Bonneville cutthroat trout restoration project, Great Basin National Park

Baker, Gretchen; Darby, Neal; Williams, Tod; Wullschleger, John

The Bonneville cutthroat trout (Onchorynchus clarkii utah; BCT) is the only salmonid native to east-central Nevada and to Great Basin National Park (the Park). It is identified as a priority species in the Park’s 1991 General Management Plan. At the time of the Plan’s completion, BCT populations throughout the area had been reduced by nearly 95% due to the introduction of nonnative fishes and habitat alterations. Timely actions by the Park and cooperating agencies have reduced the threat of extinction by restoring the species to four of six historically occupied watersheds within the Park. BCT reintroductions have taken place in Strawberry Creek, South Fork Big Wash, Upper Snake Creek, and South Fork Baker Creek. In addition, a population initially identified as hybridized in Mill Creek was shown by geneticists to be pure Bonneville cutthroat trout. Populations in Pine and Ridge Creeks on the west side of the Park were also identified as pure BCT. Currently, there are seven populations of BCT in 25 km (15 mi) of streams in and near the Park. The Park has instituted a BCT monitoring program that is helping to track the speed with which reintroduced fish populations become viable. Within the next five years, reestablished BCT populations are expected to expand and occupy 31 km (19 mi), or 52%, of their historic stream habitat within the Park. The BCT reintroduction project has also enabled the Park to obtain data on how other components of the aquatic ecosystem respond to different restoration techniques. In particular, it has added to the body of evidence that the piscicide antimycin is less detrimental to aquatic insects than rotenone. These results may help others planning similar projects. The Park’s work in BCT reintroduction was a major factor in the US Fish & Wildlife Service’s decision not to list the species as threatened under the Endangered Species Act (ESA). This was a significant, proactive move by the Service that has eased any ESA regulatory burden on private landowners within the range of BCT in Nevada. As a result of this reintroduction project, the Park has strengthened its relationship with interagency partners and has become a leader in reestablishing BCT in Nevada. Specific accomplishments included: Four populations of Bonneville trout were reestablished in Park stream reaches with a total length of 13.1 km (8.1 miles); two additional populations present in streams in and adjacent to the Park at the time the project began were determined to be genetically pure. Reintroductions appear to have been successful, with all reintroduced populations showing recruitment and expansion of territory. All populations were verified as genetically pure BCT. Three fish removal methods were compared, including cost, effectiveness and impacts. Data on recovery of aquatic macroinvertebrates following treatment with two different piscicides was collected and analyzed; results suggest difference in recovery rates under ideal and less than ideal conditions. A detailed inventory of the macroinvertebrates and mollusks in the project streams was completed. Valuable water chemistry data for five streams and one lake were collected and entered into the Environmental Protection Agency’s STORET (Storage and Retrieval) water quality database. Together with other agencies, the Park produced the brochure, Snake Range Recreational Fisheries, which informs anglers about the BCT restorations, aquatic ecosystems, potential diseases, and fishing license information, along with a full-color map.

Bonneville cutthroat trout restoration project, Great Basin National Park

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