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and water temperature conditions should provide a basis for understanding critical spawning <br />periods and means to reduce bass survival. Otolith evidence also suggested fast growth of age-0 <br />smallmouth bass to a predatory size in the Yampa River, which has negative consequences for <br />native fish survival. Evidence we gathered collectively suggested that habitat changes during <br />drought, and associated higher abundances of smallmouth bass, have resulted in reduced <br />diversity, distribution, and abundance of native fishes in the study area. There are several <br />hypotheses that may explain why native fishes have not responded to predator removal in the <br />study area. The first is that an insufficient number of predator fish may have been removed. A <br />second and associated hypothesis is that habitat change, in the form of altered flows and water <br />temperatures, has differentially favored smallmouth bass and reduced native fishes during the <br />recent drought period. However, a direct effect of habitat change on much reduced abundance of <br />small-bodied native fishes seems unlikely. A third potential explanation for lack of a small- <br />bodied native fish response to predator removal may be an insufficient number of adult native <br />fish available to produce larvae. A final hypothesis for lack of small-bodied native fish response <br />to bass removal in the treatment reach was compensatory increases in small bass survival <br />because of large bass removal. However, this hypothesis is not supported by capture rates of <br />age-0 smallmouth bass in control and treatment areas because capture rates in control areas are <br />as high or higher than those in the treatment reaches in each year. We recommend continued <br />sampling as currently conducted to monitor response of native fishes. More extensive and <br />intensive predator removal and changes in environmental conditions may yield insights into <br />native fish response. We also recommend investigating whether abundance levels of adult native <br />fishes are sufficient to produce enough larvae to elicit a response to predator removal and discuss <br />means to accomplish that. Additional investigations of early life history of smallmouth bass may <br />assist with efforts to reduce their survival and recruitment. <br />iv <br />