Salmon Sea Lice Treatment Welfare

Sea lice infestations and their treatments both pose welfare challenges in Atlantic salmon aquaculture.

Key Facts

Sea lice are ectoparasites that feed on salmon skin and mucus, causing tissue damage and stress
Heavy infestations cause lesions, immune suppression, and increased mortality in farmed salmon
Chemical treatments including hydrogen peroxide and azamethiphos cause acute stress during application
Thermolicer and Hydrolicer mechanical treatments have their own welfare implications from temperature shock and physical handling
Cleaner fish — wrasse and lumpfish — are used as biological control and have their own welfare needs

Welfare Considerations

Sea lice management in salmon farming involves a cascade of welfare considerations. Infestation itself causes chronic suffering through tissue damage and parasitic feeding. Treatments — whether chemical, thermal, or mechanical — cause acute stress in the fish being treated. Cleaner fish introduced to eat lice may suffer from being in an environment poorly suited to their needs and from being consumed by salmon. The best welfare outcome requires minimizing both infestation burden and treatment frequency through good site management, early intervention, and development of treatments with minimal welfare impact.

What You Can Do

Choose salmon from operations with certified low sea lice burden and responsible treatment protocols
Advocate for mandatory cleaner fish welfare standards in salmon aquaculture certification
Support development of sea lice treatments with reduced fish welfare impact
Reduce farmed salmon consumption or choose plant-based omega-3 sources
Donate to research into biological and genetic sea lice resistance in farmed salmon