Yellowstone Wild Trout Populations Nonetheless Wholesome After Floods


Yellowstone Nationwide Park and the encircling space noticed record-setting floods this June. The once-in-a-thousand-year flood occasion wreaked havoc throughout a lot of the park’s northern loop because the Yellowstone River reached historic levels, damaging roads and taking out bridges on its method by Paradise Valley and previous the city of Livingston. Soda Butte Creek, the Lamar River, and different iconic trout streams within the park additionally topped their banks, which had some anglers frightened in regards to the potential results on wild trout populations there.

Some two months later, the street connecting the park’s Northern and Northeastern entrances remains closed to non-public automobiles. Visitation numbers in Yellowstone are still down, and the Nationwide Park Service continues to evaluate the damages. However because the rivers have dropped to late-summer flows, NPS workers can say with confidence that the June floods didn’t inflict any long-term harm on native trout and grayling populations contained in the park.

Learn Subsequent: Watch: Historic Flood Hits Yellowstone, Spurs Evacuation from National Park  

In response to Tood Koel, the park’s chief fisheries biologist, the one harm occurred on Slough Creek, a well-known tributary of the Lamar River. And even then, he explains, that harm was minimal.

“We bought fairly fortunate,” Koel says. “The rain and the flooding had been very localized, so most of our initiatives weren’t affected.”

Utilizing Pure and Artifical Limitations to Separate the Natives from the Non-Natives

Yellowstone’s Native Fish Populations Still Healthy in the Wake of June Floods
A westslope cutthroat trout in Yellowstone Nationwide Park. Chris Hunt

For no less than the final decade, the Nationwide Park Service has labored to revive and defend Yellowstone cutthroat trout populations inside the park’s boundaries. They’ve additionally centered on restoring Westslope cutthroat trout and Arctic grayling, that are native to the park’s streams that type the headwater reaches of the Missouri River.

Yellowstone’s grayling are distinctive as a result of they characterize the southernmost native inhabitants in North America. Whereas these fish are uncommon immediately, they had been so widespread within the Madison and Gallatin Rivers when the park was first designated that early anglers believed their populations would by no means be depleted. About 20 years after the primary non-native trout had been launched in these rivers, nonetheless, all of the grayling had been gone.

As a part of the long-term effort to return grayling and cutthroat trout to their native waters, Koel’s group has put in artifical fish limitations all through the park. Considered one of these limitations is situated on the decrease finish of Slough Creek, and it was put there to stop rainbow trout from encroaching upstream into the creek’s iconic meadow reaches. (Rainbows and cutthroats can mingle on the spawning redds, and the result’s a fertile hybrid often called a “cutbow.”)

Koel says the principle barrier held throughout the intense flooding that started on June 12, however {that a} bypass channel close to the decrease finish of Slough Creek failed. Happily, Koel doesn’t imagine this failure resulted in any rainbows shifting upstream.

“There’s nonetheless a really important barrier above that channel,” Koel says. “So the possibilities of something making its method up the creek had been slim.”

Farther south, within the Gibbon River drainage, Koel’s group depends on two impassable pure limitations to maintain non-native rainbow, brook, and brown trout from mixing with native species within the Gibbon’s higher reaches. These pure limitations are often called Little Gibbon Falls and Virginia Cascade.

upper gibbon river chris hunt
A view of the Higher Gibbon River in Yellowstone Nationwide Park. Chris Hunt

Whereas non-native trout haven’t been stocked within the park since 1958, the higher Gibbon above the falls was as soon as overrun with brook trout, which had been first launched within the late 1800s. Due to a protracted and tough course of that concerned eradicating all non-native trout and restocking natives, the higher river is now the unique house of westslope cutties and grayling. And due to the numerous pure limitations that exist on the Gibbon, the June floods didn’t have any impacts on this undertaking.

As for the opposite necessary limitations within the Nationwide Park, Koel explains that two different initiatives within the higher Missouri drainage had been in query when the flooding began. Specimen Creek, a tributary of the Gallatin River, is now house to a reintroduced inhabitants of Westslope cutthroat trout. These fish thrive above a man-made barrier a number of miles above the creek’s confluence with the Gallatin, and Koel says he was relieved to search out that barrier nonetheless intact after the deluge.

He was equally relieved when he found {that a} barrier on Grayling Creek—which runs into the Madison shortly earlier than it reaches Hebgen Lake—additionally survived the high-water occasion. Above this barrier, the creek remains to be house solely to cutthroat trout and grayling. 

Netting Lake Trout and Making Progress

The park’s most bold native trout restoration effort has been happening on Yellowstone Lake, which is the most important lake within the park. By the mid-2000s, biologists estimated that 90 p.c of the lake’s spawning-age Yellowstone cutthroat trout had been gone because of the clandestine introduction of lake trout there. This stocking possible occurred someday round 1990.

laker from Yellowstone lake Chris Hunt
The creator holds a lake trout that he caught from Yellowstone Lake. Chris Hunt

These lake trout, native to the Nice Lakes, had been actually consuming the cutthroats out of home and residential. The Nationwide Park Service and a bunch of conservation teams—together with Yellowstone Forever, The Greater Yellowstone Coalition, and native Trout Unlimited chapters—have raised cash to pay for the netting of lake trout for the reason that late 2000s. And that effort is laborious. For years, the Park Service contracted with business gillnetters to take away tons of of 1000’s of large lake trout. Yearly, the netters stored catching an increasing number of lake trout, however the common measurement of the lakers stored getting smaller. 

That effort is now paying off. 

“We’re seeing the runs we noticed earlier than the lake trout took over,” Koel says of the cutthroats’ spawning migrations into the lake’s tributaries, significantly the higher Yellowstone River that flows by Wyoming’s distant Thorofare region. “There are large cutthroat up there within the spring. It’s so good to see the hassle working.”

In the present day, the business netters are gone, however the elimination of lakers continues. Through the use of telemetry gear and putting gillnets strategically all through the lake, the park’s lake trout elimination crew managed to catch round 300,000 small, sexually immature lakers over the course of 2021. Efforts are nonetheless underway this summer season and can final by October. 

“It’s undoubtedly serving to,” Koel says. “The lake is coming again into stability, and the longer term seems brilliant.”

The gillnetting of lakers will proceed, however the way forward for the lake’s native cutthroats is dependent upon a gradual stream of funding to maintain these elimination efforts going. And there’s no assure that funding will final without end. 

On the entire, although, Yellowstone’s native fish populations stay wholesome, and the flooding’s minor impression on the park’s fisheries restoration efforts amounted to a dodged bullet. As for Koel and his group?

“We’re full steam forward,” he says. “We nonetheless have work to do, however we proceed to make progress.”

Chris Hunt is an award-winning journalist and the creator of “Catching Yellowstone’s Wild Trout: A Fly Fishing History and Guide.”


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