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<br />13 <br /> <br />Colorado Sauawfish Activitv: San Juan River <br /> <br />As a result of the 1991 biological opinion, Reclamation agreed to fund <br />approximately 7 years of research on the San Juan River and its tributaries. <br />While these studies are not yet complete, annual reports indicate that a small <br />reproducing population of Colorado squawfish exists on the San Juan River. <br />Based on radio telemetry studies and visual observations, two potential <br />spawning areas have been located at river mile 132.0 and 131.15 (Miller 1994, <br />Ryden and Pfeifer 1995a). Both of these sites are located in an area of the <br />river known as the "Mixer" (river mile 133.4 to river mile 129.8). The <br />highest concentration of adult Colorado squawfish in the San Juan River occur <br />between the Cudei Diversion (river mile 142.0) and Four Corners (river mile <br />119.2). Ryden and Pfeifer (1995a) report that a Colorado squawfish captured <br />at river mile 74.8 (between Bluff and Mexican Hat) made a 50-60 mile migration <br />to the Mixer during the suspected spawning season in 1994. The fish then <br />returned to within 0.4 river miles of its original capture location. <br /> <br />Successful reproduction was documented in the San Juan River in 1987, 1988, <br />1992, 1993, and 1994, by the collection of young-of-year Colorado squawfish. <br />Majority of the young-of-year squawfish were collected in the San Juan River <br />inflow to lake Powell (Buntjer et al. 1994, Lashmett 1994, Platania 1990). <br />Some young-of-year squawfish have been collected from the vicinity of the <br />Mancos River confluence in New Mexico and in the vicinity of the Montezuma <br />Creek confluence near Bluff, Utah, and at a drift station near Mexican Hat, <br />Utah (Buntjer et al. 1994, Platania 1990). In 1994, a young-of-year squawfish <br />was collected at the confluence with the Mancos River, which is the first <br />specimen collected at this site since 1987 (Frank Pfeifer, USFWS, pers. <br />comm.). <br /> <br />The San Juan River is one of only three remaining areas where a wild, <br />reproducing population of Colorado squawfish still persists. The San Juan <br />River subbasin, isolated from the Colorado and Green River subbasins, provides <br />a third population of wild fish, contributing an additional essential buffer <br />against a catastrophic event (such as an oil spill) elsewhere in the basin. <br />While the Colorado squawfish population may be small in the San Juan River, it <br />may be important as unique genetic stock. Because of this the Colorado River <br />Fishes Recovery Team (consisting of scientists from the entire Colorado River <br />Basin, including representatives from State wildlife agencies of California, <br />Arizona, New Mexico, Utah, and Colorado, as well as Federal representatives <br />from the National Park Service, Reclamation, and the Service) recommended that <br />the San Juan River be added to the Colorado squawfish recovery plan. The <br />updated Colorado Squawfish Recovery Plan (August 6, 1991) states that the <br />species can be downlisted to threatened when all recovery areas (including the <br />San Juan River from Lake Powell upstream to the confluence of the Animas <br />River) have naturally self-sustaining populations. The San Juan River also is <br />included in the delisting criteria. <br /> <br />Critical Habitat <br /> <br />Critical habitat has been designated within the 100-year floodplain of the <br />Colorado squawfish's historical range in the following section of the San Juan <br />River Basin (59 F.R. 13374). ' <br />