Sea lice infestations in salmon farming cause significant welfare problems, and the treatments used also carry welfare costs. Finding better solutions is a priority for salmon welfare improvement.
Salmon lice create a welfare dilemma: the lice themselves cause suffering through skin damage and chronic stress, while most available treatments also cause acute welfare costs. Chemical treatments can damage gills and cause burns. Thermal and mechanical treatments cause intense acute stress. Cleaner fish are subject to poor welfare in many operations, used as tools without appropriate care. The most welfare-positive long-term solutions include genetic resistance breeding, improved cage environments that reduce lice exposure, and development of truly non-stressful treatment methods. The scale of the problem reflects the fundamental challenge of intensive salmon farming.