How proximity between salmon farms and wild salmon migration routes creates welfare and conservation risks and what spatial planning can reduce them.
The interaction between salmon aquaculture and wild salmon populations is one of the most consequential welfare and conservation interface problems in fisheries management. Individual wild smolts infected with sea lice from farm facilities experience welfare harm and reduced survival. Wild populations that receive escaped farmed fish face genetic disruption that compromises their local adaptation. The cumulative effect of these interactions is both welfare harm at the individual level and population-level conservation damage. Spatial planning — siting farms away from wild salmon migration routes and rivers — is the most effective preventive measure, but economic pressures have historically allowed farms to be sited near productive wild salmon rivers.