Rotenone in Fisheries: Are the Rewards Worth the Risks?

7. Overview of a Large-Scale Chemical Treatment Success Story: Strawberry Valley, Utah

Leo D. Lentsch, Charles W. Thompson, and Robert L. Spateholts

doi: https://doi.org/10.47886/9781888569339.ch7

Abstract.—The waters in Strawberry Valley, Utah, were chemically treated with rotenone to remove all fish species in 1990 to restore a recreational salmonid fishery. This treatment was one of the largest chemical rehabilitation projects ever undertaken, the area encompassing approximately 170 square miles including 55 tributaries to the upper Strawberry River and Strawberry Reservoir. Fish inhabited a total combined length of 161 miles of stream channel and numerous springs. Treatment volume was reduced from 400,000 to 300,000 acre-feet by treating the epilimnion when the reservoir was stratified. Approximately 875,000 lbs of powdered rotenone and 4,000 gallons of 5% liquid rotenone were used. Over 6,000 workdays using 260 personnel and $3.8 million were required to complete the task. Several innovative procedures for handling and applying rotenone (powder and liquid) were developed to include 1) use of 1,000 lb bags to handle the powder, 2) use of a epilimnetic treatment procedure, 3) mixing powdered rotenone into a slurry with a venturi device, and 4) development of rotenone sandmix that maintains fish toxicity in seeps for 12 hour periods. Summarized here are the objectives, treatment proposal approach, public involvement efforts, regulatory procedures, research and development efforts, and logistical strategies used by the Utah Division of Wildlife to accomplish a chemical treatment of this magnitude. The results of the Strawberry Valley treatment are more than one million hours of fishing pleasure and opportunities for large cutthroat trout and kokanee salmon.