Salmon Migration and Hydropower Barriers

Hydropower dams block salmon migration routes, with fish ladders providing only partial passage and the stress of navigation causing significant welfare harm during an already physiologically demanding life stage.

Key Facts

An estimated 40% of historical salmon habitat in the US is blocked by dams without fish passage
Atlantic salmon populations in rivers with dams are on average 90% lower than in undammed rivers
Fish ladders reduce but do not eliminate passage barriers with successful ascent rates of 40 to 90% depending on design
Salmon attempting to pass fish ladders experience elevated cortisol and energy expenditure
Four Snake River dams have been proposed for removal in a major salmon restoration project

Welfare Considerations

Migrating salmon face a life stage that is already physiologically extreme — they stop eating, rapidly reshape their bodies for freshwater, and navigate thousands of kilometers against current. Dam passage adds to this burden through the energy cost and stress of fish ladder navigation, delayed migration timing, and potential failure to pass that prevents reproduction. Fish that successfully pass ladders arrive at spawning grounds with depleted energy reserves, reducing reproductive success. Dam removal is the most effective solution for both welfare and conservation, and several major removal projects have demonstrated dramatic salmon recovery.

What You Can Do

Support Snake River dam removal and similar salmon restoration projects
Donate to Trout Unlimited and American Rivers dam removal campaigns
Advocate for improved fish passage requirements in dam relicensing proceedings
Choose Pacific salmon certified by fisheries that maintain free-flowing river habitat