Hydroacoustic and Video Surveys in the Northern Gulf of Mexico in Louisiana's Artificial Reef Planning Area: A Comparison of Biomass and Community Structure

There has been relatively little study of the efficacy of decommissioned oil and gas platforms as artificial reef habitats for various species of fish in the northern Gulf of Mexico (GOM).  Hydroacoustic and video surveys were conducted quarterly from June 2013 to June 2014 at three standing and two toppled oil and gas platforms located approximately 130 km off the coast of Louisiana at 90 m depth; to gain information about the spatial biomass distribution and community structure at various structure types. The toppled platforms in our study became a part of the Louisiana Artificial Reef Program in 2002.  Stereo cameras and Go-Pros were utilized for video surveys, allowing us to record counts and lengths of fishes.  Hydroacoustic surveys were used to define the spatial distribution of fish biomass (MVBS, S_V) in relation to distance and depth up to 500 m from the center of each site.  The spatial biomass distribution was highest near the structure itself, and declined rapidly with distance.  The community structure of fish varied depending on season and depth layers in water column.  Coupling non-invasive methods allows for effective monitoring in order to determine what impacts artificial reef structures in the GOM have on associated fishes.