Chemical and physical treatments for sea lice in salmon farming cause significant welfare harm and require careful management alongside preventive approaches.
Sea lice treatment causes acute welfare harm through chemical irritation, physical handling during bath treatment, and injury from mechanical systems. Crowding prior to and during treatment adds stress. Repeated treatments compound these welfare impacts. The welfare cost of treatments must be weighed against the welfare cost of untreated lice infestations which cause skin damage and physiological stress. Integrated pest management prioritising prevention reduces treatment frequency and associated welfare harm.