MT, USA — For some, fish may not rank high on the list of important casualties in a wildfire.
But the thought of losing a robust group of Yellowstone cutthroat trout south of Big Timber troubled Jim Olsen.
Those cutthroat are among “our best,” said Olsen, a fisheries biologist for the Montana Department of Fish, Wildlife and Parks.
For weeks, he and other Montana fish biologists have been trying to save a population of cutthroat trout threatened by the aftermath of this year’s gigantic Derby Mountain fire.
In the Deer Creek drainage, wildlife officials fear that erosion could send tons of debris into the waterways and kill thousands of the cutthroats, already a species struggling in the northern Rocky Mountains.
That might not have been a big deal, but these particular Yellowstone cutthroats are some of the heartiest in the area, partly because they’ve shown they’re able to live alongside brown trout, which tend to out-compete cutthroats on their own turf.
So, as the Derby Mountain fire still smoldered, state and U.S. Forest Service officials hatched a plan to get some of the fish out, take them to another creek not damaged by the fire and return them to Deer Creek once the threat of erosion had eased.
There was some talk of simply shoring up the slopes around Lower Deer Creek, but the burned area was too large.
“Moving some of the fish was really the only cost-effective way to protect that population,” said Bill Avey, Big Timber district ranger for the Gallatin National Forest.
The move is an “extreme measure” but necessary for the cutthroats in Lower Deer Creek, which make up the bulk of the only population along the middle Yellowstone River, said Scott Barndt, acting deputy ranger in the Big Timber district.
Wildfire is a natural part of that ecosystem – it helps rejuvenate the landscape and even provide long-term benefits for fish – but the Yellowstone cutthroat trout there are isolated from their relatives and might not be able to cope with large-scale loss of habitat, even if it’s temporary.
“Our first preference is always to leave them where they’re at, because they’re there for a reason,” Barndt said. “But we couldn’t take a chance and not do something.”
Over the years, state and federal agencies have spent about $100,000 to preserve the cutthroats in Lower Deer Creek and the genetics that have allowed them to live with brown trout for 50 years.
After the fire, fish managers were faced with finding a way to protect that population, along with others in Upper Deer Creek and Placer Gulch.
They settled on a number of approaches, including dumping hay in Placer Gulch to protect the few hundred or so cutthroats there.
“We’re trying to spread the risk around,” Barndt said.
The emergency transplantation project from one stream to another is apparently the first of its kind in Montana. The technique has proved successful in Utah.
“We had to try,” Olsen said. “Hopefully it works.”
They hustled to put the plan in writing and get it approved because as fall and winter approached, the odds of heavy rains and sloughing hillside debris at Deer Creek – 19 tons an acre in a worst-case scenario – only increased.
“We didn’t have much of a window to do it,” Olsen said.
Early last week, Olsen and his crew spent several days along Lower Deer Creek removing more than 300 Yellowstone cutthroats with the help of a device that sends a brief electrical pulse through the water, stunning the fish long enough to scoop them up.
The initial plan was to put the young fish into coolers and fly them out by helicopter. When the weather turned bad, they were forced to drive the fish out on ATVs and a specially adapted pickup truck with a fish tank in the back.
The rugged slopes along the creek were blanketed with ash, burned timber and wide swaths of black. The fire, which torched more than 207,000 acres, was the largest in Montana this summer and among the largest in the nation.
“Some places were just fine and other places were just toast,” said Ben Bailey, an FWP fisheries technician working on the project.
On Thursday, the crew drove the fish to Thiel Creek on Alvin Ellis’ property just southeast of Luther.
The creek, about 30 miles from Lower Deer Creek, was one of four chosen by FWP as a possible destination for the cutthroats. They made the list mostly because of the quality of its water and habitat, access for crews doing the transplants and cooperation from private landowners.
The crew spent the morning scooping the fish out of coolers – most of them are young and just a few inches long – and releasing them into the creek.
A week before, Olsen and Bailey, with the help from some Joliet students, walked nearly two miles of Thiel Creek, using the electro-shocker to remove about 3,000 brook trout and transport them down the creek, a move meant to reduce competition for the arriving cutthroats.
A beaver dam will temporarily help keep the brook trout from swimming back upstream and mixing with the cutthroats. Next spring, a barrier is to be built to keep the fish separated.
The crew had hoped to move about 1,000 fish to four nearby creeks, but the few hundred they caught last week may have to do.
It could take up to five years for the slopes in the Deer Creek drainage to stabilize so the cutthroat – or more likely, their offspring – can return.
Until then, the fisheries crew is hoping the trout’s new home in the shallow twists and turns of Thiel Creek is hospitable and will allow their survival.
As the morning’s work wound down on Thursday, Olsen and Bailey paused on a wooden bridge to watch a few of the young fish skitter along the creek bottom.