Integrated Management of Sea Lice on Farmed Salmon

Sea lice are among the most damaging parasites in Atlantic salmon farming, and integrated pest management is replacing reliance on chemical treatments to improve welfare and sustainability.

Key Facts

Sea lice feed on salmon skin, mucus and blood, causing lesions and secondary infections
Heavy infestations cause chronic stress, reduced feeding and immunosuppression in fish
Chemical treatments such as hydrogen peroxide and azamethiphos are stressful to apply
Cleaner fish species including wrasse and lumpfish eat lice off salmon hosts
Snorkel barriers and deep lights reduce lice attachment by keeping salmon below the lice-rich surface
Laser systems can target and kill individual lice without chemical use
Coordinated area management reduces lice spread between neighbouring farms

Welfare Considerations

Sea lice cause measurable suffering in farmed salmon through tissue damage, stress and reduced immune function. Heavy infestations correlate with physiological stress markers. Chemical treatments, though effective, add further acute welfare costs. Integrated management combining preventive design, biological controls and coordinated farm husbandry reduces both lice burden and treatment frequency, improving welfare outcomes. The welfare of cleaner fish used in biological control is also a growing concern requiring attention.

What You Can Do

Choose farmed salmon from producers using certified integrated lice management programmes
Support research into non-chemical lice control and cleaner fish welfare
Advocate for mandatory lice threshold reporting and area management coordination
Ask retailers to require lice management standards from their salmon suppliers
Raise awareness of cleaner fish welfare as part of the salmon welfare picture