Farmed Salmon Welfare and Sea Lice Treatment

Sea lice infestations in farmed Atlantic salmon are a major welfare challenge, with treatment methods ranging from bath treatments to mechanical removal carrying their own welfare costs.

Key Facts

Sea lice cause skin erosion, fin damage, and secondary infections in infested salmon
A single farmed salmon can carry dozens of sea lice in severe infestations
Thermal delousing using hot water is effective but causes stress and surface burns
Biological control using cleaner fish like wrasse raises separate welfare concerns for those species
Mechanical lice removal devices cause acute stress measured by cortisol elevation
Enclosed containment systems that prevent sea lice entry represent a structural solution

Welfare Considerations

Sea lice management in salmon aquaculture creates a welfare dilemma: the infestation causes chronic suffering, but many treatment methods impose acute stress and injury. The ideal solution — prevention through enclosed containment systems — is becoming more commercially viable but requires significant investment. In the interim, treatment protocols should prioritize those with the best welfare-efficacy tradeoff, mandatory monitoring should trigger treatment before severe infestations occur, and the welfare of wrasse cleaner fish used as biological control must also be properly considered.

What You Can Do

Choose farmed salmon from producers using enclosed containment or rigorous welfare monitoring
Support certification schemes that include sea lice welfare standards
Reduce Atlantic salmon consumption given ongoing welfare challenges
Advocate for investment in enclosed aquaculture systems that prevent sea lice
Support research into low-welfare-impact sea lice treatments
Ask salmon producers about their sea lice management and treatment welfare protocols