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In the Juniper Springs reach, two northern pike (630 and 640 mm) spent all or part of October 1986 to March 1987 with four Colorado squawfish (494, 538, 544, and 620 mm) in a major backwater at RM 95.7. By late October 1987, one eolorado squawfish (494 mm) left this backwater and moved approximately 3 miles upstream to the river segment near Government Bridge. By late January 1988, one of the northern pike (630 rom) also moved out of this same backwater, and moved upstream into the same area. It may be significant that the smallest radio-tagged individual of each species left the backwater habitat earlier than the larger fish. The remaining pike and three Colorado squawfish stayed in the backwater at least until mid~February 1987 when contact with the pike was lost. The squawfish stayed in the backwater through early March 1987. Fish species associations were also observed during sampling of specific habitat types. Among the three species of primary interest, including northern pike, channel catfish, and Colorado squawfish, the relative frequency of capturing ea~h in spring backwater habitat was slightly over 30% (Figure 8). The relative frequency of capturing these same species in poo1-eddy- embayment habitat was dominated by northern pike at 50%, and Colorado squawfish at 40%. These results indicate all three species may be found in spring backwater habitat in equal numbers, suggesting this habitat type is important to each species. With the reduction in backwater availability the remainder of the year, northern pike appear most reliant on pool-eddy habitat and channel catfish the least. A competitive exclusion of Colorado squawfish and channel catfish by northern pike in pool-eddy habitat may be inferred, but examination of co-occurrence data for the eight possible combinations of the three species does not support this inference (Table 6). Colorado squawfish and channel catfish, both being adapted to riverine systems, would be able to exploit habitats with higher flows, and would be less restricted to low- velocity pools than northern pike. Sampling in these habitat types comprised 22 sampling efforts in spring backwaters and 20 sampling efforts in pool-eddy- embayment habitat. The associations observed indicate Colorado squawfish were found in the presence of northern pike and channel catfish or either gamefish species alone in 41% of the sampling efforts in spring backwaters, and in 50% of the sampling efforts in pool-eddy habitats in the summer and fall. 31