Marine Mammal Bycatch: Dolphins, Porpoises and Fishing Gear

Marine mammals including dolphins, porpoises and seals are accidentally caught in fishing gear causing drowning and serious injury, with mitigation measures available but inconsistently applied.

Key Facts

An estimated 300,000 cetaceans die in fishing gear entanglement annually worldwide
Gillnets are the most lethal gear type for small cetaceans including harbour porpoises and common dolphins
Acoustic deterrents — pingers — reduce porpoise bycatch by 50-95% in gillnet fisheries
Regulatory requirements for pinger use exist in some EU and US fisheries but compliance monitoring is challenging
Baiji river dolphins are believed extinct in part due to gillnet bycatch in the Yangtze River
The vaquita — the world's most endangered marine mammal — numbers fewer than 20 individuals due to bycatch

Welfare Considerations

Marine mammal bycatch causes drowning — an oxygen-dependent animal trapped underwater in fishing gear suffers progressive hypoxia and panic before losing consciousness. The scale of annual cetacean bycatch mortality — hundreds of thousands — represents one of the most significant sources of large mammal suffering from fisheries. Effective mitigation exists in the form of acoustic pingers, but regulatory requirements and compliance monitoring are inadequate. Consumer certification choices and advocacy for stronger fishery regulations represent the most available levers for this issue.

What You Can Do

Choose seafood from certified fisheries with documented low marine mammal bycatch
Support pinger use requirements in gillnet fisheries through advocacy and consumer pressure
Donate to organisations working on marine mammal bycatch mitigation and monitoring
Engage with campaigns to protect vaquita and other critically bycatch-threatened species
Support stronger international bycatch monitoring and reporting requirements in fisheries management