Sublethal effects of a new antifouling candidate on lumpfish (Cyclopterus lumpus L.) and Atlantic cod (Gadus morhua L.) larvae.

Sublethal effects of medetomidine, a new generation antifouling compound, on lumpfish (Cyclopterus lumpus L.) and cod (Gadus morhua L.) larvae were examined. The effects on respiration rate and on colour adaptation of newly hatched larvae were assessed after 24-96 h exposure. Exposure of lumpfish larvae to the experimental concentrations resulted in a significant decrease in respiration rate (Lowest Observed Effect Concentration (LOEC) = 5-10 nM) and in the percentage of dark larvae (LOEC = 4 nM). However, no effects on respiration rate of cod larvae were detected. In addition to lumpfish larvae being affected at low concentrations of medetomidine, a reversibility of the effects was observed when 96 h-exposed larvae were incubated in clean seawater for 24-48 h. Considerations relating to the future commercialisation of medetomidine for antifouling purposes are discussed.