Alteration in oxygen consumption of fresh water fish Puntius stigma exposed to sublethal concentrations of insecticide Phytofos

Abstract

Now a days large number of new insecticide formulations are used to protect the crops from various insects. Water pollution caused by insecticide is a serious problem it affects the aquatic animals adversely. Static bioassay experiments were conducted to find out 96 hr LC 50 value for fish Puntius stigma. For finding out respiratory response, the  fishes of average length 3.7 Cm. were exposed to 0.4 mg/l (1/10 96 hr LC 50) and 0.8 mg/l (1/5 96 hr LC 50) concentrations of Phytofos. The respiratory response in terms of oxygen consumption was recorded at 24,48,72 and 96 hours.At the end of first 24 hours there is  an increase in oxygen consumption is noted at 0.4 mg/l and 0.8 mg/l concentrations. At 48 hours exposure there is decrease in oxygen consumption at concentration 0.4 mg/l and at concentration 0.8 mg/l. At the end of 72 hours, there is a fall in oxygen consumption rate at both the concentration is recorded. At the end of 96 hours exposure, a reduction in oxygen consumption rate at concentration 0.4 mg/I and a just a little more fall in oxygen consumption at concentration 0.8 mg/l is noted. On transfer to toxicant free water (after 96 hours to 120 hours exposure) fishes showed recovery. Oxygen consumption in fishes are discussed with respect to time of exposure and sub lethal concentrations of insecticide Phytofos.