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INTRODUCTION The Upper Colorado River Endangered Fish Recovery Program (Program) has determined that control of nonnative fishes is necessary for recovery of the four big river endangered fishes, Colorado pikeminnow, razorback sucker, bonytail, and humpback chub. Escapement of nonnative fishes from reservoirs or other impoundments and dispersal into endangered fish occupied riverine habitats where they potentially pose a significant predatory or competitive threat has been identified as a problem (U.S. Fish and Wildlife Service 2002). Screening of reservoir outflow to reduce escapement of target nonnative fishes, a costly procedure, has been implemented at Highline Reservoir and attempted at Elkhead Reservoir (Miller and Laiho 1997; Colorado Division of Wildlife 2005). Another option for controlling escapement of nonnatives is to make recommendations to reservoir managers to limit spills and/or releases that may also allow for escapement of nonnatives or to chemically treat the reservoir's stilling basins following spills and/or releases. Each of these options has its drawbacks and limitations and the need for such nonnative fish control measures needs to be evaluated on a case-by-case basis. Starvation Reservoir, in northeastern Utah, was identified in the March 2000 Recovery Implementation Program Recovery Action Plan for such an evaluation beginning in 2002. Presently, northern pike (Esox lucieus) are of great concern in the Yampa and middle Green rivers. However, other highly piscivorous species, including walleye and smallmouth bass, began increasing in abundance in the middle Green River around 2001 or 2002, likely in response to warmer water temperatures associated with drought conditions (Bestgen et al. 2006). Starvation Reservoir was identified as a very likely source for escapement of both walleye and smallmouth bass. The reservoir is located in the Strawberry River drainage and receives inflow