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. 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. The pacific oyster, Crassostrea gigas, was introduced from Japan and extends from Alaska to Baja California pacific oyster eastern oyster Distribution

3. 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 30 o C for best growth Growth to 15 cm – 9 to 12 months in the Gulf of Mexico Salinity – 10 to 22 ppt for best growth Oyster Biology

4. 1. Reach sexual maturity at 1 year of age. 3. Water temperatures above 25 o C 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 2. Protandric - Young oysters are usually male and change to female after first spawning season. Life History

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

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

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

8. 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 Triploid Oysters

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

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

11. 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. Nursery

12. 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. Growout of Spat on Whole Shell

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

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

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

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

17. 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 fouled cleaned Control of Fouling

18. 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!! Harvest of Reef Oysters

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

20. 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. Purging

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

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

23. 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! 1999 U.S. Oyster Yields

24. The End

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