Inter-Annual and Size-Related Differences in the Diets of Three Sympatric Black Bass in an Oklahoma Reservoir

ABSTRACT

We quantified the diets of juvenile and adult largemouth bass (Micropterus salmoides), smallmouth bass (M. dolomieu), and spotted bass (M. punctulatus) in Skiatook Lake, Oklahoma in 1997 and 1999 to assess inter-annual and size-related differences in food resource use. The diets of juvenile and adult largemouth bass consisted mainly of fish, but juveniles consumed a significant number of dipterans during both years. Smallmouth bass and spotted bass adult diets were similar to each other in both years; crayfish and fish were the predominant food items. Juvenile smallmouth bass and spotted bass were mainly insectivorous with fish and crayfish also making up a proportion of the diet. Mean diet overlap was greater in 1999 compared to 1997. These findings are consistent with the expanding population hypothesis that predicts increased niche overlap.