Distribution and Food Habits of Young-of-the-Year Fishes in a Backwater Lake of the Upper Mississippi River

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Abstract
The distribution patterns and food habits of young-of-the-year (YOY) fishes in a lentic area adjacent to the main channel of pool 7 of the upper Mississippi River were studied. Habitats sampled grouped distinctly based on percent composition and abundance of YOY fishes with those having submergent vegetation dominated by a number of important sport species. In late spring, the grouping of stations depended on the presence or absence of newly transformed northern pike (Esox lucius). In early summer, stations did not differ as distinctly in composition, but in total abundance of young. Those stations with submergent vegetation had total catches which were more than double those elsewhere. By late summer, submergent and mixed vegetation stations formed a distinct assemblage influenced by the preponderance of three species of sunfishes. Their diets suggested that species inhabiting areas of submergent vegetation were very flexible in their choice of food resources. Black crappie (Pomoxis nigromaculatus), rock bass (Ambloplites rupestris), and bluegill (Lepomis macrochirus) fed on similarly sized items. Increased sedimentation or deposition of dredged material in backwaters may adversely and severely affect recruitment of several sport fish species by reducing or removing critical beds of submergent vegetation.