Fish Health - Managing Sea Lice

Sea lice are small, external parasites found naturally in the ocean. In B.C. there are two species of sea lice, Lepeophtheirus salmonis, which preys only on salmon species, and Caligus clemensi, which preys on numerous species of fish, including herring and sticklebacks.

Our salmon enter the marine farms from freshwater hatcheries free of sea lice. Once in the ocean, farmed salmon can pick up sea lice from the natural environment.

Sea lice are generally not a health problem for our fish, but there are concerns that farmed salmon could pass them back to the wild stocks, particularly very small wild salmon smolts.

For this reason, sea lice are regularly monitored and counted on our fish. This is done in accordance with government regulations.

Sea Lice management strategies may include harvesting the fish, or feeding the fish feed which contains SLICE®, a licensed veterinary drug that rids the salmon of the parasite. SLICE® is milled into the feed, and is a Health Canada-approved treatment for sea lice in farmed Atlantic salmon. This is the only government-approved sea lice treatment in B.C.

• Since 2004, Mainstream Canada has been involved in a collaborative wild fish sea lice monitoring program in Clayoquot Sound.

• Mainstream Canada is also involved in a collaborative wild fish sea lice monitoring program in the Broughton Archipelago.

• Mainstream Canada regularly posts monthly sea lice counts for all of its farm sites.