Spring chinook season comes to close

Idaho Fish and Game officials have closed spring chinook fishing on the lower Salmon and Little Salmon rivers, bringing an unexpected early end to the disappointing season.

Agency officials shut down springer fishing on the Clearwater River and its tributaries last month after they calculated too few adult hatchery fish would return to meet spawning goals at hatcheries. That season was over before the annual run hit its stride.

In contrast, fishing proceeded on the lower Salmon and Little Salmon rivers for a few weeks while the fish were actually present and anglers harvested more than 600 chinook over the past two Thursday through Sunday fishing periods. Fishing was expected to be even better in the next installment scheduled to begin Thursday.

But that changed Monday when Fish and Game biologists used genetic sampling to test the strength of the run. Previous predictions were based on data from tiny electronic tags carried by a percentage of adult hatchery chinook. The second level of testing revealed the run was not as strong as originally predicted, and anglers had all but exhausted the harvestable surplus during last week’s open fishing period.

Joe DuPont, regional fisheries manager for the department at Lewiston, said the genetic-based run prediction indicated about 9,102 adult spring chinook bound for Rapid River Hatchery passed Bonneville Dam. When buffers are applied to account for fish that die before reaching Idaho and for those that successfully make the journey but are neither caught nor show up at the hatchery, the forecast dropped to 3,654. Rapid River Hatchery needs to collect 2,353 adult chinook for spawning, known as brood stock, leaving only 1,302 to be split between tribal and sport anglers, or about 650 for each group.

Through Sunday, sport anglers had harvested 622 hatchery chinook from the two rivers near Riggins, leaving only about 29 for the next fishing period.

“Unfortunately, using the best data we have, we think the right thing to do is shut this entire fishery down so we can meet brood needs. Hopefully, the adults we collect for this year’s brood stock will make a difference in future fisheries,” DuPont said in a weekly update posted to the agency’s website.

Kerry Brennan, a part-time guide at Riggins and owner of the Little River Bait and Tackle Shop, said the abrupt closure caught the fishing community there by surprise.

“It’s kind of a sudden thing,” he said. “We were not expecting a real long season but we were expecting it to be a little longer than this.”

Salmon fishing lends an economic boost to Riggins even if the season is less predictable than the fall and spring steelhead seasons.

“It’s a drag for Riggins,” Brennan said. “None of us are entirely dependent on salmon fishing but, man, it’s sure nice. It’s fast and furious. The last few years it’s been tough, but we usually get a couple, three weeks out of it, maybe a month. We were hoping things had kind of bottomed out there and would come back around and get better. Evidently we weren’t at the bottom and now I hope we are. If this ain’t the bottom, it’s going to be pretty scary.”

DuPont said poor ocean conditions, which led to reduced survival, are likely the biggest reason the run was so small. But he also noted that in 2017 when most of this year’s returning adult chinook migrated to the ocean as juveniles, those from Clearwater hatcheries faced high saturated gas levels because of flow regimes exiting Dworshak Dam. One of the power units at the dam was down for repairs and the Army Corps of Engineers had to spill more water than normal. Water plunging over spillways at the dam created supersaturated gas in the water that can harm juvenile fish.

DuPont said fish that were released into the North Fork of the Clearwater River, just downstream of the dam, returned at a lower rate this year than normal.

“It makes me think when we released those fish in supersaturated water, it had an effect,” he said.

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273. Follow him on Twitter @ezebarker.