Sea lice are a major parasite problem in Atlantic salmon farming, and the treatments used to control them raise significant animal welfare concerns alongside effectiveness questions.
Sea lice management is a welfare problem embedded within a production problem. The parasite itself causes suffering; many of the treatments cause additional suffering. The welfare costs of de-licing operations — crowding, hypoxia risk, mechanical damage, thermal shock — are substantial and not always adequately considered in operational decisions. Laser-based systems and genetic resistance breeding offer better welfare-production combinations than current standard practices. The welfare of cleaner fish, often kept in dense, barren conditions and discarded when lice loads are managed, is an additional concern that receives inadequate attention.