Sea Lice Management in Farmed Salmon: Welfare Trade-offs

Sea lice infestation is the primary welfare and health challenge in Atlantic salmon farming, with treatments causing their own welfare harms.

Key Facts

Sea lice cause lesions, osmotic imbalance, and secondary infections in salmon
A single salmon farm can harbour millions of lice, affecting wild salmon passing by
Chemical treatments including emamectin benzoate are associated with resistance development
Mechanical treatment methods including hydrolicer cause significant scale and fin damage
Biological control using cleaner wrasse has its own welfare implications

Welfare Considerations

Sea lice are one of the most significant welfare problems in salmonid aquaculture. Untreated infestations cause pain, immune suppression, and death. Chemical bath treatments expose fish to stressful handling and chemical toxicity. Mechanical delousing causes physical damage. Cleaner wrasse used as biological control often suffer poor welfare in salmon pen conditions themselves. Integrated pest management combining all methods with welfare monitoring represents best practice.

What You Can Do

Choose ASC-certified farmed salmon with verified sea lice management standards
Advocate for sea lice monitoring data to be publicly available for all farms
Support research into low-welfare-impact sea lice control methods
Reduce salmon consumption or choose wild-caught from sustainable fisheries
Engage with salmon brands about their sea lice management welfare protocols