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Floodplains are presumed to be important rearing habitat for the endangered razorback sucker (Xyrauchen texanus). To help recover this endemic Colorado River Basin species, the Upper Colorado River Endangered Fish Recovery Program implemented a floodplain acquisition and enhancement program. Levee removal was initiated in 1996 as one component of this floodplain restoration program. The goal of the Levee Removal Study was to evaluate the system responses to levee removal and make specific recommendations concerning the value of floodplain/river reconnecting for endangered species (specifically razorback sucker) recovery.
In the White River basin, water demand has increased with human development. Water development projects impact White River hydrology and sediment transport which can, in turn, affect resident Colorado pikeminnow populations. The objectives for this study were: 1) to compile historical biological, hydrological and physical data for the White River, 2) to analyze physical, chemical and biological features of the White River important to endangered fishes and, 3) to identify parameters for long-term monitoring to insure these features are maintained. We examined physical, chemical and biological characteristics during three development periods in the UCRB: early (1895-1945), middle (1946-1984) and post Taylor Draw...
Despite successful reproduction by razorback suckers (Xyrauchen texanus) in the middle Green River, recruitment beyond the larval stage has not been recently observed. Bonytail (Gila elegans) are essentially extirpated in the wild and nearly all bonytail present in the Green River are hatchery-stocked fish. Floodplain wetlands may provide important rearing habitat for both larval razorback sucker and bonytail. However, survival of razorback suckers in restored floodplain habitat has not been observed since 1997, even when larvae were introduced directly into floodplain sites. Large nonnative fish populations in floodplain habitats have likely suppressed survival. The recent drought eliminated, or reset, nonnative...
Flow recommendations for the Duchesne River represent an integration of physical processes needed to maintain channel complexity and substrate quality (high flow needs), with maintenance of adequate flows needed for endangered fish access, and productivity needed to sustain the prey base supporting Colorado pikeminnow (base flow needs). High flow recommendations for the Duchesne River were designed to maintain the geomorphic processes that form and maintain the present level of channel complexity, dictate habitat availability for endangered fishes, and provide discharge needed to rearrange substrate. These processes are based on the flows needed to mobilize bed load, maintain channel movement, and transport fine...
Floodplain restoration is an important element of the Upper Colorado River Endangered Fish Recovery Program. Floodplain restoration was initiated in 1996 by lowering natural and manmade levees that were preventing natural floodplain function by limiting the frequency and duration of river-floodplain connection.
ABSTRACT.-We compared diet of young-or-year Colorado squawfish (Ptychocheilus lucius), an endangered cyprinid, with diets of other fish <75 mm total length (TL) collected from backwaters of the Green River between river kilometers 555 and 35 during summer and autumn 1987. Species included native Rhinichthys osculus, Catostomus discoholus, and C. latipinnis, and nonnative Cyprinella lutrensis, Notrupis stramineus, Pit"l1&'Phales promelas, Ictalurus punctatus, and upamis cyanelll1s. For (;,-8.ch species, diet varied with size and between upper and lower river reaches but not between seasons for Hsh of similar size. Larval chironomids and ccratopogonids were principal foods of most fishes. Copepods and cladocerans...
The 2.3-mile reach of the Lower Gunnison River between the Redlands Diversion Dam and the confluence with the Colorado River is important habitat for Colorado squawfish and razorback sucker and is designated critical habitat for these two fishes. The purpose of this study was to recommend a minimum streamflow for passage of sub-adult and adult Colorado squawfish and razorback sucker during low-flows in this reach.