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Miller (1979) presented habitat curves for 34 adult squawfish collected in the Colorado River in 1979. Those curves indicate a pre- ference for boulder-bedrock substrate and some smaller preference for deep areas (20-30 feet). The fish used in that analysis primarily came from Black Rocks, a deep, incised 1/4 mile portion of the Colorado River with an extruded black schist substrate. Since that area is unusual, and similar habitat is not generally available in other portions of the Upper Colorado Basin, these data must be used with caution when pro- jecting habitat availability in other areas. This raises the general question, does habitat preference vary dramatically between portions of the upper )bas in? The answer appears to be no, although some 1 oca 1 pre- ference changes do occur depending on the type of habitat available. Movement Many accounts of squawfish "spawning migrations" can be found in the older literature, and in discussions with "old timers" (Minckley 1973). No actual scientific accounts are known, except for movement of large numbers of ripe males during mid-late sUlTlTler into the Yampa River in 1968-1970 (Holden and Stalnaker 1975b). In 1981, radio-tagged adult squawfish from the upper Yampa River moved up to 145 km downstream to the lower Yampa. Other adults tagged in the Green River moved upstream about 80 km into the Yampa River. These radio-tagged fish were located near several ripe males and a female that had apparently just spawned. The seasonal increase in adult numbers in the Yampa River was also noted by Seetha 1 er (1978) . The probab 1 e reason for th i s movement into the 12