The American oyster is native to the Atlantic coast of North America from the Canadian Maritimes southward around Florida, and all along the Gulf of Mexico to the West Indies and Venezuela. It has been introduced along the Pacific coast in California and Washington, and also in Hawaii.

HABITS:

The American oyster lives in water that is temperate (warm all year) and not too cloudy. They grow only in areas where salt and fresh water mix together, like salt marshes. They are efficient filter-feeders: planktonic plants and animals are drawn into gills by the beating of many small hairs (cilia), then moved along by the hairs to the labial palps and mouth.

SPAWNING:

Spawning takes place when the temperature increases to within a range of 68-90° F. individual females release 14-114 million eggs free in the water; fertilization is external. After hatching, young drift as veligers for two to three weeks; upon locating suitable substrate, they settle to the bottom, attach themselves, and remain there for their adult life.

GROWTH:

In the Maritime Provinces of Canada, 4-7 years to reach 3 in.; in Long Island Sound (U.S.), 1 year to reach 0.75 in., 3 to reach 3 in., and perhaps 20 to reach 15 in.; in the Gulf of Mexico, 2 years to reach 3.5 in.

USES:

An important aquaculture industry based in the farming of this species has developed in the U.S. East Coast and the Gulf of Mexico.

CULTURE:

American oysters are well suited for farming because they are in demand, grow rapidly, can be spawned artificially without great difficulty, and need not be impounded because they attach to the bottom. By using off-the-bottom rearing techniques, greater production of well-shaped oysters can be achieved. Extensive literature on species biology and results of aquaculture trials are readily available in government manuals.

REFERENCES:

Breisch, L. L., and V. S. Kennedy. 1980. A selected bibliography of worldwide oyster literature. University of Maryland Sea Grant Publication UM-SG-TS-80-11. College Park: University of Maryland Sea Grant Program.

Burrell, V. B. Oyster culture. Pages 235-273 in J. V. Huner and E. E. Brown, editors. Crustacean and mollusk aquaculture in the United States. Avi Publishing Company, Westport, CT.

Galtsoff, P. S. 1964. The American oyster Crassostrea virginica Gmelin. Fishery Bulletin 64:1-480.

Shaw, W. N. 1969. The past and present status of off-bottom oyster culture in North America. Transactions of the American Fisheries Society 98:755-61.