The DEEPEND (Deep Pelagic Nekton Dynamics of the Gulf of Mexico) Consortium is a 105-member, 19-institution research initiative to characterize the oceanic ecosystem of the northern Gulf of Mexico to infer baseline conditions in the water column. The deep-pelagic represents both the largest and the most understudied habitat on Earth. Although evidence has shown that the surface and deep community assemblages are linked, the exact pathways and linkages remain primarily undiscovered. In 2010, the Gulf of Mexico experienced the BP Deepwater Horizon Oil Spill (DWHOS). Although portions of oil made it to the surface while others were dispersed, all of the oil was at one point present in the water column, interacting with the pelagic community. The full extent of the DWHOS’s effects on the pelagic community is still not known. Starting in 2015, DEEPEND began a five-year sampling, sensing, modeling, and laboratory analysis program assessing ecosystem dynamics, identifying drivers of variability, and investigating consequences of the spill on ecosystem attributes. The obtained data establishes a time-series with which one can detect natural and anthropogenic changes. This research was made possible in part by a grant from The Gulf of Mexico Research Initiative, and in part by the National Oceanic and Atmospheric Administration's RESTORE Science Program under award NA19NOS4510193 to Nova Southeastern University. Data are publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at https://data.gulfresearchinitiative.org.