Salmon advocates have come across what they feared -- what every West Coast salmon fisherman should fear -- in British Columbia's Fraser Valley, not too far from the Washington border.

"It was a beautiful Coho salmon, in first blush of spawning colors ... on the way home carrying the richness of a life at sea, her body shut down infected with a virus her ancestors never had a chance to prepare her for," renowned B.C. biologist Alexandra Morton wrote on her blog this weekend.

"We found her drifting head downstream passing Harrison Mills. We scooped her up, took a sliver of her heart and gills, and sent them to one of the world authorities on Infectious Salmon Anemia virus."

Infectious salmon anemia, or ISA, has now been detected in two Canadian locales nearly 400 miles apart. The ISA virus was earlier found in two steelhead taken near Rivers Inlet on the British Columbia coast. Now it's in the Fraser River, one of the world's greatest salmon streams.

Does this give reason for alarm?  Damned right it does.

It also gives reason for United States scientists to take a cue from Sen. Maria Cantwell, D-Wash., and immediately evaluate the virus and its potential impacts on wild salmon off the West Coast and Alaska.

Canada's Department of Fisheries and Oceans, a long-time promoter of fish farms that raise salmon in pens, can be trusted about as far as you can hand-roll a purse seine. The DFO is the department that ignored its own scientists and allowed the North Atlantic cod to be decimated.

The virus has decimated Atlantic salmon being farmed in Chile. A 1996 outbreak forced the killing of 9.6 million farm salmon in New Brunswick as a means of ISA control. (The DFO generously compensated salmon farmers in the amount of $40 million for disease management.)

Salmon farming is a big deal in British Columbia. Salmon pens can be seen -- and smelled -- in such renowned recreation destinations as Clayoquot Sound on Vancouver Island, and the Broughton Archipelago between the island and the B.C. mainland.

What's being farmed? Atlantic salmon. Northwest wild salmon, on their way to and from the Pacific Ocean, pass millions of Atlantic salmon in pens. Sea lice from pens in the Broughton Archipelago have been linked to the decimation of wild pink salmon stocks in the vicinity.

Morton has become a public hero -- she was runaway winner when The Tyee, an online news service, solicited nominees for the Peoples' Order of British Columbia. But she has been a target of the DFO for pointing out inconvenient truths about salmon farming.

"If you move diseases across the world and brew them among local pathogens, in an environment where predators are not allowed to remove the sick, you get pestilence," Morton warned recently.

The province's fish farm lobby is saying no evidence of an outbreak has been established, and that the Canadian Food Inspection Agency must still conduct its evaluation.

On Tuesday, the U.S. Senate passed an amendment by Cantwell and a half-dozen West Coast senators -- including Republican Sen. Lisa Murkowski of Alaska. It requires federal scientists to investigate and come up with a rapid response plan to prevent spread of infectious salmon anemia.

"Pacific Northwest wild salmon support tens of thousands of local jobs," Cantwell said. "We need to take immediate action to protect these jobs by quickly developing a salmon virus action plan."

The amendment is included in an appropriations bill passed with bipartisan support in the Senate. It goes to a House-Senate conference committee. Hopefully, the Republicans won't make a mess of things by trying to mandate abstinence-only sex education or some other sop to the religious right.

The U.S. must be front and center. Salmon should be tested coast-wide, from Alaskan waters north of Dixon Entrance to the Sacramento River in California. The Canadians should be called upon to set up a scientific panel independent from the DFO.

One more thing: Given what's happening, the state of Washington should take a dim view of a proposal from Oregon-based Pacific Seafood to establish a salmon farm west of Port Angeles on the Strait of Juan de Fuca.

Salmon bound for the "Mighty Fraser" and U.S. rivers migrate through the Strait of Juan de Fuca. No way, no how, can infectious salmon anemia be penned in north of the border.

Get ahead of this, for the sake of our not-yet-wrecked part of the world. Don't imperil a natural species -- salmon -- that helps define us. And, yes, let Alexandra Morton get home to where she lives, next to two of North America's great fjords.

"I just want to live between Kingcome and Knight Inlets," she wrote wearily on Saturday, "and not watch it die."