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Recovery goal downlisting demographic criteria(USFWS 2002c) for humpback chub require <br /> each of five populations in the upper Colorado River basin to be self-sustaining over a 5-year <br /> period, with a trend in adult point estimates that does not decline significantly. Secondarily, <br /> recruitment of age-3 (150-199 mm TL)naturally produced fish must equal or exceed mean adult <br /> annual mortality. In addition, one of the five populations (e.g., Black Rocks/Westwater Canyon <br /> or Desolation/Gray Canyons)must be maintained as a core population such that each estimate <br /> exceeds 2,100 adults (estimated minimum viable population number). <br /> Population estimates for four of the five upper basin population are shown in Figure 8. No <br /> population estimate is available for the Yampa/Green River population in Dinosaur National <br /> Monument(see Baseline section for further details). The Desolation/Gray Canyons population <br /> of wild adults was estimated at 1,300 in 2001, 2,200 in 2002, and 940 in 2003 (Jackson and <br /> Hudson 2005). Sampling in 2001 and 2002 was conducted in summer,whereas beginning in <br /> 2003, sampling was shifted to fall to avoid capturing Colorado pikeminnow that use Desolation <br /> Canyon for spawning. In a report on 2006-2007 estimates,researchers (Badame 2012) indicated <br /> that this population was trending downward. Badame (2012)linked declining catch of <br /> humpback chub in the upper portions of Desolation Canyon in the 2006-2007 estimates with <br /> increasing densities of nonnative smallmouth bass. Utah Division of Wildlife Resources <br /> (UDWR)researchers recommended securing a representative sample of adults in captivity. In <br /> 2009, 25 adults were taken to Ouray National Fish Hatchery. In 2011, six sites throughout <br /> Desolation Canyon were monitored for adults, 55 individual adults were encountered,but <br /> recaptures were too few to calculate a population estimate. <br /> 25 <br />