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FUpper Colorado River Subbasin: Colorado pikeminnow <br /> subadults — <br /> 1000 <br /> w <br /> m 900 <br /> E <br /> V 800 <br /> W <br /> 700 <br /> M <br /> 600 <br /> 7 <br /> a 500 <br /> 400 <br /> m <br /> 300 <br /> c 200 <br /> 100 — T — <br /> 0 <br /> 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 <br /> Year <br /> Figure 2. Colorado pikeminnow recruitment abundance estimates (calculated using the same <br /> mark recapture methodology as for the adults) for the Colorado River (Osmundson and White <br /> 2009, 2014; Service 2015a). Recruits are age-6 (400-449mm TL). Error bars represent the 95 <br /> percent confidence intervals. The 2013 and 2014 are preliminary and represented by hollow data <br /> points. <br /> To summarize, in the Upper Colorado River Subbasin,the Colorado pikeminnow subpopulation <br /> may be self-sustaining,but the number of adults is below the level needed for recovery. <br /> Recruitment is quite variable over time, but has exceeded adult mortality in approximately half <br /> of the years when measured over the past two decades. The number of age-0 (young of year) <br /> Colorado pikeminnow is also quite variable over time,but appears to be less, on average, since <br /> the year 2000 than prior to 2000 (Figure 5). Colorado pikeminnow are also generally distributed <br /> throughout the Colorado River now to the same extent that they were when they became listed. <br /> GREEN RIVER <br /> Population estimates for adult Colorado pikeminnow in the Green River subbasin began in 2000. <br /> Sampling occurs on the mainstem Green River from the Yampa confluence to the confluence <br /> with the Colorado River and includes the Yampa and White Rivers. The initial year of sampling <br /> did not include the lower Green River(near the confluence of the White River to the confluence <br /> with the Colorado River). Beginning in 2001, the sampling regime has consisted of three years <br /> of estimates followed by two years of no estimates (Bestgen et al. 2005). The first set of <br /> estimates showed a declining trend; however, estimates collected in 2006-2008 showed an <br /> increasing trend approaching the level of the estimate made in 2000 (Figure 3) (Bestgen et al. <br /> 2010). Data from the third round (2011-2013) of population estimates for the Green River <br /> subbasin are still being analyzed(thus no confidence intervals are shown for the 2011-2013 <br /> estimates in Figure 3) (Bestgen et al. 2013). Preliminary results from Bestgen (2013) analysis <br /> 9 <br />