Electrofishing

After enjoying a successful commercial fishing trip on the upper section of the South Fork of the Snake River, Amaan Husain, of Denver, considers the message put out by opponents to the shocking program being conducted by the Idaho Department of Fish and Game. The agency’s goal is to remove over 12,000 rainbow and rainbow hybrids in an attempt to promote the native cutthroat trout population.

As anglers take to the water this year, they will again share the South Fork of the Snake River with Idaho Department of Fish and Game crews electroshocking fish in an effort to boost native cutthroat trout numbers.

Fish and Game began removing non-native rainbow and rainbow/cutthroat hybrids called “cutbows” in the spring of 2018 as part of a new management strategy based, in part, on 2017 angler surveys. According to Fish and Game Regional Fisheries Biologist Patrick Kennedy, the state surveys anglers every five years to determine what management strategies the public wants to see. And protecting native cutthroat topped the list.

In the early 2000s the department documented declining cutthroat numbers, while rainbow and cutbow populations showed steady growth. The agency changed rules on the South Fork to try to motivate anglers to harvest the non-native species, opening the river to a year-round season and offering anglers no limit on the non-natives.

The agency even launched an incentive program, offering a bounty on harvested fish worth anywhere from $50 to $1,000. Nonetheless, the non-native populations grew, and Fish and Game began removing non-native trout from the South Fork by the thousands through an electroshocking program funded by the Bureau of Reclamation, Kennedy said.

The state of Idaho owns water regulated at Palisades Dam, which is the beginning of the South Fork. The Bureau of Reclamation, a federal agency, authorizes flows out of Palisades Dam after receiving recommendations from a state advisory committee.

Additionally, the state owns the fish in the river, and Fish and Game manages those fish for the public, guided by the carefully crafted surveys conducted every five years. Still, some anglers question that approach, suggesting that catch-and-release practices show support for keeping as many big fish in the South Fork as possible, regardless of species.

“We use a rigorous scientific approach, carefully designed angler opinion surveys, to manage bias,” Kennedy said. “You could argue that catch-and-release is a vote against harvest, but there is no control for bias there.”

Kennedy and his crew removed 6,000 non-natives in 2019 before COVID-19 shut down the program in 2020 because adequate social distancing could not be achieved on boats used in the electroshocking program. Cranking up again in 2021, close to 10,500 non-natives were electroshocked and removed, while anglers harvested another 2,279 fish, Kennedy said.

“This year our goal is to remove 11,700 fish, but we will continue to need angler harvest,” he said.

Kennedy said electroshocking on the South Fork could continue for another three to five years, but ultimately it may prove to be a nonviable tool for such a large body of water. The goal is to get rainbow populations around the Conant river access down to 10%.

Prior to electroshocking the South Fork, Kennedy and Idaho Fish and Game Fisheries Manager Brett High electroshocked Palisades Creek, an important spawning tributary to the South Fork. From 2011 to 2015, crews electroshocked fish along the entire creek through a program funded by the Bonneville Power Administration.

“We removed rainbows and returned Palisades Creek to a conservation population of native cutthroat,” Kennedy said. “We’re very proud of that, and the success there led to the idea of shocking the South Fork, even though it is a considerably larger body of water.”

Different fork, different fate

You need only look north in order to better understand the motivation for native cutthroat conservation efforts on the South Fork.

The Henrys Fork, which joins the South Fork near Idaho Falls to form the Snake River, is arguably one of the most famous trout fisheries in the country and perhaps the world. Before the more recent fame of the South Fork, the Henrys Fork was one of the most popular destinations for anglers looking for healthy trout populations. But in a river that is connected to the South Fork, there haven’t been any cutthroat trout since 1930, according to Rob Van Kirk, senior scientist for the Henry’s Fork Foundation.

“We can find records of rainbow trout stocking as early as the 1870s,” Van Kirk said. “Rainbows will invade anything and everything. By the time anyone ever thought about native fish conservation on the Henrys Fork, things were too far gone.”

Prior to the introduction of non-native trout such as rainbows, brook trout and brown trout, Van Kirk said, cutthroat were the only trout in the Upper Snake Basin for about a million years. Roughly 15,000 to 17,000 years ago, the Bonneville Flood created Shoshone Falls, the natural barrier located near Twin Falls, Idaho, that isolated cutthroat trout from the rest of the lower Snake River that flows west, into the Columbia River and ultimately the Pacific Ocean.

So for at least 15,000 years, cutthroat were the only species of trout above Shoshone Falls. Within that population, there were different varieties of cutthroat, some with fine spots and some with large spots, but Van Kirk said they were all genetically pure. When the Palisades Dam was completed in 1957, fine spotted cutthroat were largely isolated above the Palisades Reservoir and the large spotted variety were concentrated in the South Fork, but Van Kirk said they are all part of the same native family.

While populations of cutthroat remained on the South Fork and above Palisades Reservoir, there are essentially no remaining cutthroat in the Henrys Fork. As early as 1958 and as recently as 1992, a nonselective piscicide called rotenone was used in the Henry’s Fork watershed to kill fish, according to Van Kirk, but application of the piscicide targeted non-game fish. Rainbows were then restocked, further diluting any remaining genetics of native cutthroat.

“Conservation is happening on the South Fork and the Teton River because cutthroat still exist there,” he said. “You should preserve what you’ve still got.”

Rainbow spike on the South Fork

Considering the fate of native fish in the Henrys Fork, how did populations of cutthroat remain in the South Fork and above Palisades Reservoir, and why did the numbers of non-natives spike?

Working with scientists such as Van Kirk, Idaho Fish and Game adopted a three-prong approach in the early 2000s to try to turn the tide on increasing rainbow numbers. Initially, those efforts actually aided the non-natives.

The first prong included the freshet or a period of high water typically associated with spring thaw. While cutthroat spawn in tributaries after the freshet, rainbows typically spawn in the main stem of the river. Innovative at the time, it was thought that a rush of high water released from Palisades Dam in the spring could displace rainbow eggs from their spawning beds located in shallow gravel. And while this method would work above flood stage of 25,000 cubic feet per second, such high flow was not a viable option. Increasing the flow in the South Fork below 25,000 cfs actually promoted rainbow numbers, according to Van Kirk, as the higher water covered more shallow gravel, establishing more places to spawn.

After understanding that the freshet was not a viable tool to suppress rainbows, the next prong was weirs or fish traps in the tributaries where cutthroat reproduce. These weirs trap all fish headed upstream, and Fish and Game then removes the non-natives. Weirs are succeeding at keeping cutthroat in the South Fork, Van Kirk said.

“But in dry years juvenile cutthroat head back into the mainstem of the river when they are still much smaller than the rainbows that hatched several weeks or months earlier,” he said. “In wet years those juvenile cutthroat are able to hold over in the tributaries and enter the mainstem as much larger fish.”

The third prong in dealing with the spike in rainbows was supposed to be angler harvest. When the South Fork was opened up to a year-round season with zero limit on rainbows — along with an incentive program with up to $10,000 in prize money — Fish and Game expected anglers to catch more fish. Instead, angler harvest diminished.

“It became obvious that it (angler harvest) wasn’t enough to keep up with the abundance of rainbows,” Kennedy said. “We knew we could not shock a big river like we had done on Palisades Creek and get the number needed to make a difference to the population unless we could increase our electrofishing catch rates.”

Fisheries Manager Brett High had the idea to shock in the spring, when electrofishing catch rates are at their highest as rainbows move into shallow water to dig redds, or spawning beds.

“The question was whether one electofishing pass over the redds would deplete the number of rainbows and result in lower catch on successive passes,” Kennedy said. “What we found was when we’d come back a week later was there were enough rainbows in the river that there would be a new group of rainbows on the redds, and catch rates stayed high, suggesting shocking in the spring may provide enough catch to put a dent in the population, even on a big river.”

What’s at stake?

Data collected by the Henry’s Fork Foundation between 2016 and 2018 suggested that the Henrys Fork brought in roughly $41 million overall annually from anglers within a six-county area. The data also identified 317 jobs associated with angling opportunities on the Henrys Fork.

With a much greater volume of water and substantially more commercial permits available on the South Fork, the millions in revenue and number of jobs at stake should cutthroat be listed as threatened under the Endangered Species Act could be significant.

“It’s not likely, but there’s always the possibility that if numbers got too low a listing would be successful,” Van Kirk said.

More than just an idle threat, Van Kirk pointed to the current listing in the lower Snake River of salmon and steelhead.

“That listing doesn’t have much of an effect in high water years, but in a low water year like we’re looking at this year, we might have to send as much as 200,000 acre-feet of water down stream,” Van Kirk said. “For much of our system, that’s the difference between a little water and no water, and 90% of maintaining a fishery is about water management.”

Outfitters’ and guides’ take

Fishing lends itself to social distancing. As such, local outfitters’ bookings have blown up during the pandemic, with many having spots only on a waiting list for most of the high season in summer. And some seasoned fishing guides object to removing thousands of trophy trout from the South Fork.

Far and away the most outspoken guide against the shocking and removal of rainbows and cutbows from the program’s inception is 33-year guide Ed Emory, who has started a nonprofit and GoFundMe.com page in an effort to stop the electroshocking.

Emory is the founder and president of the South Fork Legacy, an organization he said was created to protect all wild fish, including cutthroat, browns, cutbows and rainbows, on the South Fork. So far he has raised $25,000.

“There is a lot of opposition to the shocking program,” Emory said. “The vote of public opinion is deafening, with less than one quarter of one percent of anglers taking fish out of the river through the incentive program. We don’t even have a pure cutthroat to save in the first place in the main stem of the South Fork.

“Like the difference between rainbow trout and steelhead, which are genetically identical but behaviorally different, the cutthroat above Palisades are significantly different than those in the South Fork.”

But veteran fishing guide Kasey Collins contends that understanding the rainbow eradication program depends on looking at the bigger picture.

“A big part of what makes the South Fork special, its identity, is forever tied to the native cutthroat trout population,” Collins said. “You can travel anywhere in the Rocky Mountain West and fish for rainbows; they are everywhere. Look no farther than the Henrys Fork for a great trophy rainbow trout river.”

Cutthroats, in contrast, are more rare.

“You need to dig to find rivers with strong cutthroat populations,” Collins said. “The South Fork in the early ’90s, before the flood of ’97, was the most robust and healthy cutthroat stream in the West. If not for the efforts of conservationists and IDFG, cutthroat trout would be rare in the South Fork today.

“These aggressive shocking tactics are a result of the widespread belief that efforts to date have not been successful enough, and the battle to protect native cutthroat is being lost. It’s a desperate attempt by biologists and IDFG to stop a non-native species from stealing the soul of our mighty South Fork.”

Kennedy encourages any angler to reach out in person, at the boat ramps, or by calling Fish and Game at 208-525-7290 to find out when and where shocking is planned before heading out to wet a line.

You can contact Hope Strong via editor@jhnewsandguide.com.

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