The European eel is one of the most critically endangered species in Europe, with population collapses reflecting a cascade of habitat and migration barriers that affect individual welfare alongside conservation viability.
Eel welfare intersects with conservation in particularly acute ways. The species' extraordinary life history - including a prolonged oceanic larval stage and transoceanic adult migration - means that individual welfare harms at any point in the life cycle have population-level consequences. Turbine mortality causes direct physical trauma - a severe welfare harm for individual eels. Passage blocking prevents eels from completing innate migratory behavior, representing a form of behavioral frustration with associated welfare costs. Eel passes and turbine shutdown protocols during migration periods address both individual welfare and population recovery goals simultaneously.