The growing abundance of sockeye salmon on the Columbia River reached a new milestone this week with passage of another record run at Bonneville Dam.
It is the third record-breaking run in the past five years.
Through Wednesday, the sockeye count at Bonneville Dam stood at 539,225 fish, with the run reaching its latter stages. Record-keeping dates to 1938, when fish counts began at Bonneville.
This year’s run eclipsed the old record of 520,959 sockeye in 2012, which came after a 2010 record run of 386,525 sockeye.
Last year’s return was 186,100 sockeye.
“It’s amazing,” said Joe Hymer, a fish biologist based in Vancouver, Washington. “The run is still coming.”
Biologists had expected a much more modest return. The preseason forecast called for 347,100 sockeye crossing Bonneville.
The largest component of the run – upward of 90 percent – come from a series of lakes in southern British Columbia at the head of the Okanogan River.
Most of the rest come from lakes connected to the Wenatchee, Snake, Yakima and Deschutes rivers.
The vast majority of the sockeyes reproduce in the wild.
Endangered Snake River sockeye have been faring better with the improved returns.
So far this season, 660 sockeye have been counted at Lower Granite Dam on the Snake River, with more to come.
The Snake River sockeye was placed on the endangered species list in 1991 after being virtually wiped out. Between 1991 and 1997, only 16 wild sockeye made it up the Snake. The run originates in Redfish Lake in the Stanley Basin in central Idaho.
Reintroduction of the fish through hatchery techniques and favorable river and ocean conditions are bringing the run back.
Elsewhere, sockeye are being reintroduced to the Yakima River in Central Washington and the Deschutes River in central Oregon.
The upswing in sockeye numbers is only partly due to hatchery efforts, Hymer said.
The biggest factor helping the fish return to abundance is management of downstream water flows that allow the juveniles to move quickly to the ocean during spring each year, he said.
Good snowpacks bringing strong water flows have combined with regulated spills at major dams to get the juveniles to the sea, where they have encountered good forage conditions in past years.
In addition, considerable work has been underway to increase habitat in the Okanagan basin of southern British Columbia, where up to 90 percent of the Columbia run spawns and rears.
Among the projects are new passageways to reopen historic lake habitat; recreation of natural stream segments; and reopening of stream spawning habitat, all in B.C.
“There has been a lot of hard work on restoration of the habitat for these fish,” said John Arterburn, Colville tribal fish biologist.
A hatchery project sponsored by Grant County Public Utility District in Washington is helping rebuild stocks in Skaha Lake, which was reopened a few weeks ago to upstream migration in a long-sought restoration project, Arterburn said.
Sockeye are distinct among Pacific salmon because juveniles spend a year in lake water before migrating to sea. Kokanee, a common fish in the region’s lakes, are a nonmigratory sockeye.
Anglers in Central Washington are already trying to harvest this year’s abundance.
An estimated 100,000 sockeye have already gotten into the Okanogan River and will make it to the spawning grounds, Arterburn said, ensuring there will be enough fish to fully populate the watershed for a new generation. But there are hundreds of thousands of fish yet to arrive for anglers to target.
Jessie Baker at the Triangle Exxon store in Brewster said that hot weather in the forecast is likely to warm the Okanogan River, causing fish to stop at the mouth and linger in cooler Columbia water before moving on upstream to spawning areas. In the past, the water temperature difference has led to the best fishing there, but boat crowds often build on weekends.
Anglers are now working the water below Wells Dam, she said.
“We keep very close track of our fish,” she said.
The Brewster area also provides opportunity to catch upriver summer Chinook, which are arriving there now.
Hymer said biologists have upgraded this year’s summer Chinook run over Bonneville Dam from 67,500 fish to 74,000 fish, which will be the fourth-largest summer Chinook run since 1980.
Columbia River abundance is expected to continue into autumn with a record run of 1.6 million fall Chinook salmon this year, an increase from the 1.26 million fall Chinook entering the Columbia last year.
“Right now, things have been going well,” Hymer said.