The European eel is Critically Endangered, having declined by over 90% in recent decades. Its remarkable life cycle — from oceanic spawning to river dwelling to Atlantic migration — creates welfare concerns at every stage, from wild populations to aquaculture.
European eel welfare encompasses both wild population decline and the welfare of eels caught for aquaculture. In wild populations, dam barriers force eels through turbines during downstream migration, causing injuries from impeller blades that kill or maim thousands of migrating silver eels annually. Infection with Anguillicola crassus — a swim bladder parasite introduced from Asia — impairs the physiology of migrating eels and reduces spawning success. In aquaculture, the reliance on wild-caught glass eels means that the aquaculture industry directly threatens wild populations. The welfare of glass eels during capture and transport — tiny, fragile animals subjected to crowding, handling, and temperature stress — is poorly studied. Improving eel welfare requires both direct interventions (safe fish passage, reduced fishing pressure) and systemic change (closing the Sargasso migration loop to the wild).