Norwegian salmon virus discovered in BC
On July 11, independent salmon biologist Alexandra Morton co-published evidence in the Virology Journal of the first occurrences of a Norwegian salmon virus beyond that country’s waters, where it has been connected to deadly diseases that have wrought havoc on aquaculture operations there. The study found instances of piscine reovirus (PRV) in both BC and Chile.
According to Morton, one of six co-authors of the paper – along with Dr. Fred Kibenge of the Atlantic Veterinary College at UPEI – “Piscine reovirus (PRV) was identified in 2010 as the causative agent of heart and skeletal muscle inflammation (HSMI) in Norway. This disease, first recognized in Atlantic salmon farms in Norway in 1999, is a condition that weakens salmon, making it difficult for their hearts to pump blood. HSMI is spreading rapidly in Norway. Marine Harvest, who grows one-fifth of the world’s farm-raised salmon, lists HSMI as the second largest cause of death of their fish in their 2012 Annual General Report.”
The fish tested included farmed salmon purchased at several Vancouver-area supermarkets.
The study found some of these fish contain a PRV sequence closely resembling a Norwegian strain carried by salmon infected by HSMI in the late 1990′s in Norway’s Lofoten Archipelago. The study also found traces of PRV in Chile which closely match a PRV sequence from the Trondheim region of Norway.
Morton asserts, “the co-authors show that piscine reovirus is in British Columbia and it came from Norway. The process of tracing viruses is similar to matching fingerprints. Scientists around the world enter viral sequence data into GenBank so matches can be run.”
The BC Salmon Farmers’ Association was quick to attack the study by way of a press release last week, lamenting, “the quality and number of samples used is quite low which means some of the conclusions reached are questionable.” The lobby also questions the evidence linking PRV to the serious salmon disease, HSMI, noting, “The Province of British Columbia does not accept that PRV causes HSMI.”
Filmmaker Twyla Roscovich recently journeyed to Norway to learn from the country’s top salmon disease experts about PRV and its link to HSMI and potential impacts on farmed and wild fish in BC. Watch her video report here.