Sea lice infestations are one of the primary welfare challenges in Atlantic salmon farming, and treatment methods themselves carry significant welfare costs that the industry must address.
Sea lice represent one of the most intractable welfare problems in Atlantic salmon aquaculture. The parasites cause chronic pain and tissue damage, while available treatment options all carry their own welfare costs: mechanical treatments physically shock fish; chemical baths cause physiological stress; and cleaner fish used as biological control agents often have poor survival rates and inadequate welfare consideration in their own right. The industry faces a genuine trilemma — untreated lice cause severe welfare harm, but available treatments are also welfare-negative. Long-term solutions require integrated pest management, development of genuinely low-impact treatments, and breeding programs selecting for lice resistance.