Sea lice infestations are a major welfare problem in Atlantic salmon farming. Treatment methods themselves cause additional welfare harms, creating a management dilemma.
Sea lice management in salmon farming creates a welfare dilemma: untreated infestations cause progressive welfare harm, but treatment methods themselves cause acute stress and sometimes direct physical harm. Thermal treatment (subjecting fish to 34°C water) causes immediate distress. Hydrogen peroxide exposure causes oxidative stress. Mechanical removal causes handling stress and physical trauma. The only approach that avoids this trade-off is preventing lice exposure entirely through closed containment — an approach that represents the future of welfare-positive salmon aquaculture but remains economically challenging in the short term.