By Jerry Painter
September 28, 2021

This year 43 sockeye salmon completed the 900-mile journey from the Pacific Ocean to their nursery lakes near Stanley in central Idaho after braving especially difficult river conditions.

The dismal return was helped somewhat when Idaho Fish and Game stepped in and trapped 201 of the endangered fish at the Lower Granite Dam, the last dam on the lower Snake River, and trucked them to the Eagle Fish Hatchery west of Boise earlier this summer. The extraordinary move was taken when the river water temperatures were deemed too warm to support the migrating fish.

Despite so few fish returning to spawn, Fish and Game said it will have about 2,750 adult sockeye available to naturally spawn in Redfish and Pettit lakes or to replenish its hatcheries. The other fish will come from captive broodstock raised in hatcheries as an “insurance policy” when the sockeye returns are especially low.

Roger Phillips, public information supervisor with Fish and Game, said 2021 was especially challenging for sockeye and he compared it to the conditions from 2015.

“It’s not our goal to short stop these things at Lower Granite (Dam) every year,” Phillips said of trapping and trucking 201 sockeye. “That’s going to be only when we have situations that are pretty dire. Like we saw in 2015 and like we saw this year.”

Normally, the sockeye would swim on their own to Sawtooth Basin. Biologists praise those fish who make it all the way on their own power.

“Our preference would have been to allow those fish to complete the last leg of their journey on their own, because from a genetic perspective, sockeye that make it back to the Sawtooth Basin have a level of fitness that we want in our captive breeding program,” said Lance Hebdon, Fisheries Bureau Chief. “But based on river conditions, trucking fish from Lower Granite Dam to Eagle was a necessary tradeoff to increase survival.”

In a normal year, about 50% of tagged sockeye who reach Lower Granite Dam make it to the Sawtooth Basin. This year, because of poor river conditions, only 6.7% of the tagged fish made it.

For 2021, Fish and Game placed 1,112 sockeye spawners in Redfish Lake and 99 in Pettit Lake. The rest of the spawners were used to replenish hatcheries.

“The goals for the Eagle and (other) hatcheries combined is to produce around 1.1 million eggs to replenish the captive broodstocks and transfer and rear at Fish and Game’s Springfield Hatchery, which is expected to grow about 1 million young sockeye to be released to migrate to the ocean in the future,” Phillips said. The Springfield Hatchery is west of Fort Hall.

Idaho’s sockeye salmon were placed on the Federal Endangered Species list in 1991. The total number of sockeye that returned from 1991-99 was 23, including two years when no sockeye returned. At that time a captive broodstock program was started.

Idaho has two hatcheries devoted to sockeye — the Eagle Hatchery and Springfield Hatchery. Of the fish that return, some go to the hatcheries for broodstock while others are released to spawn naturally. From 2010 to 2019, the annual average sockeye returning to Stanley Basin has been 558 fish, Fish and Game reports. In the distant past, sockeye returned to Idaho in the tens of thousands. Lately, the number tends to bounce up or down depending on a variety of conditions.

“As always, it’s difficult, if not impossible, to know what challenges sockeye will face in the future,” Phillips said. “In order to thrive, salmon need good rearing and migration conditions in Idaho’s lakes and rivers, adequate food in the ocean, and cool rivers for their return to Idaho. When all three are available, the fish have shown amazing resiliency, and they are capable of bouncing back and returning in large numbers.”

Phillips said should the drought continue into next year with warm “lethal” water conditions, Fish and Game may have to step in again to trap and truck the sockeye past Lower Granite Dam.

“We found with steelhead that if the Columbia River is warm, they’ll tuck into the tributaries in cooler waters hanging out there until the river cools down, then they’ll come back and complete their migration,” he said. “But we don’t know what sockeye do when they’re faced with that. They’re a smaller fish and have a narrower window to get up here and spawn. We don’t know how they react to warm water. That’s why we hedged our bets this year and pulled some of these fish out so that we know that we have some.”