Impact of the acute ammonia toxicity on phyllosoma Stage I of a slipper lobster, Ibacus novemdentatus and its recoverability from the ammonia exposure

Slipper lobsters are one of the commercially important crustaceans worldwide and are expected to be a potential aquaculture species. This study aimed to determine the acute toxicity of ammonia for Stage I larvae of a slipper lobster, Ibacus novemdentatus, and to examine whether they could recover after the ammonia exposure. Total ammonia (TAN) exposures at six different concentrations (0, 1, 2, 4, 8, and 16 mg L-1) to 10 larvae in each treatment demonstrated that the mean lethal concentration of TAN for 96-h (LC50-96 h) fluctuated in accordance with the larval viability: 2.81 mg L-1 (0.21 mg L-1 of unionized ammonia, NH3-N) when the larvae showed the survival rate of 47.7% from hatching to the Stage II at 0 mg L-1 of TAN, and 6.88 mg L-1 (0.56 mg L-1 of NH3-N) when 96%. Stage I larvae showing the survival rates of 96% revealed their ability to recover from the 24-h TAN exposure at up to 8 mg L-1 and then reached Stage II. By using an application factor of 0.1, the estimated LC50-96 h in the present acute toxicity test suggests that the NH3-N should be maintained at 0.05 mg L-1 or lower in a long-term rearing of this species larvae.

Automated summary

Slipper lobsters are globally important commercially and potentially viable for aquaculture, as evidenced by their ability to recover from ammonia exposure at concentrations up to 8 mg L-1, with an estimated LC50-96 h of 0.05 mg L-1 NH3-N for long-term rearing.