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<br />RESULTS <br /> <br />Study site abundance-- Abundance of adult smallmouth bass in the 24-mile study site <br />at Little Yampa Canyon declined 17% from 2,888 (SE = 597) fish in 2004 to 2,394 (SE <br />= 566) fish in 2007 after 3 years (2004-2006) of fish removal (Table 3). There was a <br />negative relationship of abundance as a function of time (log e [abundance] = 167.01 - <br />0.0793 * year; ,2 = 0.48). However, overlapping 95% confidence intervals among all <br />years suggested no significant differences in estimates. Precision was highest (CV = <br />7%) in 2006 when abundance was estimated after two marking occasions that year and <br />was moderately good (CV = 13-24%) in other years when abundance was estimated <br />after one marking occasion (Table 3). Capture probability of smallmouth bass at Little <br />Yampa Canyon averaged 11 % (Table 3). <br /> <br />Density of smallmouth bass derived from annual point estimates of abundance ranged <br />from 100 to 143 fish per mile at Little Yampa Canyon (Table 4). CPUE of adult <br />smallmouth bass captured by boat electrofishing was positively correlated with bass <br />density when CPUE was based on either the first marking occasion or the average of all <br />sample occasions each year (Figure 2). CPUE on the first sample occasion provided <br />the best predictor of density (CPUE [1 sl occasion] = 0.07 * density - 2.62; ,2 = 0.81). <br />CPUE of smallmouth bass captured at Little Yampa Canyon declined 22% from 10.4 <br />fish/hour in 2004 to 8.1 fish/hour in 2007 (Table 4; Figure 3). <br /> <br />Abundance of adult smallmouth bass in the 5-mile treatment reach at Lily Park declined <br />19% from 1,519 (SE = 1,479) fish in 2004 to 1,233 (SE = 268) fish in 2007 after 3 years <br />(2004-2006) of removal (Table 3). There was a negative relationship of abundance as <br />a function of time (log e [abundance] = 152.73 - 0.0728 * year; ,2 = 0.21). However, <br />overlapping 95% confidence intervals among all years suggested no significant <br />difference in estimates. Abundance estimates at Lily Park were moderately good (CV = <br />13-25%) in all years except 2004 when the point estimate was very imprecise (CV = <br />97%). As with Little Yampa Canyon, precision was best at Lily Park in 2006 when <br /> <br />10 <br />