Deadly salmon disease found in some B.C. fish farms

Posted May 21, 2016 by Karen Graham
A deadly viral disease that proved to be devastating to Norwegian salmon farmers in the 1990s has been found by federal scientists in farmed salmon in British Columbia.
Chinook salmon fish
Chinook salmon fish
U.S. Fish and Wildlife Service
Heart and Skeletal Muscle Inflammation (HSMI) is a viral disease of farmed Atlantic Salmon that has been reported from Norway, Scotland and Chile. The disease affects the heart and red skeletal muscles and has a morbidity rate of about 20 percent.
Kristi Miller, part of a team of federal scientists studying farmed fish samples from sites along the B.C. coast was quoted by CBC News as saying, "The concern is that it is a disease that hasn't previously been detected in B.C. and at the present time we really don't have sufficient evidence to know if it causes mortality or is a production issue here."
Miller is the head of genetic research in the Department of Fisheries and Oceans (DFO). She confirmed that pathologists had found lesions on salmon at one farm in Johnstone Strait, along the north-east coast of Vancouver Island. The lesions are indicative for the fish having HSMI, said Miller.
"We know that this virus, in other parts of the world, can be observed in fresh-water origin fish and we believe we know that here in B.C. in Atlantic salmon. But in Norway, while the virus can be observed in fish in hatcheries the prevalence of the virus can become much, much higher in the marine environment," Miller said Friday.
Miller also says the DFO is studying the relationship between HSMI and another viral infection, Piscine Reo-virus (PRV) that is often found in conjunction with HSMI. PRV was first identified in 2011 on examination of farmed Atlantic salmon from Norway that displayed signs of two similar heart diseases, HSMI and Cardiomyopathy Syndrome (CMS).
DFO says that while PRV is associated with HSMI in Atlantic Salmon farmed in Norway, PRV has yet to be proven as a causative agent in HSMI or other fish diseases. The DFO is now taking steps to better understand what these findings mean and to map a way forward. To date, HSMI has not been diagnosed in wild Pacific salmon and has only been observed in farmed Atlantic salmon says the DFO News Release.