The NOAA NRDA Gulf of Mexico Offshore Fish and Nekton Program: Rationale, Design and Sampling/Sensing Synopsis

The Deepwater Horizon Oil Spill was not only unique for its material volume but also for its depth, ~1500 m, necessitating a wholewater- column approach for assessment. Given the absence of data regarding the pelagic fauna at these depths, a large-scale program was developed that included at-sea sampling/sensing, sample analysis, and database management. A four-cruise survey aboard the NOAA ship Pisces was conducted to provide data on the pelagic nekton from the surface to 1600 m, with emphasis between 800-1400 m (subsurface plume depth). Multi-frequency acoustic data were collected simultaneously to further characterize the horizontal and vertical distribution of pelagic biomass. Additionally, a 107-station survey grid was sampled over nine months on the R/V Meg Skansi using discrete-depth trawl gear paired with multi-frequency acoustics. Given the wide geographic (LA to FL, 29-27N), temporal (4 seasons), and depth (0-1600 m) ranges encompassed in the program, this is putatively the largest deep-pelagic sample set ever collected. Biological sample with coupled acoustic data analysis is currently ongoing, with initial results reflect the speciose character of the Gulf of Mexico oceanic province.