Escaped farmed salmon interact with wild populations through competition, disease transmission, and genetic introgression. These interactions have welfare implications for both wild and farmed fish populations.
The interaction between farmed and wild salmon represents a welfare issue with ecosystem-level dimensions. Disease transmission — particularly sea lice — from farm populations to wild juvenile salmon causes high mortality in affected populations. The welfare of individual wild salmon suffering sea lice infestation is compounded by the population-level effects on genetic integrity and spawning success. Wild salmon are keystone species with ecosystem dependencies: their welfare affects bears, orcas, eagles, and the river ecosystems they fertilize. Aquaculture practices that minimize wild salmon interaction — through closed containment, site selection, and lice management — protect both individual animal welfare and ecosystem health.