Welfare science of sea lice treatment in farmed Atlantic salmon, covering the welfare impacts of louse infestation, treatment stress, and the search for less harmful management approaches.
Sea lice management presents aquaculture welfare teams with a genuine dilemma: untreated louse infestations cause chronic pain and tissue damage, while available treatments cause their own acute stress and welfare harm. There is no currently available management approach that is both effective and welfare-benign. This situation is driving research into louse prevention rather than cure — through genetics, environmental management, and novel farm designs that reduce louse transmission. Improving the welfare of salmon during necessary treatments — by optimizing water temperature, reducing handling time, and ensuring full recovery before return to sea — can reduce the harm of unavoidable interventions. The long-term solution requires either disease-prevention approaches or entirely new farming systems that eliminate the louse challenge.