Sea lice are parasitic crustaceans that cause significant welfare problems in farmed Atlantic salmon, requiring management strategies that themselves carry welfare implications. Balancing parasite control and treatment welfare is a central challenge.
Sea lice management creates a compounded welfare problem - the lice themselves cause pain and tissue damage to salmon, while treatments used to remove them also impose welfare costs ranging from mild stress to mortality at high doses. Cleaner fish introduced as biological control face significant welfare challenges of their own, as many wrasse species are poorly adapted to aquaculture conditions and suffer high mortality rates. A welfare-conscious approach to sea lice management prioritizes prevention through site selection and fallowing periods, uses cleaner fish only when welfare conditions can be met, employs treatments at minimum effective doses, and monitors fish behavior to detect treatment stress. The long-term solution likely involves genetic resistance combined with better farm management.