Seasonal gonadal changes, spawning and condition index of oyster Crassostrea madrasensis (Preston) in the Korampallam creek, Tuticorin

Abstract

Seanod changca in the gonad of edible oyrter Crassosma madmsensis were oberved hir- tologically in samples colleated &om Korampallam creek during February 1987 to January 1988. Two peak spawning reasons wore observed in March and September. Gametogenerir atarted in May 1987 and ripe atagea wore noticed from September 1987. Spawning occurred during Sep- tember to Ootober. A second cycle of gametogenerir began during November 1987 and higher percentage of ripe rtages were noticed during March 1987 and spawning commenced in early March. Oyaten showed 5.60% of apent stage8 with reridual eggs throughout the year except August, September. December and February. Oyden panred through indoterminate atage before the advance of gametogenesis. No hermaphrodites were observed during thin period.