Should Yellowstone eradicate trout in Soda Butte Creek in order to restore its native cutthroat population?

Drastic measures may be in store for one of America's greatest trout streams
Soda Butte Creek in Yellowstone National Park.

Soda Butte Creek in Yellowstone National Park is widely regarded as one of the most beautiful trout streams in the entire world. Throughout its reaches, anglers can fish for cutthroat and cutthroat-rainbow hybrid (cuttbow) trout, and its upper reaches holds brook trout that rise eagerly to dry flies. Soda Butte is a healthy, vibrant fishery. But the presence of brook trout, an invasive species, has many worried for the troubled, native Yellowstone cutthroat trout. Pure-strain Yellowstone cutthroat trout are struggling to survive throughout much of the park's range but are thriving in Yellowstone's Lamar River, into which Soda Butte Creek drains. Concern over Soda Butte's brook trout population is so significant, that the park is considering poisoning the upper portion Soda Butte to eradicating all trout in the creek and restocking it with pure-strain Yellowstone cutthroat trout.

The proposed action is part of a planned cooperative effort between the National Park Service and partner agencies Montana Fish, Wildlife & Parks, the Wyoming Game & Fish Department and the U.S. Forest Service. The project would target brook trout and hybridized cutthroat trout, but would also kill any other fish in the project area -- Soda Butte Creek and its tributaries upstream of Icebox Canyon. Overall, 38 miles of stream are targeted. Removal would be accomplished via the application of an EPA-approved piscicide (rotenone), which is a naturally occurring plant compound that degrades quickly and does not persist in the water supply.

According to the project's proponents, removal of all fish in the upper Soda Creek is the most practical course of action given that two decades of mechanical eradication efforts (manual removal of brook trout and other target species via electrofishing) has failed to wipe out brook trout populations.

Montana Fish & Wildlife's environmental assessment of the project states that "Soda Butte Creek presents an opportunity to work towards several goals and meet some objectives. By removing nonnative brook trout from the upper Soda Butte Creek watershed, project partners are working to ensure the long-term, self-sustaining persistence of Yellowstone cutthroat trout within its historic range. Brook trout pose a threat to the Soda Butte Creek population and they are spreading downstream into YNP. Given the ability of brook trout to displace Yellowstone cutthroat trout, they are a risk to not only Soda Butte Creek, but the entire Lamar River watershed. Removing brook trout would contribute to securing Yellowstone cutthroat trout throughout the Lamar River watershed, which is among the conservation objectives in the MOU. Removal of the existing hybridized fish is also consistent with goal of maintaining genetic integrity. Although existing fish are slightly hybridized, they remain a source of nonnative genes to Soda Butte Creek and the Lamar River watershed."

But opponents of the project claim the four-agency partnership proposing the actions is grossly overreacting, citing the impacts that the project will have on angling in Soda Butte -- most notable amongst them the fact that angling opportunities on upper Soda Butte will cease to exist for many years. But objectors also call the project a waste of money, calling Soda Butte's brook trout a non-threat to Yellowstone cutthroat populations elsewhere in the park -- noting the long-time presence of brook trout in the creek's upper reaches, and the continued decline of their population thanks to electrofishing efforts.

Anglers are widely divided on the issue, perhaps due mostly to the health and excellent angling opportunities that currently exist throughout the entire length of the creek. In order to determine whether the project will proceed, Yellowstone National Park and Montana Fish & Wildlife are accepting public comments until June 13th. To make your voice heard, visit


Leave them! I spend a lot of time in the hills. I have worked and grown up in the outfitting business. I have caught those Brookies for a long time. They are, in my opinion, a survivor. And better tasting too. The cost to get rid of them and replace them with cuts is more than this country and state can afford. Many animals use them as a food sorce because they live in high mountain, narrow streams; where cuts would not survive.

The solution to this problem is simple: It requires a 12" sauté pan, clarified butter, a nice Pouilly Fume, and some lemon wedges...

Crystal, you've been catching brookies for a long -time in Soda Butte Creek? Funny, because when I look at the data presented by Montana Fish & Game, they are exceptionally rare. They have been suppressing them since they showed up in the '90s. Can you ID fish?

The current resident Yellowstone cutthroat throat population is 99.5% genetically pure, meaning it's a 'core population'; 'genetically unaltered'. And yet they are willing to kill them - crazy.

The brook trout numbers were at a peak in 2005 with 1, 104 counted via electroshocking. Most recently in 2014 there were only 102 counted and only 7 young-of-year); that's less than 3 brook trout per mile. The electroshocking has proven successful and they should keep doing it. Don't poison Soda Butte Creek and kill it's prized core population of Yellowstone cutthroat trout only to replace them with hatchery raised fish.

I love Soda. Quite a few years ago we fished the upper section near the gate and I did have some action on Brookies. They were beautifully colored and fun. We went back the next year after they started the electro shocking and all of the fish were gone. Such a beautiful river completely decimated. No brookies or cutts. It was sad. I would hate to see that happen to the rest of the creek. If they start catching brookies in Pebble then I would say something should be done. If the anglers start killing brook trout when caught I think we can control this. The mountains around the park are all loaded with brookies. I can't see how killing Soda would be a long term solution.

This spring of 2016, MT FWP stated that their primary source for genetically pure Yellowstone cutthroat trout in this region, Goose Lake (above Cooke City, MT - not to be confused with the Goose Lake chain near the Firehole River, which is now a source for Westslope cutthroat trout) ) was contaminated with rainbow trout. So when streams like Soda Butte Creek are poisoned and the fisheries biologists are relying on sources like Goose Lake for genetically pure Yellowstone cutthroat trout to repopulate the stream - now what? This project on Soda Butte Creek was unnecessary. Phase 2 of electroshocking, salvage, poisoning and restocking is to occur in August of 2016 but there's been no mention of it yet in the local press or from YNP or MT FWP sources.

Well, after the second year of rotenone poisoning and salvaging, about 25% of the wild Yellowstone cutthroat trout population in Soda Butte Creek were salvaged, the rest were lost. To top it off they dumped in 800 hatchery raised fish instead of restocking with wild trout broods. Unnecessary project.

Jim Brandau, you've spent too much time in the spin zone. You need to report the facts as they really are, not as you wish them to be.

Bill O'Reilly, then you show me the "facts". I've followed this project since it's inception and I've been in contact with YNP fisheries biologists. What's your specific problem with my comment? Got different info or numbers? Let's see them.

"Bill O'Reilly", 4 1/2 months later and still no response from you? Keep trolling - maybe you'll catch something. JackAss!

You had action on brookies in Soda Butte Creek? Then I suggest you pick up a fish ID guide, because the density of brook trout has been kept exceptionally low for years because of the massive effort to remove them. If you caught any fish, the probability of them being brookies was probably less than 1%. Soda Butte Creek and the Lamar are exceptional Yellowstone cutthroat trout streams, and the Park is working to allow many generations of your family the opportunity to catch cutthroats.

So here we are August of 2023 and they are going to poison Soda Butte Creek AGAIN with rotenone in mid August. News release just hit 2 days ago. 2015, 2016 and now 2023 rotenone in Soda Butte Creek.