Aquaculture Welfare

Salmon Lice: Biological Control and Welfare Impacts

Salmon lice infestation is one of the most significant welfare and production challenges in Atlantic salmon farming, with both the parasites and treatments causing welfare harm.

Key Facts

Salmon lice (Lepeophtheirus salmonis) are ectoparasites that feed on salmon skin and mucus
Heavy infestations cause lesions, secondary infections and osmoregulatory failure
Chemical treatments (hydrogen peroxide, emamectin benzoate) have welfare side effects
Biological control using cleaner fish (wrasse, lumpfish) reduces chemical use but raises wrasse welfare concerns
Resistance to chemical treatments is increasing, driving development of non-medicinal approaches

Welfare Considerations

Salmon lice welfare is a multi-species problem. The salmon host suffers from parasite-induced lesions and treatment stress. Cleaner fish used for biological control experience welfare issues including starvation, aggression and high mortality if poorly managed. A holistic welfare approach considers all species involved in the production system.

What You Can Do

Choose salmon products certified by schemes with strong lice management welfare standards
Support development of lice control methods that minimise welfare impacts
Learn about the ecology of salmon lice and their impacts on wild salmon
Advocate for welfare standards that include cleaner fish care requirements