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The habitat suitability criteria can be questioned on several accounts. First, the data from which the curves were based for both the Yampa River (Miller and Modde 1999) and White River (Valdez et al. 1987) were from relatively few contacts (47 for daytime resting fish, 20 for night foraging fish, and 149 for White River fish). Second, most ofthese data were from fish located by triangulation using radio telemetry techniques, and it is difficult to know the precise water column depth and velocity of the habitat that fish were occupying. - Third, and most important, is the question of transferability of habitat suitability curves from one stream to another. Freeman et al. (1997) tested transferability for nine fishes (darters and shiners) in Alabama streams and concluded microhabitat criteria for riftle fishes were more likely to be transferable than for fishes that occupied a variety of pool and riftle habitats. On the other hand, two reasons give us confidence that the White River and night foraging suitability curves give approximately correct results. It is reassuring that the White River data and the night foraging data from the Yampa River gave similar curves, and it is understandable that the Yampa daytime resting curve does not apply to the White River, because depths> 1.2 m are rare in the White River. And finally, other depth and velocity curves similar to those we used have been developed (Valdez et al. 1987). Colorado Pikeminnow Habitat Colorado pikeminnow in previous studies in the Colorado, Green and Yampa rivers used a variety of habitat types throughout the year (Archer and Tyus 1984, Tyus and Karp 1989, Maddux et al. 1993, Osmundson 2001). Studies in the White River found that adult Colorado pikeminnow used primarily pool and run habitats (Valdez et al. 1987, Irving and Modde 1994, Irving and Modde 2000). This study found that most of the habitats in the White River consisted 14