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Preseason Forecast Pegs Upriver Fall Chinook Return,
by Staff
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The prospects for late summer fishing on the mainstem Columbia River look great with a forecast return of fall chinook salmon projected to be the highest since 2004, and the "upriver bright" portion of that run expected to be the biggest ever.
A total of 432,500 adult URBs are expected to return to the mouth of the river in 2013 on their way to hatcheries and spawning grounds upstream of Bonneville Dam in Idaho, Oregon and Washington. Such a return would break the record, 420,700, set in 1987. Bonneville is located near river mile 146.
The forecasts are preliminary and will be updated in the coming weeks.
The URB run includes Snake River wild fall chinook, listed as threatened under the Endangered Species Act. The preseason forecast released Feb. 13 by the Washington Department of Fish and Wildlife predicts the 2013 Snake River wild fall chinook return to the mouth of the Columbia will be 31,600, which would nearly double last year's record total return of 16,700. That record dates back to at least 1986.
The Snake River run has been on a high in recent years, with Columbia mouth returns just shy of 15,000 in 2011, and 15,400 in 2010, according to the WDFW-Oregon Department of Fish and Wildlife July 2012 Joint Staff Report. Both of those Snake River wild returns, as well as the 2012 total, were almost twice the 2002-2011 average.
Most of the URB chinook are destined for the Hanford Reach area of the Columbia River, Priest Rapids Hatchery on the mid-Columbia, and the Snake River. Smaller URB components are destined for the Deschutes and Yakima rivers.
The high forecasts are built on the fact that, in the Snake, a record jack count -- about 4,000 2-year-old fish -- were counted at the lower Snake's Lower Granite Dam last year, and the number of 3-year-old fish, nearly 8,000, was also "very high," according to Stuart Ellis. Lower Granite is the last of eight mainstem hydro projects that most of the fish must pass on their way up the Columbia and Snake.
Ellis is a Columbia River Inter-Tribal Fish Commission biologist who serves on the Technical Advisory Committee. TAC, made up of federal, state and tribal fishery officials, develops run-size forecasts based on, among other factors, broodmate relationships. In other words, big 2- and 3-year-old returns in one year in most cases means that a lot of 3 and 4 year olds will return the next year from that same brood year class.
"It makes out to be a huge forecast," Ellis said. Similar indicators pumped up overall forecasts. Snake River fall chinook of hatchery origin last year returned as 2 and 3 year olds in the second highest numbers ever. The overall URB run showed similar trends.
The Snake River "wild" fall chinook are fish that "were born in the gravel," Ellis said.
A share are of wild parentage, others may have been spawned in the Snake or its tributaries by a mixture of wild and hatchery parents.
A surge in abundance in the Snake overall is due in many respects to a hatchery supplementation effort led by the Nez Perce Tribe that acclimates in-stream hatchery-produced juvenile fish in hope that they will return as adults to spawn in the wild.
Biologists determine by genetic analysis and other means which of the fish actually got their start in the wild.
The overall Columia-Snake basin fall chinook return is expected to number 677,900 to the mouth of the Columbia. That would be greater than the 10-year average of 547,900 and the highest total since 2004.
Columbia River fall chinook are comprised of six major management components: Lower River Hatchery, Lower River Wild, Select Area Brights, Bonneville Pool Hatchery, URBs, and Mid-Columbia Brights. The upriver run is comprised of stocks produced upstream of Bonneville Dam, and includes URB, BPH, and a portion of MCB stocks.
URB forecasts have been relatively accurate, with actual returns ranging from 79 to 120 percent of the preseason estimate from 2006-2011 except for a 2007 return that was only 62 percent of the prediction. Last year's preseason forecast was for an URB return of 353,500; the actual return was 298,100 or 84 percent of the forecast.
Also expected is a return of 70,000 "pool upriver bright" fall chinook, which would be a record. The highest actual return ever was 67,400 in 2003. PUBs represent the upriver component within the MCB management stock. They are a bright stock reared at Little White Salmon, Umatilla, and Klickitat hatcheries and released in areas between Bonneville and McNary dams. Natural production of fish derived from PUB stock is also believed to occur in the mainstem Columbia River below John Day Dam, and in the Wind, White Salmon, Klickitat, and Umatilla rivers, according to the joint state staff report.
The new preseason forecast includes an anticipated 31,600 "Bonneville upriver brights," which would be more than double last year's return but similar to the recent 10-year average of 39,100. BUB production occurs just downstream of Bonneville Dam at the Bonneville Hatchery in Oregon.
The Bonneville pool hatchery run is not expected to be as plentiful. The preseason forecast is for a return of 38,000, which would be about 40 percent of the 10-year average (89,200). Last year's return was 56,800.
The BPH stock is produced primarily at the Spring Creek Hatchery in the Bonneville pool, although natural production of the fall chinook tule stock also occurs in the Wind, White Salmon, and Klickitat rivers.
The Feb. 13 forecast says an estimated 88,000 lower river hatchery fall chinook will return, which is similar to the five-year average of 87,000. The projected lower river wild return, 14,200, would exactly match that run's 10-year average.
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