Gametogenic patterns of the larviparous oyster Ostrea nomades from Karachi, Pakistan (northern Arabian Sea)

The larviparous oyster Ostrea nomades from two different localities was examined histologically and found to be mostly hermaphroditic. However, pure males, pure females and indifferent oysters were also found. The hermaphrodites of O. nomades were classified into three categories: ambisexual, predominantly female and predominantly male. Gonadal development appears to take place throughout the year with increasing activity and ripening in the winter months, leading to immediate spawning and later resorption. The number of brooding larvae of O. nomades was low at both collection sites.