European and Japanese eel aquaculture involves species with complex life cycles and welfare requirements that current farming practices frequently fail to meet.
Eel welfare involves profound ecological and behavioral considerations beyond standard aquaculture welfare concerns. European eels spend their entire lives building toward a single trans-Atlantic spawning migration to the Sargasso Sea — a behavioral drive so fundamental it persists throughout their years in farm environments. This migratory motivation likely creates chronic frustration in farmed settings analogous to other strongly motivated but blocked behaviors. The dependence on wild glass eels for seed stock means eel farming directly drives capture of an endangered species, entangling welfare with conservation harm. Slaughter welfare has historically been poor — drowning in ice water or exposure to air without prior stunning — though electrical stunning adoption is improving. The combination of endangered species dependence, migratory frustration, and inadequate slaughter welfare makes farmed eel one of the most welfare-ethically complex aquaculture choices.