CHRONIC EFFECTS OF DIMETHOATE ON THE REPRODUCTIVE POTENTIAL OF THE FRESH-WATER TELEOST, CLARIAS-BATRACHUS

In a study of the fresh-water teleost Clarias batrachus L., fish were exposed to a commercial 300 g litre(-1) EC formulation (of dimethoate at 10.8 mg AI litre(-1)) for a period of six months extending over pre spawning, spawning and postspawning phases of the annual reproductive cycle. A parallel group of fish without dimethoate served as control. Significant reduction in the fecundity pattern of exposed fish was not iced throughout the experimental period. The gonadosomatic indices of both male and female exposed fish were reduced when compared with the control fish. The reduction continued until the termination of the exp eriment. It was inferred from the present study that, at this level, t his pesticide affects the reproductive potential of this fish.