Laser-based automated sea lice removal from farmed Atlantic salmon offers a non-chemical treatment option whose welfare implications require careful evaluation against chemical treatment alternatives.
Laser lice treatment presents a genuine welfare comparison challenge that illustrates the complexity of welfare trade-off analysis in aquaculture. Chemical treatments including hydrogen peroxide involve all fish in a bath treatment causing acute stress and some adverse effects. Laser treatment affects individual fish at the moment of lice removal, with avoidance responses suggesting some aversive sensation. Whether cumulative laser exposure over a production cycle imposes less total welfare burden than periodic chemical treatments depends on treatment frequency, fish behavioral responses to each approach, and lice burden reduction efficacy. Current evidence cautiously favors laser systems as a net welfare improvement over chemical alternatives, but ongoing research is needed to characterize salmon behavioral responses to laser exposure and long-term welfare outcomes.