Sea Lice information
Lepeophtheirus salmonis (commonly referred to as sea lice) are natural external parasites of wild fish occurring in all oceans. Wherever salmon are farmed, sea lice and salmon must be managed to ensure the health and wellbeing of the fish. The impact on farmed stocks can be minor or significant depending on the region of operation. Through a combination of good husbandry and management, biological and medicinal control, presence of sea lice on Marine Harvest Canada fish farms are kept to a minimum. As infection originates from wild sources and the parasite is native to all the world's oceans, total lice prevention is not possible.
Routine monitoring of our fish provides early information as to the presence of two common sea lice (Lepeophtheirus salmonis and Caligus clemensi). In British Columbia, the health effect of sea lice on farmed salmon stocks is a comparatively minor fish health concern that is controlled by using veterinarian prescribed medications in the rare case it is needed to address fish health concerns. A greater concern in British Columbia at present is the potential for farmed salmon, once infected by wild fish sources, to be a source of infection to wild salmon, particularly small juvenile Pink and Chum salmon as they migrate to sea in the spring.
When introduced into saltwater, our salmon are free of sea lice, but as they grow, infection does occur from wild sources in the marine environment such as stickleback, herring and migrating wild salmon. Marine Harvest Canada's sea lice and salmon monitoring and management actions are designed to limit the potential for our salmon to infect wild fish by timing of entries into saltwater, scheduling of harvest of adult fish and application of SLICE, a medication that disrupts the growth and breeding of lice on our fish.
In addition, Marine Harvest is actively engaged in research in both Europe and British Columbia to better understand the potential impact associated with the relationship between our salmon and wild fish. In support of research and the need for transparency, Marine Harvest Canada has posted sea lice data from our farms on our website since 2003. Read more about our Sea Lice Management Practices.
Fish Farm Locations and Biological Information