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<br />razorback suckers, (4) associate razorback sucker spawning dates with mainstem discharges and <br />temperatures, and (5) estimate growth rates and describe the diet of razorback sucker larvae in <br />existing nursery habitats. Studies included two projects of the Recovery Implementation <br />Program for the Endangered Fish Species in the Upper Colorado River Basin (Colorado River <br />Recovery Implementation Program - Wydoski and Hamill 1991) conducted as part of the <br />Flaming Gorge Research Program (FGRP), which was initiated as a Reasonable and Prudent <br />Alternative in the 1992 Final Biological Opinion on operation of Flaming Gorge Dam, and <br />research contracted by the National Park Service through a 3-year (1993-1995) program on <br />endangered fishes in Colorado River basin parks funded by the Natural Resource Preservation <br />Program (Muth and Wick 1997). The two FGRP projects were (1) Annual assessment of <br />spawning success, larval distribution, and habitat selection of main-stem razorback suckers in <br />the middle (1992-1996) and lower (1996) Green River (number 34); and (2) Investigation of <br />potential razorback sucker and Colorado squawfish spawning in the lower Green River, <br />1994-1995 (number 38). Project 38 was designated as a Hypothesis-Testing study, and project <br />34 was part of the Core-Research Effort, which was based on a life-history approach for <br />monitoring the biological responses of target species to recommended flows, and was specifically <br />related to Element 1 (Reproduction) and Element 2 (Age-O Recruitment). This integrated report <br />serves as the end product for project 34; a separate final report will be prepared for project 38 <br />(Chart et aI., August 1997, draft). <br /> <br />METHODS <br /> <br />Study Area and Sampling Sites <br /> <br />The area studied during spring and early summer 1992 through 1996 included up to five <br />reaches of the middle Green River, A-E, and three reaches of the lower Green River, F-H <br />(Figure 1). Reaches were selected based on proximity to previously documented areas of <br />razorback sucker spawning activity (e.g., lower Yampa River in the Echo Park reach and Green <br />River in the Escalante reach) or to reported localized captures of individual tuberculate or ripe <br />fish, and the presence of quiet-water habitats connected to the main channel and accessible to <br /> <br />4 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />