Presenter: April Cook (Nova Southeastern University)

Description:
The Deepwater Horizon (DWH) disaster was unique for its size and the range of ecosystems affected. Of these, the deep-sea pelagic ecosystem was by far the largest. Assessment of impact to this ecosystem was hindered by a lack of existing data, necessitating an extensive, multi-year survey of the fauna from the sea-surface to 1500 m depth. In the last ten years we have reported results from two of three sequential research programs that have profoundly changed our perspective of this ecosystem. First, the Gulf is one of the most diverse pelagic ecosystems in the World Ocean, owing to a number of factors. With 897 species of fishes identified since 2010 (including 186 new records), we now know that the majority of fish species in the Gulf spend all or part of their lives in the pelagic realm. Second, the pelagic fauna is highly connected vertically due to daily migrations and horizontally due to advection, including an onshore component. This finding necessitates a holistic approach to the management of the Gulf as a large marine ecosystem. Third, pelagic populations in the Gulf have plummeted since DWH. Declines occurred between Sep 2011 and April 2015, and subsequent sampling/analysis (to August 2018) has not shown signs of recovery. Available evidence suggests that trophic levels in the open Gulf are tightly linked, suggesting that reductions in intermediate levels could reverberate throughout the system. Here we describe ongoing efforts of the DEEPEND|RESTORE program to further investigate population trends and drivers, as well as translate offshore data products into resource management tools. With the deepening trajectory of the oil industry in the Gulf (i.e. increasing likelihood of future spills), the vital role the deep-pelagic fauna play in carbon sequestration, and the linkages between the deep-pelagic fauna and federally managed species (e.g., cetaceans, tunas, billfishes, sharks), sustained observation of the open ocean Gulf is critical.