Farmed Salmon Sea Lice Management

Sea lice infestation is one of the most significant welfare and production challenges in Atlantic salmon aquaculture, requiring integrated management approaches.

Key Facts

Lepeophtheirus salmonis and Caligus spp. are the primary sea lice species affecting farmed Atlantic salmon
Sea lice attach to salmon skin, feeding on mucus, skin, and blood, causing wounds, osmotic stress, and immune compromise
High louse burdens cause visible lesions, reduce growth rates, and increase mortality — especially in smolts
Treatment methods include chemical therapeutants, biological controls (cleaner fish), laser systems, and mechanical treatment
Resistance to multiple chemical treatments has developed, making integrated pest management essential

Welfare Considerations

Sea lice cause genuine and measurable suffering in affected fish. Wound tissue, inflammatory responses, and osmotic disruption are all physiologically stressful. Cleaner fish such as wrasse and lumpfish used as biological control also experience welfare challenges in aquaculture environments. High-welfare sea lice management addresses the welfare of both target and non-target species.

What You Can Do

Choose certified higher-welfare salmon from producers with transparent sea lice monitoring and management data
Support research into non-chemical sea lice controls that minimise fish stress
Ask retailers and restaurants about the source and welfare standards of the salmon they sell
Advocate for regulatory minimum standards for sea lice burden thresholds on salmon farms