We examined ontogenetic, interspecific, and seasonal trophic patterns among sympatric sunfish species, redspotted sunfish,Lepomis miniatus; redear sunfish,Lepomis microlophus; and bluegill,Lepomis macrochirus, in an estuarine bayou. In particular we studied these feeding patterns in relation to relative abundances of prey from different benthic feeding habitats. All three sunfishes showed ontogenetic divergence in their trophic niches, reflecting different ecomorphological specializations. Small fishes depended on zooplankton, whereas larger fishes of all three species shifted their diets to benthic macrofauna. A potential for trophic resource partitioning was reflected by dietary differences among the three sunfish species. One impalied mechanism for resource partitioning was feeding habitat, as redear sunfish frequently used sediment-associated prey, while bluegill showed greater use of water-column-associated prey, and redspotted sunfish often used SAV-associated prey. However, all three sunfishes apparently used each feeding habitat to some degree; and, trophic differences were more clearly based on prey type than on feeding habitat. Redear sunfish, which can crush hard-shelled prey, exhibited the most distinctive diet. An apparent seasonal shift in feeding habitat occurred in autumn/winter, as indicated by increased overlap between diets and SAV. This shift was facilitated by changes in the relative abundances of several common prey types between benthic habitats. The relative abuandance and use of freshwater and estuarine-derived prey also varied seasonally, suggesting a possible trophic benefit of consistent prey availability in the estuarine bayou.

Sargassum-associated juvenile gray triggerfish and planehead filefish exhibited flexible feeding strategies in terms of their use of epifauna or pelagic zooplankton. Four diet samples represented instances of co-occurrence and segregated occurrence. Co-occurring gray triggerfish had the most specialized diets consisting mainly of pelagic copepods and hyperiid amphipods. Conversely, segregated triggerfish as well as both co-occurring and segregated filefish had broader diets mainly consisting of Sargassum epifauna, such as bryozoans, portunid crabs, and hippolytid shrimp. Still, co-occurring planehead filefish also consumed somewhat more zooplankton than segregated planehead filefish. Ontogenetic diet transitions were not as distinct for gray triggerfish as for planehead filefish. Our study demonstrates that juvenile tetradonts can be flexible in their use of benthic versus pelagic feeding strategies. Consequently, the influence of these key consumers on Sargassum food webs may vary spatiotemporally.