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Results and Discussion <br />Adult Relative Abundance <br />Results of electrofishing surveys conducted during May and June of both 1986 <br />and 1987 indicate that certain areas in the 15-mile reach may be <br />concentration points for many Colorado squawfish and razorback sucker of the <br />Grand Valley during spring runoff. During this time the number of <br />squawfish caught or seen per hour of shocking was approximately 3.8 times <br />that caught or seen in the adjacent 18-mile reach of river immediately <br />downstream. The number of razorback suckers shocked in the 15-mile reach <br />was about 3.6 times larger than in the lower 18-mile reach (Table 1 and <br />Appendix). <br />Although relatively little sampling effort was expended in the Gunnison <br />River below the Redlands Diversion in spring (May), 1987, one squawfish was <br />seen there during 1.7 hours of shocking. During our July and August <br />electrofishing efforts in the lower Gunnison, Colorado squawfish were either <br />caught or seen at rates of 2.00-2.23 fish per hour (Table 2). Almost all of <br />these captures or observations were made in the plunge pool of the Redlands <br />Diversion Dam, the use of which by squawfish dropped off entirely in <br />September. Many squawfish seem attracted to a 1.2-mile section (RM 174.4- <br />175.5) of the 15-mile reach during spring, and to the plunge pool of the <br />Redlands Diversion during summer. Radio-tracking data on the movement of <br />adult Colorado squawfish, reported below, also support this conclusion. No <br />razorbacks were seen in the lower Gunnison during our sampling efforts. <br />5