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<br />. <br /> <br />33 <br /> <br />. <br /> <br />squawfish used backwaters almost exclusively in the Colorado! River near <br />Grand Junction, although times of capture were not noted. <br />Small humpback chubs have similar habitat preferences tb small <br />squawfish but use more of a variety of areas, especially eddlies. No <br />previous study has reported on preferred habitats of small humpback <br />chubs. <br />Habitat preferences of adult humpback chubs have generallly incl uded <br />eddies near fast current (Holden and Stalnaker, 1975) and/o~ depths of <br />20+ feet (Kidd, 1977). The data collected during the presenlt study show <br />no distinct preference for either depth or velocity, although some hump- <br />backs were caught in very fast currents (2.5 fps) and in veny deep areas <br />(20 ft.). <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />Concerning electivity curves, the Cooperative Instream Flow Service <br />Group has set guidelines for evaluating reliability based on number of <br />fish captured. They suggest the following reliability level!s: excellent, <br />200 individual measurements; good, 50-200 samples; and fair~ less than <br />50 measurements. Using these criteria, none of the curves ~hown above <br />can be rated excellent, young-of-the-year squawfish and hum~back chubs <br />are good, and the others only fair. The additional information from the <br />literature would probably increase the reliability of the young-of-the- <br />year squawfish data, but would add little reliability to th~ other groups. <br />It is doubtful that a two-month study of rare Colorado;Basin fishes <br />can produce sufficient data for excellent reliability, except for young- <br />of-the-year fish. The endangered status of the Colorado sq~awfish and <br />humpback chub suggest extreme rareness, as, in fact, they ate. Several <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />. <br />