Aquaculture Disease Management: Antibiotics and Welfare

Disease management in aquaculture is a critical welfare and public health issue, with antibiotic use, disease outbreaks, and treatment methods all carrying significant welfare implications for farmed fish.

Key Facts

Disease is the largest single cause of economic loss in aquaculture worldwide
Norway has dramatically reduced salmon antibiotic use through vaccine development — from kilograms per tonne to milligrams
Chile, a major salmon producer, still uses substantially higher antibiotic quantities than Norway
Antimicrobial resistance (AMR) is a concern both for fish health and for human medicine
Sea lice infestations in farmed salmon are a major chronic welfare problem — heavy infestations cause open wounds
Cleaner fish (wrasse, lumpfish) are used as biological sea lice control — but their own welfare in cages is poor
Chemical treatments for sea lice including hydrogen peroxide and azamethiphos cause acute distress in fish
Vaccination programs for multiple bacterial diseases have transformed welfare and antibiotic use in salmon farming

Welfare Considerations

Disease outbreaks in aquaculture cause mass mortality events and prolonged suffering from infection, tissue damage, and physiological dysfunction. Sea lice infestations in farmed salmon are a chronic welfare issue — severe infestations cause open lesions on the head and body that expose muscle tissue, causing ongoing pain while the fish continues to live in the crowded, stressful environment of a sea cage. Treatments for sea lice, while necessary, often cause additional acute stress. The success of vaccination programs in Norwegian salmon farming demonstrates that disease management without heavy antibiotic use and with better welfare outcomes is achievable — but implementation is uneven globally.

What You Can Do

Choose salmon from countries and producers with strong disease management and low antibiotic use records
Support mandatory antibiotic use reporting and AMR surveillance in aquaculture
Advocate for sea lice management standards that protect both salmon and cleaner fish welfare
Support research into disease-resistant fish strains and improved vaccine development
Reduce salmon consumption from producers with poor welfare and antibiotic records