Salmon virus fears voiced, caution advised
Scientists and fishermen are following news of a deadly fish virus found in British Columbia salmon. It’s a scary situation, but it may not be as bad as it sounds, at least for now. And it’s not a threat to people who eat salmon.
Infectious salmon anemia has badly damaged populations of farmed Atlantic salmon. So when scientists found the virus in a pair of wild, Pacific sockeyes, they were worried.
Should they be?
“It’s not a time to panic or overreact. I think some folks have been a little bit overly concerned about it,” says Ted Meyers, chief pathologist for Alaska’s Department of Fish and Game.
If confirmed, he says the virus, found in two central British Columbia fish, needs to be watched, and understood. That’s because it is a deadly disease that affects the blood and internal organs of salmon.
“Basically, they develop an anemia and they hemorrhage. And it can kill market-size fish,” he says.
The virus has badly damaged captive Atlantic stocks in Chile, Norway, Scotland and eastern Canada.
Pacific salmon are different, and Meyers says several thousand earlier tests by the British Columbia government showed no presence in wild fish.
But he warns this disease adapts.
“It’s possible that some of these viruses could mutate to potentially affect Pacific salmon. But that would probably occur under situations where there’s a selective pressure, like a hatchery situation or a pen farming situation or something of that nature,” Meyers says.
That’s what happened to farmed Pacific cohos in Chile in the late 1990s. Infectious salmon anemia spread quickly through cohos raised in net-pens along with Atlantic salmon and rainbow trout.
“We shouldn’t underestimate the power of viruses,” says Dale Kelley, who heads up the Alaska Trollers Association.
The Juneau-based group is among commercial fishing organizations that want action.
“It’s a pretty scary situation for us all and we want to put it into context. We would like to continue to urge the Canadians and other fisheries professionals to make sure that they’re doing as much as fast as they can,” she says.
Some politicians agree. Alaska Senators Lisa Murkowski and Mark Begich have joined Washington Senator Maria Cantwell to ask Congress to require U.S. agencies to become involved. They want an emergency research effort to calculate how much of a threat the virus may pose.
Canadian officials have stepped up their interest. But they say they will decide on an action plan after they confirm identification of the virus.
Kelley says the initial diagnosis came from a lab that specializes in infectious salmon anemia. So, she asks, why wait?
“What we’ve seen out of Canada is a press release that says, if our tests, a few weeks down the road, come up with a finding of ISA, then we’ll be bring people together and then we’ll talk about what to do,” Kelley says. “It seems like there’s probably some information they could be gathering up, before winter hardens everything up, to at least give them a boost on sorting out the extent of the problem.”
Those concerned assume the virus came from Atlantic salmon in British Columbia fish farms. It appears to be the same European strain found in Norway and Scotland.
The fear is close quarters could quickly spread the illness, which could further spread it to wild stocks. Those fish could then carry the disease up the coast into Southeast, and other Alaska waters.
Other pathogens attack Pacific salmon, and some are widespread.
One, known as the IHN virus, also causes hemorrhaging and organ failure.
State pathologist Ted Meyers says it’s common in Alaska sockeyes. It’s adapted to live in Chinook, chums and steelhead down south. But in this state, it hasn’t crossed those boundaries.
“We’re always concerned about this virus potentially mutating and being able to affect other species. But so far our hatcheries have been following a sockeye salmon culture procedure, which really mitigates or reduces the risk from this virus,” Meyers says.
He says the hatchery procedure has been in place for close to 30 years and it’s been successful.
The salmon viruses pose no threat to people. But some fisheries advocates worry consumers won’t understand that, and word of the latest problem could hurt salmon sales.