Summary
An analysis of records of static net bycatch sampling in the United Kingdom from 1996-2023 found that use of acoustic deterrent devices (ADDs) reduced harbor porpoises bycatch per haul (BpH) to 0.23 of the background rate. BpH increased for harbor seals and grey seals (Phoca vitulina and Halichoerus gryphus) when ADDs were used. Current efforts to reduce harbor porpoise bycatch may be increasing seal mortality in the same fisheries.