Disease outbreaks in aquaculture cause enormous welfare harm and economic losses. Biosecurity measures that prevent disease are simultaneously welfare and sustainability interventions.
Disease outbreaks in aquaculture cause intense, prolonged suffering to large numbers of fish. Viral haemorrhagic septicaemia, infectious salmon anaemia, and similar conditions cause debilitating illness with mortality that may peak over days to weeks. The stress of crowding and poor water quality during outbreaks amplifies welfare harm. Biosecurity measures that prevent disease outbreaks are therefore among the most impactful welfare interventions available in aquaculture. The analogy with human public health is clear: prevention is far preferable to treatment, both for welfare reasons and for practical ones. Investment in biosecurity infrastructure, surveillance, and staff training should be seen as a core welfare responsibility of aquaculture operations, not an optional extra.