Sea lice removal treatments in salmon farming create significant welfare impacts from mechanical, thermal and chemical delousing procedures that must be balanced against the welfare harm of infestation.
Delousing welfare involves a genuine ethical dilemma — the untreated sea lice infestation causes chronic welfare harm while the treatments themselves cause acute welfare harm. The goal of welfare-centered delousing management is minimizing the combined welfare harm of infestation and treatment through preventive approaches that reduce the need for interventions, gentle handling protocols that minimize crowding stress, and treatment method selection based on welfare impact alongside efficacy. The industry trend toward non-medicinal treatments including warm water and mechanical methods has reduced antibiotic use but not necessarily reduced welfare impact. Prevention through site fallowing, current management and cleaner fish remains the most welfare-positive strategy.