Westslope Cutthroat Trout Expansion and Genetic Rescue in South Fork Willow Creek (Smith River drainage) Draft Environmental Assessment Checklist FWP-CEA-FSH-R4-25-011

Montana Fish, Wildlife & Parks (FWP) is proposing to expand the nonhybridized westslope cutthroat trout (WCT) Oncorhynchus lewisi population in South Fork Willow Creek (Smith River drainage) into its fishless headwaters above a bedrock barrier that currently limits upstream fish movement in the drainage. The section of South Fork Willow Creek where WCT will be introduced is entirely within the Helena-Lewis and Clark National Forest, Belt Creek-White Sulphur Springs Ranger District. Presently, the nonhybridized population of WCT in South Fork Willow Creek is isolated to a 0.25-mile reach of stream between two bedrock barriers. While small, isolated populations may be safer from hybridization and competition with nonnative fishes, they are at increased risk of extinction from catastrophic events (e.g. fire, drought) and may eventually suffer negative consequences of inbreeding (Wang et al. 2002). The most recent genetic analysis of this population indicates genetic variation is very low compared to other WCT populations in the Missouri River drainage and is a clear candidate for assisted translocation focused on providing gene flow. FWP is proposing translocation of a small number (5-10 adults) of individuals from a nearby population of nonhybridized Smith River WCT to alleviate genetic load and increase fitness and persistence probability of the South Fork Willow Creek population (Kovach et al. 2022). There is an estimated 4.6 miles of suitable habitat that is presently fishless above the upper bedrock barrier. Expansion and translocation of nonhybridized WCT into the fishless headwaters of upper South Fork Willow Creek would likely secure this population resulting in 4.8 miles of protected WCT habitat and a population of over 2,500 individuals.

 

Related Document: Westslope Cutthroat Trout Expansion and Genetic Rescue in South Fork Willow Creek (Smith River drainage) Draft Environmental Assessment Checklist FWP-CEA-FSH-R4-25-011 (pdf)

Deadline: Comments must be received by 03/15/2025 at 5:00pm 

Email comments to:  alex.poole@mt.gov

Mail comments to: Montana Fish, Wildlife & Parks

            Alex Poole

FWP Region 4

            4600 Giant Springs Road

            Great Falls, MT 59405