Toxicity of copper sulfate for survival, growth, molting and feeding of juveniles of the tiger shrimp, Penaeus monodon

Abstract

The aim of this study was to determine the acute and chronic toxicity of copper sulfate for juveniles of Penaeus monodon. The 96-h LC50s (median lethal concentrations) of copper on juvenile P. monodon (0.63±0.13 g) were 3.13 and 7.73 mg/l in seawater of 15‰ and 25‰, respectively. The mortality rates of P. monodon juveniles (0.19±0.02 g) following exposure to 0 (control), 0.45, 0.90, 1.80 and 4.50 mg/l copper after 30 days was 0%, 0%, 5.6%, 22.2% and 55.6%, respectively. After 30 days of exposure, the body weight and total length of shrimps exposed to copper at 0.90 mg/l and higher was significantly lower ( P<0.05) than those in the control. The 30-day EC50 (concentration that reduced weight gain by 50% of that of the controls) and 60-day EC50 were 2.82 and 1.89 mg/l copper, respectively. The ratio of carapace length to total length of shrimps exposed to copper at 0.90 mg/l was significantly higher ( P<0.05) than the controls. Following exposure to copper as low as 0.90 mg/l, P. monodon shortened the time to the first molt, and decreased its growth and molting frequency. Following exposure to copper as low as 5.0 mg/l, P. monodon juveniles (6.25±0.09 g) decreased their feeding. The MATC (maximum acceptable toxicant concentration) was 0.45 mg/l copper based on the growth and molting of shrimps weighing 0.18–1.03 g, and was 1.0 mg/l copper based on the feeding of shrimps weighing 6.25 g.