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water flows between 0-525 cfs (USFWS 1986). Five humpback chub (age 11-III years) were captured in water 20 to 29 feet deep. An additional age-I humpback chub was caught in water less than 10 feet deep. Humpback chub in the upper Colorado River (Valdez 1981; Valdez and Clemmer 1982) occupy deep, swift riverine areas. Valdez et al. (1982b) and Wick et al. (1979, 1981) found humpback chub in Black Rocks and Westwater Canyons in water averaging 50 feet in depth with a maximum depth of 92 feet. In these localities, humpback chub were associated with large boulders and steep cliffs. In the Lower Basin, humpback chub are found in the same general types of canyon habitats as in the Upper Basin (Minckley 1973). These general habitats are characterized by swift waters and rocky substrates, with the humpback chub most often utilizing shorelines, eddies and backwaters (Kaeding and Zimmerman 1983; Maddux et al. 1987; Valdez et al. 1992). In the Little Colorado River, large main channel pools, pools adjacent to eddies, and areas below travertine dams are often used by adult humpback chub (Minckley et al. 1981). MOVEMENT/MIGRATION Generally, humpback chub show fidelity for canyon reaches and move very little (Miller et al. 1982c; Archer et al. 1985; Burdick and Kaeding 1985; Kaeding et al. 1990). In the Grand Canyon, humpback chub move from the main channel Colorado River into the Little Colorado River to spawn (Kaeding and Zimmerman 1983). Juvenile fish have been collected about 160 miles below the Little Colorado River (Maddux et al. 1987; Valdez et al. 1992). Movements of adult humpback chub in Black Rocks on the Colorado River were essentially restricted to a 1 mile reach. These results were based on the recapture of Carlin-tagged fish and radiotelemetry studies conducted from 1979 to 1981 (Valdez et al. 1982b) and 1983 to 1985 (Archer et al. 1985; USFWS 1986; Kaeding et al. 1990). BONYTAIL (Gila elegans, Baird and Girard 1853) The bonytail chub is the rarest native fish in the Colorado River. Formerly reported as widespread and abundant in mainstream rivers (Jordan and Evermann 1896), its populations have been greatly reduced. The fish is presently represented in the wild by a low number of old adult fish (i.e., ages of 40 years or more) in Lake Mohave and perhaps other lower basin reservoirs (USFWS 1990a). The fish were once common in Lake Mohave and Wagner (1955) observed the fish in eddy habitats. A few individuals were reported in other locations, but concentrations of the fish have not been recently reported (Kaeding et al. 1986). The discussion on bonytail habitat needs is presented differently than the other three endangered species in this document. The Bon_ytail Recovpa Plan (USFWS 1990a) divides 30