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30 The dominant fishes collected during 1977 by Prewitt et al. (1978) in the White River in Colorado were flannelmouth suckers (71%), mountain white- fish (11%), bluehead suckers (8%), and roundtail chubs (6%), all native species (Table 2). In the Utah portion of the White River endemic fish were found to be more abundant than exotics at all 6 upper stations during 1974-75; only at the 2 stations in the lowest section of the river were exotics more abundant (Crosby, 1975). By 1978 native fishes dominated the fish fauna at only 3 stations in the upper Utah portion of the White River and exotic fish dominated the fauna at one station in the upper part of the White River and all middle and lower stations. From these studies it is evident that exotic fish have replaced endemic species in the lower section of the White River, Utah and are becoming more numerous upstream as well. This pattern of endemic fish displacement has occurredin several other western rivers and streams (McAda et al., 1977; Holden and Irvine, 1975; Deacon and Bradley, 1972; Cross, 1976). McAda et al. (1977) noted that in the San Rafael River the displacement of native by exotic species was probably due to the difference of habitat between the upper and lower sections of the river. The White River fish fauna may also have been influenced by habitat. The river can be partitioned into three habitat types. From the Utah-Colorado State border to .5 mi (.9 km) above Ignatio (Fig.7),the river was a combination of shallow ( <1 m) rapids composed of small rubble and deep rapids containing large boulders. The river was often restricted by high canyon walls which resulted in few large backwater areas. Occasionally, side channels split off from the main channel and where the two rejoined, pools were formed. Numerous small deep pools along the banks and behind debris were also present. The middle section of the White River, from Ignatio to Atches Wash (Figure 13), had a wide diversity of habitat which varied from