The Atlantic bluefin tuna (Thunnus thynnus) is both a critically important apex predator and one of the world's most commercially valuable fish. Wild capture methods — particularly purse seining — cause extreme welfare impacts before fish reach ranching cages or markets.
Purse-seining creates catastrophic crowding stress: bluefin tuna panic and swim frantically within the tightening net, causing oxygen depletion, cortisol spikes, and lactic acid accumulation that leads to muscle damage. Tuna caught in set nets drown within minutes. Transfer from purse seine to ranching cages involves additional handling trauma. Welfare science for bluefin is limited but confirms they have complex nervous systems and show fear responses comparable to other vertebrates. Sustainable fishing alternatives including hook-and-line sport fishing followed by live release, or strict quota enforcement reducing overall catch, offer welfare improvements over industrial purse seining.