Benthic imagery in reef ecosystems: toward operational Essential Ocean Variables and Essential Biodiversity Variables

Elizabeth Hasan^1,2,3, Dominique Pelletier¹, Jacquomo Monk³, Neville Barrett³, Ben Scoulding⁴

¹IFREMER, France - ²Université de Bretagne Occidentale, France - ³University of Tasmania, Australia - ⁴CSIRO, Australia

Essential Ocean Variables (EOV) and Essential Biodiversity Variables (EBV) have been defined by the Global Ocean Observing System and the Group on Earth Observations Biodiversity Observation Network, respectively, as conceptual frameworks for consistent global monitoring of ocean and biodiversity health. Benthic imagery has become an important observation tool as it allows access to waters that were not previously visually surveyed, surveys can cover large spatial extents in less time than other visual methods, and data are retained for further assessment, quality assurance, and outreach. Yet, EOVs and EBVs have been insufficiently described so far in terms of their application to benthic imagery. Many benthic imagery studies indeed calculate metrics that fall into the EOV and EBV categories but are not reported in relation to these frameworks. However, progress towards the United Nations Sustainable Development Goal 14 and the global biodiversity conservation goals objectives (including the goals of 30 by 30) requires cross-border spatial analyses of ocean health and therefore regionally and globally scalable and interoperable EV metrics. To assess the current state of contributions of benthic imagery to global assessment of ocean health, this study reviewed the literature on reef ecosystems, both temperate and tropical, utilizing benthic imagery. The metrics reported by each study are organized into the EOV and EBV categories related to benthic habitat and communities. The goal of this synthesis is to inventory the EOVs and EBVs that are extracted from imagery and assess the knowledge gaps that benthic imagery can and cannot address in terms of large-scale conservation policy assessments. The result will serve as a guide to data producers and users for how benthic imagery can be incorporated into policy with EOV and EBV conceptual frameworks.