It’s been a tough couple of years for one of the Columbia River Basin’s most iconic fish – wild Idaho steelhead. After 30 years of recovery efforts, return numbers for the long-distance, high country steelhead are currently close to where they were when listed as threatened under the Endangered Species Act in 1997.
That’s not progress. But that’s also not to say these resilient, unpredictable Snake River basin steelhead won’t bounce back to some extent. It has happened before when numbers dipped to alarming lows, as is the case today. Low years have indeed been followed by strikingly better years.
Idaho wild steelhead are interesting in their life cycle and behavior, and coming from central Idaho, they are an important marker for the success of Columbia Basin salmon recovery.
These are wild fish that traverse eight dams — from Bonneville Dam to Lower Granite Dam — and then must make their way many more miles into spawning habitat in Idaho. I assume if recovery efforts are successful in taking care of these fish, many other ESA-listed salmon and steelhead along that hydro corridor will benefit.
Generally, Idaho steelhead are divided by A-Run and B-Run and enter the Columbia River June to August. A-Run are smaller, spend one year in the ocean, and enter freshwater earlier than the larger B-run steelhead, which spend two years in the ocean and begin their upstream migration later in the year.
A-run steelhead occur throughout the steelhead-bearing streams in the Snake River basin and inland Columbia River, while B-run steelhead originate in the Clearwater and Salmon River basins. Some Snake River steelhead populations have both A-Run and B-Run fish.
Once in the Columbia River estuary upstream migration timing varies, depending on age and size. Wild fish pass Bonneville Dam earlier than hatchery fish. Peak passage of all Snake River Basin steelhead (Oregon, Washington, Idaho) at Bonneville has shifted by about two weeks from late July to early August, probably in response to warming temperatures and reduced flows in the river. Most Idaho steelhead pass Bonneville during August and September.
Idaho steelhead will delay their migration up the Columbia and Snake Rivers, and pull into cooler tributaries for temporary holding. Most Snake River steelhead arrive in the Snake River and tributaries in early fall.
After migrating hundreds of miles these fish hold over the winter in the Snake River basin’s (central Idaho, northeast Oregon ) high elevation watersheds and then spawn the following spring, March to May. Idaho fish winter in larger rivers and start moving upstream again in the spring. Some are capable of spawning more than once, returning to the ocean and then back up the Columbia and Snake rivers.
With spring flows, juvenile outmigrating steelhead (juveniles may rear in freshwater for 1-3 years) typically reach Bonneville Dam by mid-May with May 19 the median date for passage of wild fish. The juveniles move quickly through the estuary and to the river’s mouth, though research shows residence time at the mouth can vary from less than a day to 10 days. Data indicates once they enter the ocean they are beyond the continental shelf in a few days and leave the California current off the Washington coast by June. Little is known about their life in the ocean.
With the completion of McNary Dam in the late 1950s, along with fish ladders, fisheries managers were able to count the wild steelhead return to the Snake River basin. In the 1962-63 season, 108,000 wild steelhead returned to Idaho, northeast Oregon and southeast Washington rivers. Over the years, as more dams were constructed, counts for wild fish at the uppermost dams generally declined over time. In the 1970s hatchery fish begin to supplement the total steelhead numbers to the point of domination.
The hatcheries, of course, were in response to the dams. They have been successful in mitigating for lost harvest opportunities in many years, but that has not helped wild fish.
In the 1976-77 season only 8,987 wild steelhead returned to the basin. When the fish were listed under the ESA in 1997 only 7,625 wild Snake River steelhead crossed Lower Granite Dam.
With biological opinions and court rulings leading to increased spill and improved surface bypass routes at the dams for juvenile passage, wild steelhead returns improved some from 2001 to 2015, when in that year 45,789 ESA-listed fish returned.
Then another dip. Last season, 2017-18, only 10,717 wild steelhead returned to the Snake River and its tributaries.
And this year, nearing the end of the count, only 12,222 unclipped steelhead have been counted passing Lower Granite.
While the dams went in, continued habitat degradation, and flow impairment added to the wild steelhead’s woes. Then, beginning in the 1980s, too many hatchery fish contributed to the species’ decline. Predation and disease are also limiting factors. Ocean conditions are a wild card every year. As for harvest mortality, about one percent of the wild A-run is caught incidentally in recreational fisheries. For the B-run, about 13 percent are caught incidentally in fall treaty fisheries and one percent in recreational fisheries.
Current recovery plans implemented by federal and state agencies and tribes are improving habitat and flow. Hatchery management is responding to the need of genetic integrity of the wild fish, as well as the need for some hatchery supplementation with the right brood stock in the right place to boost naturally spawning fish.
But clearly, the numbers show that hydropower, whether blocking access to historic habitat, or making passage difficult from central Idaho to the ocean and back, have whacked these fish hard. Once the four Lower Snake dams were in place the wild fish numbers would never come close to a recovery number.
And what is that number?
NOAA’s Columbia Basin Partnership report “A Vision For Salmon and Steelhead: Goals to Restore Thriving Salmon and Steelhead to the Columbia River Basin” says the Snake River basin historically produced runs of 600,000 wild steelhead.
The collaborative Partnership says the region’s goal for these wild steelhead today should be: Low, 21,000 fish; Medium, 63,000 fish; High, 105,000 fish.
The medium goal hasn’t been reached since the lower Snake River dams went in, not even close. And the high goal? That will require decades of intense restoration and protection efforts and a revolutionary change in Columbia Basin salmon recovery. Such a goal seems impossible without dam breaching as a key recovery component.
So for now, looking at today’s dismal numbers, I would consider success, realistically, that low annual goal of 21,000. It’s doable, I suppose, if we keep making improvements at the dams, continue to improve habitat and flow, and if often enough ocean conditions go our way. Maybe.
—Bill Crampton, [email protected]
For more about Idaho steelhead see:
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