Good news-bad news: Older steelhead making up bulk of return to the Snake, Salmon rivers
LEWISTON – There’s a good news-bad news scenario shaping up in this year’s return of steelhead to the Salmon and Snake rivers.
The bad: One-ocean steelhead aren’t showing up as projected.
The good: Two-ocean fish are bailing us out.
We are talking about the A-run here – steelhead that return mostly to the Snake, Salmon and Grande Ronde rivers. Most of them spend just one year in the ocean before returning as adults, But a small fraction stay at sea for two to three years.
As far as timing, the older fish tend to lead the charge and are followed by the youngsters. That profile has shaped up this year.
The front end was loaded with two-ocean and three-ocean fish, so much so that early returns spiked above the 10-year average.
But with the meager showing from one-ocean fish, the run trails the 10-year trend.
Joe DuPont, regional fisheries manager for the Idaho Department of Fish and Game, said 90% of the run, as measured at Bonneville Dam on the Columbia River, has been composed of two-ocean fish. The Grande Ronde run is made up of about 83% two-ocean fish.
“Usually, it’s kind of the other way around,” DuPont said. “So we are missing a huge portion of that run. Hopefully, it means those fish decided to stay out in the ocean another year.”
Last year, scientists from NOAA Fisheries recorded the second-best ocean conditions in a 24-year data set. That should be good news for anadromous fish, and both spring chinook and sockeye returns exceeded expectations.
But steelhead behave a little differently. When they reach the ocean as juveniles, steelhead tend to head out to the open ocean. Chinook, sockeye and coho tend to stick closer to shore. Scientists have a long data set of near-shore ocean conditions but know little about conditions farther out or exactly where steelhead go.
DuPont said the two-ocean component of the A-run is higher than average and higher than fisheries managers would have expected, based on last year’s return of one-ocean fish.
“We could potentially see more two- and three-ocean fish come over Bonneville than we have since 2010 or 2011,” he said. “I would say they are bailing us out.”
The bigger B-run steelhead that tend to spend two years in salt water are just starting to show up at Bonneville Dam. Those fish are mostly bound for the Clearwater Basin and the Middle Fork of the Salmon River. It’s super early, with just 5% of the run above the dam, but DuPont said numbers are promising.
“The numbers we are seeing are great. We haven’t seen this many fish since 2011,” he said. “Granted, it’s still very early, but it’s an exciting start.”