Survival of hatchery spring chinook salmon released this past spring below central Washington’s Lake Wenatchee was substantially higher (approximately 45 percent) than for those released above the lake (approximately 10 percent).
That result prompted the Grant County Public Utility District to alter its strategy for the spring of 2012. All of the available smolts -- about 20,000 -- will be acclimated in portable tanks at the so-called “bridge” site two miles above the lake on the White River, and hauled downstream for release below the lake.
“We are adaptively managing the White River spring chinook program based on the data we have collected this year,” said Todd Pearsons, Grant PUD fisheries scientist. “We are actively implementing strategies to increase the performance of the White River Program.”
The survivals were charted from the various release points down the Wenatchee and Columbia rivers to John Day Dam, a journey that involves swimming roughly 250 miles and negotiating four hydro projects.
Because survival rates were higher for fish that were trucked from upriver acclimated tanks and released below Lake Wenatchee, biologists believe a lake effect is occurring and are continuing to evaluate predation as a source.
The White River Spring Chinook Program is intended to prevent the extinction of White River spring chinook, an important and unique spawning aggregate of spring chinook salmon in the Wenatchee River basin that is critical for recovery of the Upper Columbia River spring chinook salmon.
This program is part of a comprehensive protection plan for spring chinook populations in the mid-Columbia River region affected by Grant PUD’s Wanapum and Priest Rapids dams.
Overall direction for the program is provided in NOAA Fisheries’ 2008 biological opinion for the two Grant County PUD dams on the mid-Columbia, (known collectively as the Priest Rapids Project). The BiOp includes provisions that were adopted as terms and conditions of Grant PUD’s current operating license, issued by the Federal Energy Regulatory Commission in April 2008.
The program development and implementation strategy has been coordinated with NOAA Fisheries Service and is operated in collaboration with a multi-agency state federal and tribal technical group that includes NOAA Fisheries, U.S. Fish and Wildlife Service, Washington Department of Fish and Wildlife, Yakama Nation, and Confederated Tribe of the Colville Reservation.
Grant PUD staff presented these survival data during an Oct. 13 public meeting in Leavenworth along with long-term spring chinook acclimation facility designs for the White River and Nason Creek sites. Nason Creek flows into the Wenatchee River downstream from the lake. The PUD is nearing the end of the permit process for the White River facility, which will be located at the bridge site, and hopes to begin construction next spring.
Grant PUD consultants, HDR, Inc. and GeoEngineers, Inc., presented the acclimation facility design plans. The design development has been a collaborative process between Grant PUD; fisheries co-managers; federal, state and local governmental officials; members of the public and other stakeholders. The final concept considers input from all stakeholders and reflects the group’s desire to minimize environmental and aesthetic impacts.
Hatchery “supplementation” – the late-stage rearing of hatchery reared fish near spawning grounds so they will return there as adults to spawn -- was deemed necessary by the NOAA Fisheries in 1995 to increase the number of returning adult chinook and to decrease the risk of extinction of the White River spring chinook. During that year, only five wild adult spring chinook were observed returning to the White River spawning grounds.
Efforts in the White River and nearby Nason Creek have been under way for more than 12 years, following the species’ listing under the Endangered Species Act in 1999.
Since 2004, Grant PUD has been releasing juvenile spring chinook salmon in the White River and Lake Wenatchee. While the rate of returning adults has increased since this program began, the return numbers are still far from what’s needed to meet recovery objectives.
Federal, state and tribal biologists believe acclimating fish over the winter months may increase survival. In the natural environment juvenile spring chinook salmon spend the winter months in their natal waters before migrating to the ocean. This provides the chemical or “odor” imprinting fish need to return as adults when it’s time to spawn.
That overwintering acclimation process could well begin in the fall of 2013 with the release of the first batch of smolts the following spring. The facility will over-winter acclimate up to 150,000 juvenile spring chinook salmon for release each spring into the White River.
The meeting presentation and information on other fish protection programs supported by Grant PUD are available online at http://www.gcpud.org/naturalResources/fishWaterWildlife/habitatHatcheries.html