Aquaculture Welfare

Farmed Salmon and Sea Lice Infestations

Sea lice are a major welfare and productivity challenge in salmon farming, causing skin erosion and systemic harm to affected fish.

Key Facts

Sea lice (Lepeophtheirus salmonis) infest farmed salmon at rates rarely seen in wild populations
Heavy infestations cause open wounds, stress-related immune suppression, and behavioral changes
Treatment with chemical agents including hydrogen peroxide causes acute distress in fish
Cleaner fish such as wrasse are used as biological controls but themselves face poor welfare
The Norwegian salmon industry loses approximately 00 million per year to sea lice

Welfare Considerations

Sea lice infestations cause demonstrable harm: fish show reduced feeding, abnormal swimming, and stress behaviors. Many treatments are themselves aversive. High-density open-net farming creates the conditions for parasite amplification. Closed-containment systems reduce infestation risk but require significant investment.

What You Can Do

Choose salmon products certified under the Best Aquaculture Practices standard
Support regulation requiring sea lice thresholds and mandatory reporting
Advocate for industry investment in closed-containment aquaculture to reduce parasite loads