Yellowfin Tuna Welfare as Bycatch in Purse Seine Fisheries

Yellowfin tuna caught as bycatch in purse seine fisheries targeting skipjack experience significant welfare harm from crowding, injury, and delayed mortality, raising welfare concerns in major tuna fisheries.

Key Facts

Purse seine fisheries set nets around floating objects (FADs) that aggregate multiple tuna species
Yellowfin caught in FAD-associated sets have higher bycatch rates than free-swimming school sets
Fish crowded in nets experience oxygen depletion, scale loss, and mechanical injury
Non-target yellowfin may be returned live but suffer delayed mortality from injuries
MSC certification for tuna requires bycatch management but welfare is not currently assessed

Welfare Considerations

Yellowfin tuna caught as bycatch in purse seine operations experience acute welfare harm from crowding in nets with oxygen depletion, injury from net contact, and stress from restricted movement. Released bycatch fish appear alive but often suffer from scale loss, fin damage, and internal injuries from crowding that lead to delayed mortality. The scale of FAD-associated tuna fisheries means this bycatch welfare impact affects large numbers of fish. Transitioning from FAD sets to free-school sets reduces yellowfin bycatch significantly and is increasingly incentivised by MSC and consumer pressure for responsible tuna products.

What You Can Do

Choose tuna labelled from free-school sets rather than FAD-associated fishing where possible
Advocate for inclusion of bycatch welfare assessment in tuna fishery MSC certification
Support fishery improvement projects transitioning from FAD to free-school fishing methods
Engage with tuna brands on their FAD reduction commitments and bycatch management
Raise awareness of yellowfin bycatch welfare in tuna fishery sustainability discussions