Westslope Cutthroat Trout
Historically the most abundant and widely distributed subspecies of cutthroat trout throughout the West, the westslope cutthroat trout (Onchorhynchus clarkii lewisi) occupies less than 5% of its former range in the upper Missouri River drainage. It evolved from a common ancestor of the Yellowstone form of the species, and shares their food and habitat requirements. By the 1930s, westslope cutthroat trout were nearly eliminated from park streams because of the stocking of competing trout (nonnative brook and brown trout) and interbreeding with nonnative rainbow trout and native Yellowstone cutthroat trout species. In most of its remaining habitat (an estimated 64% of the approximately 641 stream miles it once occupied in the park), it exists only in a hybridized form.
Integral to our native species restoration program is having brood sources from which to reestablish native populations. A brood should be accessible, secure from contamination, self-sustaining, genetically diverse, abundant, of traceable origin, and pose no risk to existing wild populations.
Genetically pure westslope cutthroat trout have only persisted in one tributary of the Madison River drainage (now called Last Chance Creek), and in the Oxbow/Geode Creek complex where they were introduced in the 1920s. In 2006, Yellowstone began efforts to restore westslope cutthroat trout in East Fork Specimen Creek and High Lake by constructing a fish barrier, removing hybridized and nonnative fish, and stocking genetically pure westslope cutthroat trout. Stocking was completed in High Lake in 2009, and in East Fork Specimen Creek in 2013. In 2015, several surveys conducted throughout East Fork Specimen Creek indicated a natural reproducing population of westslope cutthroat trout, with all fish appearing healthy. The long-term goal for this watershed is to integrate East Fork Specimen Creek into a larger westslope cutthroat trout restoration project that includes the North Fork to improve the resilience of this isolated population to natural threats.
Another restoration project is being conducted in Goose Lake and two other small, historically fishless lakes in the Firehole drainage. Nonnative fish removal was conducted in 2011 and staff stocked fry from 2013 to 2015. In 2016 an overnight population survey yielded 12 fish around 7 inches long. The long-term project goal is to one day use this pure westslope population as a brood source, providing offspring for restoration projects elsewhere within the upper Missouri River system.
The largest westslope cutthroat trout restoration effort in Yellowstone is the Grayling Creek project (See: Arctic grayling), which will restore westslope cutthroat trout to over 20 miles of native habitat. Future projects for westslope cutthroat trout and fluvial grayling include native fish restoration in North Fork Specimen and Cougar creeks as well as the upper Gibbon River. Once these projects are completed, an additional 61 kilometers (38 miles) of stream will be restored to native fish.
Mottled sculpin live in shallow, cold water throughout Yellowstone except the Yellowstone River above Lower Falls and in Yellowstone Lake.
Yellowstone’s minnows are small fish living in a variety of habitats and eating a variety of foods.
Suckers are bottom-dwelling fish that use ridges on their jaws to scrape flora and fauna from rocks.
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