Aquaculture

Farmed Salmon Sea Lice Treatment Welfare Impacts

Sea lice treatments in salmon farming vary in welfare impact, with chemical and mechanical methods presenting different challenges.

Key Facts

Thermolicer (warm water bath) causes thermal stress and physical discomfort but is chemical-free
Hydrolicer uses pressurised water jets which can cause scale loss and physical injury
Emamectin benzoate (SLICE) is an in-feed treatment that causes chronic lice mortality
Resistance to multiple treatment chemicals is now common in sea lice populations
Combining methods in an integrated pest management approach reduces treatment frequency

Welfare Considerations

Each delousing treatment carries welfare costs - thermal stress, mechanical trauma or chemical exposure. The welfare impact of treatments must be weighed against the welfare harm of untreated lice infestation. Reducing infestation through prevention (cleaner fish, closed containment, fallowing) is preferable to repeated treatment.

What You Can Do

Support aquaculture companies investing in lice prevention rather than reactive treatment
Choose salmon certified to standards requiring integrated pest management for lice
Advocate for sea lice treatment welfare assessment as part of aquaculture certification
Support research into effective, low-welfare-impact lice control methods