Feeding Ecology of Reef Fish at Artificial Reefs in the Northwestern Gulf of Mexico

Two heavily exploited species in the Gulf of Mexico (GOM), Red Snapper Lutjanus campechanus and Gray Triggerfish Balistes capriscus, were used as model species to contrast the feeding ecology of demersal and midwater predators at nearshore (16-60 km offshore) artificial reefs (ARs).  Red Snapper (demersal, n=115) and Gray Triggerfish (midwater, n=51) were collected via vertical longline and trap surveys across six AR sites (comprised of various reef types) ranging from 13 –31 meters in depth from August- November of 2014. Epaxial muscle tissue was used to obtain species-specific isotope ratios, and stomach contents were identified to the lowest possible taxon. Stable isotope ratios of carbon (δ¹³C), nitrogen (δ¹⁵N), and sulfur (δ¹⁵S) paired with stomach content analyses were used to compare the feeding ecology of model species, and also to examine ontogenetic dietary shifts of Red Snapper across different reef types. Red Snapper stable isotope values for carbon (mean = -17.70) and nitrogen (mean = 14.60) were enriched relative to Gray Triggerfish, while sulfur (mean = 18.76) was more depleted.  Results of this study will impart valuable insight on the functional role of ARs to these model species, and will be discussed in terms of species life history and fisheries productivity.