Disease and parasites spilling from fish farms to wild salmon populations affect wild fish welfare and conservation. Minimizing farm-to-wild disease transmission protects both.
Wild salmon exposed to elevated sea lice levels from nearby fish farms experience increased parasite burden that impairs swimming, feeding, and immune function. This farm-to-wild disease transmission causes welfare harm to wild fish and threatens wild salmon conservation. Farm management that reduces environmental disease pressure through fallowing, biosecurity, and biological lice control protects wild salmon welfare.