Disease prevention through biosecurity is the most welfare-positive approach to managing infectious disease in aquaculture. Prevention avoids both disease suffering and the welfare costs of treatment interventions.
Disease prevention is both the welfare-optimal and economically rational approach to aquaculture health management. Prevention avoids the welfare harm of disease itself — immune suppression, behavioral changes, pain responses — and the additional welfare costs of treatment interventions including chemical baths and handling stress. Biosecurity investment requires upfront cost that is recovered through reduced losses and treatment costs over time. The dramatic success of salmon vaccination in reducing antibiotic use without reducing production demonstrates that welfare-optimal disease prevention is economically viable.