Disease is the leading cause of welfare compromise and mortality in aquaculture. Prevention through good husbandry, vaccination, and biosecurity provides far better welfare outcomes than treating established disease.
Aquaculture disease welfare follows the same prevention-over-treatment principle as other livestock systems, amplified by the practical difficulty of treating fish disease at commercial scale. Handling fish for disease treatment causes additional acute welfare stress that compounds the burden of the disease itself. Prevention through vaccination, good water quality management, biosecurity protocols, and stress reduction provides far better welfare outcomes. The Norwegian salmon industry provides an instructive case: mandatory vaccination programs and improved biosecurity have dramatically reduced antibiotic use while improving fish welfare. Consumer demand for certified aquaculture products with documented disease management protocols creates incentives for this approach.