Cutthroat fry

These young-of-the-year cutthroat trout didn’t survive the draw down in releases from the Jackson Lake Dam. They were photographed downstream of Pacific Creek landing on Monday.

Fisheries managers and advocates want anglers and river runners to log and share the locations of fish and aquatic insects that have become stranded in dewatered and disconnected braids of the Snake River.

The cause of the stranding is an approximately 90% reduction in water releases from the Snake River Dam that occurred between last Thursday and today.

While floating the Pacific Creek to Deadman’s Bar stretch of the Snake River on Monday, Orvis store manager and entomologist Maggie Heumann saw some of the early casualties of the vastly reduced flows. She described seeing a heap of dead cutthroat trout fry and also insect species that were being hit hard.

“We’re taking a look at the macroinvertebrates as we go down, and it’s not looking good,” Heumann told the Jackson Hole Daily. “They haven’t had time to move.”

Every fall, water released out of Jackson Lake Dam into the Snake River is tapered down to the winter-long release rate, typically around 300 cubic feet per second. But 2021 was out of the ordinary because flows stayed considerably higher than average through the summer and into the fall to satisfy agricultural demands in Idaho. The effect was that the transition into the winter flow rate was more abrupt.

Fly fishing guides, advocacy groups and the Wyoming Game and Fish Department responded to the more rapid change by monitoring how the Snake River and its dependent wildlife are being influenced by a 90% drop in water over less than a week. Currently, not much is known about how the web of aquatic and terrestrial life responds.

“I wish we did know,” Game and Fish Regional Fisheries Supervisor Darren Rhea said. “We’ve got very limited historic data on what channels dry up when, so that’s why it’s so important to try to get this information.”

Game and Fish is intending to intervene by saving fish that do become stranded, Rhea said, by using the “simplest and easiest” means possible: Nets and buckets.

That’s where the call to the public comes in.

“We don’t have plans to specifically rescue fish in one location or another,” Rhea said. “It’s going to largely be dictated by what we observe and what others observe.”

Trout Unlimited is encouraging people who venture out onto the Snake to log stranded fish sightings on its TU Rivers app. Alternatively, photos, observations and locations can be emailed to Leslie Steen, leslie.steen@tu.org.

Steen pointed out that there’s been a big grassroots monitoring effort set in motion by the faster draw down in 2021.

“Everyone’s trying to understand, in a dramatic year like this, what the impacts are,” she said.

Trout Unlimited’s science team is using drone photography to document how the river responds, and those photos will be analyzed by the Teton Conservation District. The National Park Service is also using remote cameras to create time-lapse videos.

Longtime fishing guide Jean Bruun has also spearheaded a water-based citizen science effort to learn how the different stretches of the dynamic Snake River respond. She buried 11 stakes in the riverbed at various points downstream from the dam and arranged for photos to be taken at each site every day during the draw down.

“The danger here is that it’s going to sound like we’re only concerned about the fishing,” Bruun said. “We’re not. We’re concerned about the river and responsibility to care for her.”

“This impacts every single living thing that lives around that river,” she added.

Contact Mike Koshmrl at 732-7067 or env@jhnewsandguide.com.

Mike has reported on the Greater Yellowstone Ecosystem's wildlife, wildlands and the agencies that manage them since 2012. A native Minnesotan, he arrived in the West to study environmental journalism at the University of Colorado.

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