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In three streams in the upper North Fork Boise River, it may in fact be dead salmon. But salmon don’t run up the North Fork anymore? Not without some help.
About a dozen people gathered at the Idaho Power substation on Amity Road in east Boise on a recent warm summer morning. Several trucks stood ready, loaded with boxes of pasteurized, frozen salmon and steelhead carcasses, and bags of manufactured pelletized fertilizer – known to biologists as salmon “analogue” meant to simulate dead salmon.
A loose convoy headed up U.S. Highway 21 past Idaho City and Mores Creek Summit, and turned off at the Edna Creek Campground. The trucks then headed down washboard switchbacks, and hairpin turns to the North Fork and up along Trail Creek where the boxes of dead fish were destined.
Fifteen boxes were dropped off at each of five points marked by orange surveyor’s tape. In the naked eye of the summer sun, researchers and helpers carried the 30-pound boxes to the stream and dumped the carcasses into the creek.
The dust-shrouded convoy then headed up nearby Hunter Creek to dump bags of “analogue,” which looks a lot like dog food, at five sites in a similar process.
Over a few days, researchers added 8,400 pounds of fish carcasses and 2,300 pounds of pellets to treat about 1.5 miles of streams. Three streams were treated with salmon and steelhead carcasses, three others with the pellets, and three similar streams were untreated but will be sampled to compare with the treated streams.
The project, with management and research facets, is the brainchild of Gregg Servheen of Fish and Game, who recognized the need to restore former salmon bearing watersheds.
Important ingredients have gone missing from some of Idaho’s most pristine streams. And now Idaho Fish and Game is working with Idaho Power Co., Bonneville Power Administration and researchers from four universities in a project to restore nutrients in streams that once had large annual loads of ocean-origin minerals, brought back to Idaho from the Pacific in vast migrations of salmon and steelhead.
About six years ago, Servheen found freshwater nutrition expert, Mark Wipfli, now of the University of Alaska-Fairbanks, and got him interested in the research aspects of the project.
“These streams used to get a lot of salmon,” said Wipfli, who holds a doctorate in freshwater ecology. “It’s a really good place to see if these ecosystems respond.”
Research in Canada and Alaska suggests than entire forest ecosystems are enriched by the carcasses of ocean-going fish. Microbes feed on the carcasses, insects feed on the microbes and fish feed on the insects; some animals, such as bears and other scavengers, may feed directly on the carcasses.
As Idaho’s runs of wild steelhead and salmon have largely been replaced by a hatchery system, streams and their watersheds have gradually become impoverished. The carcasses and pellets will return nutrients to the ecosystems once brought by returning adult salmon now blocked from this watershed by dams.
So how do scientists measure the results?
Salmon take on 95 percent of their mass in the ocean – connecting the ocean to the land by bringing back biologically important nutrients. Scientists can track those nutrients through the ecosystem by testing plants and animals for a certain form of nitrogen common in the ocean but rare on land.
Researchers will sample fish, vegetation, insects, birds and other animals along the nine streams this summer and fall to monitor the effects of introducing marine nutrients. Next year, they plan more treatments in the same streams.
“We have funding for three years,” Wipfli said. He and Servheen hope to get funding for three more. Both would like to see the long term effects of simulating the annual return of salmon.
The nine streams were selected through a screening process to find sterile streams at the same elevation, with similar geology and gradient, in a fish-bearing watershed. This is the first study of its kind in this scope – ecosystem study – other studies have looked only at the streams themselves.
The research portion of the project includes professors, researchers and graduate students from the University of Idaho, Idaho State University and Washington State University, in addition to fish biologists and managers from Fish and Game and Idaho Power.
For the biologists this is a research project, but for Servheen and other Idaho Fish and Game fishery managers it is a management project in watershed restoration to improve the fishery, the riparian vegetation and the animal.
“We are doing restoration and habitat enhancement,” Servheen said.
The project is funded at more that a million for the first three years, by the BPA as part of mitigation for effect of dams and by Idaho Power as part of its federal hydropower licensing requirements.
What potential effects might be observable – other than the odor of dead fish? People in the area might see more wildlife attracted to the carcasses in the stream, more songbirds, bears and increased plant growth.
Anglers might find more and larger fish.
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