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. DRAFT . shows that this significance is driven by the single observation at 2.3 feet/second in the 1988 no ice cover data. Substrate . The frequency distributions for substrate utilization for the 1987, and 1988 without ice and 1988 with ice cover are provided in Figure 24. Statistical test between the 1987 versus 1988 no ice data as well as tests for the 1988 ice versus no ice data were not significant and is readily seen by visual inspection of the frequency data. It should also be noted that although the primary substrates selected were dominated by silt and sand, the frequency data suggest that this preference is influenced by the presence of larger secondary substrate elements within the gravel and cobble size ranges. . 7.1.1.2 Razorback SUcker . The results of comparisons between 2-hour and 24-hour monitoring for depth, velocity, and substrate distributions were significantly different for all comparisons except velocities for point measurements. This indicates that razorback suckers may utilize habitats slightly different throughout a full day than reflected in the 2-hour sampling. . The statistical tests for habitat measurements taken at the fish (point) and one meter either side (in, out) reveal no significant differences between any distributions for the three sets of tests conducted. This indicates that, in the winter, razorback suckers utilize habitats which are relatively uniform over an area one to two meters from the fish. This is to be contrasted with the results of the Colorado squawfish analyses which indicated that this species utilizes small regions of lower velocity within areas with higher velocity, a phenomenon which is also reflected in different substrate types. . Depth The frequency distributions associated with depth utilization for the 1987, 1988 without ice and 1988 with ice are provided in Figure 25. Table 8 contains summary information associated with these collections. . Statistical test for differences between the 1987 and 1988 without ice cover data showed significant differences for the variance and the man (F=1. 70, T=2 .62). This difference is related to a small number of observations at greater depths for the 1987 data set (see Figure 25). No significant difference in the variance of the 1988 no ice versus ice cover data was found (F=1.17), while the means were significantly difference (T=4.38). This difference is apparent from an examination of Figure 25, where the 1988 ice data set has a single observation below 1.0 feet and no observations above 7.0 feet. The limited number of samples for the ice cover partition should be noted however, and this difference may in fact by an artifact of the test statistic rather than a real indication of differences in utilization for the species. . . 38 .