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Green River Subbasin: Colorado pikeminnow subadults <br /> 3000 <br /> w <br /> M <br /> m <br /> E 2500 <br /> LU <br /> W <br /> N <br /> U <br /> 2000 <br /> C <br /> 7 <br /> a 1500 <br /> 41 <br /> m <br /> 1000 <br /> bb <br /> 1 J <br /> 500 <br /> L <br /> U <br /> N <br /> 0 <br /> 2000 2002 2004 2006 2008 2010 2012 2014 <br /> Year <br /> Figure 4. Estimated numbers of Colorado pikeminnow recruits(400-449 min TL)in the Green <br /> River subbasin(Yampa,White,Middle Green,Desolation-Gray Canyons, and Lower Green)for <br /> 2001-2013. Data from Bestgen et al.(2010). Estimates of recruitment for the most recent <br /> 2011-2013 sampling period are preliminary. <br /> Bestgen et al. (2010)recognized that the mechanism driving frequency and strength of <br /> recruitment events was likely the strength of age-0 Colorado pikeminnow production in <br /> backwater nursery habitats. Osmundson and White (2014) saw a similar relationship between a <br /> strong age-0 cohort in 1986 and subsequent recruitment of late juveniles five years later,but that <br /> relationship was more tenuous in later years. Researchers are particularly concerned with what <br /> appears to be very weak age-0 representation in the Middle Green reach (1999 thru 2008) and in <br /> the lower Colorado River(2001 thru 2008) (Figure 5). In some years,the Bureau of <br /> Reclamation has released higher summer base flows in the Green River based on the <br /> understanding that this may improve survival of young Colorado pikeminnow and disadvantage <br /> smallmouth bass. <br /> 11 <br />