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Fly Fishing the Gros Ventre

Fly Fishing the Gros Ventre

A revitalized DIY cutthroat trout stream at the gates of Grand Teton National Park

The hamlet of Kelly, Wyoming is decisively funky. It's a warm, quiet vortex comprised largely of yurts. Its denizens have a penchant for living green. Blooming vegetable gardens rest amid walls of hand-cut cord wood, essential to make it through the winter. Kelly rests on the shores of the Gros Ventre River (pronounced grow-vont) just east of Grand Teton National Park, and in its waters resides an exceptionally healthy population of native cutthroat trout. But until 2013, those fish were thwarted from reaching almost 100 miles of spawning habitat.

Just south of Kelly, the Newbold Dam stretched across the Gros Ventre until it was removed on March 19, 2013. The dam was a rickety barrier, comprised of logs and rocks. It was built to support a flour mill in 1917 and was later rebuilt in 1937. By that time, the flour mill had burned down, and the dam was re-purposed to irrigate surrounding agricultural land.

Its recent removal was orchestrated through a joint venture between Trout Unlimited and the Grand Teton National Park. And today, cutthroat trout run freely from the trickling headwaters of the Gros Ventre to the main stem of the Snake River.


Removal of the Newbold Dam has already dramatically increased the numbers of small cutthroat in the Gros Ventre, and in the long run should help sustain native trout populations in the main stem Snake River.

The Gros Ventre is a critical tributary of the Snake. Apart from its perfect spawning gravel habitat, hot springs in the river upstream from the Newbold Dam historically provided a thermal advantage during the winter, which increases the likelihood of survival and enhances growth for juvenile cutthroat. But access to the nursery area had been partially blocked by the Newbold. According to Rob Gipson, regional fisheries supervisor for Wyoming Game and Fish, the dam was "a very effective partial barrier to upstream movement of smaller cutthroat, sculpin, and dace." He said larger fish were able to jump a decrepit section of the dam, but smaller fish were not.


Electrofishing population estimates before and after the removal clearly demonstrated a positive effect on the cutthroat population. Gipson stated that, "In September of 2007 we estimated only 42, 5- to 9-inch cutthroats per mile. By October of 2013 estimates suggested there were 157 fish of that size per mile."

Effectively, the population base of small fish tripled, and so did the usable river miles upstream of the old dam site. More important, radio-tagging studies show that already, adult cutthroat trout are migrating into the upper Gros Ventre in early winter, presumably to spawn.

Off the Beaten Track

You get to the Gros Ventre by coasting eastward past Kelly and into the arid hills adjacent the Tetons. As you drive, the road twists and winds in serpentine fashion, slicing through dusty hillsides of crumbling stone and sand. Eventually you pass the cataclysmic debris of the June 23, 1925 landslide. On that day the hills released and let rip an earthen bulldozer that crossed and dammed the Gros Ventre, creating Lower Slide Lake. Fortunately for the cutthroat, and unfortunately for the residents of Kelly, the slide dam failed two years later, opening the watercourse for spawning fish, but temporarily flooding Kelly in the process. Both have fully recovered today.


While the Gros Ventre is an excellent walk-and-wade adventure, I floated it one weekend last summer with Nick Brosnan and Trevor Klein, both Jackson locals and strong boatsmen. In the Jackson area there's a drift boat in every other yard, but we used Klein's raft, given the fact that parts of the Gros Ventre can be shallow and rockytoo much of a "drag" most of the year to take a drift boat.

We launched the three-man inflatable just below Upper Slide Lake and floated over ten miles downstream to our shuttle. Klein's raft is sporty. Cobalt blue and outfitted with a utilitarian frame suitable for fishing, it spins on a dime and easily bounced through the quickwater and the occasional Class II or Class III rapid. It's like a riparian rally racing car, and both men spun and dashed between tight canyon walls and overhanging, raft-hungry granite ledges with ease. Within minutes of starting we were into fish. They'd feed somewhat indiscriminately on dry patterns and streamers alike, but there was one thing that these fish had in common: they were small, native, and beautiful.

All of the fish we caught were Snake River fine-spotted cutthroat trout (Oncorhynchus clarki behnkei). Unlike the biologic pollution that has occurred on many other rivers in the West through thoughtless stocking programs, the Gros Ventre has been largely spared. All of the fish that live there belong there, and they exist without competition from nonnative species. It's their home, for some of them a nursery water where they'll grow strong before moving on to the unforgiving water of the raucous Snake River.


For fly fishers it's off the beaten track, not nearly as famous as the nearby Snake River, but likely just as significant in terms of Western fishing for native trout.

The Gros Ventre is a striking river. Emerald green from a mossy bottom and clear as bath water, it winds through jagged canyons and rolling hills. It's lined by towering pines and rows of cottonwood trees. Long stretches of slick or quick water are hyphenated with foamy haystacks and bleach-white roostertails of rapids that squeeze through the canyon walls. The river braids on occasion, but always finds confluence, where resting pools harbor dense pods of fish.

As we worked our way down the river and closer to the Snake, the fishing only became better. The day was warm with the sun kissing the tips of the mountaintops; fair weather cumulus clouds drifted overhead, passing us an occasional shadow of relief from the hot weather. On the shoreline hoppers scaled long blades of grass, toppling over and into the river and often swirling directly into the mouths of opportunistic fish. We mimicked these patterns with large foam hopper patterns. The fish aren't picky here and in late summer, any high-floating dry fly with rubber legs will take plenty of fish.

Admittedly we lost many fish for each one landed, but under the heat of the day these fish slurped our flies from the surface of seams, banks, and deeper pools. The clarity of the water allowed us to see crimson fish torpedo from the depths of a jade pool, open their jaws, and crush our flies, sending our lines tight into the air, spraying off crisp water in the process.

About halfway through our float we approached a broad bend in the river. A wide bench of rock pressed the water toward the surface, creating a pour-over. Adjacent the spill sat a series of sharp boulders and in the belly of the pool was a large boulder garden. It wasn't particularly technical for a skilled boat pilot like Klein, but warranted a scout.

After we evaluated the section, I got out to photograph the run from the granite ledges overhanging the river. I plodded down the river, sending insects flying as I pushed through the grass and brush. A snake erupted from under a rock and dashed up the hill. As I looked up the hillside to gauge its trajectory, an antelope crossed the hillside above me and wandered away in a relaxed, unhurried fashion.

As Klein approached the section, Brosnan cast toward a seam just upstream. Two strips later the water detonated with the meal of a fat cutthroat, one that went aerial to the end that it literally almost jumped in the boat, bouncing off the raft's edge before being gently released by Brosnan. We continued downstream through a myriad of riffles and runs, skinny pinches in the river bedded with whitewater and deep pools.

At the beginning of our float most of the fish were tiny, but as we gradually descended downstream the size of the fish increased, as did their vigor and their vibrance. By the end of our float the fish were reliably twice, or even three times the size of their upstream brethren.

Most trout in the Gros Ventre are smallish 8- to 12-inch fine-spotted cutthroat, but much larger specimens migrate into the tributary from the Snake River.

We floated the river on a bluebird Sunday, yet saw no other boats and almost no other anglers. Perhaps it fishes so well due to light pressure, perhaps due to a very diverse ecosystem and an abundance of habitat.

Whatever the reason, the Gros Ventre is an evocative river that strikes a chord of how fishing in the Wild West must have been before Jackson Hole had a drift boat in every yard, before there were yurts in Kelly, before there was a dam in that town. I imagine camping on its shores, perhaps having approached on horseback, casting to the same hungry, appeasing fish that live there today.

There's a proud intimacy to the Gros Ventre. It's a river where you can touch the banks, sometimes literally, and watch trout sip insects from the glassy surface. It's a place where you're forced to connect with the river, not remit to its power, not try to coax it to cooperate with us, the much lesser force.

As we drifted through the last canyon the evening's rays were just starting to ignite the tips of the trees on the rim. A gentle mist began to fill between the canyon walls; insects were just starting to hatch.

I cast one last time to a feeding pod of native trout. My fly evaporated in a swirl as my line came tight. As I raised my rod my line crossed the sun's rays as they sliced into the canyon walls. My line glowed as the sun penetrated into the water. At the end of my line writhed a fat, apricot-colored fish. He broke the surface, rolled his head just long enough to reveal a beady eye, and with that my line went limp in the evening limelight.

Brian Irwin is a family physician, freelance writer, and outdoors photographer (brianirwinmedia.com). He lives in Madison, New Hampshire.

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