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<br />:. t.". ,I I!' ".- <br /> <br />002453 <br /> <br />Table 3, Distribution of razorback sucker within the Green River subbasin <br /> <br />River Occupied HabitatlRivenniles Limits of Distribution <br />Green Lodore Canyon to Colorado River Coldwater releases from Flaming Gorge <br /> confluence (360 RM): -100 adults from Dam previously restricted distribution; <br /> Yampa River to Duchesne River; warmed releases may allow for range <br /> population augmentation ongoing. expansion upstream into historic habitat. <br />Yampa Craig, CO to Green River confluence Present in low numbers in historic <br /> (141 RM); few wild fish remaining. habitat. <br />White Taylor Draw Dam to Green River Found in low numbers; distribution <br /> (62 RM.); few wild fish remaining. upstream blocked by Taylor Draw Dam, <br />Duchesne Lower 1.2 RM above Green River; few Found as small aggregations at river <br /> wild fish remaining, mouth during spring runoff. <br /> <br />Historically. razorback sucker were widely distributed from Mexico to Wyoming in warm-water <br />reaches ofIarger rivers of the Colorado River Basin. Riverine habitats required by adults include <br />deep runs, eddies, backwaters, and flooded off-channel environments in spring; runs and pools often <br />in shallow water associated with submerged sandbars in summer; and low-velocity runs, pools, and <br />eddies in winter. Spring migrations of adult razorback sucker were associated with spawning in <br />historic accounts, and a variety oflocaI and long-distance movements and habitat-use patterns have <br />been documented. Spawning in rivers occurs over bars of cobble, gravel, and sand substrates during <br />spring runoff at widely ranging flows and water temperatures (typically warmer than l40C). <br />Spawning also occurs in reservoirs over rocky shoals and shorelines. Young razorback sucker <br />require nursery environments with quiet, warm, shallow water, such as tributary mouths, <br />backwaters, or inundated floodplain habitats in rivers, and coves or shorelines in reservoirs. Threats <br />to the species include streamflow regulation, habitat modification, competition with and predation <br />by nonnative fish species, and pesticides and pollutants (USFWS 2002d). <br /> <br />Pursuant to Section 4(b)(2) of the ESA, on March 21,1994 (59 FR 13374) the Service designated <br />critical habitat for the razorback sucker within its historic range, including the Yampa River and its <br />1 OO-year floodplain from the mouth of Cross Mountain Canyon in T. 6 N., R. 98 W., section 23 (6th <br />Principal Meridian) to the confluence with the Green River in T. 7 N., R. 103 W., section 28 (6th <br />Principal Meridian). Razorback suckers generally are found in the Middle Green River between the <br />confluence of the Duchesne and the Yampa. They occupy the lower reaches of Yampa Canyon <br />during spawning and may occur irregularly elsewhere in Yampa Canyon. <br /> <br />Recovery goals for the razorback sucker prescribe 14 management actions needed for recovery, of <br />which the following eight actions are applicable to the YampalGreen River complex: <br /> <br />I. Reestablish populations with hatchery-produced fish. <br />2. Provide and legally protect habitat (including flow regimes necessary to restore and maintain <br />required environmental conditions) necessary to provide adequate habitat and sufficient <br />range for all life stages to support recovered populations. <br />3. Ensure adequate protection from overutilization. <br />4. Ensure adequate protection from diseases and parasites. <br /> <br />Management Plan for Endangered Fishes in the Yampa River Basin <br /> <br />17 <br />