Infectious salmon anemia found in wild sockeye salmon in British Columbia; researchers, salmon farmers worry as virus cost billions of dollars, killed millions of Atlantic salmon in Chile in 2007, 2008
November 8, 2011
– Three weeks after a potentially deadly virus was found for the first time in two juvenile wild sockeye on the Pacific Coast, it has been found again — this time in other wild salmon from British Columbia's Fraser River.
At the same time, salmon farmers on both sides of the international border have been highlighting the work of a Norwegian expert who got slightly different results when he tested for the virus, infectious salmon anemia (ISA), in the first two young sockeye.
So, is there a fish crisis, or isn't there?
In a word: maybe.
Researchers, salmon farmers and wild-salmon advocates have been on alert since mid-October, when laboratory results in Canada showed that two young sockeye from Rivers Inlet in northern B.C. were carrying trace amounts of a European strain of ISA.
The reasons for the anxiety are clear. While ISA poses no harm to humans, a related strain of the virus cost billions of dollars and killed tens of millions of farmed Atlantic salmon in Chile in 2007 and 2008.
On Sunday, U.S. Sen. Maria Cantwell, D-Wash., toured a U.S. Geological Survey laboratory in Seattle that specializes in fish diseases to highlight the efforts of state and federal agencies to establish rapid-response plans in the event more evidence of ISA surfaces.
"In the past it has moved through salmon populations with devastating quickness, causing the chain reaction of dying stocks," Cantwell said.
The virus wiped out more than half the salmon in Chile. But Chile doesn't have wild salmon, and scientists fear any virus found here could not only hurt fish farmers but could mutate into a strain that weakens or kills millions of Northwest wild fish.
Thus far there is no evidence that any Pacific Coast fish are sick. And before last month, no tests in Washington state or B.C., where millions of Atlantic salmon are grown in net pens, had ever surfaced showing evidence of ISA.
And so far, the only two labs that have completed tests on potentially infected fish haven't reached the same conclusions. While the laboratory in Norway did find trace amounts of ISA, it was only in one of the first two young sockeye, and it was barely at detectable levels.
One seafood-industry media outlet said the results showed there was "no evidence to support the recent ISA virus scare."
But the results don't mean the virus isn't a threat, researchers said. It could be that the fish in question were just too degraded for adequate follow-up tests.
"These samples were not high quality," said Jim Winton, a fish virologist with the Geological Survey. "The Norwegian lab correctly said that not all of the samples could be tested positive."
But "I think this highlights again the need to begin to do our own surveys," Winton said.
Meanwhile, last week's test results by a highly regarded Prince Edward Island fish virologist finding ISA in adult coho, chinook and chum from the Fraser River have not yet been verified by a second round of testing. But the find itself has been enough to add urgency to the quest for information.
"If it can be verified, and a lot of this relies on verification, it's telling me it's in multiple species, in multiple generations, which leads me down a path that makes me think it might have been here for quite some time," said John Kerwin, who oversees disease testing in fish farms and hatcheries for the Washington Department of Fish and Wildlife.
Would that make the risk higher or lower that the ISA virus could evolve into something harmful to wild fish? It's too soon to say, Kerwin said.
That's why the Geological Survey, the state and other federal agencies are putting together plans to begin screening hatchery, farmed and wild salmon in the Northwest for the virus — both juveniles migrating to sea and adults in coastal areas.
The survey plan is expected to be finalized in coming weeks.
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