Wyoming G&F fights for the cutthroats

POWELL — Standing near the North Fork of Soldier Creek on Aug. 10, Mark Smith, Cody region fisheries biologist for the Wyoming Game and Fish Department, said native cutthroat trout once occupied more than 500 miles of streams in these parts.

Then, in the late 1800s, brook trout from the eastern United States were introduced in the Bighorns by the department and fishing clubs, Smith said.
“They were stocked pretty liberally,” he said.
Now, the cutthroat is fragmented to 10 percent of its historic waters. Brook trout are out-competing cutthroats, and a single fire could wipe out the entire cutthroat population if blazing trees in the dense timber superheated the creeks. Killing some brook trout on the west slope of the Bighorn Mountains is necessary to improve the Yellowstone cutthroat population.
In 2008-09, brook trout were removed from Buckskin Ed Creek. Two weeks ago, cutthroats from lower Soldier Creek were deposited in Buckskin.
Thanks to a series of natural barriers, the cutthroats will remain in the creek, Smith said.
The relocated cutthroat population is expected to expand, affording fishing opportunities in the future. Smith said the department is not acting out a vendetta upon brook trout; it simply wishes to encourage healthy populations of cutthroats in select locations in the Bighorns.
Smith broke out a topographical map. Blue lines tracing drainages indicate the areas where brookies must be removed. Lines delineating elevation changes are a hair apart and the blue lines, long. Cleaning out brookies by hand would be physically impossible, so Smith oversees an operation to squirt small doses of Rotenone into North Fork of Soldier Creek at drip stations.
At a Rotenone site, the stuff is diluted with water in a 5-gallon jug. The tap dribbles the white liquid like milk squeezed from a cow’s udder. Below, the chemical foam big bubbles like dish detergent in a sink. A Rotenone sand mix in pillowcases was anchored in small seeps where the chemical did not mix well. Rotenone will naturally detoxify itself within two hours, but detoxification stations also were employed, Smith said.
The detoxification stations use potassium magnate to neutralize Rotenone. Potassium magnate is like powdered sugar, so it is placed in pillow cases to leach out of the cloth’s pores, Smith said.
The small doses of Rotenone are toxic only to animals with gills. It would be fatal to amphibians such as frogs or newts, but there are no such critters in this stretch of the Bighorns.
Rotenone is not toxic to humans or other mammals in the quantities the department is using, Smith said.
In the tropics, Rotenone roots are harvested to dispatch fish for human consumption, Smith said.
I don’t think you could synthesize a better chemical for killing fish,” he said.
Thanks to the barriers, once the brook trout are killed, they will be unable to re-colonize the stream unless they are stocked illegally, Smith said.
In a meadow of tall grass and petite flowers of blue and yellow, the North Fork of Soldier Creek sparkles and gurgles as though delighted to be sharing the sunshine with the people clustered around it. A net is stretched across the creek to capture any dead brookies, and a bag of potassium magnate hangs just downstream of the net. Like grape Kool-Aid whisked to a foamy froth, the potassium magnate blends with the water and tumbles over rocks down the narrow stream.
After a short hike upstream, Smith stops by a clear pool where the Rotenone has done its job. Like lost bass lures, several dead brookies float on the bottom of a pool. Another in its death throes, makes a half-hearted flop as though striking a fly on the surface before washing down the stream. Dead fish that aren’t caught in nets decay rapidly, and some are scavenged by predators.
“In three days you’ll be lucky to find any,” Smith said.
Not surprisingly, Smith is an avid angler. Normally, it’s his objective to ensure the proliferation of fish, not their demise.
“So,” Smith said watching the brookies flounder, “it’s kind of weird to be happy to see them go.”
But there will still be plenty of brookies around to catch, Smith said. “We don’t have any intention of removing brook trout everywhere, so there are always going to be those (angling) opportunities.”
For example, brookies will remain in the Middle Fork of Paintrock Creek, he said. Brookies tend to over-populate, and many brook trout in the Big Horns are stunted as a result. Cutthroats don’t overpopulate, so they grow larger, Smith said. Below an inactive talus slope, huge granite boulders seem to sprout from the soil. Nearly hidden beneath the stones are narrow channels. Trout sensing the Rotenone evade the chemical and hole up in small seeps, Smith said.
At a location like Soldier Creek, with rivulets everywhere, treatment is complex. It will require at least two treatments one per year but more likely three, Smith said. If the department finds baby brookies next summer, it means spawning brook trout survived, so another treatment will be required.
It will likely be summer 2012 before cutthroats are returned to Soldier Creek, Smith said. The setting is a narrow stream surrounded by timber; a sort of meadow oasis in the forest where and animal can drink or a stealthy angler could stalk an unwary trout.
It’s a lovely spot where a fisherman could admire nature while enjoying the fruits of the department’s labor to right a wrong.
“This is native cutthroat country,” Smith said.
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