It’s been a series of unfortunate events for endangered Snake River sockeye and the people who track them.
Fish managers already expected the 2019 run to be among the worst in a decade (CU No. 1911 ). Like other Pacific salmon, they’re still suffering effects of poor ocean conditions. Adults experienced a massive die-off in 2015 from warm water, and most of the juveniles raised in the Springfield Hatchery and released in Redfish Lake Creek from 2015 through 2017 died on their way to the ocean before hatchery managers corrected a problem with water chemistry.
It’s also a tough year for fish managers trying to track this year’s returns.
As of Aug. 6, 62,940 sockeye had passed Bonneville Dam, and 337 of those had turned off to swim up the Snake River and over Ice Harbor Dam. But just 178 were counted at Lower Monumental, 71 at Little Goose, and 61 at Lower Granite.
So far, only one has made it all the way to the Redfish Lake Creek trap.
There’s limited data and lots of uncertainty about why sockeye are dropping off between dams. The Columbia River Technical Management Team attempted to help by closing the adjustable spillway weir at Little Goose Dam, but expect little success since a similar operation last year resulted in no significant change.
Fish managers believe Columbia River sockeye are mistakenly swimming up the Snake River and getting counted before they turn back.
Such fish are called Mid-C dip-ins, Russ Kiefer, a TMT member and research biologist for the Idaho Department of Fish and Game, told Clearing Up.
Kiefer said genetic work from past years has shown that sockeye from the mid-Columbia often “dip in” to the Snake River for a time before finding their way back to the Columbia.
“We think the most likely thing that’s going on is Mid-C dip in. But without fish on hand or [passive integrated transponder] tags or genetics, we can’t confirm it,” he said.
Some small Chinook and steelhead have also been misidentified by fish counters as sockeye.
At Ice Harbor, Kiefer noted, one fish counter is in charge of watching two windows—the ladder that gets the most use and a video of the ladder that’s less used.
“Normally it wouldn’t be that difficult, but we’ve had half a million shad,” he said. “They’re a relatively similar-sized fish, and you’re trying to count a hundred fish or so that are mixed up with a half a million shad.”