Concerned that 10 years of work to remove brook trout from Soda Butte Creek has been ineffective, Montana Fish, Wildlife and Parks officials are considering poisoning about 12 miles of the stream just outside Yellowstone National Park to kill the nonnatives.
“Brook trout are spreading farther and farther into the park,” said Ken Frazer, fisheries manager for FWP in Billings. “We can’t keep doing what we’ve been doing. It’s a losing battle.”
A meeting was held in the small town of Silver Gate, near the park’s Northeast Entrance, recently to discuss the idea with locals. About 40 people attended and supported the agency, Frazer said. The next step is to formalize the idea by writing an environmental assessment and releasing it for public comment, possibly next year.
Soda Butte Creek bubbles to the surface just below Colter Pass, about 2 miles east of Cooke City in the Beartooth Mountains. A small tributary to the creek was a stronghold for brook trout, but had been blocked from the lower portion of the creek and Yellowstone National Park by a barrier erected to keep old mine tailings away from the creek at the McLaren Mill site.
It wasn’t until 2003 that brook trout were first found in lower Soda Butte Creek. That’s when FWP traced the source back to the small tributary. In 2004 and 2005, FWP treated the tributary with a fish poison to remove the brookies and then restocked the stream with native Yellowstone cutthroat trout.
“The tributary is only a foot wide or less, and now its chock full of cutthroat,” Frazer said.
But prior to the poisoning, enough brook trout escaped and infiltrated the rest of Soda Butte Creek to cause problems. FWP, the Gallatin National Forest and Yellowstone park fisheries staffs have been working cooperatively to electro-fish the creek every fall for about the past decade in an attempt to remove brook trout, but the fish keep hanging on despite the agencies’ best efforts.
“If you look at where there’s been success removing brook trout with mechanical means, it’s in smaller streams with less woody debris,” said Scott Barndt, watershed program manager for the Gallatin National Forest. “So we were initially skeptical it would work but thought we should try.”
The electro-fishing effort seemed to be exceeding expectations initially, but as Barndt pointed out, missing only a few brook trout meant that they would never be eradicated from the stream. As the fish swam downstream into even more difficult habitat from which to remove them, the threat to the Lamar River, which Soda Butte flows into, increased.
“Our goal is to maximize the chance of success but minimize the amount of cost and impacts on the public and user groups,” Barndt said.
“At the end of 10 years, we had to re-examine if this is sustainable for the long-term with this amount of effort.”
The electro-fishing also revealed rainbow trout above what was believed to be a natural fish barrier on Soda Butte Creek, a waterfall in Icebox Canyon near Silver Gate. Rainbows will interbreed with cutthroat trout.
To help stall upstream movement of nonnatives like rainbow trout, Yellowstone National Park’s fisheries staff installed a barrier in Icebox Canyon last fall.
“During drought years it appears some fish did get over it,” Barndt said. “Rainbows are the track and field stars of the salmonid family. If any fish can do it, rainbows will.”
All of the work on Soda Butte Creek ties in to an overarching plan to try and restore Yellowstone cutthroat trout habitat in the upper reaches of the Yellowstone River — once a stronghold for the fish. During the past few years, park staff has redoubled its efforts to protect existing cutthroat trout and remove nonnatives.
“These actions on Soda Butte Creek are just part of an overall strategy to conserve the cutthroat trout of the Lamar River watershed,” wrote Todd Koel, director of Yellowstone’s native fish conservation program, in an email.
Koel said he will give a presentation about the work at the Yellowstone Science Conference in Mammoth Hot Springs, Wyo., on Oct. 8.