A proposal to kill trout in South Fork Sixteenmile Creek in order to reintroduce native westslope cutthroat trout has been modified.
The South Fork is located east of Maudlow on the east face of the Bridger Mountains.
In a decision notice published on May 2, Fish Wildlife and Parks Region 3 supervisor Pat Flowers said instead that the agency will selectively remove rainbow trout and significantly hybridized fish and allow slightly hybridized fish to re-colonize the stream above a constructed fish passage barrier.
“Although FWP is confident that an introduced population could be successful after removal of the existing population and that FWP’s preference under the initial proposal was to create a pure WCT population, FWP concedes that it is worth the additional time and expense in attempting to conserve and enhance the existing hybridized population,” the agency wrote in its decision notice.
The project has an estimated price tag of $181,962 for construction of the fish passage barrier. The labor, materials and mileage costs were estimated at an additional $10,337 to implement the initially proposed action over five years. Trying to preserve the hybridized trout will cost an estimated $17,663. But if the revised work doesn’t produce the desired results, the initial expenses will also be incurred, resulting in a total cost of about $28,000.
The work will be evaluated over the next three to six years. If the evaluation determines that selective removal is not effective, complete removal and re-introduction will be implemented.
FWP has partnered with the Gallatin National Forest on the project. Twelve comments on the draft environmental assessment were received. The change from the original proposal was based on concerns expressed by some downstream landowners.
Westslope cutthroats only occupy about 400 to 450 stream miles in the Upper Missouri River Basin — around 5 percent of their historic habitat. The Sixteen Mile project will increase that number by about 6 miles.