European and Japanese eels are critically endangered, yet eel aquaculture relies entirely on wild-caught juveniles. Welfare concerns span capture, transport, farming conditions, and slaughter for one of the world's most consumed fish.
Eel welfare is entangled with a conservation crisis that makes welfare improvement even more urgent. Wild juvenile capture, the sole source of farmed eel stock, causes acute stress during capture, transport in crowded containers, and acclimatisation to farm systems. Eels show high tolerance for hypoxia but this does not mean crowding causes no welfare harm — cortisol studies confirm significant stress responses. Slaughter welfare for eels is among the worst of any commercially farmed species — they are highly resistant to stunning and survive for many minutes in ice slurry. Electrical stunning calibrated for eels is feasible but rarely used commercially. Spiking (brain destruction) or decapitation are more reliable killing methods but require individual handling. The combination of conservation crisis, welfare-poor slaughter, and reliance on wild capture makes eel one of the most ethically complex seafood choices available.