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<br />Ictalurus punctatus (22.5-70.0 mm TL, mean 42.9), and 18 green sunfish Lepomis <br />cvanellus (20.7-56.8 mm TL, mean 39.6). <br /> <br />Characterization of Diets <br /> <br />No major or consistent seasonal differences in diet measures were observed within <br /> <br />species for fish in similar size intervals. Accordingly, data for summer and fall were <br /> <br /> <br />combined for species and length intervals by river reach. Trends in values of proportional <br /> <br /> <br />importance of each food category were similar between the two diet measures for all fishes, <br /> <br />therefore only values for mean of volume percentages are reported herein. <br /> <br />Insects, zooplankton, algae, plant seeds, and organic and inorganic debris were the <br /> <br /> <br />main dietary components over all fish analyzed, but their relative importance in diets varied <br /> <br /> <br />among fishes or subsets within a species (Table 1). Based on total number of food <br /> <br /> <br />categories included in the diet of each fish species, diets of Colorado squawfish and red <br /> <br />shiner were the most diverse (18 and 17 food categories, respectively) followed by speckled <br /> <br />dace (15), fathead minnow, channel catfish, and green sunfish (12 each), sand shiner (11), <br /> <br /> <br />flannelmouth sucker (9), and bluehead sucker (6). Diversity of food consumed was greater <br /> <br />in the lower than upper reach for red shiner, Colorado squawfish, flannelmouth sucker, <br /> <br /> <br />channel catfish, and green sunfish, whereas diets of sand shiner, fathead minnow, and <br /> <br /> <br />speckled dace were more diverse in the upper reach (the diet of bluehead sucker was <br /> <br />analyzed only for fish from the upper reach). Diet diversity relative to fish length was <br /> <br /> <br />greatest in red shiner, sand shiner, fathead minnow, Colorado squawfish, speckled dace, <br /> <br />and bluehead sucker 21-30 or 31-40 mm TL and in flannelmouth sucker, channel catfish, <br /> <br /> <br />and green sunfish > 40 mm TL. Mean % fullness of digestive tracts was highest in fish <br /> <br />21-30 or 31-40 mm TL for all species. <br /> <br />7 <br />