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Ecology and salmon related articles

Columbia Freshwater Spending Helping Fish
During Poorer Ocean Conditions

by Laura Berg
NW Fishletter, April 4, 2016

Graphic: Adult sockeye salmon returns to Lower Granite Dam and to Redfish Lake weir on the upper Salmon River, Idaho, 1991-2013. Investments in the Columbia River Basin's freshwater environment are helping to sustain fish populations during times when ocean conditions are less hospitable to salmon, the Northwest Power and Conservation Council was told at its March 8 meeting in Portland.

The Council was given an optimistic projection for salmon and steelhead runs in the basin in 2016. Bill Tweit, with Washington Department of Fish and Wildlife, said that overall salmon and steelhead returns will reach 2.1 million fish this year, the eighth-highest recorded. At 2.9 million fish, last year's was the third-highest recorded.

The showstoppers this year are, once again, likely to be the Chinook salmon runs.

Tweit told the Council that about 1.3 million spring, summer and fall Chinook are projected to make their way back to the Columbia River in 2016.

The largest number of these returning Chinook will be upriver fall Chinook headed to areas above Bonneville Dam. That number is forecast at 756,300 fish, less than in 2015 but greater than the 10-year average. The 2015 figure was more than 950,000 fall Chinook over Bonneville Dam, the most since dams were built on the Columbia.

Spring and summer Chinook forecasts are expected to be above the 10-year averages and similar to 2015 run sizes, while the sockeye, at 101,600 fish, are expected to return at only 35 percent of the 10-year average.

The Snake River fall Chinook forecast is for about 12,000 natural-origin and 20,000 hatchery fish to pass Lower Granite Dam. Both run sizes are above 10-year averages, Paul Kline, of the Idaho Department of Fish and Game, told Council members.

The Snake River summer steelhead estimate for in 2016-2017 is for about 50,000 natural-origin and nearly 100,000 hatchery fish at Lower Granite, which Kline described as "encouraging."

Predictions for Columbia River summer steelhead are for 265,400 fish to cross Bonneville Dam, 92 percent of the recent 10-year average, WDFW's Tweit said.

Winter steelhead, a wild run, is expected to number 16,900 at the Columbia River mouth, or similar to the 10-year average of 16,200 fish, Tweit said.

Based on ocean abundance, coho returns to the Columbia River are forecast to be more than 300,000 to the river mouth and about 90,000-plus above Bonneville Dam. Both figures amount to less than the 10-year averages, Tweit observed. The majority of upriver coho are early returning wild coho.

NOAA Fisheries' Brian Burke echoed Tweit's lower expectations for coho in 2016, emphasizing the poor ocean conditions in 2014-2015.

Looking at coho as smolt-to-adult returns, Burke said the ratio was 1.5 percent, well below the 10-year average.

Recent ocean indicators were anomalous, he explained. For instance, the small fishes that juvenile salmon feed on were not abundant, and sea surface and deep-water temperatures were abnormally high, he said.

Based on a variety of ocean indicators, he predicted that 660,000 fall Chinook would pass Bonneville Dam this year, then drop to 427,000 in 2017. Only Burke made forecasts for 2017.

His projection for this year's upriver fall Chinook run size was lower than the 756,300 forecast reported by WDFW's projections. The higher number is an estimate by the Technical Advisory Committee, which uses different modeling data to arrive at its predictions.

Burke also forecast a downturn in the outlook for upriver spring Chinook in 2017 of 94,000 fish, which is significantly lower than the 10-year average for these spring Chinook.

Council Vice-Chair Bill Booth of Idaho asked the biologists if all the habitat and passage improvements have helped even in the face of poor ocean conditions.

Tweit said that improvements prior to and during the 1990s were "dulled" by bad ocean conditions. "But when these conditions switched again," he said, "we got some dividends to help build overall populations."

"The system is more resilient now," he said. "It won't be as bad as in prior years with poor ocean conditions.

"While upper Columbia River spring Chinook are not rebuilding quite as well, other stocks of salmon and steelhead are rebuilding or at least stable," Tweit said.

"The fall Chinook story is pretty extraordinary. Before returning to the Columbia River, these fish are substantially exploited in ocean fisheries. A lot of these fish are seen in Southeast Alaska," he said.

The Council's March briefing on fish runs included, for the first time, sturgeon and lamprey along with salmon, steelhead and eulachon (or smelt). Last year was the first year eulachon and chum were described along with steelhead and other salmon runs, reflecting the broader approach being taken by fish managers and planners throughout the basin.

For white sturgeon, Tom Rien, with Oregon Department of Fish and Wildlife, said the decline of the population below Bonneville Dam, including the lower Willamette River and the Columbia estuary, had "triggered fisheries managers to close this area to retention effective 2014."

Similarly, stock declines in the three reservoirs behind lower Snake River dams caused fish regulators to close these areas to fishing beginning in 2015.

Rien said the sturgeon in reservoirs behind Bonneville, The Dalles and John Day dams are more numerous than in the late 1970s, 1980s and most of the 1990s, but recent sturgeon numbers have fallen again. Consequently, stricter harvest limits are now in effect in all three pools.

White sturgeon populations above McNary Dam in the reservoirs behind Priest Rapids, Wanapum and Rocky Reach dams were not discussed during the Council briefing, as they are largely managed by Grant and Chelan PUDs along with the Yakama Nation.

The eulachon population will show a downturn in 2016, Rien predicted. A new abundance estimator, based on spawning stock biomass, indicates fewer eulachon came back this year after three years of higher returns.

Between 2011 and 2015, the highest estimated abundance was 17 million pounds in 2014. This year's projected biomass is less than 4 million pounds. Rien said that eulachon abundance is very cyclical. The species was designated in 2010 as threatened under the Endangered Species Act.

Pacific lamprey, widely distributed from Alaska to Southern California, were once plentiful in the Columbia basin prior to dam building and even into the 1960s when counting stopped, said Brian McIlraith, of the Columbia River Inter-Tribal Fish Commission.

McIlraith told the Council that the Warm Springs tribe calculated that the lamprey population at Willamette Falls was between 2 million and 4 million fish in 1946. But the population has dwindled dramatically since. When counting resumed in 1996, daytime counts at Bonneville have ranged from 100,000 in early 2000 to less than 20,000 in 2010, which is likely a historic low, he said.

The population rebounded a bit in 2015, with 38,500 crossing Bonneville Dam, although fewer than 1,000 passed Ice Harbor Dam on the Snake River and none were counted at Wells Dam on the upper Columbia, the CRITFC biologist said. Fewer lamprey pass the upstream dams.

Given lamprey's historical abundance, "we should be doing better than this," he remarked, indicating that increasing lamprey population abundance is related to improving adult passage at Columbia basin dams.

Laura Berg
Columbia Freshwater Spending Helping Fish During Poorer Ocean Conditions
NW Fishletter, April 4, 2016

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