It is normally somewhat pear-shaped in outline, but members of this species vary greatly in size and shape. After spawning in early spring, the oyster loses a great deal of weight. This event usually coincides with the spring bloom of phytoplankton, their primary food source. Reproduction Reproductive organs can be readily observed only during the breeding season. There is no reproductive activity during the winter.
Sexual maturity is a function of size rather than age.
The first spawning usually occurs when the oyster is 2 years of age. Behavior Oysters usually colonize in beds. Competition for space is a most important source of mortality. Uncrowded, oysters can live to be 20 years old. The beds are a permanent social structure unless they are separated physically and forcefully.