Habitat differences in the feeding ecology of red snapper (Lutjanus campechanus, Poey 1860): a comparison between artificial and natural reefs in the northern Gulf of Mexico

Abstract

Red snapper (Lutjanus campechanus, Poey 1860) support a valuable commercial and recreational fishery in the northern Gulf of Mexico; however there is much debate as to the role of habitat, particularly reef structures, in the feeding ecology of this species. Furthermore, little information is available from fish collected on large natural reefs, such as those on the continental shelf edge, thought to be the historical center of abundance. Previous research indicates that little nutrition is derived directly from artificial reefs; rather the majority of prey comes from surrounding soft bottom habitat. The goal of this study was to determine if there are differences in the feeding ecology of red snapper between standing oil and gas platforms, toppled platforms designated as artificial reefs, and natural reefs on the continental shelf edge, using a combination of gut content and stable isotope analyses. Results indicate that fish dominated diets at all three sites, but that differences exist in the contribution of major prey items by percentage dry weight among habitats. Red snapper collected from standing platforms consumed primarily fish, squid, and shrimp, while greater amounts of crabs, shrimp, and other crustaceans were consumed at toppled platforms. On the natural reefs, diets varied the most, consisting of both fish and crustaceans. Stable isotope analyses suggest fish collected over the standing platforms are more enriched in δ15 N, indicating feeding at a higher trophic level than the other habitats. No differences were observed in mean values of δ13C or δ34S, indicating consistency in basal resources among habitats.