Farmed Salmon and Lice Treatment Welfare

Sea lice infestations on farmed Atlantic salmon require chemical and mechanical treatments that themselves cause significant welfare harms — creating a cycle of disease and treatment stress.

Key Facts

Sea lice cause open sores, fin erosion, and systemic stress in infested salmon
Chemical treatments including hydrogen peroxide cause burns and disorientation in fish
Mechanical treatments using freshwater or warm water baths cause thermal stress
Lice resistance to treatments is increasing, requiring more intensive interventions
Enclosed recirculating aquaculture systems eliminate sea lice exposure entirely

Welfare Considerations

Sea lice treatment creates a welfare paradox: the infestation causes chronic irritation and immune suppression, while the treatments cause acute physiological stress and physical injury. Hydrogen peroxide bath treatments cause gill burns; warm-water treatments cause disorientation and mortality. The frequency of treatments in heavily infested systems means salmon experience repeated acute welfare events throughout their production cycle. Closed containment systems that eliminate lice exposure represent a welfare improvement that also addresses environmental contamination concerns.

What You Can Do

Choose salmon from closed containment or recirculating aquaculture systems where available
Support regulatory standards that penalize repeated treatment events as welfare indicators
Advocate for sea lice management regulations that prioritize prevention over treatment
Donate to Fish Welfare Initiative research on treatment welfare optimization
Reduce farmed salmon consumption from open-net pen systems with high lice burdens