Sea louse burden thresholds for treatment reflect welfare thresholds at which fish welfare is significantly impaired, requiring welfare-based rather than purely regulatory approaches.
Sea lice welfare thresholds set by regulators represent the maximum acceptable burden before mandatory treatment, not the point at which welfare is first impaired. Welfare research demonstrates that adverse welfare effects begin below regulatory trigger levels. Variance in louse distribution means some fish carry high individual burdens while the mean remains below the trigger. Welfare-conscious louse management uses lower voluntary treatment thresholds than regulatory requirements, monitors individual variance, and prioritises prevention to maintain burdens below welfare-impacting levels. This welfare-above-minimum approach requires industry commitment beyond regulatory compliance.