MODULATION IN BEHAVIOR AND RESPIRATORY DYNAMICS OF THE FRESHWATER FISH Labeo rohita ON SUBLETHAL DIAZINON EXPOSURE

Present study was performed to investigate the impact of sublethal concentrations of Diazinon on different behavioral aspects of Labeo rohita. LC50 of Diazinon for 96 hrs by static bioassay test was found to be 0.004ml/l. The fishes were exposed for 96 hrs. Diazinon exposure caused decrease in resting period, increase in opercular movement and air gulping, increase in jerk, threat and burst swimming behavior. Slow response during feeding, swimming on the upper surface of water hanging vertically, spreading throughout aquarium was also observed in pesticide treated fishes. In the highest concentration i.e. 0.01ml/l mortality of fishes occurred. Fishes died with bending of the mid section of the body and opening mouth. Fishes lay down motionless at the bottom of aquarium before death. Fading of body colour was also observed in Diazinon treated fishes. These results suggest that sublethal concentrations of Diazinon have negative impact on the behavior and respiration of Labeo rohita.