European eels face catastrophic population decline, raising both conservation and individual welfare concerns as they encounter multiple human-made hazards during their extraordinary migrations.
European eel welfare is intertwined with their conservation crisis in ways that make the two inseparable. Individual eels face welfare challenges at multiple points in their extraordinary lifecycle. Glass eels and elvers harvested for aquaculture or restocking programmes experience handling stress during capture and transport. Adult eels in rivers encounter water quality problems, physical barriers from weirs and culverts, and the swim bladder parasite that impairs their ability to regulate buoyancy during the critical oceanic migration. Silver eels - mature adults beginning their once-in-a-lifetime spawning migration - face turbine mortality at hydroelectric stations, which can kill 30-70% of eels attempting passage depending on station design. Eel pass technology exists but is not universally installed. The combination of these threats across a lifecycle that spans decades and two ocean basins makes recovery extremely difficult. Each individual eel that reaches the Sargasso Sea to spawn has survived extraordinary challenges - protecting them during migration is both a conservation imperative and a welfare duty.