Migratory Fish Welfare and Dam Barriers

Dams blocking fish migration routes cause enormous welfare and population-level harms for salmon, eels, shad, and other migratory species.

Key Facts

An estimated 1.2 million dams block rivers globally
Atlantic salmon must navigate multiple dams to reach spawning grounds
Eel populations have declined by 95% partly due to dam-related mortality
Fish passes help some species pass dams but are often inadequate for others
Dam removal programs in Europe and North America have restored migratory fish runs

Welfare Considerations

Fish attempting to pass dams through turbines experience pressure trauma, impeller strikes, and disorientation causing injury and death. Fish blocked below impassable dams exhaust themselves attempting to leap barriers before spawning failure. Eels ascending to freshwater feeding grounds and descending to marine spawning areas are killed in large numbers in turbines. Reduced population sizes from dam impacts cause inbreeding stress in remaining individuals. Fish passes that are inadequately designed cause exhaustion injury in fish attempting to negotiate poorly calibrated passages.

What You Can Do

Support dam removal programs on rivers with significant migratory fish populations
Advocate for improved fish pass standards on existing dams
Donate to Atlantic Salmon Trust or Wild Trout Trust river restoration programs
Support sustainable hydropower standards that include fish welfare requirements
Raise awareness about the connection between dam infrastructure and migratory fish welfare