Since April 13, national fish hatcheries in the Columbia River Gorge have released more than 10 million juvenile Chinook salmon into the lower Columbia River and its tributaries, continuing a 70-year program that supports tribal and sport fish harvests worth millions of dollars.
The hatcheries, part of the Columbia River Gorge National Fish Hatchery Complex, also support a program that affirms Native American treaty-reserved fishing rights in the Columbia River Basin and helps conserve wild salmon stocks, including several salmon species protected under the Endangered Species Act (ESA).
On April 13, Spring Creek NFH and Little White Salmon NFH released more than 8 million tule fall Chinook salmon. On April 17, Carson NFH released nearly 1.2 million spring Chinook into the Wind River, and on April 20, Little White Salmon NFH and Willard NFH released 1 million more.
“This [spring Chinook] project helps maintain a fish population that is incapable of becoming self-sustaining due to habitat loss resulting from flooding, siltation, and fluctuating water levels caused by the Bonneville Pool, and it also provides fish to reaffirm tribal treaty-reserved fishing rights,” said Speros Doulos. Manager of the Columbia Gorge NFH Complex. “The reliable return of adult spring Chinook to the Columbia River and Drano Lake is recognized as a major contributor to these popular fisheries.”
Returning adult spring Chinook support Columbia River sport, commercial and tribal fisheries in the river and a highly successful tribal fishery in Drano Lake, Doulos said.
In addition to the spring Chinook releases, Spring Creek NFH in Underwood, Wash., released 6.2 million sub-yearling tule fall Chinook salmon last week directly into the Columbia River. This important stock of fish supports river and coastal fisheries of Washington and British Columbia. The hatchery will release another 4.5 million sub-yearling salmon in early May.
Chinook production at Columbia River Gorge NFHs is operated in “segregated harvest programs” to avoid ecological risks with the federally listed lower Columbia River Chinook salmon or steelhead native to the Wind River. The hatchery releases fulfill important legal responsibilities the U.S. government has to Native American tribes under the U.S. v. Oregon Management Agreement, as well as federal government responsibilities to mitigate for lost salmon production and spawning grounds due to the construction of hydropower projects that are part of the Federal Columbia River Power System.
Hatchery releases over the past couple weeks are timed to coincide with the annual outmigration of young salmon to the ocean, a cycle that begins with the young fish making a downstream journey — swimming backwards — to the Pacific Ocean, where they will live for one to five years or more, then return as adults to their natal (home) streams, where they spawn and die.
In addition to its fish releases, the Carson NFH transferred nearly 250,000m Spring Chinook pre-smolts (juvenile salmon nearly ready to migrate to the ocean) to the Confederated Tribes of the Umatilla Indian Reservation. The transfer continues a seven-year partnership to re-establish a salmon run in the Walla Walla River that was extirpated for 80 years until 2005, when the Umatilla Tribe’s reintroduction program began.
Willard NFH in Cook, Washington, has already transferred 609,000 coho salmon in pre-smolt stages to seven different Yakama Indian Nation acclimation sites, including the Leavenworth NFH Complex in the Wenatchee and Methow river basins. These rivers are tributaries of the Columbia River and the work undertaken by the Service and the Yakama Nation are part of a larger Mid-Columbia River Coho Reintroduction Program.
The rearing of locally adapted Mid-Columbia (Wenatchee Basin) coho began 11 years ago when Willard NFH first received eggs collected from adults returning to the Wenatchee River.
A smolt is a juvenile salmon whose physiology is adapting from living in freshwater to saltwater ecosystems. Smoltification occurs as young salmon migrate towards the ocean, and includes changes in scales that become
larger and silvery – traits more advantageous in ocean environments. Remarkable modifications to gills and lungs also occur, allowing the young fish to ‘breathe’ oxygen from salt water via a process called osmoregulation, according to Don Campton, Pacific Region Fisheries Program Science Advisor.
“Osmoregulation is comparable to humans acclimating at high altitudes before climbing a mountain,” said Campton.
A salmon’s migration and ability to locate and return to the stream where it was born is considered one of nature’s most remarkable phenomena. Salmon and steelhead (rainbow trout that migrate to the ocean) have acute senses
of smell; they are believed to be able to detect chemical signature concentrations in water as small as one or two parts per million, equivalent to being able to sniff out a single drop of water in 250 gallons. Members of the salmon family, Salmonidae, have existed on Earth for at least 50 million years.
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