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DRAFT22 <br />Discussion <br />We have refined the definition of quality habitat to show Colorado squawfish select for <br />habitats that are large, deep and permanent. These habitats are generally scour channel (SC) <br />habitats occurring below large sandbar complexes. The availability of this type of habitat is <br />negatively correlated with high spring peak flows and more weakly negatively correlated with <br />~~ <br />sar~p g fl ~ Non-native cyprinids also select for SC type habitats. Although the strong <br />;~ _. <br />selection of SC habitats by squawfish would seem to suggest that squawfish would increase as <br />this habitat availability increased, this is not the case. However, non-native cyprinids increased <br />dramatically with an increase in SC habitat. ~ 5~~q ~.,,~ ~ 7 <br />J w e,.f~ <br />To recapitulate the resultsw water years restxl~ larval production (Kevin ~d <br />Bestgen, unpub ' ata) high,~abitat volume and area, high temperatures, high growth rates, "~`S ' <br />w <br />and high overwinter survival. This might logically suggest that low water years would also result <br />in high numbers of squawfish present in the fall and following spring, which does not occur. The <br />~~a~ <br />confounding factor is the presence ofnon-native cyprinids. Low water years also result in high <br />numbers of NNCs. High numbers of NNC are negatively correlated with Colorado squawfish. <br />a~CSF ~ <br />that the negative effects ofNNCs a ~eient-~o offse~the positive effects of <br />%~ is a-t-a ~ ~ Su~y~a-d ' <br />increased habitat and growth. U <br />Comparison with other nursery habitat results <br />Nursery habitat studies were also conducted in the Huddle Green River near Ouray and in <br />the Colorado River near Moab. The middle Green River study results were reported by Keith Day <br />(draft, 1997). Day reports similar habitat preferences by Colorado squawfish. ,Peak flows were <br />~~; ~ ~ <br />-22- <br />