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nonnative fish. Terrace floodplains would be available at the same time as depression wetlands and offer favorable nursery habitat. However, ifterrace floodplains are lost at flows of 447 m3/s, the first razorback sucker larvae to appear in the river would have had access to the floodplain for only 14 days in 1995, and in 1996 flows did not exceed 447 m3/s when larvae were present (Figure 17). Thus, the majority of larvae would have had less than 14 days in the floodplain in 1995 and no larvae had access to floodplain in 1996. Following the brief use of favorable nursery habitat in a terrace floodplain, larval razorback sucker would be exposed to colder temperatures, fewer velocity refuges, and much lower zooplankton densities after returning to the main river channel. Because flood flows recede gradually, most backwaters that provide low velocity refuge, favorable temperatures, little cover, and marginal prey densities (according to Papoulias and Minckley 1990) would not have appeared (i.e. 109 m3/s) until 36 d after larvae had been in the river in 1995. In 1996; larvae were first collected after flows receded below 447 m3/s and never had access to floodplain habitats. The time from collection of the first razorback sucker to collection of the last razorback sucker larvae collected in 1996, and to the time flows reached 109 m3/s, was 37 d and 13 d respectively. Papoulias and Minckley indicated that larval razorback sucker die if they do not feed within 20 to 30 d following hatching. Extending flows of 447 m3/s in 1995 and 1996 would have allowed more drifting larval razorback sucker access to floodplain wetlands in the Ouray area. Larvae in terrace wetlands would have had longer access to favorable nursery environment, and the time larvae or juveniles would have to remain in the river prior to the appearance of backwaters would decrease, reducing downstream drift loss and associated mortality. A major difference between fish reared in depression and terrace/main channel habitats would be a reduction in growth of the latter. Slower growth of fish using the floodplain terrace/main channel scenario would result in smaller fish in a backwater habitat with lower prey densities and less cover. Therefore, fish reared in terrace floodplains and the main channel would have access to lower prey densities, a greater size range of predators for a longer time without cover than fish reared in depression wetlands. This study demonstrated that Old Charley Wash (i.e. depression wetlands) provided an environment that allowed growth and survival of razorback sucker from the larval to the juvenile lifestage. Age-O razorback sucker grew and survived in an environment with high prey densities, cover and nonnative fishes. If it is assumed that the same number of age-O fish survived in other large depression wetlands in the Uintah Basin (i.e. Leota Bottoms, Wyasket Bottoms, Johnson Bottoms, Stewart Lake, Sportsman Lake, etc) significant numbers of age-O would have survived into the fall. The questions that emerges from this.study are; what would be the fate of the large number of nonnatives produced in depression wetlands if released into the Green River, and would they have a negative impact on endangered fish (i.e. age-O Colorado squawfish) in the Green River? The ongoing levee removal study should provide insight into this question. Given the data and discussion above, I offer the following management recommendations: 1. Because depression wetlands have demonstrated potential for growth and survival of age- o razorback sucker in flooded bottomlands, the recovery program should maximize the management of some large depression wetlands to produce and release native fishes into the Green River. Conversion of depression wetlands to terrace floodplains offers a quality nursery environment for larval fishes for a short time but does not offer a substitute for the duration of favorable conditions that optimize growth and 45