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IDFG Traps and Transports Sockeye to Ensure Broodstock by K.C. Mehaffey NW Fishletter, August 6, 2025

In 2025, Idaho has collected and moved ~150 Sockeye

The Idaho Department of Fish and Game trapped a portion of the adult Snake River sockeye run and transported them to the Eagle Fish Hatchery in July to use as broodstock.

The trapping occurred only during regular fish sampling at the dam. In 2021, the agency collected about one-third of the sockeye that passed the dam to transport upstream, IDFG fish biologist Jonathan Ebel told fellow members of the Columbia River Technical Management Team July 9.

Ebel said with low flows and the potential for a rapid change in migration conditions, his agency opted to trap and move a smaller portion of the run by truck as insurance. He said the weather and corresponding river conditions have been relatively good for sockeye so far this year, but an extended heat wave could quickly change that.

Ebel said that travel times and conversion rates for passive integrated transponder-tagged sockeye detected at Bonneville Dam are looking good so far. He said there were "two runners" that moved quickly through the system early in the migration season, but other sockeye are making the journey in an average length of time.

Later in the meeting, Jon Roberts, representing the U.S. Army Corps of Engineers, said modeling indicates that the water temperature at Ice Harbor Dam was between 1 and 1.5 degrees Fahrenheit cooler on July 7 than it would have been if the Corps had not started releasing cool water early at Dworshak Dam.

Requested by NOAA Fisheries to aid endangered Snake River sockeye, the change in operations was implemented despite objections by several TMT members representing states and Columbia Basin Native American tribes.

Roberts said water in the Ice Harbor forebay was stratified, which helps fish find a cold-water refuge when surface water becomes heated.

But the operation also resulted in the early release of more than 10 percent of the cooler Clearwater River water reserved to help fish migrate in the Snake River through the hot summer months.

Erick Van Dyke, who represents Oregon on TMT, noted that the target for salmon managers is to keep Lower Granite Dam water temperatures at 68 F or lower for the entire summer.

The question of whether the early release of cold water from behind Dworshak Dam benefitted sockeye arose again at TMT’s July 23 meeting.

According to the TMT facilitator's summary, Ebel believes the relatively good passage through Snake and Columbia river dams this July was likely due to a lack of sustained heat waves that kept water temperatures tolerable for sockeye.

But Emi Melton, who represents NOAA Fisheries at TMT, said warmer temperatures were anticipated earlier in the season. She said two Snake River temperature gages indicated that the Snake River has only been warmer in June and July in 5 to 20 percent of prior years.

She said from NOAA Fisheries' perspective, the release of colder water early in the season likely helped more Snake River sockeye navigate the dams this year, and noted that counts at Lower Granite Dam were 151 percent of average so far.

As of Aug. 4, a total of 1,069 sockeye had passed the dam.

Related Pages:
Count the Fish, 1977 - 2024 by GAO on Nation's Salmon Recovery Efforts

Biologists Truck Snake River Sockeye Salmon to Cooler Idaho Waters by Courtney Flatt, Oregon Public Broadcasting, 8/4/24
Idaho Fish and Game Brings Sockeye in Unseasonably Warm River to Eagle by Abby Davis, KTVB, 8/4/24
Idaho Fish & Game Trucking Sockeye Salmon from Lower Granite Dam on Snake River by Evan Ellis, Big Country News, 7/22/24
Snake River Sockeye Run Sputters by Eric Barker, Lewiston Tribune, 7/27/23
11 Adult Sockeye Make Way to Sawtooth Basin by Eric Barker, Lewiston Tribune, 8/5/22
Dismal Returns: 43 Sockeye Make the Journey from the Pacific to Central Idaho in 2021 by Jerry Painter, Post Register, 9/30/21
Study: Strays Dominate Snake River's Trapped Natural-Origin Sockeye by K.C. Mehaffey, Northwest Fishletter, 9/7/21
Research: Sockeye are in Hot Water by Eric Barker, Lewiston Tribune, 10/2/20