Farmed Salmon Lice Management: Welfare-Centred Approaches

Sea lice infestations are a major welfare challenge in Atlantic salmon farming, and managing them with minimal harm requires integrated pest management strategies and careful treatment selection.

Key Facts

Sea lice (Lepeophtheirus salmonis and Caligus elongatus) are the primary parasites of farmed Atlantic salmon
Heavy infestations cause skin damage, fin erosion, and reduced welfare, as well as significant mortality
Mechanical treatments (thermolicer, hydrolicer) are effective but cause acute stress and mortality
Biological control using cleaner fish (wrasse and lumpfish) is increasingly used but raises wrasse welfare concerns
Preventive approaches including deeper feeding, snorkel barriers, and selective breeding are gaining ground

Welfare Considerations

Sea lice management creates welfare dilemmas: untreated infestations cause chronic suffering, but many treatments themselves cause acute pain and stress. The welfare of cleaner fish used as biological control has received insufficient attention - wrasse have complex behavioural needs that are rarely met in cage environments. An integrated approach prioritising prevention, minimising treatment frequency, using the least harmful effective treatment, and improving cleaner fish welfare represents best practice.

What You Can Do

Support aquaculture certification schemes that include rigorous lice management welfare standards
Advocate for investment in preventive approaches including selective breeding for resistance
Engage with aquaculture companies to improve cleaner fish welfare standards
Support research into non-invasive lice monitoring technologies
Choose salmon products certified to standards requiring welfare-centred lice management