Cleaner fish used as biological control for sea lice in salmon farming raise their own welfare concerns while offering potential alternatives to chemical treatments.
Biological lice control through cleaner fish presents a genuine welfare paradox. Replacing chemical treatments that harm salmon may seem like a welfare improvement, but the cleaner fish themselves are often kept in poor conditions with high mortality rates. Wild-caught wrasse face the stress of capture, transport, and stocking into unfamiliar, high-density environments. The scale of cleaner fish use - tens of millions annually in Norway alone - means that their welfare deserves serious attention. The transition toward captive-bred cleaner fish that are better adapted to farm conditions represents a welfare improvement for both cleaner fish and the salmon they protect from lice.