Wrasse and lumpfish are deployed as biological sea lice control in salmon aquaculture, creating welfare concerns for these cleaner fish that are often overlooked.
Wrasse welfare represents a largely invisible welfare crisis within salmon aquaculture. These small, intelligent fish are deployed in alien environments — salmon pens with entirely different conditions from their rocky coastal habitat — and experience extraordinary mortality rates. Welfare harms include cold temperatures exceeding their thermal tolerance, salmon crowding, inadequate refugia to escape aggressive interactions, and inappropriate feeding conditions. Wrasse that fail to clean salmon may be starving in an environment full of food they cannot access effectively. The industry's reliance on wild-caught wrasse has conservation implications in addition to welfare concerns. Welfare standards for cleaner fish are emerging but lag far behind those for salmon.