Farmed salmon escaping from net pen aquaculture compete with wild salmon for resources and spread diseases creating welfare impacts on wild populations.
Salmon farm escapes create welfare impacts that extend far beyond the escaped individuals. Wild salmon face increased competition for food from escaped farm fish that are physically larger due to selective breeding. Sea lice transferred from farms to wild juvenile salmon can cause significant mortality in fish already facing multiple migration stressors. Genetic contamination from introgression of farm genetics reduces the evolutionary fitness of wild populations over multiple generations.