Hatchery Chinook salmon

Hatchery Chinook salmon.

Spring Chinook returns to Bonneville Dam this year are not just good—they're great.

With more than 149,000 adults passing the dam as of June 1 and two more weeks to go, fish managers again updated the expected run size. They're now predicting 181,600 adult spring Chinook passing Bonneville Dam by June 15.

Early this year, excitement surrounded the forecast of 122,900 spring Chinook returning to the Columbia River. In mid-May, the forecast jumped to an estimated 180,000 spring Chinook at Bonneville Dam, and Washington and Oregon added 11 more days to recreational fishing for spring Chinook on the lower Columbia River, and two more days upstream of Bonneville Dam. Washington Department of Fish and Wildlife officials noted the run was on track to be the 11th best run in more than four decades.

On June 2, Washington and Oregon added more Spring Chinook fishing days and upped the daily harvest limits above Bonneville Dam. Through June 1, 149,031 spring Chinook passed Bonneville Dam—more than double the recent five-year average for that date.

The numbers are significantly better than the 10-year average spring Chinook return.

NOAA Fisheries researchers credit vastly improved ocean conditions for this year's improved spring Chinook returns. The conditions are rated in a "stoplight chart" that considers 16 ecosystem indicators, ranging from ocean temperatures and the amount of upwelling of cold, salty water filled with chlorophyll to the ocean's biomass of cold-water northern copepods.

According to the Fish Passage Center—where spring Chinook tallies run through May 31 and summer Chinook counts begin June 1—in only 14 other years have total spring Chinook returns been higher than 149,000 fish since counting began in 1938.

Since the 1930s, spring Chinook returns to Bonneville Dam in many years have numbered in the tens of thousands—including the last five years. Only four years brought counts higher than 200,000 spring Chinook—all since 2001, when a record 393,027 spring Chinook passed Bonneville Dam.

Another reason for optimism is this year's return of spring Chinook jacks. These younger males that return a year early help fish managers predict how many adults will come back the following year. By June 1, just under 20,000 jack Chinook had passed Bonneville Dam—above last year's return of 11,784 spring Chinook jacks, and also surpassing the 10-year average of 13,982 jacks.

Some fish managers warn against making too much of the great returns.

Jay Hesse, who represents the Nez Perce Tribe on the Columbia River Technical Management Team, cautioned against excessive optimism. People need to remember the 10-year average includes some extremely low returns, he told fellow TMT members at the June 1 TMT meeting. He said this year's returns are still low in some areas, although higher than where they've been for the last five years.

At Lower Granite Dam on the Snake River, just over 49,000 spring Chinook had been counted as of June 1, compared to almost 24,000 last year and a 10-year average of 37,326 Chinook. At Wells Dam—the farthest upstream dam with fish passage in the upper Columbia River—2,678 spring Chinook had been counted as of May 31, compared to 2,329 fish last year and a 10-year average of 3,366 Chinook.

In the Willamette River, 12,697 spring Chinook had passed the Willamette Falls Dam as of May 30. That lags behind both last year's year-to-date run of 16,990 spring Chinook and the 10-year average of 19,673 fish by May 30.

Tucker Jones, Columbia River and ocean salmon program manager for the Oregon Department of Fish and Wildlife, said he does not think the Willamette River's poor returns so far are due to changes in hydroelectric operations farther upstream.

Jones told NW Fishletter that spring Chinook passage at Willamette Falls is complicated. "They really like to start passing when temperatures warm up and flows are declining," he said. "They were starting to build at the end of April and then right at the end we got that big series of storms. Temperatures dropped and flows really peaked, so fish stopped going through the ladder almost entirely," he said.

With flows coming down and temperatures rising, spring Chinook passage at Willamette Falls picked up at the end of May, he noted. Suddenly, the number of spring Chinook counted at the dam jumped from fewer than 10 adults per day in mid-May to 1,531 adults on May 22 and remained at more than 850 adults per day since then.

But the totals are still tracking significantly lower than the 10-year average, Jones said. "I think there's a chance they could catch up, but the counts are going to have to stay strong for several more days," he added.

Considering the overall spring Chinook returns to the Columbia Basin, Jones said, "I think one year is not necessarily a trend. And, I think we have some of the best ocean conditions in the last 20 years, so this is a welcome respite from where things have been. But I don't think it, by any stretch, means we're out of the woods."

Still, he added, salmon are resilient and productive, so when conditions line up, it can boost productivity and offer more hope for future runs.

He said the extra fishing days this year also made some people happy. During the last week of May, lower Columbia River anglers made about 8,000 trips, caught about 1,450 spring Chinook and kept just over 900 of them, he said.

© Copyright 2022 NewsData, LLC, 5625 NE Elam Young Pkwy, Ste 100 Hillsboro, OR | Terms of Use | Privacy Policy Powered by BLOX Content Management System from TownNews.com.

K.C. Mehaffey covers fish issues for Clearing Up, and is editor of the NW Fishletter. She joined the NewsData writing team in February 2018. From lawsuits to scientific studies, she is enjoying the deep dive into the Columbia Basin's many fish topics.