European eels face a welfare and conservation crisis from river barriers that prevent their migration between freshwater feeding grounds and marine spawning grounds.
European eel welfare involves both individual and population-level harm. Turbine passage mortality inflicts severe physical trauma — lacerations, swim bladder rupture and death — on silver eels attempting to descend rivers for spawning. At the population level, the near-total collapse of the species represents a welfare catastrophe for countless individuals each generation. River barrier removal, eel pass installation and hydropower turbine management to minimise eel mortality during downstream migration are all welfare-improving interventions with population benefits.