Longline fishing causes significant seabird bycatch globally, with tens of thousands of birds drowned annually on hooks intended for tuna, swordfish, and other commercial species.
Seabird longline bycatch causes acute welfare harm at a scale that is difficult to comprehend: hundreds of thousands of individual drowning deaths annually, in addition to non-lethal entanglement injuries in birds that escape. Drowning is not an instantaneous death - hooked birds pulled underwater struggle for extended periods before succumbing. Non-lethal interactions, in which birds escape from hooks, may leave embedded hooks or cause wing injuries that impair future foraging success. The welfare tragedy is compounded by the fact that effective solutions exist and are well understood: bird-scaring lines (streamers that deter birds from approaching the baiting zone), underwater line setting (deploying lines below the surface away from diving reach), and blue-dyed bait (less visible to surface-feeding birds) collectively reduce bycatch by over 90% at minimal cost. The barrier to implementation is not technical but economic and regulatory: without mandatory requirements, fishing operators have insufficient incentive to adopt measures that add even small costs to operations. Consumer certification demand for sustainable seafood has driven voluntary adoption in some fisheries.