Indian edible oysters (Crassostrea nmdrasensis) of average size 6.4 ± 1.2 cm x 4.3 +. 0.8 cm were exposed to two sublethal concentrations of copper viz. 0.5 ppm and 1 pprn at a salinity of 12 ppt for a period of four weeks. Adductor muscle, mantle and gill tissues were dissected out and subjected to histological examination. The results revealed extensive damages to the adductor muscle, mantle and gills of the copper treated oysters. The maximum damage occurred in the epithelial cells of all the tissues studied in the oysters exposed to copper. It was also observed that the physiological responses such as opening and closure of the shell valves and feed filtration were impaired in the animals exposed to copper

Edible oyster Crassostrea nzadrasensis, histopathology, copper toxicity