The effort to rejuvenate a fish stock listed as endangered under the Endangered Species Act took another step forward with the release this spring of nearly 114,000 hatchery-reared spring chinook salmon smolts in a variety of acclimation scenarios on the White River basin and in Lake Wenatchee.
The releases from temporary aluminum acclimation tanks at streamside (38,500), a side channel filled with White River water (11,750 in an earlier release), an in-stream net (14,600) and from Lake Wenatchee net pens (49,000). White River feeds in near the head of the lake in central Washington.
The releases mark a first test of the concept of overwinter acclimation in the Wenatchee River tributary. F fish managers hope the fish will return to spawn and help boost the number of naturally spawning fish. Numbers of naturally spawning fish dipped as low as the single digits in the White River in the 1990s, according to Todd Pearsons, Grant County Public Utility District fisheries biologist.
Research shows that fish that spend winter months in the river or creek of their birth appear to have higher survival rates and are more likely to find their way back to spawn as adults than fish released after a short-term acclimation.
“There is an increasing trend toward going to overwintering acclimation,” Pearsons said. The goal is to “get them on the odor (or the natal stream) for as long as you can.” The PUD intends to get the fish out in the water in October, and release them in springtime. Most streamside acclimation programs begin in the late winter and spring.
“It’s a lot more costly; it’s a lot more difficult,” Pearsons said of overwintering acclimations. And it comes with more risks. Wild fish that rear in rivers generally smaller than their hatchery reared cousins when it comes time to head toward the Pacific Ocean in springtime. And when it comes to survival, bigger means better. But the Grant PUD project is designed to mimic wild populations as much as possible.
“We don’t want to replace wild fish with hatchery fish,” Pearsons said.
The releases are part of a program to shore up spring chinook salmon populations in the White River and Nason Creek, two tributaries to the Wenatchee River. The goal of the White River program is to prevent the extinction of, conserve and ultimately rebuild the naturally spawning White River spring chinook salmon spawning aggregation.
Spring chinook that inhabit the two Wenatchee tributaries are part of the Upper Columbia “evolutionarily significant unit” first listed in 1999 by NOAA Fisheries Service. The program is being funded by Grant County PUD as mitigation for impacts on fish and wildlife caused by the dams it owns, Wanapum and Priest Rapids.
The supplementation project is part of a collaborative effort between Grant PUD, fisheries co-managers, federal, state and local governmental officials, members of the public and other stakeholders.
Grant PUD’s temporary facility includes 12 portable tanks, one roughly two miles from the mouth of the White River and three others 11.5 miles upstream. The tanks along the White are designed to acclimate juvenile spring chinook this year and next. A long-term facility is expected to be ready to receive fish in 2013.
A permit application for construction of a long-term facility was submitted to Chelan County, Washington State Department of Ecology, Washington State Department of Fish and Wildlife and U.S. Army Corps of Engineers this month. Once these organizations have reviewed the application, it will be available for public comment. Construction of the long-term acclimation facility is scheduled to begin in 2012.
The long-term acclimation facility has been designed to address concerns regarding aesthetics and environmental impacts. A minimized facility footprint is planned for both the planned White River facility, and one to be built later on Nason Creek. The facility allow fishery managers to overwinter up to 165,000 juvenile spring chinook salmon on-site for release each spring into the White River.
The critically endangered White River spring chinook is genetically distinct from other chinook species; it is also unusual, as it is one of few chinook populations that migrate from a glacially fed river, through a lake (Wenatchee) to reach the ocean. The spring chinook released this week will be tracked as they make their way to the Pacific and back to spawn in three to six years.
Through its 2008 license, Grant PUD has a role in protecting salmon and steelhead populations impacted by the Priest Rapids Project, including species that spawn far above Wanapum and Priest Rapids dams.
“Grant PUD is committed to the spring chinook program and value the trust the public, agency and tribal stakeholders have placed in us,” said Grant PUD Commissioner Bob Bernd. “It is important that we fulfill our license with a sense of stewardship for the land and respect for local communities. We appreciate the many partners who helped us get to this milestone. We feel confident in this efficient design that has a light footprint on the land.”
“While this program had a slow start, we can all look forward to its future,” stated Chelan County Commissioner Ron Walter who is also a member of the Upper Columbia Salmon Recovery Board and Grant PUD’s White River policy group. “I am encouraged by Grant County PUD`s commitment to work with local citizens on projects in Chelan County."
NOAA Fisheries determined 1999 and reaffirmed in 2005 that Upper Columbia River spring chinook were at risk of becoming extinct in the foreseeable future and listed them under the ESA. There are three remaining populations in the Upper Columbia ESU -- in the Wenatchee, Entiat and Methow river basins.
The (1,400-square-miles) Wenatchee basin has five remaining spawning areas -- in the Chiwawa, White, Little Wenatchee and upper mainstem Wenatchee rivers and Nason Creek.
Grant's White River captive broodstock program was begun in October 1997 with the collection of eggs and fry from naturally spawning spring chinook. The products of that effort were young fish that were raised to adulthood to be used as "captive broodstock." Since 2004, their progeny has been directly outplanted in the river with little acclimation.
The source for broodstock is 135 (or fewer) natural origin eggs or fry that are collected from up to 50 redds in the river. The last collection will occur during 2009. After rearing in captivity to adulthood, these adults are spawned and their progeny are grown to smolt size for release back into the White River, according to the project’s hatchery genetic management plan.
In the future, the program will transition into an adult-based supplementation phase. Starting as soon as 2012, White River origin adults will be trapped and spawned to produce the 150,000 smolts targeted for release, according to the Grant PUD. This release level is anticipated to result in the average return of approximately 698 adult fish annually.
White River spring chinook salmon are being raised at the Little White Salmon National Fish Hatchery located just east of Stevenson, Wash., in the Columbia River Gorge, before they are transported over 240 miles to their home stream in the White River basin for acclimation and spring release.
Grant PUD commissioners and staff plan continued communication regarding the White River Spring Chinook Program, and the neighboring Nason Creek program. Details are available online: http://www.gcpud.org/naturalResources/fishWaterWildlife/habitatHatcheries.html