A Coast-Wide Video Survey Around Small Oil and Gas Platforms throughout Louisiana's Dynamic Nearshore Coastal Zone: How Do Fishes Respond to Eutrophication and Hypoxia Around Standing Platforms?

Fish assemblages around 205 small oil and gas platforms in the nGOM were surveyed during summer of 2013-14.  The survey covered the entire Louisiana coastline, limited to nearshore waters less than 50 feet deep.  We used a remotely deployed video array to characterize fish assemblages, and a YSI sonde for detailed surface to bottom hydrographic profiling (temperature, salinity, DO, turbidity).  Analyses of video provided insights into the response of reef associated fishes to coastal hypoxia.  As artificial reefs the platforms are unique in that they offer vertical relief through the entire water column for fishes and small invertebrates.  They also occur off Louisiana throughout the latitudinal and longitudinal extent of what is commonly known as “the dead zone”.  We observed a high degree of variability in hydrographic conditions coinciding with freshwater input from the Mississippi-Atchafalaya River system and the numerous coastal bays of Louisiana, and related this to fish distribution.  Variable water column stratification and fish presence allowed us to draw inferences about ecosystem services provided by this expansive de facto artificial reef network at a time when these structures are rapidly being removed as production operations move offshore.