Atlantic salmon face welfare threats from migration barriers, warming rivers, and sea lice from fish farms that exhaust and kill fish during their demanding spawning migration.
Atlantic salmon welfare during migration is compromised at multiple points by human infrastructure. Fish arriving at impassable dams exhaust themselves attempting to leap barriers, sometimes injuring themselves or dying without reaching spawning grounds. The physiological demands of the spawning migration are already extreme — fish stop feeding and draw entirely on body reserves — making additional energy costs from obstacles particularly damaging. Sea lice infestations from aquaculture add further welfare harm, with heavy loads causing lesions, behavioral disruption, and mortality in vulnerable juvenile salmon. Restoring free-flowing rivers and reducing aquaculture-wild fish interactions protects salmon welfare and population viability simultaneously.