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reflecting a slight increasing trend in abundance of recruits in the lower Green River reach. <br />Estimates of Colorado pikeminnow recruit abundance in the lower Green River were less precise <br />than abundance estimates for adults, with CV's that ranged from 23 to 41 %. <br />Basin-wide abundance estimates.-River-wide annual abundance estimates for Colorado <br />pikeminnow adults (? 450-mm TL) and recruits (400 to 449-mm TL) reported are the sum of <br />annual abundance estimates for reaches in the multi-strata model. Abundance of adult Colorado <br />pikeminnow apparently declined over the period of sampling in the Green River Basin (Table 9, <br />Fig. 8). In 2000, when sampling was restricted to the middle Green River Basin (middle Green <br />River, Yampa River, White River), abundance of adult Colorado pikeminnow was estimated at <br />3,030 (SE = 287) individuals. No sampling effort was allocated to the Desolation-Gray Canyon <br />and lower Green River reaches that year, so no abundance estimates were possible. In 2001, <br />when sampling was basin-wide and included Desolation-Gray Canyon and lower Green River <br />reaches, abundance of adult Colorado pikeminnow was 3,304 (SE = 206), but abundance <br />declined in 2002 to 2,772 (SE = 283) and to 2142 (SE = 233) in 2003, suggesting a 35% decline <br />over the period. Confidence limits did not overlap for 2001 and 2003 basin-wide estimates. <br />It seems reasonable to assume that abundance of Colorado pikeminnow in unsampled <br />Desolation-Gray and lower Green River reaches in 2000 was similar to that estimated in 2001. If <br />one sums estimates for those reaches in 2001 (1,054) with the 2000 middle Green River estimate <br />(3,030) and uses that as a basin wide estimate (4,084) for 2000, abundance of adult Colorado <br />pikeminnow may have declined by as much as 48% over the period 2000 to 2003. This <br />suggested evidence of an apparently negative trend in abundance over time for Colorado <br />pikeminnow in the Green River. The average CV for river-wide abundance estimates for 2000 to <br />2003 was relatively low at 9 % (range 6 to 11%). <br />30