Toxicity of Copper Sulphate on Behavioural Parameter and Respiratory Surveillance in Freshwater Catfish, Clarias Batrachus (Linn.)

Abstract

Industries are the major sources of heavy metal pollution and it is released into water and soil. Heavy metals cause several ill effects to aquatic living organisms and environment. The toxicity of copper sulphate to the freshwater fish, Clarias batrachus was studied using static bioassay method. The LC50 in 96h was found to be 33 I¼g/L. Behavioural changes when exposed to lethal concentration of copper sulphate showed increased opercular movement, increased surface behaviour, loss of equilibrium, change in body colour, increased secretion of mucus, irregular swimming activity, rapid jerk movement, partial jerk and aggressiveness. The swimming behaviour was in a cork-screw palter, rotating along horizontal axis. In sub lethal treatment, the schooling behaviour of the fish was slowly disrupted, the ventilation rate was increased. The fish at 21st days of exposure exhibited balanced swimming and active feeding and behaved in normal way. Oxygen consumption was decreased in lethal concentration (-22.64 to -70.13%), but in sub lethal concentration decreased trend was improved and reached normal level at 21st day (-25.10 to -2.19). Alterations in oxygen consumption may be due to respiratory distress as a consequence of impairment in oxidative metabolism. Fish in sub lethal concentration were found under stress, but that was not fatal.