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to The Recovery Program placed a high priority on habitat management in the Green and Yampa Rivers through protection of instream flows. Because of the importance of providing legal protection for instream flows, the Service considers, within the Section 7 process, the legal protection of flows essential to offsetting project impacts. ~, , The consolidated biology report (Tyus and Karp 1991) summarizes the distribution, abundance, and habitat use for the endangered fish. Much of the species biological information discussed below was extracted from that report. COLORADO SQUAWFISH General Status Historically, Colorado squawfish occurred in mainstream habitats of the Colorado River system. The species was found in the Colorado River from the Utah-Arizona border to the Sea of Cortez in Mexico, and the Salt and Gila Rivers of the lower Colorado River Basin. However, all lower basin populations are considered extirpated (Minckley 1973). In the Upper Colorado River Basin, Colorado squawfish occurred in the Colorado, Green, Yampa, White, Dolores, Gunnison, San Juan, Uncompahgre, and Animas Rivers and in many smaller tributaries. Although still occurring in much of its former upper basin range, most areas contain only remnants of their former number and few reproducing populations exist. All life history phases of the Colorado squawfish are considered in this biological opinion and include migration, spawning, and larval recruitment to the adult life stage. These phases are closely related with specific flow events and habitat requirements. The recovery goals for Colorado squawfish established through the Recovery Program are to "maintain and protect self- sustaining populations and natural habitat." Adults Adult Colorado squawfish are widely distributed in the Yampa and Green Rivers, and the fish is considered more abundant in the Green River than any other location (Holden and Stalnaker 1975; Tyus et al. 1982a and 1982b; Behnke and Benson 1983; Tyus, in press). In the mainstream Green River, adults are most prevalent in upper (i.e., near Ouray, Utah) and lower (i.e., near Labyrinth Canyon) sections (Tyus et al. 1987). During the winter months, adult Colorado squawfish occupy a variety of low velocity habitats including slow runs, slackwaters, eddies, and backwaters (ephemeral along-shore embayments) (Valdez and Masslich 1989; Wick and Hawkins 1989). Colorado squawfish select certain river reaches in the Green and upper Yampa Rivers and generally remain active in these areas all winter (Valdez and Masslich 1989; Wick and Hawkins 1989). The fish presumably use ice as cover and some local movements are probably made to avoid floating ice jams (Valdez and Masslich 1989).