Acute toxicity of several conventional drugs in aquaculture to juvenile grouper Epinephelus coioides.

The acute toxicity of five conventional aquacultural drugs including formaldehyde,povidone iodine,quaternary ammonium salt complexing iodine,trichloroisocyanuric acid,and CuSO4 +FeSO4(5∶ 2)to juvenile grouper Epinephelus coioides were studied at a salinity of 19~21,pH of 8.09~8.30and water temperature of(29.5±1.5)℃ using a static bioassay test.The results showed that the 24hLC50 was found to be 316.084mg/L for formaldehyde,54.8527mg/L for povidone iodine,22.502mg/L for quaternary ammonium salt complexing iodine,1.973mg/L for trichloroisocyanuric acid,and 12.984mg/L for CuSO4 +FeSO4(5∶2).The 48hLC50 was 290.581 mg/for formaldehyde L,52.3070 mg/L for povidone iodine,21.161 mg/L for quaternary ammonium salt complexing iodine,1.839 mg/L for trichloroisocyanuric acid,and 9.414 mg/L for CuSO4 +FeSO4(5∶2),with the safe concentrations of 73.67mg/L,14.27 mg/L,5.614 mg/L,0.479 mg/L,and 1.485 mg/L,respectively.The grouper showed sensitivity to these aquacultural drugs significantly.The findings suggest that formaldehyde, povidone iodine,quaternary ammonium salt complexing iodine and trichloroisocyanuric acid could be used safely in production,but CuSO4 +FeSO4(5∶2)should be used carefully.