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Presentation by Karen Jensen Marine Aquaculture 2013. Shrimp in Aquaculture. Common Saltwater Species. Whiteleg shrimp Penaeus vannamei. Family Penaeidae. Giant tiger prawn Penaeus monodon. Economic importance. World production of captured and farmed shrimp is ~6 million tons
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Presentation by Karen Jensen Marine Aquaculture 2013 Shrimp in Aquaculture
Common Saltwater Species • Whiteleg shrimp • Penaeusvannamei • Family Penaeidae Giant tiger prawn Penaeusmonodon
Economic importance • World production of captured and farmed shrimp is ~6 million tons • 25-30% of worldwide saltwater shrimp production is in ponds • Texas produces the most of any state- 8 million lbs in 2001 • Florida has the largest hatcheries • Penaeusvannamei aquaculture has boomed in recent years • 2011: 2,877,542 tons produced • Market price decreasing, 3-3.5 USD/kg in 2005 • Main suppliers to US: Thailand, Ecuador, India, China, Vietnam • Penaeusmonodon • 2011: 662,453 tons produced • Market price in Japan: 9-14 USD/kg in 2004
Life cycle • After hatching • 6 nauplius stages • Attracted to light, feeds on yolk • 3 zoea stages • 3 mysis stages • Postlarvae are carried to the protection of estuaries • Development through larval stages takes ~3 weeks • Juveniles and adults migrate offshore and mature in the ocean • Also spawn offshore • Females grow faster and larger
Reproduction in captivity • Many hatcheries collect gravid females from the sea to spawn in captivity • No control of genetics, disease tolerance • Captive maturation can be done • Large tank at low density: 5-7 shrimp per meter • Constant conditions- temp, pH, light, good nutrition- are important for maturation • Eyestalk ablation in females • After spawning, the female releases eggs into the water, fertilizing them by simultaneously rupturing the spermatophore • 150,000-200,000 eggs per spawn (P. vannamei) • 500,000-750,000 eggs/spawn (P. monodon)
Production methods • Hatcheries • Eggs hatch within 24 hours • After hatching, nauplii are stocked into V or U-shaped tanks • ~3 weeks to reach postlarval stage • Nurseries • Smaller ponds or intensive raceways act as an intermediate between hatchery and grow-out size • Not always used • Most US prawn farms are semi-intensive or intensive ponds • Must make up for land costs, short growing season • Extensive ponds common in South/Central America, where land is cheaper • Ponds stocked in April/May • Stocked at post-larval stage, <1/2 inch
Harvest • Harvest in October when temps drop and growth slow • Potentially 3 crops per year in a warm climate- not in US • Drains are invaluable in shrimp ponds • Gently sloping ponds with drains allow shrimp to concentrate in a catchbasin
Feeding • Ponds are fertilized prior to stocking • Stimulates phytoplankton and zooplankton production • Artificial supplemental food still necessary • Lower protein needed for P. vannamei: 18-35% • 36-42% for P. monodon, more carnivorous • Protozoea can be fed diatoms • Mysid stages can be fed Artemianauplii • Broodstock fed squid, mussels, and cockles
Water Chemistry Parameters • pH 7-9 • DO 5-15 ppm • Temperature 26-29 ˚C • 5-35 ppt salinity • 100-500 ppm hardness (Ca2+ concentration) • Lower may reduce calcified shell • Higher may produce encrustations on the shells • Hardness increased by addition of calcium in the form of agricultural gypsum
Marine Shrimp Aquaculture Advantages Disadvantages • Very popular food item in the US, Japan, and increasingly in EU • Fast-growing (~6 months) • FCR 2:1 or lower • Some natural food supplied • Disease-resistant strains are being produced • Pond must be near brackish water source • Mangrove ecosystems used in pond construction (improving) • Few hatcheries produce post-larval shrimp • Must have pristine water quality • Higher densities usually required to make a profit, increases risk