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interpreted largely as migrations between feeding-wintering areas and spawning <br />habitats. Movements of over 200 miles by individual fish have been documented <br />(Miller et al. 1983; McAda and Kaeding 1989). In addition to these short-term <br />movements of adult fish, the year-round distribution of some adult Colorado squawfish <br />upstream from the nearest spawning areas (e.g., in the Yampa River) suggests that <br />there must also be a long-term, upstream movement, perhaps of juvenile fish, to <br />populate these upstream areas (Tyus 1986). Although the actual role that the <br />blockage of such movements might have played in the decline of Colorado squawfish <br />in the upper basin is unknown, providing fish passage past instream barriers has <br />come to be considered an important means to aid the recovery of the species. <br />The placement of fish passageways has been identified in the Recovery <br />Implementation Program for Endangered Fish Species in the Upper Colorado River <br />Basin (USFWS 1987) and the Colorado squawfish Recovery Plan (1990) as one of <br />several means to aid the recovery of Colorado squawfish. An important goal of the <br />Recovery Implementation Program is to provide for both the new water development <br />and recovery of the endangered fish. Within the upper Colorado River basin, several <br />man-made structures constitute either complete or partial movement barriers for <br />Colorado squawfish (Figure 1; Table 1). These structures range from high-head dams <br />like Flaming Gorge on the upper Green River to low-head structures like the Grand <br />Valley Diversion on the upper Colorado River, and they occur within both the historic <br />and present ranges of the Colorado squawfish. <br />2