Acute Toxicity Bioassays of Cadmium and Mercury on the Juveniles of Asian seabass Lates calcarifer (Bloch)

The present study was undertaken to investigate the acute toxicity of two heavy metals cadmium and mercury in the juve- niles of Asian seabass Lates calcarifer (Bloch) which is considered as an important candidate fish species for brackishwater and freshwater aquaculture. Experiments for the bioassay were performed in static bioassay test condition according to the standard guidelines. The experiment was carried out in the FRP tanks under laboratory condition. The behavioral changes in the fish were observed for all test concentrations of both cadmium and mercury. Median lethal concentrations (LC50) were calculated for 24h, 48h, 72h and 96h by probit analysis. The LC50 values for 96h and 95% confidence intervals for the juveniles of seabass L. calcarifer showed 6.08 ppm for cadmium and 1.03 ppm for mercury. Furthermore, the ex- posed specimens showed dose and duration dependent, abnormal behavior and hyperactivity. Mercury indicated more toxic than cadmium for seabass L. calcarifer.