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<br />Following the Levee Removal Study, Birchell and Christopherson (2004) continued <br />assessment of juvenile and larval razorback sucker survival in floodplain wetland habitats. <br />Hatchery produced age-1 and larval razorback suckers were introduced into floodplain sites <br />during atwo-year study to monitor growth and survival. Survival of age-1 juvenile razorback <br />suckers during this study ranged between 56 and 72 percent. However, larval survival was not <br />detected. High numbers of nonnative fish in the floodplain study sites likely suppressed larval <br /> <br /> <br />razorback survival. The large numbers of nonnative fish were the result of multiple cohorts of <br />nonnative fish that had reproduced in the floodplain sites over several years (Birchell et al. <br />2002). <br />Drought conditions in 2001 dewatered the floodplain sites and eliminated, or reset, <br />nonnative fish populations. Nonnative fish numbers are expected to be lower in these same sites <br />during the first inundation period following a reset because the only fish present entered from the <br />river during surface water connection. Hypothetically, the best opportunity for larval native fish <br />i <br />survival and eventual recruitment in floodplain habitats may occur the first year following a reset <br />of the nonnative fish population. The objective of this study was to describe razorback sucker <br />and bonytail survival and growth in the presence of known densities of nonnative fish in a reset <br />floodplain wetland environment. <br />This report combines the results of two different studies. The Utah Division of Wildlife <br />Resources (UDWR) had planned to use The Stirrup to conduct razorback sucker survival , <br />enclosure studies, and the Vernal, Fish and Wildlife Service (FWS) office had planned on using <br />Old Charlie Wash for bonytail survival studies. River flows were not high enough to fill either <br />site, prompting researchers to pump river water to artificially fill The Stirrup floodplain. The ' <br />Vernal FWS decided to combine the bonytail with the razorback suckers in The Stirrup <br />enclosures. Both projects were conducted independently. After the projects were completed the <br />Program Director asked the researchers to combine the two projects into one report, this report. <br />2 ~ <br />