Feeding guilds among artificial-reef fishes in the northern Gulf of Mexico

Abstract

To examine the diets of 25 demersal artificial-reef-associated fish species, 540 fishes were collected with spears and hand-nets off Panama City, Florida, in the summer of 1993. Fishes were preserved whole in the field. Stomach contents were later analyzed by frequency of occurrence, numerical abundance, and percent volume. These measures were combined into an Index of Relative Importance (IRI). The data set was then analyzed with cluster and detrended correspondence (DCA) analyses. Forage items of the reef fishes were dominated by fishes, xanthid crabs, unidentified items, squids, polychaetes, and penaeid shrimps. The DCA and cluster analysis revealed that these 25 artificial reef fishes could be organized into seven feeding guilds: lower structure pickers, ambush predators, lower structure crustacean predators, upper structure pickers, upper structure predators, water column pickers, and reef-associated open-water feeders. All of the demersal gamefish in this study were in the same feeding guild (i.e., reef-associated open-water feeders). Species in this feeding guild were associated with artificial reefs diurnally and foraged away from reefs nocturnally. Our data indicate that many important artificial-reef-associated fishes in the northern Gulf of Mexico obtain most of their energy foraging away from the artificial reef structure.