A record sockeye return crosses Lower Granite Dam—but they're not all Idaho fish

Idaho Fish and Game saw this year’s sockeye return hit a record number—which is good news—but with an asterisk. Through Aug. 19, 2,835 fish were counted at Lower Granite Dam about 30 miles downstream from Lewiston; most of those fish probably won't return to Idaho. That’s the highest sockeye return since fish counting started at the dam in 1975, topping the previous record of 2,786 fish in 2014. 

“There’s a huge return of Columbia River sockeye. And in the past, some of those fish have strayed into the Snake River and crossed Lower Granite Dam,” said Eric Johnson, Idaho Fish and Game Senior Fisheries Research Biologist. 

About 750,000 sockeye crossed Bonneville Dam on the Columbia River this summer, and nearly all were bound for the upper Columbia. Large sockeye returns typically mean more strays, and Johnson noted even half a percent straying into the Snake River could result in 3,000 to 4,000 fish crossing Lower Granite Dam. Fish and Game sockeye managers have never seen a Columbia River stray make it all the way to the Sawtooth Basin.

Sockeye typically start arriving in the Stanley area around the third week of July. They were on cue this year with the first fish being trapped on July 23. Sockeye will continue returning into October, but most are expected to arrive during August and September. 

Based on tags implanted in some of Idaho’s sockeye, Johnson said about 970 of the sockeye that crossed Lower Granite are likely heading to the Sawtooth Basin near Stanley, which is about 400 miles from Lower Granite Dam. Now, it’s a waiting game to see how many Idaho sockeye arrive.

Through Aug. 19, 33 sockeye had arrived in the Stanley area. Earlier this summer, Fish and Game staff also trapped and transported 255 sockeye from Lower Granite to the Eagle Fish Hatchery near Boise when the summer heatwave was warming river temperatures to levels that are dangerous for sockeye.

Fish and Game captures sockeye in traps at Redfish Lake Creek and in the Upper Salmon River upstream from the confluence of Redfish Lake Creek. Returning sockeye are either trucked to Eagle and held for genetic testing before being spawned at the Eagle Hatchery or allowed to spawn naturally in Redfish, Petit or Alturas lakes.