Sea lice infestation is the most significant ongoing welfare challenge in Atlantic salmon farming - causing skin damage, stress, and mortality at large scale.
Sea lice welfare in salmon farming is a persistent challenge that industry, regulators, and welfare organisations have grappled with for decades. The welfare harm from heavy infestations is severe - open skin lesions expose salmon to secondary infection, osmotic imbalance, and chronic pain. Treatment methods themselves cause welfare stress: bath treatments require crowding and handling; warm water treatments cause thermal stress; laser systems can cause eye damage. The welfare of cleaner fish used as biological control agents is a growing concern - wrasse and lumpfish have poorly understood welfare needs and high mortality rates in sea cage environments.