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3 <br />and reproductive strategy of the Colorado squawfish. These studies have <br />led to preliminary revisions regarding hypotheses presented by Vanicek <br />and Kramer (1969), Seethaler et al. (1976), Holden (1977, 1980), Seethaler <br />(1978), Joseph et al. (1977), and Behnke and Benson (1980) on the <br />distribution of successfully reproducing Colorado squawfish populations, <br />habitat requirements and the general ecology of this endangered species. <br />The purpose of this study was to collect data on prespawning, <br />spawning and postspawning movements of Colorado squawfish in the Yampa <br />River (Fig. 1) and to expand the findings of previous studies. In <br />addition to movement patterns and habitat utilization, temperature <br />preferences of the Colorado squawfish were investigated. <br />METHODS <br />Radiotelemet <br />Twelve Colorado squawfish, greater than 550 millimeter (mm) total <br />length (TL), were collected from the Yampa River during March and April, <br />1982, for radiotransmitter implantation. Collections were made during <br />these months when cool water temperatures minimized the chances of <br />infection due to field surgical procedures. Six fish were collected <br />above Juniper Springs Canyon river km 146.4 (mile 91), 3 above Cross <br />Mountain Canyon river km 93.3 (mile 58) and 3 below Cross Mountain <br />Canyon river km 85.3 (mile 53) using electrofishing gear and experimental <br />gill nets as described by Wick et al. (1981). <br />Electrofishing efforts were continued until July 8, 1982, from <br />river km 177 to 72.4 (mile 109.9-45). This extended sampling was <br />conducted in preferred habitats, indicated by the presence of radiotagged <br />squawfish, to verify habitat preference data and to provide additional