European eels are critically endangered, with populations at less than 10% of 1970s levels. Hydroelectric dams, weirs, and other river barriers prevent eels from completing their migration, causing injury and population collapse.
Eels passing through hydroelectric turbines suffer blade strikes, barotrauma, and shear stress. Studies show turbine mortality rates of 20-50% at individual sites. Eels that survive passage may be injured and unable to complete their oceanic migration. River barriers that prevent migration condemn eels to incomplete life cycles without reproductive success.