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Oyster Culture in North America

Oyster Culture in North America. • SRAC 0432 The Cultivation of American Oysters •SRAC 0433 Biology and Culture of the Hard Clam ( Mercenaria mercenaria ) •SRAC 0434 Aquacultured Oyster Products: Inspection, Quality, Handling, Storage, Safety

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Oyster Culture in North America

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  1. Oyster Culture in North America •SRAC 0432 The Cultivation of American Oysters •SRAC 0433 Biology and Culture of the Hard Clam (Mercenaria mercenaria) •SRAC 0434 Aquacultured Oyster Products: Inspection, Quality, Handling, Storage, Safety •SRAC 4300 Extensive Culture of Crassostrea virginica in the Gulf of Mexico Region •SRAC 4301 Hard Clam Hatchery and Nursery Production •SRAC 4302 Oyster Hatchery Techniques

  2. Distribution The eastern oyster, Crassostrea virginica, is native to the East coast of Canada and United States, Gulf of Mexico and Caribbean, and as far south as the Northern coast of South America. pacific oyster eastern oyster The pacific oyster, Crassostrea gigas, was introduced from Japan and extends from Alaska to Baja California

  3. Oyster Biology Feeding Habits–feed on anything 3-12 microns in size by filtering from the water and receive nutritional value from phytoplankton and detritus Water temperature – 25 to 30oC for best growth Salinity – 10 to 22 ppt for best growth Growth to 15 cm– 9 to 12 months in the Gulf of Mexico

  4. Life History 1. Reach sexual maturity at 1 year of age. 2. Protandric - Young oysters are usually male and change to female after first spawning season. 3. Water temperatures above 25oC trigger spawning in the Gulf of Mexico. 4. Salinity above 10 ppt. 5. Spawn between March and November Larval period is 14 to 21 days

  5. Spawning & Fertilization Sperm triggers females to release eggs. Females can release millions of eggs! Larvae with a muscular foot looking for a site to set. sperm

  6. Wild-Caught 1.Seed Production - wild Seed can be collected from the wild on shells and artificial substrates (cultch) placed near spawning grounds.

  7. Hatchery-Reared 2. Seed Production - hatchery Adults are induced to spawn and the larvae are fed algae until they are ready to set.

  8. Triploid Oysters Triploid oysters that can not reproduce are produced in a hatchery. Triploid oysters grow faster than normal diploid oysters and have good flavor (high glycogen content) during the summer spawning season. gonad

  9. Eyed Larvae Larvae ready to set can be placed in upwellers containing crushed shell or tanks with bags of shell tanks larvae upwellers crushed shell

  10. Cultchless & Spat on Shell Spat on crushed shell are single set and spat on whole shells are multiple or cultch set.

  11. Nursery Spat can be placed in protected intertidal zones to grow and harden for several months. Exposing the oysters to the air protects them from predators.

  12. Growout of Spat on Whole Shell Spat on whole shell are grown: 1. On the bottom in reefs 2. On ropes suspended off the bottom Shells with spat are moved from spawning or nursery grounds to growout areas. Little care is given to the oysters. Culture is extensive.

  13. Cultchless Growout 2. Cultchless or single oysters are grown in: bags trays

  14. Cultchless Growout Trays and bags are suspended off the bottom by ropes tied to rafts and floats or on stationary platforms. Culture is extensive. raft platform floats Oyster density and sizes, predators and fouling are controlled.

  15. Grading Shaker table grader Oysters are graded several times to assure uniform growth and size at harvest. Uniform sizes Variable sizes

  16. Control of Predators Predators are controlled by exposing the oysters to air, keeping the oyster off the bottom and manual cleaning. starfish black drum crabs oyster drill

  17. Control of Fouling cleaned fouled Removed by drying, pressure spraying, manual cleaning and dipping in a toxic solution. Fouling organisms compete for space and food with oysters and restrict water flow through enclosures

  18. Harvest of Reef Oysters Reef oysters are harvested from the bottom with tongs and dredges. Oysters are ready for harvest in 1 to 5 years depending on water temperatures. Dying lifestyle in Florida!!

  19. Harvest of Farmed Oysters Oysters cultured in bags, trays and on ropes are harvested mechanically because of their weight.

  20. Purging Oysters are often contaminated by bacteria and viruses harmful to the consumer of raw oysters. Oysters can be purged by moving them to clean water in the ocean or on land.

  21. Market shucked canned live Oysters are sold live, fresh and frozen on the half shell and shucked, canned and smoked. Fresh on half shell Frozen on half shell

  22. World Yield of Oysters France 152,129 United States 125,870 China 2,284,663 Korea 185,339 Japan 222,853 about 3,944,000mt in 2000

  23. 1999 U.S. Oyster Yields Wild and farmed harvest of oyster meat was 12,587 mt. Eastern oyster meat was 9,109 mt (72%) of total harvest. Pacific oyster meat was 3,478 mt (28%) of total harvest. Meat is 10% of the whole oyster weight!

  24. The End

  25. http://pars.ifas.ufl.edu/Technical%20Session/03-0129-ShirleyBaker/CLAMMRS02-Web_files/frame.htmhttp://pars.ifas.ufl.edu/Technical%20Session/03-0129-ShirleyBaker/CLAMMRS02-Web_files/frame.htm

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