SEASONAL GONADAL CHANGES IN THE ADULT OYSTERS, OSTREA VIRGINICA, OF LONG ISLAND SOUND

Abstract

During the cold season gonads remain quiescent. At that time the gonadal follicles are small and contain only cells of the early stages of gametogenesis. Rapid development of gonads occurs in the spring and oysters are ripe in June. Gonads of partially spawned oysters are characterized by the contraction of follicles, invasion of phagocytes, and cells of the connective tissue which fill intrafollicular spaces. Re-sorption of the gonad is completed in Oct. and they enter the indifferent stage during which the sexes are indistinguishable. Sex reversal, if occurring, probably takes place during this stage when the sexuality of an oyster is least defined. At the end of the indifferent phase, gametogenesis occurs but is soon stopped by low temp. Sexes are again distinguishable and remain so all winter.