered toabout 20 C (68 F) to reducestress.

Farmers who harvest and sell liveshrimp to wholesalers at pond

bank can expect prices of $4.50 to$5.50 per pound. Farmers whoinvest in hauling trucks and equip-ment can expect to receive morethan $7.50 per pound for deliv-ered shrimp.

Other culture systems

Since the mid 1990s, researchershave been developing super-inten-sive, closed-recirculating shrimp

production systems. Recentadvances in this technology have

made it possible to produceshrimp year round under highdensity conditions (3 to 7 kg/m2).These systems are still in theresearch and development phaseso capital and operating costs aremuch higher (more than $3.50 per

pound) than with pond productionmethods ($1.25 to $2.50 per

pound). The economic feasibilityof these production systems is cur-rently limited to markets where

prices are consistently high (morethan $5.00 per pound). Super-

intensive production systems aremarginally profitable when theprice falls below $5.00 per pound.These systems are not economical-ly feasible when there is consider-able competition or profit marginsare low, but they do show promisefor year-round production or forfacilities that must be locatedinland in biosecure areas.

Bait shrimpaquaculture information

Contacts by state

Alabama

D.A. DavisDepartment of Fisheries and Allied

Aquacultures, Auburn UniversityFlorida

R. L. GandyMote Marine Laboratory ShrimpResearch Program, Sarasota

Mississippi

T. R. HansonDepartment of AgriculturalEconomics, Mississippi StateUniversity

South Carolina

C.L. BrowdySouth Carolina Department ofNatural Resources

Texas

T. M. SamochaTexas Agricultural ExperimentStation Shrimp Research Program

Selected readings

Cohen, J., T.M. Samocha, J.M. Foxand A.L. Lawrence. 2005.Biosecured production of juve-nile Pacific white shrimp in an

intensive raceway system withlimited water discharge.

Aquacultural Engineering32(3-4):425-442.

Davis, D.A. and C.R. Arnold.1998.The design, management and

production of a recirculatingraceway system for the produc-tion of marine shrimp.

Aquacultural Engineering17:193-211.

Gandy, R.L. 1997. U.S. nationallive bait shrimp market survey.

Masters thesis, Texas A&MUniversity-Corpus Christi,Corpus Christi, Texas.

Gandy, R., T.M. Samocha, E.R.Jones, and D.A. McKee. 2001.The Texas live bait shrimp mar-ket.Journal of Shellfish Fisheries20(1):365-367.

de Garza, Yta, D.B. Rouse andD.A. Davis. 2004. Influence ofnursery period on the growthand survival ofLitopenaeusvannamei under pond produc-tion conditions.Journal of theWorld Aquaculture Society35:357-35.

Hanson T.R., R.K. Wallace, L.U.Hatch and W. Hosking. 1999.Coastal Alabama recreationallive bait study, Report on the1997 and 1998 Alabama livebait market surveys. Report

prepared for the AuburnUniversity Marine Extensionand Research Center, 4170Commanders Dr., Mobile,Alabama. AUMERC 00-1. 30

pp.

Mays, R., J.A. Venero, D.A. Davis,D.B. Rouse and I.P. Saoud. (in

press). Nursery protocols forthe rearing of the brownshrimp,Farfantepenaeusaztecus: effects of stockingdensity, salinity and EDTA ongrowth and survival.Journal of

Applied Aquaculture.

Sandifer, P.A., J. S. Hopkins, A.D.Stokes and C.L. Browdy. 1993.Preliminary comparisons ofthe nativePenaeus setiferus andPacificPenaeus vannameiwhiteshrimp for pond culture inSouth Carolina.Journal of the

World Aquaculture Society24:295-303.

Samocha, T.M., B.J. Burkott, A.L.Lawrence, Y.S. Juan, E.R.

Jones and D.A. McKee. 1998.Management strategies for

production of the Atlanticwhite shrimpPenaeus setiferusas bait shrimp in outdoor

ponds.Journal of WorldAquaculture Society 29:211-220.

Samocha, T.M. and R. Gandy.2000. Protocol for nursery

raceway.Acuacultura delEcuador39:72-77.

Zajicek, P., D. Zimett, C. Adamaand A. Lazur. 1997. Live baitshrimp market analysis andfarm enterprise budget.Bureau of Seafood andAquaculture. FloridaDepartment of Agriculture andConsumer Services.


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The information given herein is for educational purposes only. Reference tocommercial products or trade names is made with the understanding thatno discrimination is intended and no endorsement by the Southern RegionalAquaculture Center or the Cooperative Extension Service is implied.

The work reported in this publication was supported in part by the Southern Regional Aquaculture Centerthrough Grant No. 2003-38500-12997 from the United States Department of Agriculture, Cooperative StateResearch, Education, and Extension Service.

SRAC fact sheets are reviewed annually by the Publications, Videos and Computer Software SteeringCommittee. Fact sheets are revised as new knowledge becomes available. Fact sheets that have notbeen revised are considered to reflect the current state of knowledge.

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