Bonneville Cutthroat Trout Restoration: Temporary Closure of Castle Creek

Contact(s): Michael Golden (435) 865-3700


IRON COUNTY, UT., July 9, 2018 - The Utah Division of Wildlife Resources will conduct a native Bonneville cut-throat trout restoration project using the piscicide rotenone within the Mammoth Creek drainage on the Dixie National Forest, beginning July 31, 2018.

The project is consistent with the conservation strategy for the species, which is designed to prevent the fish from being listed under the Endangered Species Act. The rotenone treatment is aimed to rid all species of fish in targeted streams, ponds, lakes and tributaries in order to restore the native Bonneville cutthroat trout to a por-tion of the Mammoth Creek drainage.

A temporary closure of these areas during the piscicide application will be necessary to allow ground crews to safely work in and around the lakes and streams without harm or injury to the public. All use of the water (wading, fishing, swimming, etc.) within the project area will be prohibited during piscicide application and neutralization.

Mammoth Creek is one of the primary tributaries of the Sevier River. In 2012, genetic testing confirmed that upper Mammoth Creek has a remnant population of native Bonneville cutthroat trout, the only known remnant population in the entire Upper Sevier River drainage. “Finding this native population is significant because de-spite the competition with the non-native fish, the Bonneville cutthroat have continued to survive,” said An-gelita Bulletts, Forest Supervisor.

“Restoring Bonneville cutthroat trout in Mammoth Creek will help to improve the status of the species, the ecol-ogy of the stream and the quality of recreational fishing,” said Mike Golden, Dixie National Forest, Fish Biologist.

The first and second phases of the project occurred in 2015 and 2016 when two of Mammoth Creek’s tributar-ies—Castle Creek and Lowder Creek—were chemically treated to remove non-native brook trout. Groundwater inflows and complex habitat in Castle Valley reduced effectiveness in 2015 so a third treatment of this area is necessary in 2018. The treatment area extends from the headwaters of Castle Creek from Sydney Valley, downstream to the stream’s confluence with Mammoth Creek. Liquid rotenone (product name: Prenfish) will be applied to target waters using drip barrels. The drips will be set during the morning and they’ll run through the afternoon.

Depending on their location, most drips will run for three to eight hours. Applying the rotenone this way will ensure that all of the fresh water sources are simultaneously treated. Charges for drip stations are cal-culated to apply the five percent active ingredient liquid rotenone at a concentration of 1.5 parts per million in the target area.

After the rotenone has been applied, potassium permanganate, an oxidizing agent, will be applied to treated waters below the target area to deactivate the rotenone in those areas.

The active ingredient in liquid rotenone is a powder derived from the roots of South American plant. Rote-none is specifically poisonous to gilled organisms because it interrupts oxygen uptake from the water at the cellular level. After the rotenone has been applied, potassium permanganate, an oxidizing agent, will be ap-plied to treated waters below the target area to neutralize the rotenone in those areas. Although liquid rote-none is relatively benign to humans, fish treated with the chemical have not been cleared by the Food and Drug Administration for human consumption. For that reason, fish that die during the project cannot be sal-vaged.

After successful removal of non-native trout, Bonneville cutthroat trout will be introduced to the stream. Similar restoration projects involving Utah’s native trout are underway throughout the state. The projects are part of conservation strategies designed to prevent the fish from being listed under the Endangered Spe-cies Act.

The 2018 area closure for Castle Creek is Pursuant to Title 36 Code of Federal Regulations 261.50 (a) and (b), the following areas will be closed during the treatments for protection of public health and safety:
Within 100 feet of Castle Creek and its tributaries from the confluence of Castle Creek with Mammoth Creek upstream through all Castle Creek drainage headwaters and the Deer Creek ditch conveyance (T36S, R8W, Sections 5, 6, 7, 8, 14, 15, 16, 17, 21 22, 23, 26 and 27, Salt Lake City Baseline and Meridian).

The temporary closure order is anticipated to be cancelled August 2, 2018 for the Castle Creek project area.

For additional information on the Bonneville cutthroat trout restoration project contact Michael Hadley, Southern Region Aquatics Biologist, Utah Division of Wildlife Resources at (435) 691-2204 or Mike Golden, Dixie National Forest Fish Biologist at (435) 865-3700.

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https://www.fs.usda.gov/detail/dixie/news-events/?cid=FSEPRD586427