Why are sea lice mentioned so often in relation to salmon aquaculture?
Sea lice are widespread, naturally occurring marine crustacean (related to shrimp and crab) parasites that infect the exterior of many wild and farmed fish species. The two most common types of sea lice are Lepeoptherius salmonis (Lep) and Caligus clemensi (Caligus). Lep infects salmon species, whereas Caligus has a much broader host range and infects salmon as well as non-salmonid species (Fisheries and Oceans Canada). Salmon farms are typically located in sheltered near-shore waters that are also commonly used by wild juvenile salmon during migration. Sea lice are attracted to these areas since there is an abundance of potential hosts, farmed and wild salmon. Wild salmon and farmed salmon live in very dynamic environment. Since the nature and impact of various biological and physical factors remain unclear, it is extremely difficult to accurately define the relationship between sea lice, salmon farms and wild salmon. Views on the meaning of observed correlations have become highly po
