Acute Toxicity and Ethological Changes in an Indian Freshwater Catfish, Clarias Batrachus (Linnaeus) Exposed to Silver Nanoparticles

This is an initial report on the acute toxicity and ethological changes in an Indian freshwater catfish Clarias batrachus (Linnaeus) exposed to silver nanoparticles. The work was conducted by the use of static renewal and probit analysis method during 2018. The 24, 48, 72 and 96 hr LC50 values were calculated 346.20, 237.33, 201.28, 171.16 mg L-1 respectively. The findings suggest that Clarias batrachus has more capacity to resist silver nanoparticles toxicity in comparison to other fishes. The fish intoxicated to 1 %, 2 %, 3 %, 4 % and 5 % of 96hr-LC50 dose of silver nanaoparticles showed various ethological changes. Buccal movements, opercular movements and the forced swimming of fish increased significantly in response to silver nanoparticles. Number of feeding attempts in silver nanoparticles intoxicated fish reduced significantly while irregular responses were observed regarding their attempt to form school/shoal. The silver nanoparticles concentrations showed strong relationship with opercular movement followed by forced swimming greater than buccal movement greater than rate of feeding greater than schooling/shoaling behaviour in Clarias batrachus. As a whole, exposure of fishes to silver nanoparticles showed significant effects on all studied behaviour. So it can be concluded that the silver nanoparticles is toxic to fishes and its excess use should be avoided.