Farmed Salmon Disease Management Welfare

Disease management in farmed Atlantic salmon involves complex welfare trade-offs between treatment procedures, chronic disease burden, and the use of cleaner fish with their own welfare needs.

Key Facts

Sea lice are the most economically and welfare-significant disease challenge in Atlantic salmon farming, with severe infestations causing tissue damage, osmoregulatory impairment, and death.
Mechanical sea lice treatments including warm water flushing and laser systems cause acute stress and sometimes injury, but avoid medication resistance issues.
Medicinal bath treatments expose entire cage populations to chemicals under crowding stress, with elevated mortality risk during treatment procedures.
Wrasse and lumpfish used as cleaner fish to consume sea lice from salmon have their own welfare needs, including species-specific habitat requirements and social needs.
Amoebic gill disease (AGD) is an emerging welfare challenge causing respiratory distress that requires freshwater bathing treatment, itself a stressful procedure.

Welfare Considerations

Salmon disease management welfare involves a cascade of welfare considerations: the chronic welfare harm of untreated disease, the acute welfare harm of treatment procedures, and the welfare of any cleaner fish used as biological control agents. No treatment is welfare-neutral, but the alternative of chronic lice or gill disease infestation causes progressive suffering. Management approaches that reduce disease pressure through genetics, site management, and vaccination - thereby minimizing the frequency and intensity of treatments needed - represent the welfare-positive aspiration. Industry investment in selective breeding for disease resistance is one of the most promising long-term welfare improvement pathways for farmed salmon.

What You Can Do

Support salmon producers investing in disease-resistant genetics to reduce treatment frequency.
Choose salmon from farms with documented integrated pest management approaches.
Advocate for welfare standards that cover cleaner fish as well as salmon in aquaculture schemes.
Support research into non-invasive disease monitoring and early intervention systems for farmed fish.