Disease is the leading welfare and economic problem in aquaculture globally. Prevention through biosecurity, vaccination, and management is more welfare-positive than reactive treatment of established disease outbreaks.
Disease prevention in aquaculture is one of the clearest examples where welfare interests and economic interests align. Disease outbreaks cause significant individual animal suffering — fish with bacterial septicaemia, viral infections, or parasite burdens experience measurable physiological distress. Prevention through vaccination, biosecurity, and management is simultaneously better for welfare and more economically efficient than reactive antibiotic treatment. The Norwegian salmon industry's success in nearly eliminating antibiotic use through vaccination demonstrates what is achievable when prevention is prioritised. Welfare-positive disease management integrates biosecurity protocols, monitoring systems for early detection, and treatment protocols that minimise the stress burden on fish during necessary interventions.