Aquatic Animals

Sea Lice Treatment Methods and Fish Welfare

Treating sea lice in salmon farms involves methods with their own welfare costs; selecting the most humane effective treatment is essential.

Key Facts

Hydrogen peroxide bath treatments cause acute stress and membrane damage
Thermal delicing uses 34C water causing osmotic stress and scale loss
Cleaner fish such as wrasse are used biologically but face their own welfare challenges
Freshwater treatments are less stressful for salmon but require infrastructure

Welfare Considerations

Every treatment method for sea lice causes some degree of stress and physical harm to salmon. The welfare calculus requires comparing the harm of treatment against the harm of untreated infestation. Biological controls using cleaner fish avoid chemical stress but raise welfare concerns about the cleaner fish themselves. Enclosed farming systems prevent infestation and eliminate treatment needs.

What You Can Do

Choose salmon certified by schemes requiring low sea lice levels
Support research into enclosed aquaculture systems eliminating sea lice
Advocate for transition from net pen to land-based salmon farming
Reduce salmon consumption from uncertified open net pen operations