Laserfiche WebLink
Population Dynamics <br />The humpback chub Recovery Goals (USFWS 2002c) provided the following <br />preliminary population estimates for adults in the six populations: <br />• Black Rocks, Colorado River, Colorado - 900-1,500 <br />• Westwater Canyon, Colorado River, Utah - 2,000-5,000 <br />• Yampa Canyon, Yampa River, Colorado - 400-600 <br />• Desolation/Gray Canyons, Green River, Utah - 1,500 <br />• Cataract Canyon, Colorado River, Utah - 500 <br />• Grand Canyon, Colorado River and Little Colorado River, Arizona - 2,000-4,700 <br />Monitoring humpback chub populations is ongoing, and sampling protocols and <br />reliability of population estimates are being assessed by the Service and cooperating <br />entities. The demographic criteria of the Recovery Goals (USFWS 2002c) for <br />downlisting the humpback chub to "threatened," call for maintaining the six populations <br />and at least one core population in both the Upper and Lower Colorado River Basins of <br />>2,100 adults that are self-sustaining with recruitment. <br />Critical Habitat <br />Critical habitat was designated in 1994 within humpback chub historical range in the <br />following sections of the upper Colorado River (59 FR 13374). The PCEs are the same <br />as those described for the Colorado pikeminnow, as is the status of the PCEs. We <br />designated seven reaches of the Colorado River system for a total of 379 miles as <br />measured along the center line of the subject reaches. The designation represents <br />approximately 28 percent of the suspected historical habitat of the species and includes <br />reaches in the Colorado, Green, and Yampa Rivers in the Upper Basin: <br />Moffat County, Colorado. The Yampa River from the boundary of Dinosaur <br />National Monument in T. 6 N., R. 99 W., section 27 (6th Principal Meridian) to <br />the confluence with the Green River in T. 7 N., R. 103 W., section 28 (6th <br />Principal Meridian). <br />Uintah County, Utah; and Moffat County, Colorado. The Green River from the <br />confluence with the Yampa River in T. 7 N., R. 103 W., section 28 (6th Principal <br />Meridian) to the southern boundary of Dinosaur National Monument in T. 6 N., <br />R. 24.E., section 30 (Salt Lake Meridian). <br />Uintah and Grand Counties, Utah. The Green River (Desolation and Gray <br />Canyons) from Sumner's Amphitheater in T. 12 S., R. 18 E., section 5 (Salt Lake <br />Meridian) to Swasey's Rapid in T. 20 S., R. 16 E., section 3 (Salt Lake Meridian). <br />Grand Countv, Utah; and Mesa County, Colorado. The Colorado River from <br />Black Rocks in T. 10 S., R. 104 W., section 25 (6th Principal Meridian) to Fish <br />Ford in T. 21 S., R. 24 E., section 35 (Salt Lake Meridian). <br />24