Farmed Salmon Sea Lice Management and Welfare

Sea lice infestations are a major welfare and economic problem in Atlantic salmon aquaculture, causing skin damage, stress, and mortality when untreated.

Key Facts

Sea lice cause significant skin lesions, anaemia, and welfare impacts in farmed salmon
Infestations above treatment thresholds cause measurable changes in salmon behaviour and physiology
Treatment options include chemical baths, laser treatments, and biological controls using cleaner fish
Cleaner fish including wrasse and lumpfish have their own welfare needs requiring management
Resistance to chemical treatments is developing in sea lice populations globally

Welfare Considerations

Sea lice represent one of the most persistent welfare challenges in salmon aquaculture. Lice feeding on salmon skin and mucus cause progressive tissue damage, inflammation, and secondary infection. High infestation levels cause behavioural changes including reduced feeding and abnormal swimming. Treatment events - whether chemical baths or mechanical removal - cause their own welfare impacts through handling stress. The welfare of cleaner fish used as biological control agents adds another dimension, as these small fish are subject to stocking densities and welfare conditions that frequently fail to meet species requirements.

What You Can Do

Choose salmon from producers with transparent sea lice management data
Ask retailers about sea lice thresholds and treatment protocols in their supply chains
Support development of welfare-positive sea lice control technologies
Donate to research into sea lice-resistant salmon genetics
Advocate for welfare standards for cleaner fish used in salmon aquaculture