Disease management in fish farming is a major welfare issue because pathogens cause significant suffering in affected fish, and treatment methods themselves carry welfare costs that must be balanced against the welfare benefits of disease control.
Disease management in aquaculture involves welfare trade-offs at every decision point: the welfare cost of disease against the welfare cost of treatment, the welfare cost of prophylactic vaccination against the welfare benefit of disease prevention, and the welfare cost of treatment crowding against the welfare benefit of effective therapy. The most welfare-positive approach is prevention through biosecurity, vaccination, and welfare-optimised rearing conditions that support immune function. When disease occurs, rapid detection through health monitoring, humane treatment protocols, and willingness to cull severely affected individuals rather than treat with low survival probability all contribute to welfare-positive disease management.