Thursday, 29 September 2011 08:58
Rotenone treatment paves the way for native cutthroat restoration.
One of Utah's native fish, the Bonneville cutthroat trout, will soon be expanded throughout the Pole Creek drainage. Pole Creek is one of the primary tributaries of Clear Creek and is located on the south end of the Pavant Range in Sevier County. The stream originates near the Sevier-Millard county line and flows south for approximately seven miles to where it meets Clear Creek. The entire length of Pole Creek lies within the boundaries of the Fishlake National Forest, while some portions of its tributaries — Skunk Creek, Grass Creek, and Three Creeks — flow across private lands. Currently, a small remnant population of Bonneville cutthroat trout occur in the headwaters of Pole Creek, upstream of a natural fish migration barrier.
The drainage above the Pole-Clear Creek confluence will be chemically treated with rotenone on October 12, 2011, in order to remove non-native fish. This area includes: approximately seven miles of Pole Creek, beginning 0.9 miles upstream of its confluence with Skunk Creek and extending to the confluence with Clear Creek; Skunk Creek from its confluence with Pole Creek upstream approximately 0.8 miles; Grass Creek from its confluence with Pole Creek upstream approximately 0.5 miles; and Three Creeks from its confluence with Pole Creek upstream to Three Creeks Reservoir, approximately 3.4 miles. In order to ensure that non-native fish are completely removed from target waters, a second rotenone treatment is planned for fall 2012.
General plans to conduct native trout restoration projects were formalized in the Conservation Agreement and Strategy for Bonneville Cutthroat Trout (Oncorhynchus clarki utah) in the state of Utah. Specific details of the Pole Creek project were outlined in the Final Environmental Assessment and Finding of No Significant Impact for Native Trout Restoration and Enhancement Projects in Southwestern Utah.
Liquid rotenone, Prentox Prenfish toxicant, will be applied to target waters using eight to ten eight-gallon drip barrels. The drips will be set on the morning of the October 12 and run through the afternoon. Most drips will run for three to eight hours, depending upon location, to ensure that all fresh water sources are simultaneously treated. Charges for drip stations are calculated to apply the five percent active ingredient liquid rotenone at a concentration of 1.5 parts per million in the target reach. Rotenone applied by backpack sprayers will be mixed at a ratio of approximately eight ounces of five percent rotenone to three gallons of filtered water.
Potassium permanganate, an oxidizing agent, will be applied to treated waters just upstream of the Pole-Clear Creek confluence to deactivate the rotenone downstream of the target area.
Although rotenone is relatively benign to humans, fish treated with the chemical have not been cleared for human consumption by the FDA. Consequently, the salvage of fish during the project will not be permitted. Bonneville cutthroat trout will be transferred from the Pole Creek headwaters to the treated section in fall 2012. Similar restoration projects involving Utah's native trout are underway throughout the state as part of conservation strategies designed to prevent their listing under the Endangered Species Act.
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