Marine Mammal Bycatch: Dolphins, Porpoises, and Whales Caught in Fishing Gear

Marine mammal bycatch kills hundreds of thousands of cetaceans annually worldwide, making it a massive welfare problem that intersects with conservation concerns for many dolphin and porpoise species. Understanding bycatch drivers informs effective consumer and policy responses.

Key Facts

An estimated 300,000 cetaceans die as bycatch in fishing gear each year globally
Gill nets, purse seines, longlines, and trawls all capture marine mammals as non-target species
The vaquita porpoise is critically endangered with fewer than 10 individuals remaining, primarily due to bycatch
Common dolphins and harbour porpoises are among the most frequently bycaught species in European waters
Acoustic deterrents called pingers reduce porpoise bycatch by up to 70% in some fisheries
Marine Stewardship Council certification requires bycatch mitigation plans for certified fisheries
Drowning in fishing gear is a prolonged and distressing death for air-breathing marine mammals
Turtle Excluder Devices and Bycatch Reduction Devices exist for many gear types

Welfare Considerations

Marine mammal bycatch causes deaths that are both ecologically devastating for vulnerable populations and deeply individual in their suffering. A common dolphin or harbour porpoise entangled in a gill net cannot surface to breathe and drowns over minutes — a terrifying and prolonged death for a highly sentient, socially complex animal. The scale of this mortality — 300,000 individuals per year — represents one of the largest human-caused wildlife welfare emergencies that receives relatively little public attention compared to more visible animal welfare issues. Technical solutions exist for most fisheries: acoustic pingers, modified gear designs, and observer programmes that can identify and address high-bycatch operations. Consumer demand for certified sustainable seafood creates market incentives for bycatch reduction.

What You Can Do

Choose seafood certified by the Marine Stewardship Council, which requires bycatch mitigation plans
Look for dolphin-safe tuna certification that verifies monitoring of bycatch in tuna fisheries
Reduce overall seafood consumption to lower demand on fisheries with high bycatch rates
Support organisations monitoring and reporting on marine mammal bycatch in European and global fisheries
Advocate for mandatory pinger use in gill net fisheries known to cause high porpoise bycatch
Support emergency bycatch closure areas around critically endangered species like the vaquita
Write to fishing regulatory bodies urging stronger bycatch reporting requirements and mitigation standards