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and spawning. Thus, lower and more stable winter flows are considered habitat requirements of razorback sucker. RECOMMENDATIONS Flow and Temperature Decline and endangerment of the Colorado River fishes is due, in part, to human-induced habitat changes. Closure and operation of Flaming Gorge and Fontenelle dams on the upper Green River changed aquatic habitats (Pearson 1967) and eliminated most of the native fishes in 128 km of river above DNM (Baxter and Simon 1970; Vanicek et al. 1970). Current operations of Flaming Gorge do not provide desirable flow and temperature conditions for downstream native fish populations. Standing crops of endangered fishes in the Green River below its confluence with the Yampa River are presumably being maintained by the more natural flow and temperature regimens of the Yampa system (Holden 1978; Tyus and Karp 1989) and by the mitigating effects of other tributary flows further downstream. Miller et al. (1982c) provided some flow recommendations for Colorado squawfish in the Green River which considered survival, rather than maintenance or recovery, of self-sustaining populations, These investigators recognized that additional flows were needed to maintain endangered fish habitat, but could not identify them because of limited information. Operation of Flaming Gorge Dam can be altered to aid recovery of the endangered Colorado River fishes, Efforts to coordinate timing of key Green (via operation of Flaming Gorge Dam) and Yampa river flow events should be explored for recovery of the rare fishes in the Green River basin. Two major changes may be necessary in Flaming Gorge operations to provide acceptable flows and temperatures for the endangered fishes: higher and warmer spring releases, and lower, more stable flows during the remainder of the year. We recommend that the following flow regimes be provided and evaluated for recovery of the target fishes: Sorino (March 21-June 21) We recommend that Flaming Gorge releases be increased in average and high water years (about 70% of the years) to pattern spring flows of the Yampa River, ~articularly with respect to timing and duration. Maximum streamflow of 113.2 m /s or more of warmest available water (highest lake levels) would provide needed fish habitat. These releases should be synchronized with Yampa River spring runoff, and occur for a period of about three to six weeks, resulting in an average flow in excess of 367.9 m3~s at Ouray, Uta~ (sum of average peak flow at mouth of Yampa River, 254.7 m Is, and 113.2 m /s released from F!aming Gorge Dam). This flow should be followed by flows of at least 56.6 m /s for an additional week. Bottomlands in the Jensen and Ouray areas would thereby be flooded, but fish access to these areas may need improvement. Water temperatures during Colorado squawfish migrations (May 23 to July 22) should range from 140C to about 220C. Water temperatures in the Ouray reach should be at least 200C by June I. 31