Virus, Genetic Link Eyed In Canadian Salmon Deaths

Sockeye salmon in one of Canada’s key but troubled fisheries on the Pacific Coast may have a genetic flaw that makes them more susceptible to disease, according to a study released Jan. 13.

Researchers have found a genetic profile in some sockeye in British Columbia’s Fraser River that indicates some are more likely to die before they are able to spawn, according to the study published in the journalScience.

It is still unknown what is killing the salmon, but a genetic flaw may make them more vulnerable to deadly viral infections, according to scientists with the Canadian government and the University of British Columbia.

The data indicates the virus infects the fish before they enter the river, according to the researchers, and can persist to their spawning grounds, some of which can be hundreds of miles inland in tributary streams.

Salmon tagged in the ocean and found to have the genetic signature were 13.5 times more likely to die before spawning than those without it. Those tagged in the river and found to have the profile were 50 per cent more likely to die before spawning.

Pacific salmon normally die after spawning.

Although last year saw British Columbia’s largest salmon migration in over a century, that followed several years of decline, including sockeye returns two years ago that fell far below what scientists had predicted.

The researchers said the findings should help them better predict how many salmon will survive to reproduce. Earlier research has said the pre-spawning death rates were between 45 per cent and 90 per cent, according to the researchers.

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