Bycatch

Bycatch refers to the incidental capture of non-target species during fishing operations. It can involve seabirds, marine mammals, sea turtles, sharks, and juveniles of target species, as well as non-target fish and invertebrates. Bycatch occurs across a range of gear types, including longlines, gillnets, trawls, and seines, and results from gear design, fishing practices, and bait choices.

Bycatch may be discarded at sea or retained for sale, and mortality is not always immediate or uniform across species. Estimating bycatch is challenging due to incomplete reporting, variability among fleets, and the private incentives to underreport. Bycatch can affect population dynamics, ecosystem structure, and the health of vulnerable species and habitats, with both ecological and economic implications for fisheries.

Management and mitigation efforts aim to reduce bycatch while maintaining fishery yields. Strategies include gear modifications (such as turtle excluder devices, bycatch reduction devices, and circle hooks), mesh size controls, time-area closures, and quotas or catch limits for bycatch. Monitoring and enforcement—through observers, video or electronic monitoring, and reporting systems—improve data and compliance. International and regional bodies, including FAO guidelines and Regional Fisheries Management Organizations, coordinate standards and research to advance selectivity and ecosystem-based approaches. Ongoing challenges include balancing conservation goals with fishing livelihoods, addressing illegal or unreported bycatch, and adapting measures to different ecosystems and fishing practices.