Non-medicinal lice removal treatments including hydrolicer, thermolicer, and laser lice removal systems have varying welfare impacts requiring careful assessment.
Non-medicinal sea lice treatments have proliferated as alternatives to chemical treatments, but each carries specific welfare costs. Hydrolicer water jet treatments can cause scale loss and tissue damage at high pressures. Thermolicer warm water exposure requires precise temperature control to avoid heat shock injury. Crowding during transfer to treatment vessels causes acute stress regardless of treatment method. Laser delousing avoids treatment-specific trauma but requires very high crowding for fish to pass through the treatment column. Welfare assessment of lice treatment methods must account for both treatment-specific harm and the crowding stress common to all approaches.