Open net pen salmon aquaculture creates welfare challenges through crowding, sea lice, disease, and the inability to meet salmon natural behavioral needs including migration drives.
Net pen salmon welfare is affected by multiple interacting factors — stocking density, sea lice burden, treatment stress, water quality, and the thwarting of migration drives — that cumulatively determine the welfare experience of individual fish. The scale of salmon aquaculture means that even modest per-fish welfare improvements produce enormous aggregate benefits. Progress requires addressing each welfare factor systematically rather than treating them as isolated issues. Consumer certification schemes that set standards across density, lice management, and slaughter provide the most comprehensive market-based welfare signal, incentivizing producers to improve across all dimensions rather than meeting minimum thresholds on individual parameters.