Salmon Lice – a Welfare Problem

The salmon louse (Lepeoptheirus salmonis) is a crustacean that lives by feeding on the salmon’s skin. Salmon lice have always existed in nature, but they need a host to survive. An adult female louse can produce several thousand eggs. In fish farms there is little distance between the hosts and thus good growth conditions for lice.

Fish with many salmon lice get sores that can become an entry point for bacteria and viruses.  If the fish gets too many lice, it will have trouble maintaining its water and salt balance, as water will leak out and salt will enter through the wounds.