Chum salmon, long considered to be functionally extinct on the Oregon side of the lower Columbia River, might again return to its tributaries if a cooperative effort of the Oregon and Washington departments of fish and wildlife proves successful.
During the first week of April, Oregon Department of Fish and Wildlife biologists released 106,000 juvenile chum salmon into lower Big Creek just east of Astoria in the first phase of project attempting to re-establish the species, which began to disappear from the Oregon side of the river more than 50 years ago.
While the reason for their decline is not completely clear, biologists believe that severe habitat degradation, among other factors, played a key role.
The approximately 50 adult chum salmon male and female pairs used to produce the 2½ -inch fry at ODFW’s Big Creek Fish Hatchery were donated to Oregon by the Washington Department of Fish and Wildlife. The adults were captured last fall in Grays River, a tributary of the lower Columbia almost directly north of Big Creek in Washington.
“Grays River stock are likely the most genetically similar to what once occupied Big Creek and other lower Columbia tributaries,” said Chris Knutsen, district fish biologist for ODFW’s North Coast Watershed. “We worked closely with our counterparts from WDFW to initiate this program in Oregon. We could not do this without fish from the Washington side of the river.”
The young salmon were released at night during an outgoing tide to increase their chances of getting past predators and surviving the 25-mile swim to the Pacific Ocean, where they will spend the next 3-4 years before returning to spawn at Big Creek.
“The quicker they get out under the cover of darkness and a strong ebb tide the better their chances of survival,” Knutsen said.
Once the fish return to Big Creek most will be captured and spawned at Big Creek Fish Hatchery to produce more eggs and fry for release in subsequent years. Ultimately, ODFW hopes to generate enough seed stock to begin out-planting chum in other lower Columbia tributaries that are considered suitable for this species. Just which streams will be selected for future releases depends on which ones have the best conditions for chum, which Knutsen says are “very picky spawners.”
Chum salmon are generally more selective in their choice of spawning habitat than other salmon species, according to Knutsen. Chum especially seek out upwelling areas associated with springs and seeps, he said, and they also prefer very clean, well-sorted gravel that is free of sands and silts that could smother their eggs.
Dozens of streams around Scappoose and Clatskanie will be evaluated by ODFW research teams because biologists believe they show the greatest potential for establishing naturally-reproducing chum populations. Biologists also believe the timing is right for reintroduction because conservation measures and habitat improvements are already well underway in the region.
“Fortunately, we have four or five years to figure out which streams will work best because it will take us that long to generate extra fish for out-planting,” said Knutsen.
If the program works as planned, chum salmon will reproduce naturally in sufficient numbers that they will no longer need a boost from Big Creek Hatchery.
“Our goal is to develop self-sustaining populations of chum salmon on the Oregon side of the lower Columbia,” said Knutsen. If ODFW is able to bring back chum salmon in the lower Columbia using this approach, the same methodology might later be used to reintroduce chum salmon in areas further upstream, he said.
Chum salmon stocks returning to the lower Columbia River and its tributaries in Oregon and Washington are listed as threatened under the Endangered Species Act and any reintroduced fish would join that listing. Included in the listing are fish from three artificial propagation programs in Washington: the Chinook River (Sea Resources Hatchery), Grays River, and Washougal River/Duncan Creek chum hatchery programs.
Grays River in Washington is the lead producer of chum along with areas immediately below Bonneville Dam, in large part in Washington, and, to a lesser extent, under the I-205 bridge near Vancouver.
According to a 2007 research paper prepared for the ODFW and NOAA Fisheries chum are seen occasionally in Oregon and chum may be intercepted at hatchery weirs or at dam passage faculties (e.g. North Fork dam on the Clackamas River or Powerdale dam in the Hood River). In 2000, ODFW did conduct a survey focused on chum. Out of 30 sites surveyed, only one chum was observed, the paper says.
“A time series of returns is available for chum trapped at the Big Creek hatchery weir. Except for 2006, only a handful of fish have shown up at the facility each year and in some years no fish have appeared,” the paper says. “It is unclear if the fish observed at the Big Creek weir were produced in Oregon or whether they are strays from the naturally producing population at Grays River across the Columbia in Washington. In 1999, a chum hatchery program was initiated in Grays River, so an unknown fraction of the fish observed in 2003-2006 are likely of hatchery origin.”
Most of the spawning that occurs in Oregon is on the mainstem Columbia near McCord Creek, which is just downstream of Bonneville, and Multnomah Falls.
The reintroduction is called for in “The Lower Columbia River Conservation and Recovery Plan for Oregon Populations of Salmon and Steelhead, which describes the population status and recovery plans for salmon and steelhead in the Youngs Bay, Big Creek, Clatskanie, Scappoose, Clackamas, Sandy, Lower Gorge, Upper Gorge, and Hood River sub-basins. The plan, approved by the Oregon Fish and Wildlife Commission in June 2010, serves as both a federal recovery plan for Oregon fish populations listed under the ESA and a state of Oregon conservation plan under Oregon’s Native Fish Conservation Policy.
The primary population groups addressed in the plan are the listed Lower Columbia River coho, Lower Columbia River chinook, the Lower Columbia River steelhead and the Columbia River chum, all of which are ESA listed.