2027: Fine-Scale Surveys of the Deep Midwater

Deep-sea fishes are agents of ecological connectivity in the largest marine ecosystem on Earth. Mobile mesopelagic fauna (inhabiting 200 - 1000 m depths) are important prey for economically valuable fishes (e.g., deep snappers and groupers) and species of high conservation value (e.g., endangered deep-diving marine mammals). However, they are one of the least studied faunal groups on Earth, with quantitative estimates of the abundance, composition, and biomass of these organisms poorly constrained. Here, we propose an integrated, multidisciplinary study to examine the short-term dynamics in composition, density, and fine-scale vertical distribution patterns of deep-living fish fauna across pelagic, benthopelagic, and benthic habitats relative to both biotic and abiotic variables. We will use an established benthic lander system (ALBEX) with novel benthopelagic imaging capabilities and a low-disturbance autonomous vehicle (VAMPIRE) to collect, in unprecedented detail, stereo images, active acoustic, and abiotic data from the oceanic rim, and leverage existing data to provide taxonomic and broad-scale ecological context. By combining these multiple approaches, we will progress our understanding of the dynamic cross-ecosystem linkages that exist between midwater prey taxa and their benthopelagic and demersal predators.