Sea lice infestations in farmed Atlantic salmon cause significant pain and tissue damage, representing one of the most serious welfare challenges in commercial salmon aquaculture.
Sea lice infestations cause sustained, significant pain. Lice attach to and feed on salmon skin and mucus, creating open wounds that expose underlying tissue. Behavioral indicators of lice-related distress include increased jumping, rubbing against net walls, and reduced feeding. "Death crown" lesions — where tissue is consumed down to the skull — represent severe, prolonged suffering in individual fish. The welfare challenge is compounded by scale: millions of fish may be affected simultaneously in net pen operations. Integrated pest management approaches — monitoring thresholds, early treatment, and prevention through selective breeding for lice resistance — address both welfare and production concerns. Moving to land-based recirculating aquaculture systems (RAS) eliminates sea lice entirely, though at higher energy cost.