Sea lice infestations in farmed salmon require treatment that itself carries significant welfare implications; balancing parasite control and treatment stress is a major aquaculture challenge.
Sea lice management in salmon aquaculture involves a welfare dilemma: untreated infestations cause chronic suffering and mortality, but current treatment methods also cause significant acute welfare harm. Warm water delousing — exposing fish briefly to 34-degree water to remove lice — causes thermal shock and crowding stress, with mortality rates that can be substantial. Chemical treatments using hydrogen peroxide or emamectin cause oxidative stress and behavioral disturbance. Mechanical systems (laser delousing) and biological control using wrasse reduce reliance on thermomechanical and chemical treatments. Research into lice-resistant breeding lines, barrier technology (snorkel lice skirts), and enclosed containment systems represents the path toward significantly reduced treatment burden.