Wild Salmon Migration Barriers and Welfare

Wild Atlantic and Pacific salmon face numerous migration barriers including dams, culverts, and weirs that impede upstream spawning migrations, causing exhaustion, injury, and reproductive failure with significant welfare consequences.

Key Facts

Approximately 90% of historical Atlantic salmon habitat in the UK has been lost or degraded by migration barriers
Salmon migrate hundreds of kilometers from the ocean to natal spawning streams, requiring unimpeded passage
Fish passes at dams vary enormously in effectiveness, with some providing inadequate passage for weaker or older fish
Warming river temperatures from climate change compound migration barrier stress by increasing energy demands
Pacific salmon populations face similar migration barrier challenges across the western United States and Canada

Welfare Considerations

Salmon attempting to pass migration barriers experience significant physical exhaustion, injury from jumping attempts, and reproductive failure when they cannot reach spawning grounds. Fish that fail to reach spawning grounds after their migration have completed an irreversible physiological transformation that prevents return to the ocean, meaning failure to spawn results in death without reproduction. The welfare and ecological consequences of migration barriers are therefore severe, affecting individual fish while also suppressing population recovery.

What You Can Do

Support salmon river restoration organizations working on barrier removal and fish pass installation
Advocate for screening small hydropower installations that entrain migrating fish
Report observations of salmon attempting to pass barriers to river conservation organizations
Reduce water use during summer low-flow periods that stress migrating salmon
Support rewilding programs that restore riparian vegetation and cool river temperatures