A Temporal Analysis of a Deep-Pelagic Ecosystem Assemblage in the Gulf of Mexico After the Deepwater Horizon Oil Spill.

Nichols, Devan, Tamara Frank, Tracey Sutton, Joana Figueiredo, TWB Environmental Research and Consulting, Inc.

In 2010, the largest oil spill in U.S. history occurred off the coast of Louisiana from April 20th to September 19th, releasing more than 4.4 million barrels of crude oil into the Gulf of Mexico (GOM). This spill was unique because it occurred in deep water approximately 1500 m below the ocean surface. This study focuses on one of the most abundant and diverse groups of pelagic decapod crustaceans in the GOM – the family Oplophoridae. This study is unique because it covers a large temporal range with data collected in 2011 and from 2015-2017, allowing for a more in-depth look at assemblage patterns. This information is important in understanding how the Deepwater Horizon Oil Spill may have affected the GOM ecosystem because pelagic decapod crustaceans are intermediate components of the food web and are, in turn, preyed upon by higher trophic levels, including commercially important epipelagic fishes. Data were analyzed with respect to year and season to determine if any trends were present. Results indicate that both biomass and abundance were significantly higher in 2011, indicating that the ecosystem has been declining since 2011. This presentation will focus on what this means for the GOM ecosystem, and what this significant decline in crustaceans may mean for the fishing industry moving forward. These data will act as a reference state for future studies in the GOM to monitor changes, or lack thereof, in the assemblage of deep-sea organisms. Similar studies could be applied in the Northeast to monitor future anthropogenic disturbances.