Sea lice infestations are a major welfare and economic challenge in salmon aquaculture. Treatment methods vary widely in their impact on fish wellbeing and environmental safety.
Sea lice represent a chronic welfare burden in open-net salmon farming, and control methods introduce additional welfare challenges. Chemical bath treatments require fish to be crowded and exposed to potentially irritating or toxic compounds. Mechanical treatments like high-pressure water jets cause physical injury. Cleaner fish used as biological control often suffer high mortality in salmon cages, creating a secondary welfare problem. The most effective long-term solution is shifting to semi-closed or land-based recirculating aquaculture systems that physically exclude parasites, but economic barriers remain significant. Welfare certification schemes are beginning to incorporate sea lice burden thresholds as welfare indicators.