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9 15°C (Heidinger, 1975), some weight loss could occur in catfish in the Green River basin. Sizes of age 0 channel catfish captured in October in 1979 to 1985 (Fig. 2) were inversely related to the river discharge (r = -0.83; P = 0.02), and positively related with water temperature (r = 0.88; P = 0.01) during the preceding July to September period (Fig. 3). The small size and low numbers of young channel catfish collected in October seine samples in 1982 to 1984 (average TL = 33mm, n = 144; Fig. 2) was presumably due to inundation of shallow shoreline nursery habitats by unusually high summer flows (range of 108 to 253.6 m3/s), rather than a direct response to increased water velocity. These shoreline embayments were about 1.5 times more numerous during years of low-to-average discharge (years = 1979 to 1981 and 1985; discharge = 62.4 to 80.2 m3/s) and the young fish were larger and more abundant during these years (average TL = 47.3 mm, n = 460; Fig. 2). Aerial photographic mapping by the Bureau of Reclamation in 1986 to 1988 also revealed that embayments were reduced in area when flows in the Green River increased above average summer flows (M. J. Pucherelli, pers. comm.). Growth response to Green River temperatures was similar to that reported by others, and average temperatures recorded during the summer growth period (18 to 22°C, Fig. 3) did not approach the 30 to 35°C optimum reported by Layher and Maughan (1985). We detected no difference in growth (for ages 1, 3, 5, 7, and 9; ANOVA; P = 0.48) or condition factor (ANOVA; P = 0.24) between low and high gradient river reaches that varied greatly in habitat conditions. This suggested either that channel catfish stocks at these locations intermingled significantly or that factors other than physical habitat were limiting growth. Although channel catfish may display extensive movement in streams