The document provides information about various shrimp species farmed for aquaculture. It details the top shrimp producing countries in 2006, with Thailand as the largest producer at 200,000 MT. Several species of shrimp are discussed, including the dominant Penaeus vannamei (Pacific white shrimp), Penaeus monodon (giant tiger prawn), and freshwater prawns of the Macrobrachium genus. The life cycle, larval stages, and farming practices for shrimp are summarized, including pond construction, stocking, feeding, and harvesting methods.
2. Thailand – 200,000 MT
China – 110,000 MT
Indonesia – 100,000 MT
Ecuador – 85,000 MT
India – 70,000 MT
World harvest of farmed/wild marineWorld harvest of farmed/wild marine
shrimp in 2006 was 6.6 million MT!shrimp in 2006 was 6.6 million MT!
3.
4.
5.
6. Shrimp Gee-WhizShrimp Gee-Whiz
• Shrimp, crabs, lobsters and crayfish all decapodsShrimp, crabs, lobsters and crayfish all decapods
(they have 10 feet)(they have 10 feet)
• Hundreds of spp. found in brackish and marineHundreds of spp. found in brackish and marine
• All farm-raised shrimp and most of the shrimpAll farm-raised shrimp and most of the shrimp
caught by fishermen belong to the Penaeidaecaught by fishermen belong to the Penaeidae
family of decapod crustaceans and are referred tofamily of decapod crustaceans and are referred to
as "penaeids".as "penaeids".
7. Gulf Shrimp IdentificationGulf Shrimp Identification
• BrownBrown
– Groove on either side of spineGroove on either side of spine
on back of headon back of head
– Similar groove on the lastSimilar groove on the last
body segment before thebody segment before the
tail segment (A)tail segment (A)
• PinkPink
– Groove on either side of spineGroove on either side of spine
on back of headon back of head
– Similar groove on the last bodySimilar groove on the last body
segment before the tail segmentsegment before the tail segment
– Dark or pinkish blotch on eachDark or pinkish blotch on each
side of body between carapaceside of body between carapace
and tail (B)and tail (B)
• WhiteWhite
– No grooves on spine or lastNo grooves on spine or last
segment before tail (C)segment before tail (C)
A
B
C
8. Penaeid Shrimp Life CyclePenaeid Shrimp Life Cycle
Shrimp have a maximum life span of about 24 months.Shrimp have a maximum life span of about 24 months.
9. Larval StagingLarval Staging
• Penaeid Shrimp pass through threePenaeid Shrimp pass through three
larval stageslarval stages
– NaupliiNauplii
– ZoealZoeal
– MysisMysis
• Postlarval (PL) follows larval stagesPostlarval (PL) follows larval stages
– Look like shrimp by this stageLook like shrimp by this stage
10. Nauplii StageNauplii Stage
• Six sub-stagesSix sub-stages
– May lose 25%May lose 25%
– Nauplii sub-stagesNauplii sub-stages
take approximately 48take approximately 48
hourshours
• 36-51 hour range36-51 hour range
depending ondepending on
temperaturetemperature
– Begin feeding at N6Begin feeding at N6
11. Zoeal StageZoeal Stage
• Zoea feed onZoea feed on
phytoplanktonphytoplankton
• Three zoealThree zoeal
substagessubstages
– 120 hrs120 hrs
– 36-48 hrs per stage36-48 hrs per stage
12. Mysis StageMysis Stage
• Look like adultLook like adult
shrimpshrimp
• Begin to swimBegin to swim
backwardsbackwards
• Three sub-Three sub-
stagesstages
– Each last 24 hrsEach last 24 hrs
13. Post LarvaePost Larvae
• Postlarvae (PL)Postlarvae (PL)
– PL1: one day PLPL1: one day PL
• 0.0008 g/PL10.0008 g/PL1
– PL 20: 20 day PLPL 20: 20 day PL
• 0.02 g/PL200.02 g/PL20
• Swimming seta present on pleopodsSwimming seta present on pleopods
• Reared in tanks or racewaysReared in tanks or raceways
• Stocked in ponds beginning aroundStocked in ponds beginning around
PL15-PL20.PL15-PL20.
15. Larval FeedingLarval Feeding
MysisMysis
• Feed large algaeFeed large algae
cells early oncells early on
• Switch to artemiaSwitch to artemia
(brine shrimp) for(brine shrimp) for
later stageslater stages
0
1
2
3
4
5
6
Artemia/ml
Late Z3-MI M I- M II
MII-MIII MIII-PL
16. Larval FeedingLarval Feeding
PostlarvaePostlarvae
• ArtemiaArtemia
– 6/ml at PL46/ml at PL4
decreasing to 0 bydecreasing to 0 by
PL11PL11
• Formulated dietFormulated diet
– 35% protein35% protein
– 3% fat3% fat
• Feeding rateFeeding rate
– 200% bwt/day200% bwt/day
– 50% X 4 times per50% X 4 times per
dayday
17. General Shrimp Farming ConceptsGeneral Shrimp Farming Concepts
• Marine shrimp are grown in earthenMarine shrimp are grown in earthen
ponds located in coastal areas ofponds located in coastal areas of
countries with tropical andcountries with tropical and
subtropical climates.subtropical climates.
• Ponds are filled with saltwaterPonds are filled with saltwater
pumped from estuaries and oceans.pumped from estuaries and oceans.
Small shrimp reproduced and raisedSmall shrimp reproduced and raised
in captivity are stocked into thein captivity are stocked into the
ponds and are ready for harvest in 90ponds and are ready for harvest in 90
to 120 days.to 120 days.
18. Farm LocationFarm Location
• Locate ponds close to good qualityLocate ponds close to good quality
brackish waterbrackish water
– 5-30 ppt5-30 ppt
– Farms can be inland if suitable aquifersFarms can be inland if suitable aquifers
are availableare available
• Soil should have high clay contentSoil should have high clay content
– 25%25%
• Water table should not be withinWater table should not be within
three feet of surfacethree feet of surface
19. Farm PermitsFarm Permits
• Construction permits from CorpsConstruction permits from Corps
of Engineersof Engineers
• Aquaculture Permits from stateAquaculture Permits from state
• Local permitsLocal permits
20. Farming StrategiesFarming Strategies
• ExtensiveExtensive
– Large pondsLarge ponds
– Low stocking densitiesLow stocking densities
– Little management or investmentLittle management or investment
• Semi-IntensiveSemi-Intensive
– Falls in between the two extreme of intensive andFalls in between the two extreme of intensive and
extensiveextensive
• IntensiveIntensive
– Smaller pondsSmaller ponds
– AerationAeration
– High stocking densitiesHigh stocking densities
– FeedingFeeding
21. Pond ConstructionPond Construction
• Ponds range in size from 1-10 acresPonds range in size from 1-10 acres
• 4-7 feet deep4-7 feet deep
• Gentle bottom slopeGentle bottom slope
• Well maintained leveeWell maintained levee
22. Gulf and Inland Shrimp SpeciesGulf and Inland Shrimp Species
• FoodFood
– Western white shrimpWestern white shrimp
• Penaeus vannameiPenaeus vannamei
– Northern white shrimpNorthern white shrimp
• Litopenaeus setiferusLitopenaeus setiferus
– Freshwater shrimpFreshwater shrimp
• Macrobrachium spp.Macrobrachium spp.
• BaitBait
– Brown shrimpBrown shrimp
• Farfantepenaeus aztecusFarfantepenaeus aztecus
23. StockingStocking
• Stock with post larvalStock with post larval
shrimp (PL)shrimp (PL)
– ½ inch in length½ inch in length
– Stock 40,000-80,000Stock 40,000-80,000
PLs per acrePLs per acre
– Havest 3,000lbs/acreaHavest 3,000lbs/acrea
24. ManagementManagement
• Fertilize ponds prior to stockingFertilize ponds prior to stocking
• Feed good quality shrimp feedFeed good quality shrimp feed
– 35% protein35% protein
– 3-5% bwt per day3-5% bwt per day
• Provide aeration when necessaryProvide aeration when necessary
25. HarvestHarvest
• Harvest in OctoberHarvest in October
• 22-36 count22-36 count
• Drain and seineDrain and seine
pondsponds
• Direct market or sellDirect market or sell
to processorto processor
27. Commonly Cultured MarineCommonly Cultured Marine
ShrimpShrimp
• Penaeus merguiensisPenaeus merguiensis – Banana prawn– Banana prawn
• Penaeus indicusPenaeus indicus – Indian prawn– Indian prawn
• Penaeus japonicusPenaeus japonicus - Kuruma prawn- Kuruma prawn
• Penaeus duorarumPenaeus duorarum – Atlantic pink shrimp– Atlantic pink shrimp
• Penaeus aztecusPenaeus aztecus – Atlantic brown shrimp– Atlantic brown shrimp
• Penaeus setiferousPenaeus setiferous – Atlantic white shrimp– Atlantic white shrimp
• Litopenaeus vannameiLitopenaeus vannamei – Pacific white shrimp– Pacific white shrimp
• Penaeus monodonPenaeus monodon – Black tiger prawn– Black tiger prawn
28. Shrimp SpeciesShrimp Species
• Giant Tiger Prawn (Giant Tiger Prawn (Penaeus monodonPenaeus monodon))
– Named for its huge size and banded tail,Named for its huge size and banded tail, P. monodonP. monodon
still accounts for most of the farmed shrimp coming outstill accounts for most of the farmed shrimp coming out
of Asia, but it's likely to lose that position toof Asia, but it's likely to lose that position to P.P.
vannameivannamei over the next couple of years.over the next couple of years.
– Native to the Indian Ocean and the southwesternNative to the Indian Ocean and the southwestern
Pacific Ocean from Japan to Australia, "tigers" are thePacific Ocean from Japan to Australia, "tigers" are the
largest (maximum length 363 mm) and fastest growinglargest (maximum length 363 mm) and fastest growing
of the farmed shrimp.of the farmed shrimp.
– They tolerate a wide range of salinities, but shortagesThey tolerate a wide range of salinities, but shortages
of wild broodstock often exist, captive breeding isof wild broodstock often exist, captive breeding is
difficult and hatchery survivals are low (20 to 30%).difficult and hatchery survivals are low (20 to 30%).
Tigers are very susceptible to two of the most lethalTigers are very susceptible to two of the most lethal
shrimp viruses: yellowhead and whitespot.shrimp viruses: yellowhead and whitespot.
– Reddish-orange on the sides and pearly-white on theReddish-orange on the sides and pearly-white on the
top and bottomtop and bottom
30. Shrimp SpeciesShrimp Species
• Western White Shrimp (Western White Shrimp (Penaeus vannameiPenaeus vannamei))
– Native to the Pacific coast of Central and SouthNative to the Pacific coast of Central and South
America,America,
– Leading farm-raised species in the WesternLeading farm-raised species in the Western
Hemisphere, representing more than 95% of production.Hemisphere, representing more than 95% of production.
– Because vannamei feeds on organisms which growBecause vannamei feeds on organisms which grow
naturally in the pond, it is cheaper to feed thannaturally in the pond, it is cheaper to feed than
monodon.monodon.
– White shrimp can be stocked at small sizes, have aWhite shrimp can be stocked at small sizes, have a
uniform growth rate and reach a maximum length of 230uniform growth rate and reach a maximum length of 230
millimeters.millimeters.
– They breed in captivity better than monodonThey breed in captivity better than monodon
– Hatchery survivals are high, from 50 to 60%. ThroughoutHatchery survivals are high, from 50 to 60%. Throughout
Latin America, hatcheries maintain captive stocks ofLatin America, hatcheries maintain captive stocks of
vannamei broodstock.vannamei broodstock.
– Look for it to become the dominant species in Asia overLook for it to become the dominant species in Asia over
the next couple of years.the next couple of years.
32. Shrimp SpeciesShrimp Species
• Chinese White ShrimpChinese White Shrimp (Penaeus chinensis(Penaeus chinensis))
– Native to the coast of China and the west coast ofNative to the coast of China and the west coast of
the Korean peninsula.the Korean peninsula.
– Chinese white shrimp grow better in lower waterChinese white shrimp grow better in lower water
temperatures (down to 16 degrees Celsius) thantemperatures (down to 16 degrees Celsius) than
vannameivannamei andand monodonmonodon
– Tolerate muddy bottoms and very low salinities—Tolerate muddy bottoms and very low salinities—
and, unlike the above species, Chinese whiteand, unlike the above species, Chinese white
shrimp readily mature and spawn in ponds.shrimp readily mature and spawn in ponds.
– On the negative side, they have a high proteinOn the negative side, they have a high protein
requirement (40 to 60%), a small size (maximumrequirement (40 to 60%), a small size (maximum
length of 183 millimeters), and a lower meat yieldlength of 183 millimeters), and a lower meat yield
(56%) than(56%) than monodonmonodon (61%) and(61%) and vannameivannamei (63%).(63%).
– Also,Also, chinensischinensis appears to be more susceptibleappears to be more susceptible
to viruses thanto viruses than vannamei.vannamei.
33. Shrimp SpeciesShrimp Species
• Freshwater Prawns (Freshwater Prawns (Macrobrachium sppMacrobrachium spp.).)
– World production of farmed prawns has risen to aroundWorld production of farmed prawns has risen to around
200,000 metric tons, worth about a billion dollars, most200,000 metric tons, worth about a billion dollars, most
of it from Bangladesh and China.of it from Bangladesh and China.
– The genus Macrobrachium, which includes about 200The genus Macrobrachium, which includes about 200
species, almost all of which live in freshwater for atspecies, almost all of which live in freshwater for at
least part of their life cycle, native to all continentsleast part of their life cycle, native to all continents
except Europe.except Europe.
– The favored species for farming has always been M.The favored species for farming has always been M.
rosenbergii, sometimes called the "giant river prawn" orrosenbergii, sometimes called the "giant river prawn" or
the "Malaysian prawnthe "Malaysian prawn
– In the United States, there are more than 500 smallIn the United States, there are more than 500 small
freshwater prawn farms (M. rosenbergii).freshwater prawn farms (M. rosenbergii).
– Resemble giant tiger shrimp, but they're bigger,Resemble giant tiger shrimp, but they're bigger,
chunkier, lighter in color, and their shells are always on.chunkier, lighter in color, and their shells are always on.
– If the bottom part of the shell on the second tailIf the bottom part of the shell on the second tail
segment overlaps the shell on the first and thirdsegment overlaps the shell on the first and third
segments, it's a freshwater prawn.segments, it's a freshwater prawn.
34.
35. Shrimp...Shrimp...
• Brown shrimp (Brown shrimp (Farfantepenaeus aztecusFarfantepenaeus aztecus))
– Found in Atlantic and Gulf of MexicoFound in Atlantic and Gulf of Mexico
– Most abundant of the three Gulf ShrimpMost abundant of the three Gulf Shrimp
– Closely related to the pink shrimpClosely related to the pink shrimp
– The brown shrimp is found in murkier andThe brown shrimp is found in murkier and
often deeper water.often deeper water.
– Spawn offshore from November to April.Spawn offshore from November to April.
– Young adults move out of protected marshYoung adults move out of protected marsh
areas from May to July.areas from May to July.
• Excellent bait speciesExcellent bait species
candidate!candidate!
36. More SpeciesMore Species
• White (Atlantic) shrimpWhite (Atlantic) shrimp
((Litopenaeus setiferusLitopenaeus setiferus))
– Found in Atlantic and Gulf of MexicoFound in Atlantic and Gulf of Mexico
– Second most harvested species in the three Gulf ShrimpSecond most harvested species in the three Gulf Shrimp
– The white shrimp is generally found in waters that areThe white shrimp is generally found in waters that are
muddier, shallower, and less salty than waters wheremuddier, shallower, and less salty than waters where
pink shrimp and brown shrimp livepink shrimp and brown shrimp live
– Spawn offshore from March to OctoberSpawn offshore from March to October
– Juvenile whites tolerate low salinity better than brownsJuvenile whites tolerate low salinity better than browns
– Young adults migrate offshore from July to NovemberYoung adults migrate offshore from July to November
37. Shrimp SpeciesShrimp Species
• Pink shrimpPink shrimp
((Farfantepenaeus duorarumFarfantepenaeus duorarum))
– Found in Atlantic and Gulf of MexicoFound in Atlantic and Gulf of Mexico
– Least abundant of the three Gulf ShrimpLeast abundant of the three Gulf Shrimp
– This species generally lives in clearThis species generally lives in clear
waters.waters.
– Spawn offshore from May throughSpawn offshore from May through
NovemberNovember
– Migrate out of marshes from April toMigrate out of marshes from April to
SeptemberSeptember
38. Broodstock PerformanceBroodstock Performance
• 40 g females, 35 g males40 g females, 35 g males
• Daily spawning rate (natural mating),Daily spawning rate (natural mating),
• As a % of the total female population: 5-8%/dayAs a % of the total female population: 5-8%/day
• Egg Production:Egg Production: 200-250,000 per female per200-250,000 per female per
spawnspawn..
• Nauplii production: 100-150,000 per female perNauplii production: 100-150,000 per female per
spawn.spawn.
• Useful productive life of the broodstock: 3-6Useful productive life of the broodstock: 3-6
monthsmonths
• Total spawns per female during her useful life:Total spawns per female during her useful life:
10-1510-15
40. Pond DesignPond Design
• 1 to 25 A in size1 to 25 A in size
• Silt soilSilt soil
• Good water sourceGood water source
– Saline wellSaline well
– Pumped fromPumped from
oceanocean
– Hauled fromHauled from
oceanocean
• Rectangular inRectangular in
shapeshape
48. Acclimation to Low SalinityAcclimation to Low Salinity
SalinitySalinity
Change (PPT)Change (PPT)
TimeTime
(hrs)(hrs)
Change PerChange Per
Hour (PPT)Hour (PPT)
32 to 1632 to 16 88 22
16 to 816 to 8 88 11
8 to 48 to 4 88 0.50.5
4 to 24 to 2 88 0.250.25
2 to 12 to 1 88 0.1250.125
1 to 0.51 to 0.5 88 0.0630.063
49. Marketing ShrimpMarketing Shrimp
• Price ranges from $1-4/lb heads on orPrice ranges from $1-4/lb heads on or
$4-10/lb tails (Size dependant)$4-10/lb tails (Size dependant)
• Sell to wholesalerSell to wholesaler
• ProcessProcess
– Remove headRemove head
– HACCP certification requiredHACCP certification required
– Market IQF or block frozen productMarket IQF or block frozen product
53. Pacific white shrimp biology
Food habits – benthic organizms, detritus
Preferred water temperatures – 25 to 30o
C
Preferred salinity – 15 to 25 ppt
Sexual maturity - 1 year
54. Life Cycle
Adults spawn at
sea, the eggs and
larvae drift to
inshore estuaries
where the
juveniles grow.
Adults move back
to sea to spawn.
55. Marine shrimp have
been harvested from
coastal waters,
processed and
shipped as frozen
product for many
years. Shrimp
farmers took
advantage of the
infrastructure to
market cultured
shrimp.
60. Ponds should be
built on salt
flats, which are
covered during
high tide twice a
month.
Mangrove forest
should be
preserved.
Mangroves are
flooded daily by the
high tides
61. Ponds are 5 to 10 ha in area, water
depth averages 1 m and bottoms are flat
and slope to a drain to aid shrimp
harvest.
64. Shrimp can be cultured:
1.Extensively
2.Semi-intensively
3.Intensively
65. Postlarvae enter
the pond with the
tide or are stocked
at < 4/m3
.
Sometimes the
pond entrance is
screened to limit
entrance of
predators. Water
is not fertilized and
shrimp are not fed.
Extensive
culture
66. Semi-intensive culture
Postlarvae are stocked into ponds at 15
to 25/m3
and are fed daily. Some water
exchange is practiced to maintain water
quality.
67. Shrimp are fed sinking
pellets which are
distributed over the
pond surface. Feeding
trays are sometimes
used to help determine
shrimp appetite.
69. Ponds are fed daily
Shrimp are
sampled weekly
to check growth
rate
Intensive Culture
70. Expansion of
pond area leads to
poor water
quality and high
shrimp mortality
Water intake pipes
and effluent
release in Taiwan
71. Diseases have reduced the shrimp
harvest in many countries.
Black-spot disease
Taura virus
72. Shrimp are benthic animals and live on the
pond bottom. Pond bottoms should be dried
to oxidize organic matter in pond mud before
stocking shrimp. Reducing organic material
improves water quality.
78. World harvest of farmed marine
shrimp in 2000 was 1,087,111 MT
Ecuador
81000 MT
India
73,000 MT
China
114,000 MT
Thailand
204,000 MT
Indonesia
98,000 MT
79. The East produced 90% of the
world farmed marine shrimp
while the West produced 10 %.
80. Harvest of marine shrimp in the U. S.
in 1999 was 2,098 MT, less than 0.2 %
of world harvest.
81. Excellent markets and
ease of culture has made
shrimp one of the fastest
growing aquaculture
industries during the
past 20 years. THE END
Notes de l'éditeur
Total world harvest from aquaculture and wild capture was 3.2 million metric tons in 1999. About 768 million metric tons, 24% of the total world harvest, of marine shrimp was farmed. The U. S. is the fourth leading producer of wild captured marine shrimp after China, India and Indonesia. However, the farmed harvest of marine shrimp in the U. S. is about 2,100 metric tons, less than 0.02% of world farmed harvest. Marine shrimp are the most popular seafood among U. S. consumers. Thailand is the leading producer of farmed marine shrimp.
Marine shrimp are farmed in most countries with a tropical climate and access to the sea. The two most popular cultured marine shrimps are Pacific white shrimp, Peneaus vannamei, and the Pacific tiger shrimp, Peneaus monodon.
The Pacific white shrimp is native to the west coast of Mexico, Central America and Colombia, Ecuador and Northern Peru. The Pacific white shrimp has been introduced into the southern U. S., the east coast of Mexico, Central America and the Caribbean and Atlantic ocean coast from Colombia to Northeast Brazil. Some Caribbean Islands have also introduced the Pacific white shrimp. The Pacific tiger shrimp is native to the warm tropical waters of the western Pacific and Indian oceans.
The Pacific white shrimp is preferred for culture in the Western Hemisphere. The white shrimp is benthic, feeding on worms and microorganisms attached to detritus found on the bottom. Preferred water temperature and salinity ranges between 25 and 30o C and 15 to 25 ppt, respectively. However, the Pacific white shrimp can be culture in low salinities and freshwater with high alkalinity, hardness and cloride ion content. In the U. S., the white shrimp can be raised in open ponds only in the summer when water temperatures permit good growth. Shrimp that are not maintained indoors in warm water will died during the winter months in open ponds. The Pacific white shrimp reaches sexual maturity in 1 year.
Adults spawn in the open ocean. Thes eggs and larvae are carried by currents into the esturaries where the young shrimp feed and grow among the mangrove forests. As the shrimp mature at 1 year of age, they swim back to the open ocean to spawn.
Marine shrimp are harvested from coastal waters by trawl nets pulled by boats. Marine shrimp captured from the ocean have been processed and marketed in the U. S. for many years. Marine shrimp is the most valueable seafood sold in the U. S. Marine shrimp farming blossomed in the past 20 years. Shrimp farmers took advantage of the processing facilities and marketing network established by the marine shrimp capture industry to export their shrimp to the U. S., Europe and Japan.
Small shrimp ( postlarvae ) for stocking ponds can be captured from the wild. Small mesh push nets are used in the shallow estuaries to capture postlarvae. Postlarvae captured in the wild often have both desireable and undesireable shrimp species along with small predacious fishes. Separation of desireable shrimp postlarvae from undesireable shrimp postlarvae is difficult and usually all postlarvae are stocked.
Postlarvae can also be produced in captivity. Numerous larval stages are passed before reaching the postlarval stage. Natural food ( phytoplankton ) must be provided to the larval stages grown in the hatchery. However, only desireable shrimp species are raised and contamination with undesireable organisms is not a problem.
Mature females can be captured ( carrying sperm packet ?) from the ocean and transported to the hatchery or the males and females can be matured in captivity. Capturing mature females from the ocean is cheaper than raising brood shrimp in cativity. However, disease transfer and genetic improvement is more easily controlled when brood shrimp are raised in captivity.
Postlarvae are stocked into earthen ponds for growout to market size.
Ponds are normally constructed on salt flats that have little vegetation and are flooded at high tide twice a month. Ponds can also be built on dry land next to estuaries that is never flood at high tide. Some shrimp ponds have been built in mangrove forest. However, building ponds in mangrove forest is more costly than building pond on salt flats or dry land. Also, mangrove forests are important nursery areas for many young marine organisms and should be preserved.
Shrimp ponds are large, 5 to 10 hectares in area, and should have flat bottoms without obstructions to assist with pond draining and shrimp harvest. Water depth averages 1 m.
Salt water is pumped from estuaries into earthen distribution canals. Water flows from the distribution canals into the ponds. Large amounts of water are normally required to farm shrimp. Large diesel fueled pumps are use to lift water into the distribution canals. Some shrimp farms can use tidal water to fill ponds. However, most farms only have access to tidal water a few days per month so pumps are needed to assure water supply on demand.
Concrete structures called “ monks” or gates control the entrance, exit and depth of water in the ponds. Screens are used to filter the water as it enters the ponds to remove unwanted aquatic organisms and to stop the shrimp from leaving the ponds with water outflow.
Shrimp are grown to markets using extensive, semi-intensive and intensive systems.
Initial efoorts to farm shrimp used extensive culture methods. Often, shrimp are allowed to enter the pond with the tide. No control over the quantity and species of shrimp that enters the pond is maintained. Sometimes the pond entrance is screened to reduce unwanted shrimp and predators from entering the pond with tidal water. The number and species of shrimp desired is stocked into the pond. Stocking density is low, less than 4 shrimp/m2. Spond water is not fertilized and shrimp are not fed. Shrimp growth and yield are dependant on natural water fertility and the food organisms produced in the pond. Shrimp yield per area is low, ( ? ), but cost of production is also low.
Water entering ponds managed semi-intensively is contolled and filtered. Stocking density is between 15 and 25 postlarvae/m2 of pond. Pond waters are often fertilized with organic or inorganic fertilizers to increase fertility. Shrimp are fed daily but naturally produced food organizms are important for fast shrimp growth and high yields. Some pond water is exchanged daily to assure that good water quality is maintained. Ponds that have little or no water exchange are aerated mechanically to maintain high levels of dissolved oxygen.
Shrimp are fed sinking pellets evenly distributed over the pond water surface. Shrimp are benthic feeders and will not rise to the water surface to eat floating pellets. Shrimp are unable to consume a whole pellet but slowly nibble the pellet, consuming small particles. Feed can be placed on trays to help determine shrimp appetite. Trays are checked 1 to 2 hours after feeding to see if the daily allotment of feed is consumed by the shrimp. If feed is not consumed, the daily allotment is is reduced.
Small circular and retangular earthen ponds and contrete tanks are used to culture shrimp intensively. Ponds are stocked with 35 to 250 shrimp/m2 and pond water exchange and mechanical aeration is provided continually. Shrimp are fed nutritionally complete pelleted feeds and natural pond foods are not important for fast growth and high yields.
Cast nets are used to capture shrimp and check for growth rate weekly. Shrimp that are not growing well must be fed more or pond water exchange increased to improve water quality.
Intensive shrimp culture has expanded rapidly in some regions. Demand to fill ponds and exchange pond waters has increased. Effluents are released back into water supply canals or estuaries. Water quality deteriorates and shrimp mortality increases due to diseases.
In some cases, the shrimp farming industry collapses because of high shrimp mortality during growout.