Farmed Salmon Health: Sea Lice, Amoebic Gill Disease, and Welfare

Disease burden in farmed Atlantic salmon involves multiple interacting pathogens that cause chronic suffering and drive intensive treatment regimes that add further welfare costs.

Key Facts

Amoebic gill disease (AGD) is a major cause of welfare compromise in salmon net pens
AGD causes gill mucus accumulation, respiratory distress, and reduced feeding
Freshwater bath treatments for AGD cause osmotic stress and handling trauma
Pancreas disease causes myocarditis and skeletal muscle pathology affecting a high proportion of farmed salmon
Sea lice and AGD frequently co-occur, compounding welfare burden and treatment requirements
Genetic selection for disease resistance is a long-term approach to reducing disease-related welfare costs

Welfare Considerations

Farmed salmon health is a welfare emergency in many production systems. The combination of high stocking densities, sea cage environments, and intensive production creates conditions where multiple diseases establish and co-circulate. AGD causes respiratory distress equivalent to breathing through mucus. Pancreas disease causes cardiac and muscle damage visible as swimming abnormalities. Treatment interventions including freshwater bathing, mechanical delousing, and chemical treatments add further acute stress. The welfare burden of disease in salmon farming is not an unfortunate accident — it is a predictable consequence of production system design.

What You Can Do

Choose salmon from operations demonstrating low disease burden and transparent welfare reporting
Support transition to land-based recirculating systems that eliminate sea lice and reduce AGD risk
Advocate for mandatory disease welfare reporting as a condition of aquaculture licensing
Reduce salmon consumption given the persistent and significant welfare challenges in production