Wild Salmon Migration: Barriers and Welfare Impacts

Atlantic salmon face numerous man-made obstacles during their spawning migrations. Each barrier causes exhaustion, delay, and injury, significantly reducing welfare and spawning success.

Key Facts

Atlantic salmon migrate up to 3,000 km from ocean feeding grounds to natal rivers to spawn
Fish passage facilities like fish ladders allow salmon to pass dams but with significant energy cost
There are approximately 20,000 barriers to fish migration in the UK alone
Sea lice from salmon farms damage migrating wild salmon passing near aquaculture sites
River temperature increases from climate change cause heat stress during summer migration

Welfare Considerations

Migration is already energetically demanding — salmon do not feed during their river migration and rely on body reserves to complete their journey and spawn. Each obstacle encountered depletes reserves further. Fish passes require significantly more energy than free swimming and delay migration. Injury from predators, salmon farm sea lice, and passage through fish passes compounds exhaustion. Salmon that do not survive to spawn die having depleted their reserves in attempting migration. The welfare cost of migration barriers is individual exhaustion and death, with population consequences of reduced spawning success.

What You Can Do

Support river restoration organisations removing obsolete weirs and barriers
Donate to the Wild Salmon Trust and Atlantic Salmon Federation
Advocate for mandatory fish passage on all new and existing barriers to migratory rivers
Support reduced sea lice levels at salmon farms near migratory routes
Engage with the rewilding movement about river restoration as a welfare and conservation priority