Laser-based sea lice removal systems in salmon farming offer a potential alternative to chemical treatments, with important welfare implications for both lice control and fish stress.
Sea lice create serious welfare harm in farmed salmon: severe infestations damage skin and underlying tissue, cause osmoregulatory disruption, impair wound healing, and impose chronic stress. Traditional chemical treatments require crowding fish into confined spaces, handling, and exposure to chemical agents — all significant stressors. Laser systems represent a genuine welfare advance if they effectively control lice without causing tissue damage to fish. Evidence suggests that when properly calibrated, laser pulses do not penetrate to fish tissue depth. However, welfare assessment of laser systems requires independent scrutiny of both efficacy claims and potential for accidental fish damage. Integrated pest management combining laser treatment with biological controls including cleaner fish remains the most promising welfare-positive approach.