Aquaculture Lice Treatment Welfare

Sea lice treatments on farmed salmon involve mechanical, thermal, and chemical methods that carry significant welfare costs for the fish being treated.

Key Facts

Sea lice infestations are the most significant health challenge in Atlantic salmon farming
Mechanical treatments include hydrolicer (high-pressure water jets) and laser systems
Thermal treatments use warm water baths to dislodge lice from fish
Chemical treatments including hydrogen peroxide baths carry mortality risks at high temperatures
Post-treatment mortality and injury rates vary significantly between treatment methods

Welfare Considerations

Sea lice treatment welfare is a significant concern in salmon aquaculture because treatments are frequent — fish may be treated multiple times per production cycle — and some carry substantial welfare costs. Thermal treatments cause scale loss, secondary bacterial infections, and mortality if water temperature is not precisely controlled. Mechanical treatments can cause injuries. Chemical bath treatments expose fish to acute chemical stress. Research into in-feed treatments and biological controls (cleaner fish) aims to reduce reliance on the most stressful treatments, but cleaner fish welfare presents its own challenges.

What You Can Do

Choose salmon from farms with transparent lice management reporting
Support research into low-welfare-impact lice treatment methods
Advocate for regulatory welfare monitoring of treatment procedures
Ask retailers about lice treatment welfare data from their salmon suppliers