Toxic Effects of Some Pesticides on Fingerlings of a Carp, Labeo rohita

The present paper deals with evaluation of acute toxicity of some popular and widely used insecticides like Endosulfan (O.C.), Malathion, Nuvacron, Nuvan, Dimecron (all O.P.) and Fenvalerate (pyrethroid) to the fingerlings of a carp, Labeo rohita. Among these insecticides Fenvalerate was found to be most toxic followed by Endosulfan, Malathion, Nuvacron, Dimecron and Nuvan, with their LC₅₀/96 hr values in the order: 0.20ppm < 0.4ppm < 0.75ppm < 1.00ppm < 1.25ppm < 5.0ppm respectively. Accordingly, the acute toxicity of these insecticides was found in order: Nuvan < Dimecron < Nuvacron < Malathion < Endosulfan < Fenvalerate. Suggestive measures include use of insecticide around fishery resources with precaution so that access of sprayed chemicals into the adjoining water bodies may be checked.