The Dynamics of Vertical Movement in the Oceanic Gulf of Mexico after Deepwater Horizon: Active Linkage of Large Vertebrates and Deep-Pelagic Nekton

Toothed whales, smaller oceanic cetaceans, seabirds, and epipelagic gamefishes rely on deep-pelagic (meso- and bathypelagic) nekton as primary or secondary prey. This trophic interaction is mediated by downward and upward vertical movements (e.g., sperm whale diving and lanternfish diel migration, respectively). This interaction also links particle-feeding lower trophic levels with top predators in a manner that spans the gamut of depth domains. This is particularly important with respect to a whole-water column disturbance such as the Deepwater Horizon oil spill. Here we present highly resolved vertical distribution and migration data collected during a large-scale, NOAA-supported, deep-pelagic (0-1500 m) survey in 2011, along with data collected during ongoing GoMRI-supported DEEPEND consortium surveys. The deep-pelagic nekton community of the Gulf of Mexico is a complex mixture of migrating, non-migrating, and partially migrating assemblages that connect surface waters with depths in excess of 1000 m. Major patterns of vertical distribution for 400+ species of fishes, shrimps, and cephalopods, the primary prey of many important species of oceanic vertebrates living near-surface, will be summarized and quantified with the goal of highlighting potential vectors of anthropogenic contaminant transfer in the deep-pelagial, the Gulf’s largest ecosystem.