What Have We Learned About the Oceanic Fish Fauna of the Gulf of Mexico? Initial Results of the NOAA Offshore Nekton Sampling and Analysis Program

The Deepwater Horizon Oil Spill (DWHOS) necessitated a whole-water-column approach for assessment that included the epipelagic (0-200m), mesopelagic (200-1000m) and bathypelagic (\u3e1000m) biomes. The latter two biomes collectively form the largest integrated habitat in the GoM. This habitat received the initial oil/methane discharge, plus millions of liters of dispersant, and contained persistent deep (~1100m) plumes of oil and dispersant. By some estimates, only half of the discharged oil and none of the methane reached the ocean surface, demonstrating that DWHOS had an extensive deep-pelagic component. Before the DWHOS we had only a basic knowledge of the deep-pelagic GoM. Data regarding biodiversity, abundance, and distribution of the pelagic fauna were not comprehensive and thus, a large-scale program, the NOAA Offshore Nekton Sampling and Analysis Program (ONSAP), was implemented as part of the NRDA process. Here we provide the initial results of a 3-month ONSAP field campaign in 2011 in which the pelagic fauna was sampled from 0-1500 m. During this campaign, from the 87,402 specimens collected, a minimum total of 459 fish species were represented. Ongoing analyses will certainly increase this number, as hard-to-identify taxa are resolved. This figure represents nearly one-third of the fish species currently known for the GoM. Of these species, 53 are previously unknown in the GoM, including previously undescribed species