Salmon lice (Lepeophtheirus salmonis) are parasites of Salmonids and are a big problem in aquaculture. It is tried to establish freshwater treatment as a method to delouse fish, however several studies have shown a suprisingly high tolerance of attached lice to low salinities. In this study, we want to examine the molecular mechanisms of osmoregulation in the salmon louse.</p><p>In this project, we exposed salmon lice to seawater, brackish water (ca. 14 ppt) and freshwater. The lice were either attached to an Atlantic salmon host or detached and the incubation periods were 4h and 1d. Lice were sampled, RNA extracted and the RNA was sequenced.