Aquaculture

Sea Lice in Salmon Aquaculture: Welfare and Control

Sea lice infestations are a major welfare problem in Atlantic salmon farming, causing skin damage, stress, and significant mortality.

Key Facts

Sea lice cost the global salmon farming industry over 1 billion dollars annually
Heavy infestations cause lesions reaching muscle tissue and head skeletal erosion
Thermal delousing using 34°C water causes significant acute stress and mortality
Cleaner fish species including wrasse have inconsistent efficacy and their own welfare needs

Welfare Considerations

Sea lice lesions cause chronic pain, immune suppression, and altered behavior in salmon. Treatment methods including hydrogen peroxide baths, thermal treatment, and mechanical removal all cause significant acute stress. The welfare challenge is that no current treatment is welfare-neutral — prevention through lower stocking density is more humane than treatment.

What You Can Do

Choose salmon from certified schemes with lice monitoring and welfare standards
Support research into vaccines and breeding for sea lice resistance
Advocate for stocking density limits that reduce lice transmission risk
Ask salmon suppliers about their sea lice treatment protocols and outcomes