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13 <br />larval foods generally reflected the most numerous animals in the <br />plankton, they also appear to forage among beds of vegetation. <br />Smaller larvae (<12 mm) from the Arizona Bay backwater ate foods <br />similar to those of larvae from the lake (Table 3), but most stomachs <br />were again empty. Larger larvae (>12 mm) had significantly fewer empty <br />stomachs. Although their diet was considerably more diverse than that <br />of smaller individuals, either there or in -the lake, primary foods were <br />the same (Table 3). <br />Sizes of food taken by larval razorback were highly variable, both <br />in the lake and in the backwater. Smallest items were rotifers and <br />largest zooplankters were Daphnia (Table 4). Chironomidae larvae in <br />stomachs of the largest sucker larvae from the backwater were the <br />largest items overall. Among predominant foods, sucker larvae took <br />individual items which were significantly smaller than in the plankton <br />population at large (t-test for comparison of means, p = 0.95). This is <br />especially notable for Daphnia which averaged 0.66 to 0.86 mm in length <br />in sucker stomachs, about half the average size (1.42 to 1.60 mm) in <br />plankton samples (Tables 2, 4). <br />Benthic invertebrates (chironomids, ostracods, trichopterans), <br />because of their generally large sizes, may contribute more to larval <br />nutrition than indicated by data on occurrence and numbers (Table 3). <br />Use of these foods, plus Macrothrix, indicates that larval suckers <br />utilize varied food resources and forage among essentially all available <br />habitats (limnetic, benthic, and macrophytic).