Aquaculture Disease Management and Fish Welfare

Disease is a major welfare challenge in fish farming. High stocking densities, stress, and inadequate biosecurity create environments where pathogens spread rapidly, causing widespread suffering.

Key Facts

Infectious salmon anaemia (ISA), amoebic gill disease (AGD), and bacterial kidney disease are among the most costly disease problems in salmon farming.
High stocking density is a key risk factor for disease transmission and also causes chronic stress that impairs immune function.
Antibiotic use in aquaculture is declining in Norway due to vaccination, but remains high in many producing countries.
Vaccination programs in Norwegian salmon farming have reduced antibiotic use by over 99% since the late 1980s.
AGD treatment using freshwater bathes causes significant handling stress and is a recurring welfare event in affected fish.

Welfare Considerations

Disease in fish farming is both a production problem and a welfare crisis. Fish experiencing parasitic, bacterial, or viral disease are suffering — they show reduced appetite, aberrant behavior, and physiological signs of chronic stress. The root cause is often the production system itself: overcrowded conditions where stress impairs immunity and disease spreads rapidly. Improving welfare requires addressing the systemic drivers — reducing stocking density, improving water quality, vaccinating where possible, and developing less stressful treatment protocols. Treating fish disease in welfare terms, not just production terms, reorients the entire management approach.

What You Can Do

Choose aquaculture products from certified operations with disease management standards.
Support research into vaccines and non-stressful treatments for common aquaculture diseases.
Advocate for stocking density limits in aquaculture regulations.
Ask producers and retailers about disease management practices in their supply chains.