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. 35 . indicates that preferred habitat concentrates juvenile squawfish and suggests they may move to areas that contain preferred habitat. There are several factors that may account for the observed preference of backwaters by young-of-the-year and juvenile Colorado squawfish. These include escape from predation and/or competition and/or the rigors of the river, and the presence of an abundant food supply. Table 3 indicates that a number of potential predators and competitors are found with the young fishes, especially young-of-the-year. Back- waters seldom provide physical protection such as undercut banks and overhanging vegetation. Therefore, escape from competition and predation do not appear to be likely concentrating factors. To escape the rigors of the main river, areas with little current probably would be selected. Many such areas exist in eddies and along the edges of runs, as well as in backwaters. No young-of-the-year squawfish and only a few juveniles were found in such areas. Therefore, escape from the stresses imposed by the river does not appear to be a major concentrating factor. Backwaters tend to be nutrient rich due to the silt substrate, and warm due to slow water exchange. These habitats are not as dramatically affected by water level fluctuations as are other habitat types. All young-of-the-year less than 30 mm found during the present study were concentrated in these areas. Such areas are the primary large river habi- tat where crustaceans (Cladocerans and Copepods) and many small aquatic insects can thrive. Vanicek (1967) found that young-of-the-year squaw- fish fed on these organisms and gradually shifted to larger aquatic in- sects and small fish as they grew larger. Backwaters, therefore, provide . . . . . . . . .