Targeted environmental monitoring for the effects of medicines used to treat sea-lice infestation on farmed fish

Farmed Atlantic salmon often suffer from sea-lice infestations, which are c ommonly controlled by the use of a variety of medicines, and the fate of th ese medicines has implications for the health of the marine environment aro und fish farms. The Scottish Environment Protection Agency (SEPA) is respon sible for monitoring and protecting the quality of Scottish coastal waters and for regulating discharges which may affect water quality, including rel eases of medicines from fish Farms. We review the utility of established bi ological effects measurements (biomarkers and bioassays) for monitoring the effects of these medicines. The specificity and suitability of biological effects techniques to the mode of toxic action, metabolism, and environment al fate of the medicines are considered. It is concluded that scope-for-gro wth measurements in wild and deployed mussels (Mytilus edulis) and lugworm (Arenicola marina) bioassays, in combination with a suite of biomarker tech niques, offer the best possibilities.