A COMPARATIVE ACCOUNT OF THE OSMOTIC RESPONSE IN ETROPLUS SURATENSIS, A BRACKISH WATER CICHLID FISH EXPOSED TO SELECTED HEAVY METALS AND PESTICIDESNisha Thomas Panikkaveetil, Sherly Williams E. and Ignatius J.Abstract Fishes are the most sought after food source throughout the world. But anthropogenic interventions have polluted their habitats affecting their health. The current study focussed on the effect of selected heavy metals viz; cadmium chloride, lead nitrate and mercuric chloride, and pesticides viz; sevin, nuvan and lindane on the branchialosmoregulatory enzyme Na+/K+-ATPase (NKA) and related ions in serum Na+ and K+. Wild Etroplus suratensis collected from two sites of Ashtamudi lake was exposed to sub-lethal concentrations of these pollutants while maintaining the saline conditions of either site. Results revealed an increase in NKA activity in both the sites. Noticeable changes in serum Na+, an increase in Site I and decrease in Site II were observed. Appreciable increase in K+ ions was also noticed in both the sites. These changes may be indicative of the health status of the fish in its normal habitat. |