Artificial Reefs as Surrogate Habitats for Red Snapper in the Northwestern Gulf of Mexico: A Fishery-Independent Comparison of Artificial and Natural Habitats

The goal of our study was to evaluate the relative abundance, size and age structure of Red Snapper among three different habitat types (standing oil and gas platforms, artificial reefs [rigs-to-reefs], and natural banks) in the northwestern Gulf of Mexico. From May 2013 - January 2015, we conducted 140 vertical line sets and captured 1538 Red Snapper ranging in size from 251 to 855 mm TL. Ages determined for 801 of these fish ranged from 2-30 years. No differences were detected in Red Snapper CPUE among the three habitats. However, a comparison of TL and TW distributions suggested that natural banks supported a greater proportion of larger fish than artificial reefs or standing platforms (K-S test, p<0.001). Mean TW-at-age regressions for the most common age groups (ages 3-7) suggested that Red Snapper grew faster at artificial reefs and standing platforms than natural bank habitats (ANCOVA, p<0.05). Mean age was positively correlated with capture depth (r=0.79) suggesting spatial variation in age composition. These results have important implications for artificial reef development and Red Snapper management in the GOM. Further use of standardized, fishery-independent surveys and additional biological data will help elucidate the role artificial structures play in maintaining the Red Snapper population.