Snake River steelhead runs story in contrast as A-run tanks and B-run surges

The two runs of Snake River steelhead are on diverging paths this year.

The A-run is struggling and the B-run is surging.

And there is a bit of good news and bad news for both, according to Joe DuPont, regional fisheries manager for the Idaho Department of Fish and Game at Lewiston.

Fisheries managers divide Snake River steelhead into A and B runs, based mostly on timing of their return. The A-run returns first and the B-run second. But there is some difference in life cycle as well.

A-run steelhead tend to spend just one year in the ocean, although a portion of the run stays out longer. The B-run fish tend to spend two years in salt water, but some fish return after just one year there.

One salts

This year’s A-run is dominated by two-year ocean fish and the one-year ocean component has collapsed. In his weekly fish report, DuPont noted 93% of hatchery A-run steelhead headed for the Snake and Salmon rivers is made up of two-year ocean fish. The good news is those fish, because of the longer time they spent feeding in the ocean, are bigger than most A-runners.

The bad news: Because of the no-show of one-year salt fish, overall numbers are down. The department had hoped to see 26,000 hatchery A-run steelhead return to the Snake and Salmon rivers. DuPont said it’s more likely to be 18,000 to 19,000. He expects the one-ocean component of the run to be the lowest recorded over the past 12 years.

In the past, the agency would likely have reduced bag limits to make sure hatcheries are able to meet their fish collection and spawning goals. DuPont said bag limits will stay at normal levels this year. The higher-than-average return of two-year salt A-run fish will help hatcheries make brood. In the rare years where the A-run is dominated by two-year ocean fish, DuPont said the percentage of female fish also is higher. Since the two-year ocean steelhead are bigger, the females carry more eggs.

“As such, we are confident that we don’t have to implement more restrictive fishing regulations this year to ensure we meet our hatchery broodstock needs,” DuPont wrote in his report.

Booming Bs

It’s possible the Clearwater Basin will see one of the bigger returns of hatchery B-run steelhead on record. DuPont said the return is on pace to be the seventh largest and the biggest since 2010. Last week, more than 29,000 hatchery B-run steelhead destined for the Clearwater Basin had passed Bonneville Dam on the Columbia River, with about a third of the run yet to come.

But it’s not all good news for the Bs that are coveted by anglers for their large size and hard-fighting ways. Just like the A-run, the one-year ocean component of the B-run is tanking. That is likely to mean that next year’s return of two-year ocean B-run fish will be below average.

“It doesn’t look very good for next year,” he said.

DuPont also pointed out that the B-run is becoming more prone to alternating year swings in abundance. The fish have tended to be more abundant in even-numbers years and less so in odd-numbered years. Columbia River sockeye have been following the same pattern.

“It’s really showing up and it’s getting more extreme and it’s kind of scary,” DuPont said. “I think we are going to start looking into it more and try to understand it. Understanding and doing something about are two different things.”

Other Pacific salmon follow a similar up-and-down cycle from one year to the next – most notably pink salmon. They flourish during odd years and are way down during even years.

Some fisheries managers believe other runs may be responding to pink abundance – the most plentiful salmon in the north Pacific.

Under this theory, fish like steelhead and sockeye tend to flourish during years when pinks are down and there is less competition for food. Hatcheries in the U.S., Canada, Russia and Japan raise and release more than 3 billion juvenile pink salmon per year. That is on top of natural fish.

“The pinks could be driving all of the salmon because there are just so many of them,” DuPont said.

Fall chinook

Fisheries managers now expect nearly 40,000 fall chinook may return to the Snake River, up from a preseason forecast of about 25,000. Through last week, about 35,000 fall chinook had been counted at Lower Granite Dam on the Snake River. The confluence of the Snake and Clearwater rivers has been choked with boats filled with chinook anglers over the past few weeks.

“When you go by the confluence, you see boats in there stacked like cordwood,” said Becky Johnson, production director of the Nez Perce Tribe’s Department of Fisheries Resources Management. “I hope there are a lot of happy anglers down there, and our guys are fishing too, so it’s good for everybody.”

The tribe is largely responsible for the fall chinook fishery upstream of Lower Granite Dam. Several years ago, it pushed for hatchery fall chinook to be released upstream of Granite and established a hatchery program to produce more juvenile fall chinook.

The tribe also reintroduced coho to the Snake River Basin after they were declared extinct in the 1980s. Coho, also known as silvers, now provide annual fishing opportunities for tribal and nontribal anglers.

Johnson said about 47,000 Snake River coho have passed Bonneville Dam, including about 7,000 bound for the Lostine River in Oregon and 40,000 for the Clearwater River in Idaho. She said coho have about a 60% conversion rate from Bonneville to Granite, meaning about 28,200 could make it above the dam.