Snehlata Singha*, Lily Banerjeeb & D.Dadelb
aDeptt of zoology, R.L.S.Y. College, Ranchi University, Ranchi, Jhrakhand, India
bDept. o Zoology, R.W.C., Ranchi Univeristy, Ranchi, Jharkhand, India.
Received 15th December , 2011; Revised 28th February, 2012
Abstract : The paper deals with the effect of an organophosphorus insecticide, Dimethoate (30% EC) on the opercular movement and oxygen consumption of a fresh water air breathing fish Catla catla and Channa gachua . Median lethal concentration (LC50) value of the insecticide was determined during bioassay study. The rate of opercular movement and oxygen consumption capacity were determined under half value of LC50 concentration of above mentioned insecticide for the periods of 1, 4, 12, 24, 36, 48, 72 and 96 hrs intervals. It was noticed that in the first few hours of experimentation the opercular movement as well as oxygen consumption capacity were increased and afterwards showed decreased trend. The experimental results depict that organophosphorus insecticide ( Dimethoate 30% EC) is toxic to the test fishes Catla catla and Channa gachua . Stress activity showed by the fishes was dependent on the concentration as well as time interval of the action of the insecticide.