European and Japanese eels are enigmatic migratory fish whose welfare in aquaculture is complicated by their complex life history and unresolved sentience questions.
Eel welfare in aquaculture raises both sentience and behavioral deprivation questions. The migratory drive in silver eels is extremely strong — farmed eels that have reached sexual maturity show strong migration-seeking behaviors that cannot be expressed in farm settings. Whether this frustration constitutes suffering depends on eel sentience, which remains less certain than for fish species with more studied nervous systems. The sustainability dimension directly intersects with welfare: because farming depends on wild glass eel capture, continued eel aquaculture contributes to the population collapse of Critically Endangered wild eels. The most welfare-positive and sustainable approach would be to reduce eel consumption significantly while research into captive breeding continues. Smoked eel consumption without sustainable sourcing is contributing to species collapse.