Studies on the toxicity of methyl parathion on fresh water fish oreochromis mossambicus

Studies were made to evaluate the effect of sub lethal concentration of methyl parathion on biochemical changes of Oreochromis mossambicus. The fishes were caught from culture pond of Vallam fish farm near Thanjavur and acclimatized to the laboratory conditions. Experiments were conducted at Serfoji college lab. LC50 values for 96 hours were determined for methyl parathion and were found to be 0.29 ppm. The fishes were exposed to 10% sub lethal concentrations of the 96 hours LC50 value for 7, 14 and 21 days along with control. The changes in carbohydrate, protein and lipid content of ovary observed at different exposure periods. Significant depletion of biochemical constituents were observed in 21 days of exposure.