Effect of monocrotophos on the optomotor behaviour of an air-breathing fish, Anabas testudineus (Bloch)

Behaviour is the recordable and observable activity of the living organisms. Fish behaviours are extremely sensitive to toxicants. The optomotor responses are useful to quantify the changes in some of the movement patterns of the fish. Monocrotophos belongs to widely used group of organophosphorus pesticides. In the present study behavioral changes were studied by exposing fish Anabas testudineus for 21 days to three sublethal concentrations of monocrotophos 1.9, 4.75 and 9.5 mg/L. Alterations in behaviour due to an exposure to sublethal concentrations of monocrotophos were estimated by measuring two parameters namely 'following' and 'reversal' which involve two optomotor responses. Two major behavioral changes observed were hypoactive and lethargy in fish exposed to 4.75 and 9.5 mg/L statistically significant at (P < 0.001) compared to the controls. Behavioural studies may be used to quickly assess and evaluate the effects of sublethal doses of pollutants that are found in the aquatic environment.