Environmental characteristics of edible oyster beds in and around Tuticorin

The investigations on various hydro-biological parameters which influence the condition factor, spawning and the resource characteristics of the edible oyster Crassostrea madrasensls around Tuticorin have been conducted in three habitats of oyster beds, namely coastal (Tuticorin Bay), mangrove (Korampallam Creek) and estuarine (Punnakayal) areas. Observations on the stages of maturity, spawning and condition of oysters in the three habitats have been made and a correlation of the above biological aspects of the oysters with the environmental factors have been attempted. A direct correlation has been observed between the biological aspects of oysters and the productivity parameters of the habitat. The water temperature also showed a direct relationship with the condition factor of the oysters. The mean value of the condition factor of the oysters were found to be at the optimum level during April when productivity parameters were observed to be at higher level. The chemical factors especially the nutrients such as nitrates and phosphates showed an indirect relationship with maturity and condition of the oysters. Among the different habitats, the mangrove area registered higher productivity rates which has a well defined relation with the condition of oysters.