Résumé
The acute toxicity of copper in the different post-embryonic stages of the penaeid shrimp Penaeus japonicus was investigated, along with the effect of sublethal Cu concentration on osmoregulatory capacity of juveniles in seawater and dilute seawater. Results indicated that survival rates tended to increase with larval development. The less tolerant stages were the nauplii and the zoeae, while the most tolerant stages were the late post-larvae and juveniles. In dilute seawater, the 48- and 96-h LC sub(50)s of juveniles were significantly lower than in full-strength seawater. Hypo-osmoregulatory capacity in both seawater and dilute seawater was significantly affected by increased ambient Cu, indicating that imbalance in plasma ions occurred. The effect of Cu on hypo- and hyper-regulation was dose- and time-dependent. The ability to recover osmoregulatory capacity after transfer from Cu-loaded to control media was variable. Osmoregulatory capacity proved to be a sensitive tool to monitor the toxic effect of Cu in shrimp.