III.

Reproduction

Oysters have varying methods of reproduction. The European oyster and the Olympia oyster of the American Pacific Coast are hermaphrodites—that is, their reproductive organs contain both eggs and sperm. The eggs are fertilized within the body and are retained in the gills until shell-bearing larvae are formed. In the American bluepoint oyster of the Atlantic Coast, the sexes are separate. Females discharge millions of eggs into the water, where fertilization occurs. The larvae develop within six hours, swim actively for about two or three weeks, and then settle on stones or shells, where they mature by the end of the first year. The reproductive season varies according to the latitude of the habitat.