A study on median lethal concentration and behavioural responses of cichlid fish, Etroplus maculatus (Bloch, 1795) exposed to organophosphorus insecticide, chlorpyrifos

K.P. Raibeemol; K. C. Chitra

Volume : IV, Issue : XI, November - 2015

A study on median lethal concentration and behavioural responses of cichlid fish, Etroplus maculatus (Bloch, 1795) exposed to organophosphorus insecticide, chlorpyrifos

K. P. Raibeemol, K. C. Chitra

Abstract :

The present study was carried out to evaluate the median lethal concentration and the behavioural responses of one of the organophosphorus insecticide, chlorpyrifos on cichlid fish, Etroplus maculatus. Fish were exposed to seven different concentrations of chlorpyrifos (3, 4, 5, 6, 7, 8 and 9 �g/ L) for 96 h maintaining control groups. Propylene glycol was used a vehicle to dissolve chlorpyrifos and so it was maintained as positive control. The median lethal concentration (LC50) for 96 h, determined by probit analysis was 6.61 �g/ L that killed 50% of the test animal. Chlorpyrifos-induced behavioural changes were continuously monitored throughout the study. Propylene glycol did not caused mortality or behavioural changes where the specimens remained active during the treatment period. However, chlorpyrifos-treated fishes showed jerky vertical movement, loss of equiliium, surface swimming, scoliosis, darkening of skin and bulging of eyes. It is concluded that chlorpyrifos caused acute toxicity and behavioural modifications in Etroplus maculatus.