Diet Ecology of Yellow Bass, Morone mississippiensis, in an Oxbow of the Mississippi River

ABSTRACT

The yellow bass (Morone mississippiensis) is native to the Mississippi River drainage and some adjacent Gulf of Mexico tributaries where it inhabits backwaters, oxbows, and reservoirs. We described the diet ecology of yellow bass in an oxbow of the lower Mississippi River, assessed differences in diets between life stages, and measured diet overlap between yellow bass and coexisting species. Indices of diet breadth differed among age groups, with the diet of age-1 yellow bass being more specialized than that of larger fish. Although the yellow bass consumed a wide array of food items, it tended to rely on certain foods during different life stages. Age-1 yellow bass fed on chironomids, amphipods, and fish eggs, which accounted for 84% of the diet by weight. Age-2+ yellow bass consumed fish, fish eggs, amphipods, and benthic insects, which was over 70% of the diet by weight. Diet overlap was not significant (P > 0.20) between age-1 and age-2+ yellow bass, or between age-1 yellow bass and age-0 largemouth bass (Micropterus salmoides), inland silverside (Menidia beryllina), or juvenile bluegill (Lepomis macrochirus), suggesting that exploitative competition did not occur. Nevertheless, interactions between yellow bass and coexisting species may take the form of intraspecific predation given the propensity of the yellow bass to eat fish eggs.