Oysters in United States

Oysters in United States
There are five species of oysters in the United States, three on the East Coast, and two on the West Coast, one of which was introduced from Japan. About two weeks after the eggs hatch the free swimming larvae attach and cement themselves to a hard surface (rock and shell) on the bottom. To provide for this attachment, oysters growers throw materials, such as the shells of quahogs (the cultch), into the water where spawning takes place. Some time after the set (attachment), the small bivalves may be removed top areas where tidal conditions provide a better supply of food. This also allows more room for growth.

Since oysters and other bivalves may be eaten raw or without sufficient cooking to destroy any disease causing bacteria that might be present , and since they are grown near the shore, often near highly populated areas, great care must be taken to make sure that bivalve growing areas are not polluted with even traces of human excrement. Control of bivalve harvesting areas is supervised by a division of the Food and Drug Administration but must be effected by state authorities.

This control consists of tests for disease indicator bacteria on shellfish growing water and ion shellfish meats, sanitary surveys to determine that traces of sewage are not reaching the growing areas, and the licensing of shellfish dealers who must record the areas from which the valves were taken, from whom they were purchased, to whom they were sold. Some bivalves may be taken from areas that do not meet the absolute specifications for approved areas but that are not grossly polluted, provided they are depurated in bacteriological clean waters, either in the ocean or in tanks, under supervision by the state.
Oysters in United States