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Hatchery Supplementation, Habitat Work Underway To Reverse Chum Salmon’s Slide Into Extinction
Posted on Friday, May 25, 2012 (PST)

The future of chum salmon in the Lewis River basin may depend on 105,000 juvenile hatchery fish released into the east fork last week by the Washington Department of Fish and Wildlife in an attempt to infuse the existing wild population.


The chum fry, each about 2 inches long, are part of a coordinated effort across the lower Columbia to restore a salmon species that once returned by the millions, but is now at risk of extinction.


Fishery managers expect that about 500 of the juvenile fish this year will return to the East Fork Lewis River as adults over the next three to five years. In recent times, the entire Lewis River system has attracted an average of only about 50 wild spawning chum each year, compared to historical returns upwards of 100,000 said Todd Hillson, a WDFW fish biologist.


"We have a long way to go to rebuild this run, but this is where it starts," Hillson said. "Over time, as the returns increase and the year-classes start to overlap, we expect that these efforts will move us toward a sustainable chum salmon population in the East Fork Lewis River and the rest of the Columbia River basin."


The expectation is that it will take about 12 to 15 years, about three generations, to determine if the hatchery supplementation effort is indeed boosting the natural population, which is a “small remnant population that has persisted over the years,” Hillson said. The creation of spawning channels and other habitat improvements such as the reopening of side channels are key to the success of the project.


Last week’s fry release is part of a long-term recovery project for chum salmon initiated by WDFW in the late 1990s with financial support from the Bonneville Power Administration. Related projects are already under way on Grays River near the mouth of the Columbia and at Duncan Creek, a small tributary near Bonneville Dam.


The Oregon Department of Fish and Wildlife also launched a reintroduction project for chum salmon on Big Creek near Astoria last year with eggs provided by WDFW from the Grays River chum program.


The north and east forks of the Lewis River converge about 3 ½ miles upstream of the river’s confluence with the Columbia near Woodland, Wash. Woodland is roughly 30 river miles downstream from Vancouver-Portland.


Fishery managers attribute the decline of chum salmon in the lower Columbia River to overfishing in the early 1900s and losses in spawning and rearing habitat from diking, dam construction and other developments. After years of dwindling runs, the federal NOAA Fisheries Service listed as "threatened" in the lower Columbia River under the federal Endangered Species Act in 1999.


The listed lower Columbia “evolutionarily significant unit” includes all naturally spawned populations of chum salmon in the Columbia River and its tributaries in Washington and Oregon, as well as three artificial propagation programs: the Chinook River (Sea Resources Hatchery), Grays River and Washougal River/Duncan Creek chum hatchery programs.


For the new project on the East Fork Lewis River, juvenile chum salmon were reared for approximately six weeks at the Lewis River Hatchery. Those juvenile fish are the offspring of 111 adult chum that returned to spawn on the Columbia River near the Interstate 205 Bridge – Woods Landing and the Rivershore Seeps -- between Portland Ore., and Vancouver, Wash.


"We chose those fish because that run has the greatest genetic similarity to native Lewis River chum," Hillson said. "In addition, returns to that area are large enough to sustain the loss of those fish."


He said the goal is to fill in the gaps. Southwest Washington’s Grays River in the lower Columbia estuary is a stronghold; and the I-205 area, as well as areas farther upstream nearer Bonneville Dam such as Duncan and Hamilton Creeks in Washington, and Multnomah Falls in Oregon, have begun to build strength as the result of more accommodating dam operations, habitat restoration, hatchery projects and other factors.


“We’re really light in the middle,” Hillson said of the need for spawners to reach out into the Columbia’s other tributaries.


Survey efforts last year in the I-205 area last year resulted in the identification of some 2,700 individual adult chum, a total that came close to matching the recent-decades’ record of 3,500 in 2002.


“But there’s very little in between” Bonneville and the I-205 area, and between I-205 and Grays River, Hillson said. The Lewis project is intended to begin to bridge those gaps.


Hillson said releasing juvenile fish is the "fun part" of salmon restoration. Before any fish are actually released, WDFW employees and area volunteers often work for weeks to restore spawning channels and other habitat the salmon need to survive.


"Rearing and spawning habitat is probably the greatest limitation we face in restoring chum salmon in the Lewis River and the lower Columbia," Hillson said. "Even though fisheries were brought under control by the 1950s, the chum never really came back because so few places were left for them to successfully spawn."


That will not be the case with the chum fry released last week.


Approximately 95,000 of those fish were released just below a spawning channel designed and built on the East Fork Lewis River by Fish First, a local salmon-recovery group. The channel is located about six miles upstream from the confluence with the Columbia.


Dean Swanson, who serves on Fish First’s board of directors and owns the property, has been active in many of the group’s other restoration projects for salmon and steelhead in the Lewis Basin.


The remaining 10,000 fry were released into Mill Creek, a tributary of the East Fork Lewis River, from property owned by Dave Brown, who operates a rescue facility for wild fish. Brown and his team of volunteers specialize in rescuing outmigrating salmon and steelhead at risk of becoming stranded in shallow water.


"Both Dean and Dave have been working to restore wild fish for a long time," Hillson said. "I can’t imagine having better partners for this project."


As part of the project the WDFW is investigating the possibility of creating a Lewis mainstem spawning channel, perhaps next year.


While chum salmon have less value to freshwater fisheries than other salmon species, they have played a historic role in the ecology of the Columbia River Basin, said Bryce Glaser, another WDFW fish biologist.


"Chum salmon once carried massive amounts of nutrients from the ocean up the Columbia River, where their carcasses benefit the stream, the soil and other fish and wildlife," he said. "Our goal is to rebuild these runs and regain the ecological benefits they bring with them."


Chum have also long been an important component of ocean harvests along the north Pacific coast.

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