Marine Mammal Bycatch: The Incidental Cost of Fishing

Marine mammals including dolphins, porpoises, and seals are unintentionally caught in fishing gear at alarming rates. Bycatch is a leading cause of cetacean mortality globally and drives some populations toward extinction.

Key Facts

An estimated 300,000 cetaceans die as bycatch annually worldwide
The vaquita porpoise, with fewer than 10 individuals remaining, is driven toward extinction primarily by gillnet bycatch
EU regulations require acoustic deterrents (pingers) on certain fisheries to reduce porpoise bycatch
The common dolphin in the Bay of Biscay faces population-level impacts from French fishery bycatch
Entangled marine mammals may drown immediately or suffer injuries before eventual death
Trawl modifications including turtle excluder devices have reduced some bycatch rates

Welfare Considerations

Entangled marine mammals face drowning if air-breathing or sustained physical injury from nets, lines, and gear. Dolphins and porpoises caught in nets drown within minutes, while seals may endure longer entanglement. The welfare implications are severe for both individuals and populations. Marine mammal bycatch in the French pair trawl fishery has attracted particular attention due to the scale of common dolphin mortality. Consumer pressure and effective regulation have driven some improvements but the problem remains severe globally.

What You Can Do

Choose seafood from fisheries certified as dolphin-safe and low bycatch by credible standards
Support organizations including WDC and WWF campaigning for stronger bycatch regulations
Advocate for mandatory bycatch observer coverage and recording in all commercial fisheries
Reduce overall seafood consumption, particularly from fisheries with poor bycatch records
Engage with government consultations on fishing regulations to support marine mammal protections
Report entangled marine mammals to British Divers Marine Life Rescue (0825 765 0000)