LAS VEGAS (KLAS) — A remote lake in Great Basin National Park will be off limits later this month as wildlife officials take an important step to prepare the lake for Bonneville cutthroat trout. It’s a project that started in March of 2020.

Starting on Aug. 22 at sunrise, the National Park Service plans to exterminate brook trout in Baker Lake using a rotenone treatment — a natural poison. The lake will be off limits for 72 hours, and access to the lake’s water will be prohibited until sunrise on Sept. 7. Camping will also be prohibited.

It amounts to a large-scale “reset” for Baker Lake, which sits at 10,600 feet at the top of a six-mile trail that gains about 2,600 feet in elevation. Fishery biologist Jon Reynolds believes the Bonneville cutthroats will have a fighting chance at reestablishing their native population when they are delivered to Baker Lake by horseback and pack mule early next year.

“You know, Bonneville cutthroat are a cool looking fish. They’re a hearty native. They’ve survived a lot, they’ve come back from the brink of extinction, so I’ve got a lot of respect for ’em,” Reynolds said.

“When I started working here, it was the first time I ever saw the fish. I love fish, but I never thought I’d be the type of person that would just really all the sudden have this love for something,” Reynolds said. “We call them ‘Bonnies’ here at the park. A lot of other agencies also call ’em — it’s sort of an affectionate nickname. And they’re just … I think they’re just a really cool survivor.”

Brook trout, brown trout and rainbow trout have been taking over much of the Bonnies’ native habitat in eastern Nevada. They are one of the few trout species native to the state. They are also the state fish of Utah. Cutthroats are named for distinctive slashes of red on their gills.

Bonneville cutthroat are still found in Baker Creek below the lake, but outlets run only at peak runoff. The rest of the year, Baker Creek is born from underground outlets and springs — a path fish can’t follow. The ambitious project to establish new native populations involves gathering Bonnies from another stream. Those fish, ranging in size from 3 inches to 10 inches, will be taken to Baker Lake and Johson Lake, which is on the same trail a little to the south.

The next few weeks will be about killing the brook trout and keeping hikers away from the lake for safety reasons. Rules against swimming, wading, fishing, drinking, cooking or washing with water from the lake will be posted at trailheads and on all trails leading to the lake, according to the National Park Service.

A YouTube video posted by the National Park Service in October of 2020 talks about the project:

Reynolds said the trail is popular with avid hikers and backpackers who like to get away from crowds. During the project, he has camped at Baker Lake during the week, and there have been weeks he has only seen about four people come up the trail. But the Friday before the Fourth of July weekend, 20 people showed up. Other Great Basin attractions — Lehman Caves, Wheeler Peak and ancient bristlecone pines — get most of the public’s attention. The park is about 4 and a half hours north of Las Vegas near the Nevada-Utah border.

“Being a fish biologist in an area like this is a dream come true,” Reynolds said.

On the trail to the lake, he has seen mule deer, and bats are a frequent sight. The park is known as a “dark sky” destination because there’s so little light pollution at night, and looking at the Milky Way and constellations brings a lot of people out. Reynolds said the sunsets can be spectacular, too.

Reynolds shared one of the most memorable moments from his time at Baker Lake.

“We’ve been lucky enough to see bighorn sheep come right down to the lake and hang out for a little bit, eat some of the grass,” he said.

Now, about two and a half years into the project, introducing the Bonnies is in sight.

“In 2023, the Back Country Horsemen of Nevada, specifically the High Desert Chapter, they will pack the fish up to Baker Lake for us on horseback and with mules,” Reynolds said. After that, the park service will monitor the cutthroat population. The hope is that the high elevations of Baker and Johnson lakes — both over 10,500 feet — will be an ideal place for the cutthroats to thrive.

“The climate is changing. It seems that droughts are becoming more frequent,” Reynolds said. “Water temperatures are becoming warmer, and catastrophic wildfires are occurring more often. Some of our smaller streams are being affected by this.”

A member of Back Country Horsemen of Nevada waters his mule after packing gear in to Baker Lake at Great Basin National Park. (Photo: National Park Service)

Baker and Johnson lakes will become “conservation populations” that can be used to restock other waters, and to create a native recreational fishery, he said. The Bonneville cutthroat population will be closely monitored, and fishing regulations might change from catch-and-release if the fish do well in the two lakes. Catch-and-release will ensure a fighting chance for the Bonnies, and there’s not a lot of “fishing pressure” in the area, Reynolds said.

Although the lake is shallow, there’s not much chance that it will freeze solid and undo all of this work. Reynolds said the non-native trout in Baker Lake were stocked before Great Basin National Park’s creation in 1986, and they have made it through every winter. There’s no reason to think the Bonnies won’t do the same. “I believe that’s pretty good evidence that even during hard winters that they can definitely survive under the ice.”

And the species has shown remarkable resiliency. “They can live in lakes, large rivers, and they can also survive in little tiny streams that are just a little bit bigger than a trickle.”

Bonneville cutthroat are primarily in Utah, but their range extends to a little bit of eastern Nevada, southeastern Idaho and southwestern Wyoming. Reynolds said that 100% genetically pure Bonneville cutthroats were believed to be extinct in the mid-1900s, but sometime in the mid-1970s, pure populations were rediscovered and an aggressive conservation program was initiated. Now there are more than 200 populations in their home range.

Monitoring at Baker and Johnson lakes is scheduled to continue through mid-2024.