European eels are critically endangered, having declined by over 95% across their range. Their extraordinary life cycle - spanning Atlantic Ocean migrations of thousands of miles - makes conservation uniquely challenging.
European eel welfare involves both individual suffering and population-level existential threat. Glass eels captured for aquaculture face severe conditions: the aquaculture of eels requires capture from the wild (they cannot breed in captivity) and intensive culture in contained systems. Silver eels migrating through hydroelectric turbines face turbine strike injury or death. Eels infected with the swim bladder nematode show reduced body condition and swimming performance that affects their ability to complete the trans-Atlantic breeding migration. The welfare significance of individual eels during their extraordinary lives - from Sargasso larvae to glass eels, through decades of river residence to silver eel migration back to the Atlantic - is remarkable. Each individual undertakes a journey of 10,000 kilometres that takes their entire life to complete. The near-collapse of this population represents a welfare and ecological catastrophe.