Atlantic salmon farming is one of the largest aquaculture sectors globally, and welfare challenges including sea lice, gill disease, crowding, and handling are among the most significant in the industry.
Farmed salmon experience multiple chronic welfare stressors. Sea lice cause painful lesions on the skin, fins, and head. Gill diseases impair oxygen uptake and cause respiratory distress. Crowding at high densities increases competition and aggression. The recurrent treatments for sea lice — including hydrogen peroxide baths and mechanical delousing — are themselves stressful and can cause injury. Welfare improvement in salmon farming requires addressing these chronic stressors through lower densities, better disease prevention, and welfare-conscious treatment protocols.