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Spring Chinook Run
Downgraded at Halfway Point

by Bill Rudolph
NW Fishletter, June 4, 2013

Just when Columbia Basin managers expected spring Chinook counts to take off at Bonneville Dam, numbers began tapering off, largely dashing any hope of coming close to the preseason prediction of 141,000 at the mouth of the river. By May 15, only 68,000 upriver springers had passed the dam.

The daily counts have been limping along around 1,000 fish per day since the first week in May, after 7,000 were counted on May 3. The slow run count kept managers from making any adjustments to their preseason prediction until May 14, when they downgraded the run size to 107,500 fish. That may have been too optimistic. At the rate fish are returning now, the run will be lucky to break 100,000 fish by June 15, when the spring counting season at Bonneville Dam officially ends.

On May 14, managers discussed late spring harvest opportunities and ended up giving commercial gillnetters one more day to fish in the mainstem, since non-Indian harvesters had not used up their allocation of ESA impacts on upriver spring Chinook. However, the commercials were still fishing in off-channel areas as part of their selective area/net pen program and were expected to continue until June 14. They had landed nearly 4,000 spring Chinook in the selective-area fishery by May 14. Prices were high, with $40/lb. fillets seen in one Seattle fish market.

But the managers decided to see how the run pans out before they reopened sport fishing below Bonneville Dam, which had been closed since April 13.

During testimony at the Columbia Basin Compact hearing on May 15, some commercial fishers recommended ending the spring fishery because Chinook in the lower river had become so scarce, according to results from ongoing tagging work with Chinook using gillnets. Others groused about the inability to use large-mesh nets that would allow smaller fish like shad to pass through the nets. Shad numbers have been increasing fast.

Most testimony from sport fishers supported a proposal that called for opening the recreational fishery May 16 and closing it June 6, but managers decided to wait until the Basin's technical management committee reported on its next run-size update May 20 before making any decision. Another option on the table called for keeping the spring rec fishery closed and adding any unused allocations to the summer Chinook season which will begin sometime next month.

The spring Chinook run may be a major disappointment, but next year's return could be a lot better, judging from the 35,000 jacks counted so far, more than three times last year's total. But these high jack counts have played havoc with harvest models.

However, the jack-based prediction model used by Basin harvest managers wasn't the only one to go astray this year. For the last few years, NOAA Fisheries scientists have been making spring Chinook predictions (to Bonneville Dam) of their own, and have been quite successful lately -- until this year, that is.

Using a collection of ocean indicators they have developed, they estimated that 2013's upriver spring Chinook run in the Columbia River would come in around 200,000 fish, counted at Bonneville Dam.

That was way more optimistic than the 141,000-fish forecast from the technical advisory committee (TAC) made up of basin harvest managers from the U.S. v. Oregon process. When expected harvest impacts were added, the feds' prediction added up to 221,000 fish -- 56 percent higher than TAC's, and nearly identical to the 2011 return, which was the second largest in the past decade.

The feds' model had been performing well until this year. For the 2012 spring Chinook return, the NOAA researchers' estimate was 179,000 fish, close to the observed return at Bonneville of 186,000 fish plus an estimated lower-river harvest of 16,000 fish, which added up to 202,000 fish -- a prediction that was off by only 12 percent. The 2011 prediction, based on data collected through 2010, matched the observed return of over 221,000 fish nearly perfectly -- it was off by only six fish.

TAC's prediction for the 2012 upriver spring Chinook run overestimated the actual return by 35 percent, but its 2011 preseason estimate was only 11 percent under. For the three years prior to that, TAC over-predicted the upriver spring run by at least 33 percent

It doesn't look like the run will get anywhere near NOAA's rosy prediction, but predictably, the scientists who put it together have been keeping a close eye on this year's returns.

NOAA oceanographer Bill Peterson, based in Newport, Ore., said the smolts that left the region in 2011 were in fine shape, so he and his compatriots are looking at a source of mortality that likely occurred much farther north in their migration, somewhere in the Gulf of Alaska. He told NW Fishletter that conditions in the gulf may have deteriorated in recent years and his agency's prediction model needs to include a factor that takes that into account.

Alaska Chinook runs have suffered serious declines in recent years, from the Yukon in western Alaska where the fish migrate throughout the Bering Sea, to the Stikine River in southeast Alaska, whose stock may be genetically related to spring Chinook in the Columbia Basin. A possible culprit could be declining plankton productivity resulting from cooler waters in the Gulf.

At an April scientific conference in Honolulu, researchers throughout the Pacific Rim gathered to discuss potential causes of productivity increases and declines of all types of salmon. One Canadian researcher emphasized the importance of eddies that can form along the edges of Gulf currents and bring nutrients like iron toward surface waters that add to plankton blooms that young fish feed on.

In Alaska's Kenai River, southwest of Anchorage, where sport fishermen have made pilgrimages to fish the bountiful, super-sized Chinook runs for many years, the 2013 early run is expected to be the lowest of the past 28 years, according to an Alaska Department of Fish and Game report.

"The 2013 early run is expected to number about 5,300 fish," said the Kenai report. "If the actual 2013 total run is similar to the preseason outlook, it will rank 28th out of 28 years and be much smaller than the 1986-2012 average run of approximately 14,000 fish."

The outlook for the Kenai's late run, made up mostly of Chinook that have spent six years feeding at sea (compared to two years for most Snake River fish), is well below average, with a forecast total of approximately 29,000 fish. If realized, this run would rank 27th out of 28 years, and be close in abundance to the 2009-2012 runs, roughly one-half the 1986-2012 average run of approximately 58,000 fish.

The spring Chinook run in the Columbia may have fooled forecasters this year, but it's still in good shape compared to returns in the mid- to late-1990s. Only 13,000 returned in 1995, and 43,000 in 1999.

Scientists like Peterson note that poor ocean conditions and long-lasting El NiƱos closer to home were likely the main factors that produced those poor returns.

"It's all a lot more complicated than our model," he said, but he is hopeful that, in the future, the NOAA predictions will include a factor that takes Alaska-area productivity into account.

Bill Rudolph
Spring Chinook Run Downgraded at Halfway Point
NW Fishletter, June 4, 2013

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