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<br />Composite PCA results for the 1985 Green River collections did <br /> <br />not yield clusters indicative of different taxa. <br /> <br />Rather, the <br /> <br />scatterplot showed as a large cluster with wide-ranging varia- <br /> <br />tion. On the otherhand, comparisons of single-site loadings with <br /> <br />those for 91ackrocks suggests that most Green River fish may have <br /> <br />been "humpback" chubs. The range of variation within Green River <br /> <br />samples extended beyond that seen for Blackrocks fish. <br /> <br />Green <br /> <br />River fish may be more variable relative to their Blackrocks <br /> <br />relatives. Perhaps geographic variatio~ was a factor. Tne Green <br /> <br />River collections spanned over many kilomet~F% while the Black- <br /> <br />rocks semple is from a single site. <br /> <br />Again, hybridization between <br /> <br />"roundtail" and "humpback" chubs cannot be absolutely discounted. <br /> <br />The results for certain Green River sites indicate the presence <br /> <br />of single morphotypes. <br /> <br />All fish at Whirlpool Canyon seem to be <br /> <br />"roundtail" chubs, while those from Coal Creek appear to be <br /> <br />"hu:npback" chubs. <br /> <br />CO!'/CLUSIONS <br /> <br />The use of PCA for the examination of morphological variation <br /> <br />among the Colorado River chubs offers objective utility for <br /> <br />studying species affiliations. <br /> <br />This preliminary study resulted <br /> <br />in hypotheses of relationship within and between collecting <br /> <br />localities, testable using biochemical :neans: <br /> <br />1 4 <br />