European and American eels undertake extraordinary oceanic migrations to spawn, but populations have collapsed by over 90%. Their welfare along degraded migration routes is increasingly compromised.
Wild eel welfare is compromised at multiple points along their complex life cycle. Juvenile eels climbing past obstacles at river entry experience exhaustion and injury. Migrating adult eels are killed in large numbers by hydropower turbines, causing a slow and traumatic death. Parasitic swim bladder worms reduce swimming capacity, making the spawning migration even more physically demanding. Overfishing of young eels (elvers) for aquaculture reduces wild population recruitment. Despite EU protection measures, enforcement has been weak and populations continue to decline. Eel passes at dams and turbine bypass systems reduce mortality but are not universally installed. The ecological and welfare loss if European eels go extinct would be irreversible.