Wild Salmon Welfare Impacts from Aquaculture

Farmed salmon operations affect wild salmon populations through sea lice transmission, escapes causing genetic introgression, and environmental contamination, with welfare implications for both farmed and wild fish.

Key Facts

Sea lice from salmon farms amplify louse pressure on wild salmon and sea trout migrating past farm sites
Atlantic salmon escapes from Norwegian farms have interbred with wild populations, reducing fitness
Farm waste including uneaten feed and faeces alters seabed communities near open-net cage sites
Wild sea trout populations have declined significantly near salmon farming areas in Norway, Ireland, and Scotland

Welfare Considerations

Wild salmon welfare impacts from aquaculture operate through sea lice amplification, genetic introgression from escapes, and habitat degradation. Wild sea trout and salmon smolts migrating past farm sites encounter artificially elevated sea lice levels that cause skin damage, osmotic stress, and mortality. These welfare harms to wild fish are not captured in farm welfare assessments that focus only on farmed animals. Mitigation through site fallowing, lice management, and escape prevention also protects wild fish welfare. Shifting from open-net to land-based closed systems eliminates most wild fish welfare impacts.

What You Can Do

Support the transition from open-net to land-based salmon farming to protect wild fish
Advocate for sea lice reporting requirements and site fallowing in aquaculture regulation
Choose salmon from land-based closed-containment systems where available
Follow wild salmon monitoring in areas with dense salmon farming to track population welfare