Atlantic bluefin tuna are highly migratory, large-bodied fish whose capture by longline and purse seine methods causes significant welfare concerns.
Bluefin tuna capture by longline involves extended periods struggling against hooks, causing exhaustion, injury, and extreme physiological stress. Fish may remain hooked for hours before being hauled. The metabolic demands of large, active fish mean stress during capture has severe physiological consequences. Purse seine capture also involves crowding and handling stress during brailing onto vessels.