Breeding for genetic resistance to sea lice in Atlantic salmon offers a potential long-term solution to reduce both parasite burden and the welfare costs of treatment.
Genetic resistance to sea lice represents a welfare improvement that compounds through generations without requiring ongoing treatment interventions. If salmon can be bred to mount more effective immune responses against lice attachment, the welfare costs of lice infestation and the treatment procedures used to control it both decline simultaneously. The approach is not a rapid solution - meaningful resistance improvements require multiple breeding generations and sophisticated genomic selection - but represents an investment in sustainable welfare improvement. The welfare implication extends to cleaner fish used for biological lice control: if salmon carry lower lice burdens through genetic resistance, the pressure to deploy large numbers of wrasse and lumpfish with their own significant welfare needs is reduced.