Sea lice infestations in Atlantic salmon farms require treatment that causes significant welfare stress, with mechanical, thermal, and chemical approaches each presenting distinct welfare challenges.
Sea lice treatment represents one of the most significant welfare challenges in salmon aquaculture, creating a cycle of infestation and stressful treatment that repeats multiple times per production cycle. Every treatment method currently available causes welfare harm to varying degrees — the welfare question is which approach minimises harm while achieving adequate parasite control. Thermal and mechanical treatments cause acute stress during the procedure; chemical treatments have subacute effects; biological control with cleaner fish has its own welfare costs. The most welfare-positive long-term solution is preventing infestation through closed containment systems or coordinated area management, eliminating the need for repeated stressful treatments. Consumers can drive demand for closed containment farmed salmon which avoids the sea lice problem entirely.