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<br />The Duffy station is the least desirable of the Yampa sites to make inferences about <br /> <br /> <br />relationships between native fish and physical habitat. This is mostly due to the low native <br /> <br /> <br />fish composition. However adult native suckers have a habitat preference for deep runs and <br /> <br />rimes, habitats that are rare at Duffy and very abundant at Com Lake. Native sucker at Duffy <br /> <br />have been replaced by white sucker and white sucker hybrids, and these fish are more <br /> <br />associated with pool habitat than native suckers. Small mouth bass is another pool-associated <br /> <br /> <br />fish that is doing very well at Duffy, but is very rare in the Colorado River. Roundtail chub is <br /> <br /> <br />a native fish generally associated with pool habitat, but this species has been severely <br /> <br /> <br />impacted by predation, and therefore its abundance is not limited by habitat availability. <br /> <br /> <br />Progress is expected to accelerate in development of meso-habitat suitability indices as <br /> <br /> <br />2-D modeling is performed. Fish data was reorganized to allow for this analysis. Fish data <br /> <br /> <br />collected by electrofishing were reorganized according to the specific location of their catch. <br /> <br />The electrofishing units have been digitized as arc-view polygons to overlay the river. Each <br /> <br /> <br />polygon has a fish attribute table and an attribute table for physical habitat. Physical <br /> <br /> <br />characteristics from each polygon will be determined based on the flow simulation that <br /> <br /> <br />matches closest to the flow at the time of the sample. The fish attribute table contains the <br /> <br /> <br />number offish by four size-groups for each species representing YOY, juveniles, small and <br /> <br /> <br />large adults. Polygons will be sorted by greatest to least fish abundance and in that way <br /> <br /> <br />habitat characteristic will also be sorted from most suitable to unsuitable. The maximum <br /> <br />number of polygons for each river is: Colorado River, Com lake (40), Clifton (50); Dolores, <br /> <br />Big Gypsum (16); Yampa, Sevens (16), Duffy (16), Lily Park (16). The fish data will be <br /> <br />presented in this format when the corresponding habitat data becomes available. <br /> <br />Fish sampling efforts will be attempted made in the 2001 field season to more <br /> <br />accurately map fish by established polygons. Observations will be made on fish that were <br /> <br />44 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />