Tuna Fishing Methods and Fish Welfare

Tuna fishing methods vary substantially in their welfare impacts on target tuna and non-target species caught as bycatch.

Key Facts

Purse seine nets can capture thousands of tuna at once, causing crowding and handling stress
Fish aggregating devices increase purse seine catch efficiency but dramatically increase bycatch
Pole and line fishing catches one fish at a time and has minimal bycatch
Longline fishing captures target tuna but also sea turtles, sharks, and seabirds
MSC certification covers sustainability but does not have strong fish welfare requirements

Welfare Considerations

Tuna fishing welfare involves both target fish welfare during capture and the welfare costs imposed on bycatch species. Large-scale purse seine operations capture thousands of fish simultaneously, exposing them to crushing pressure, oxygen depletion, and acute stress during retrieval and processing. For bycatch species — sea turtles, sharks, marlins, and seabirds — incidental capture is often fatal even with release. Pole and line fishing methods have the lowest bycatch rates and cause death quickly to individual target fish. Consumer choice for pole and line or similarly selective methods can shift fishing practice.

What You Can Do

Choose tuna products certified to pole and line or similar low-bycatch fishing methods
Avoid tuna products caught using fish aggregating devices which dramatically increase bycatch
Support fishery management policies that phase out the most bycatch-intensive tuna fishing methods
Ask retailers about the fishing methods used in their tuna supply chains
Reduce tuna consumption from conventional purse seine fisheries