Yellowfin tuna are large, fast, highly migratory fish whose welfare during capture and handling is compromised by exhaustion, barotrauma, and the extreme physiological stress of commercial fishing methods.
Yellowfin tuna welfare during capture involves multiple overlapping stressors that are difficult to address in industrial-scale fisheries. Longline capture results in fish being hooked — potentially through the mouth, eye, or body — and remaining alive on the line for many hours while the vessel continues to set and retrieve gear. During this time fish experience exhaustion from struggling, osmotic stress from wounds, and potentially painful hook trauma. Purse seining compresses large shoals into progressively smaller net volumes, causing oxygen depletion and physical crushing. Neither method allows for rapid, humane dispatch at point of capture. Pole-and-line fishing, where individual fish are hooked and rapidly hauled aboard, permits faster dispatch and is associated with better welfare outcomes, though the hauling and death process still causes stress. Consumer choice of pole-and-line caught tuna directly rewards the method with better welfare credentials, though any single-instrument welfare comparison between fisheries is complicated by differences in bycatch, scale, and what counts as humane dispatch.