It is cultured now in Australia, New Zealand, Europe, many parts of Asia such as Korea and China, and in North and South America. Ron Lovell is a free-lance writer who lives in Gleneden Beach, Oregon. Oyster is the common name for any of about 50 species of marine bivalve mollusks. Several oyster species are important food commodities, including the Pacific oyster farmed on the West Coast of the United States. Species known as pearl oysters belong to a separate family.
Oysters attach themselves to rocks or lie on the sea bottom.
Unable to move, they are often dislodged from either resting place by waves. Their shell is irregularly oval in shape. It consists of a left and right valve joined together at the narrow anterior end by an elastic ligament that acts as a hinge. Attached to both valves is a strong muscle called the adductor, which keeps the shell tightly closed. When the adductor relaxes, the elastic ligament pulls the valves apart.