Deepend|restore (d|r) has developed a multi-mode sampling, sensing, and analytical program to assess trends in pelagic populations of the deep gulf of mexico, as well as the putative drivers of…

Deepend|restore (d|r) has developed a multi-mode sampling, sensing, and analytical program to assess trends in pelagic populations of the deep gulf of mexico, as well as the putative drivers of variability in these trends. With respect to population trends, the most substantive finding of this program is the sudden (within 3.5 y), severe, and sustained (> 10 y) decline in the abundance of oceanic micronekton (deep-living fishes, shrimps, and cephalopods) since the deepwater horizon oil spill. Micronekton are important prey for over 130 species of management concern in the gulf. With respect to drivers, findings indicate that multivariate parameters (depth, mesoscale oceanographic features, light environment) in concert with animal behavior appear to be the primary drivers of pelagic assemblages. No natural environmental factor that correlated with observed declines was identified. D|r has actively focused on resource management application and integration, with the most fruitful interactions occurring in six thematic areas: 1) gulf oceanic micronekton as prey of species that are actively managed, federally protected, or targets of ongoing restoration activities; 2) provision of information for past, current, and future natural resource damage assessments; 3) quantification of gulf oceanic biodiversity; 4) elucidation of other ecosystem services provided by oceanic micronekton; 5) quantification of microplastic ingestion and its ecological effects in the open gulf, and 6) capacity building for future research and resource management. These areas are discussed in detail herein. In the renewal period, d|r proposes to continue direct sampling and active acoustic sensing to assess population trends, with the note that there may be signs of nascent recovery in some taxa. These trends take on added importance given recent reports of oceanic cetacean population declines, relocations, and strandings of emaciated individuals. Our statistical analyses will add a biomass component to what has been an abundancecentered approach, which should enable greater ecosystem modeling utility. As with sampling, d|r proposes continuation of genomic diversity, organic contaminant, and microplastics ingestion analyses, with augmentations to each. D|r proposes a new highpriority optional element, detailed in a stand-alone addendum. The proposal concludes with a brief discussion of next steps in gulf open-ocean resource management beyond the renewal period.