Organosomatic Index and Behavioural Responses of Clarias Gariepinus to Dichlorvos.

Abstract

This study assessed the effect of Dichlorvos on the organosomatic index (hepatosmatic, cardiosmatic, renatosomatic and splenosomatic indices) and behavioural responses of Clarias gariepinus. Thirty five healthy juvenile Clarias gariepinus species. (mean weight 57.92 + 1.85g; mean length 24.17+0.17 cm) were exposed to sublethal concentrations of dichlorvos (0.30,0.40,0.5.50 and 0.60 ppm). The fluctuations in the organosomatic indices were not significant (p>0.05). However, all the indices recorded their highest values at the highest concentration of dichlorvos (0.60PPm). Obvious abnormal behavioral responses such as restlessness, quick circular movements, rolling on the back, excessive mucus productions on the body surface were observed among the exposed fish. This study showed that sub lethal concentrations of dichorvos had adverse effects on Clarias gariepinus. Thus, dichlorvos should be used with caution in agricultural field applications likely to introduce acute levels of the toxicant into the environment.