Sea lice infestation is one of the most significant welfare challenges in Atlantic salmon farming. Developing genetic resistance in farmed salmon offers a long-term welfare improvement pathway.
Sea lice cause chronic welfare compromise in farmed Atlantic salmon - skin lesions cause pain, immune activation generates ongoing physiological stress, and heavy infestations impair normal behaviour. Genetic selection for louse resistance offers a pathway to reducing this welfare burden without the stress of treatment procedures or the environmental impact of chemical controls. Cleaner fish provide a welfare benefit to salmon but raise their own welfare questions that require management attention. A welfare-positive approach to louse management integrates genetic progress with husbandry improvements and targeted, minimally-stressful treatment when necessary.