Stable isotope data from reef fish collected at natural reefs sites in the northern Gulf of Mexico from November 2010 – August 2011.

Approximately 50 grams of white muscle tissue was removed from reef fish to perform stable isotope analysis. Muscle tissue samples were dried at 60°C for at least 24 hours, and then ground into a fine powder with a glass or agate mortar and pestle. Mortars and pestles were cleaned with 2% nitric acid and rinsed with Milli-Q water between samples to prevent cross contamination. Ground samples containing between 0.2 and 0.5 g of pulverized dried tissue were placed in sterile plastic centrifuge tubes and shipped to a contract laboratory to perform analysis of d13C, d15N, and d34S with a Europa Scientific GSL/Geo 20-20 stable isotope ratio-mass spectrometer (SIR-MS). The isotopic ratio of a sample relative to the ratio in a standard was reported as a delta value.