Atlantic and Pacific bluefin tuna are prized for sashimi and subject to both wild overfishing and controversial ocean ranching practices with significant welfare implications.
Bluefin tuna welfare in ranching involves the stress of wild capture, transport, and extended confinement. Sea cage densities can restrict natural behaviour for animals built for long-distance open-ocean swimming. Feed conversion in ranching relies on large quantities of wild-caught baitfish, extending welfare harms. Wild-caught tuna experience acute stress and often injury during purse seine operations. Slaughter practices at harvest determine end-of-life welfare. Ike jime - a Japanese spike-and-bleed method - causes rapid brain death and is more humane than conventional slaughter.