Mainstream Canada tests positive for IHN
During routine fish health tests on 14 May, Mainstream Canada's Dixon Bay farm tested positive for the IHN (Infectious Haematopoietic Necrosis) virus.
The farm site has been isolated and is currently being prepared for depopulation, if deemed necessary upon completion of the investigation. The company is following strict protocols to limit the spread of the virus.
The Canadian Food Inspection Agency (CFIA) has been notified and is investigating the finding, and Fisheries and Oceans Canada's National Laboratory is conducting confirmatory testing.
"We are very concerned about this fish health event and are taking every step to make sure it is contained and any risks minimised," said Fernando Villarroel, Mainstream Canada's managing director.
The IHN virus is naturally carried by Pacific salmon, trout and herring. Studies show wild Pacific salmon have a natural resistance to the virus and very rarely suffer ill effects from it.
However, the virus causes Infectious Haematopoietic Necrosis disease in farmed Atlantic salmon. Since Atlantic salmon are not native to the Pacific coast, they have not had hundreds of years to develop a natural immunity to the virus, like their Pacific cousins. The disease can cause high degrees of mortalities on Atlantic salmon farms if not quickly managed and contained.
"This is the first diagnosis of IHN among farmed Atlantic salmon in BC since 2003. Although IHN kills up to 100% of exposed Atlantic salmon, wild salmon in marine waters are very resistant to IHNV infection," said Gary Marty, fish pathologist for the BC Animal Health Centre.