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Jackson Hole, WY News

Rainbows being given the boot

Prized non-native trout are getting the ouster from the Snake’s South Fork, and fishery administrators are asking for acceptance.

Rainbow trout electrofishing

SWAN VALLEY, IDAHO — Patrick Kennedy cradled a massive trout, the kind of fish an angler can remember forever.

Every bit of 4 pounds and easily clearing 20 inches long, the ruddy-cheeked spotted wild salmonid had been subdued with electricity and then strategically hoisted with a net from the prized waters in the South Fork of the Snake River. Its next stop, before a dinner plate, was a decidedly tamer environment: the oval-shaped Trail Creek Fishing Pond dug from the base of Teton Pass near Victor.

“This is a nice fish,” said Kennedy, a new regional fisheries biologist for the Idaho Department of Fish and Game. “And it’s an important fish for the guides. If a client caught that fish, they wouldn’t want to bonk it, that’s for sure.

“You can understand the controversy,” he said.

The life history of the trophy trout sealed its fate. Every spring, cutthroat and rainbow trout mingling in the South Fork spawn batches of fry that hybridize. The strain of fish that results — including the one in Kennedy’s hands — is a cross called a “cutbow,” a variation of native and exotic trout that now must go, at least when Idaho Fish and Game fisheries crews get ahold of them.

Last Thursday alone that happened 338 times to cutbows and full-blooded rainbows in a stretch of the South Fork just downstream of where Highway 26 climbs up onto the agricultural plain leading out of Swan Valley. Over the course of this spring perhaps 5,000 rainbows will be immobilized with electricity, netted and hauled away to six put-and-take fishing ponds that dot southeast Idaho. The effort to selectively remove rainbow trout is the next step of a controversial, challenging and likely long-lasting effort to prop up the Yellowstone cutthroat, the South Fork’s native trout that dominated the fishery as recently as the turn of the century.

Rainbow trout electrofishing

Idaho Department of Fish and Game personnel and volunteers scoop up rainbow trout on the South Fork of the Snake River during electrofishing operations Thursday west of Swan Valley, Idaho. The department will be catching and removing rainbow trout from the popular section of the Snake in eastern Idaho until May 23 as part of a feasibility study to see whether reducing the number of rainbow trout using electrofishing can be an effective management technique to improve cutthroat recovery. As of halfway through the electrofishing season, the crews had caught over 3,000 rainbows.

For 15 years South Fork anglers have been able to keep unlimited numbers of rainbows and cutbows. Fisheries biologists have even implanted imperceptible $50 to $1,000 money tags into the snouts of swarms of the exotic trout to incentivize the cull. Nevertheless, the catch-and-release ethic that’s pervaded fly-fishing for decades has held on, and the South Fork’s rainbow population was able to withstand the blow of more fish ending up on anglers’ smokers and grills. When Idaho electrofishing boats set out to gauge populations at a historic monitoring stretch near the Conant Boat Ramp last fall, there were more rainbow trout than ever before: an estimated 3,000 per mile, and at a proportion of more than three rainbows for every two cutthroat sampled.

“Frankly, we failed as outfitters,” said Justin Hays, general manager of the fishing outfit for the Lodge at Palisades Creek. “We were tasked by Idaho Fish and Game with helping remove the hybrids and the rainbows, and our guests didn’t want to kill fish. Our guides are troubled that they’re killing this nonnative species that they make their tips on.

“But at the end of the day,” he said, “we support the movement.”

Exotic fish

Anglers revere rainbow trout because they’re hard-charging and high-flying. Rainbows are adaptable — found in the wild in every U.S. state outside of Florida — and they’re a go-to stocker trout for fishery managers around the country, even being turned loose below Palisades Dam into the South Fork as recently as the 1980s. The species is native to Pacific coastal watersheds, including portions of the Snake River watershed downstream of the natural barrier posed by Shoshone Falls.

Unlike rainbow and brown trout, cutthroat on the broader landscape are reeling, having even been proposed for protective status under the Endangered Species Act in the early 2000s. The subspecies endemic to the Northern Rockies range exists today in only about a third of its historic five-state range. Habitat loss, climate change and introduction of exotic competitors are all factors in the long-term decline. Anglers needn’t drive farther than to the Snake’s equally famous Henrys Fork to see an example of a fishery where cutthroat are gone and their exotic comrades are thriving.

Rainbow trout electrofishing

At left, Patrick Kennedy releases a cutthroat trout that was accidentally scooped up with a group of rainbows while electrofishing on the South Fork of the Snake River in early May. The aim of the project is to reduce the number of rainbow trout — and rainbow/cutthroat hybrid, see at right — in the South Fork in an effort to increase the struggling native cutthroat population.

It was the cutthroat, reputed for indiscriminately eating dry flies off the surface, that made the South Fork into the “Yankee Stadium of fishing,” longtime South Fork angler and News&Guide columnist Paul Bruun said.

“It’s big water, and it’s got the fish per mile, and it’s got multiple species,” Bruun said. “I’ve seen this coming for a while. You see these mob scenes of all these rainbows where you don’t see any cutthroat.”

Bruun for years was an outspoken critic of lethal intervention to help native cutthroat trout at the expense of non-native fish, such as killing lake trout in Yellowstone Lake or remnant rainbow trout populations that still linger today in Flat Creek and the Gros Ventre River. He has since changed his tune, publicizing the about-face in the September 2015 column, “It’s hard to admit my poor trout thinking.” It’s anglers’ continued reluctance to kill, in Bruun’s view, that’s crippling Idaho’s efforts to knock back the South Fork’s rainbows.

“The only problem is the outfitters think that the rainbows are just fine,” he said. “They’re not killing them. It’s a conundrum.”

Even fishing outfitter Hays — who champions the state’s suppression efforts — said he won’t make his employee guides kill rainbows. And so they don’t. Out of the 32 licensed Lodge at Palisades Creek guides whose clients ply the South Fork’s waters all summer, perhaps just eight encourage killing, he said.

“It’s a hard sell, man,” Hays said. “We are a business that provides memories of moments for people. Killing a fish is not the memory that gets those guests to come back to us.”

After South Fork stocking stopped more than three decades ago, native Yellowstone cutthroat trout, for a while, were king. Rainbows for years were all but absent, but via natural reproduction they gradually rose back to prominence. By 2002 there started to be years in which the exotic trout was just as prevalent as the homegrown fish. Non-native brown trout, too, have held on in the South Fork, even increasing in number over the years, though they’re considered less of a threat because they’re fall spawners that don’t taint the genetics of the natives.

Rainbow trout electrofishing

Each rainbow caught while electrofishing is checked for an implanted chip as part of the Idaho Department of Fish and Game’s “angler incentive program,” which encourages fishermen to keep rainbows caught on the South Fork by offering a cash reward in exchange for the head of the fish. Rainbows that beeped positive for the chips were tossed back into the waterway.

Fisheries managers saw trouble brewing a long way out and way back in 2004 changed the fishing regulations to allow anglers to bag an unlimited number of rainbow trout year-round. By 2010 the “angler incentive program” had been conceived. By the thousands, money fish were caught, tagged and turned loose. The program is simple: Anglers can net a cash reward in exchange for the head of a rainbow trout. But the low-odds program appeared to be having an insignificant effect — the return was only 1,500 to 2,000 rainbows a year — and was about to be discontinued, Idaho Fish and Game Regional Fisheries Manager Brett High said.

“There was a horrible chance of winning — half a percent — so we lost a lot of participants,” High said.

Anything helps

Based on the most recent creel survey, just 13 percent of caught and kept rainbows’ decapitated heads were being turned in and scanned. A research project around that time concluded angler harvest was a big factor in holding the rainbow trout population back. Managers changed their minds and kept the incentive program afloat.

The fight to save the South Fork’s cutthroat isn’t limited to killing and relocating competitors. Every major spawning stream that feeds into the river downstream of Palisades for miles is now outfitted with a weir that captures fish migrating upstream. The structures on Pine, Palisades, Rainy and Burns creeks are checked daily during the spring spawning run, and only pure cutthroat are let through. Consequently, the South Fork’s rainbow trout have lost their institutional knowledge of these important upstream spawning grounds on Caribou-Targhee National Forest streams.

“We know that we’re having success there,” Kennedy said. “We think that we’ve eliminated the rainbow trout life histories that used to run into the tributaries, but we still see rainbow trout trying to pioneer that good habitat.”

Idaho Falls-based Trout Unlimited employee Chris Hunt, a rabid native trout proponent who once ran a blog called “Eat More Brook Trout,” underscored the importance of the weirs.

“I’m not a biologist, but I do know that what’s saving the genetic integrity of the South Fork’s cutthroat is the series of weirs along the tributaries,” Hunt said. “That’s the saving grace, right there. I’m pleased that Fish and Game has kept that effort up, despite seemingly losing the battle in the main river.”

South Fork Snake River Trout Population Estimates

Before 2002 the Yellowstone cutthroat trout had a hold on the Snake River’s South Fork, but in intervening years rainbow trout populations have been similar to or higher than those of cutthroat.

The federal agency that makes decisions about water releases at Palisades Dam could also take a big swipe at the South Fork rainbows, which spawn a few weeks earlier than cutthroat. A strategically timed torrent of water from the Bureau of Reclamation could cause ruin to entire age classes of the non-native fish by sweeping their eggs downstream, but the flushing flow tactic probably isn’t on the table.

“The modeling suggests that we need about 25,000 [cubic feet per second] out of the dam,” Kennedy said. “Flood stage is 22,000 cfs. The reality is that it might not be a tool.”

Water managers are helping, however. The Bureau of Reclamation is underwriting Kennedy and his crews’ efforts to selectively catch and haul rainbows to six fishing ponds in Fish and Game’s Upper Snake region. It’s a big task.

Nineteen weekdays this spring state jetboats will be out on stretches of the South Fork dangling electrical anodes into the water.

The goal is to catch and move 3,000 rainbows and cutbows, a threshold that was achieved this week — with nearly half the electrofishing season to go.

The South Fork’s impressive productivity as a below-dam “tail water” fishery is obvious seeing and participating in the selective fishing firsthand. As the jet boats powered past cutbanks and through eddies Thursday, clouds of whitefish, suckers and all three types of trout would go belly up, sporadically twitching this way or that in the current. Quickly they bounced back to life, though at least twice Thursday bald eagles took advantage of the “floating dinner plate,” one fisheries technician joked.

It was equally obvious that rainbow and cutbows were a large part of the fish assemblage. When a boat would hit a rainbow “redd” on suitable cobbles for spawning, oftentimes they’d surface in bunches. The nonnatives netted and let loose in tubs onboard were nice, too: The average rainbow relocated this spring has stretched the tape to 16 inches, and the largest measured a pinch shy of 2 feet, Kennedy said.

A long slog

Even while the catch is outpacing expectations twofold, there’s a good chance that Idaho Fish and Game will need to up the effort to meaningfully affect the population. The numbers are grim. The state agency’s best — though admittedly rough — estimate for the total number of rainbow trout in the South Fork is 90,000 fish.

“We’re trying to remove 3,000, but is that a big deal?” Kennedy said. “It might not be to the population, but it is to the public. We’ve got to ease our way into this.”

Rainbow trout electrofishing

The Idaho Department of Fish and Game hoped to pluck 3,000 rainbow trout from the South Fork, and will likely reach that number this week and exceed their mark by 2,000 to 3,000 fish by the time the operation ends May 23.

The advocacy world largely stands in support. Trout Unlimited’s Hunt said he has “no criticism whatsoever” of the state biologist’s efforts.

“I know a lot of anglers don’t, but I applaud Fish and Game for going after rainbows on the South Fork,” Hunt said. “This is one of the last big water habitats for native Yellowstone cutthroats.”

The Henry’s Fork Foundation is also contributing resources, recently starting up a “South Fork Initiative” to improve the watershed, including its native fishery.

Convincing the angling community — and cultivating a generation of shameless South Fork rainbow killers — is the next challenge.

South Fork Lodge fly shop manager and fishing guide Chris Conant is skeptical of what he sees as an “arbitrary” and poorly communicated effort to treat rainbow trout as a blight. He’d rather see the fishery managed for trophy trout regardless of the species, but if Idaho Fish and Game is going to target rainbows, they ought to really go after them.

“We’re not against the effort on the whole, but at some point it’s got to get to the point where this is going to be effective — or not,” Conant said. “If we can get back to it being just cutthroat in there that would be pretty awesome, but I’m not sure that’s in the realm of possibility.”

Hunt urged the Idaho fisheries managers to keep at it.

“All I can say is I don’t want them to give up,” he said. “Please don’t give up.”

That was Bruun’s take, too.

“I think they’ve got to do something, even though it’s going be very unpopular with a lot of people,” he said. “None of this is ever going to be popular.”

Rainbow trout electrofishing

Kayden Estep, a fisheries technician for the Idaho Department of Fish and Game, releases rainbow trout into the fishing pond south of Victor on Thursday. This impressive specimen is the same one cradled by Patrick Kennedy in the photograph at the top of this story.

Contact Mike Koshmrl at 732-7067 or

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.

(11) comments

rich quinlan

Nope food stands , outfitters lunches , and cotton candy , guides apres fish dinners , would only be for those fish snobs who don't / won/t clean their own fish. the G& F cater to these entitled folks way too much . Wyoming fishing licenses 2 to 1 tourist versus local , its an industry .

Jay Westemeier

I'm not really sure that you understand the subject of the article Mr. Quinlan. G&F is implementing a program that will cut the number of rainbows and other non-native species from streams so that the native cutthroat populations can grow. Why do you think that caters to your so-called fish snobs and guides? Most of the guide services and fisherman they serve are against this program because it reduces their chances of catching greater numbers of trophy size fish. Maybe you just despise all of the non-resident fisherman who actually help strengthen Wyoming's trout fishery. And if you believe that these fisherman practice catch and release because they don't know how to clean a fish or enjoy eating them, you're just plain wrong. Catch and release is a personally chosen practice that helps preserve the fishery.

Kevin Naze

Top photo you described as a rainbow/cutthroat hybrid. Bottom photo, which caption says is the same fish, is described as a rainbow.

Jeff Smith

So, if I understand the article, taxpayer dollars via Idaho state employees, are being used to stock private fishing ponds ?

Mike Koshmrl Staff
Mike Koshmrl

Jeff, the pond near Victor is public, as are the other ponds.

Jeff Smith

Thanks for the info.

rich quinlan

In many states the game and fish folks combined with the fly guys in 500 dollar outfits are ruining fishing. There are so many restrictions on fishing areas and bait/lure types that its gotten to the point of servicing only outfitter and flyguys wishes and they dont even want to eat trout .

Jay Westemeier

Please list the states where fishing has been ruined by these regulations. Not sure why anyone would despise catch and release.

Jeff Smith

Very true Rich. The wealthy elite took over the west long ago. It has become a rich man's playground.
Now via the USFS in AspenHole, they even got special regulations passed to help them bank fish several areas.
There are so many guides and fat cats, they feel there isn't enough water for them all it would seem.

rich quinlan

I believe in as much access as possible for kids and elders , not a support group for the guides and outfitters. Work on having safe access to the fishery and this will take care of volume and folks who actually want to eat a trout can do that.

Jay Westemeier

Easy access to all of Wyoming's trout streams would not be feasible. I'm assuming you mean paved walkways and ramps? Might as well add food stands and cotton candy while you're at it. These things and the influx of rainbows and browns have commercialized a fishery that used to be unique to the rest of the country.

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