This dataset is a compilation of spatial layers and scientific data underpinning the 2022-23 revision of the nomination proforma for the "North Atlantic Current and Evlanov Sea basin" (NACES) marine protected area (MPA) in the OSPAR Maritime Area (Region V, Wider Atlantic). An analysis of seabird tracking data by BirdLife International led to identification and subsequent designation of the site in 2021. The seafloor was not included as part of this designation, but a two-year process was agreed to review the available evidence with the aim to expand the conservation objectives of the site to encompass the seafloor. This review process included compiling new data available from many sources including those collected during the European Union iAtlantic project (2019-2024) to expand the underlying evidence base. This led to the compilation of both existing and newly collected datasets on geodiversity and oceanography, as well as benthic and pelagic biology. This new compilation reaffirms the importance of the NACES area, for example as a significant Atlantic frontal zone with high mesoscale activity and high potential for upwards and downwards bentho-pelagic coupling. This in turn is illustrated by a diverse benthic marine invertebrate fauna, with some species at the northernmost extent of their geographical ranges. The complex oceanography of the region helps explain its productivity, supporting a hotspot for mesopelagic fish and the seabirds and other higher trophic taxa that feed upon them. This collaborative effort led to an amendment of OSPAR Decision 2021/01 and the expansion of conservation objectives from the initial focus on seabirds and the ecosystems and processes that support them to include a broader suite of species and habitats, including the seafloor and subsoil thereof, and the associated ecosystems, and their processes and functions. This geodatabase includes multiple layers relating to local and regional boundaries. These include the boundary of the NACES MPA, Milne Seamount Complex MPA, and wider OSPAR MPA network, as well as the Mid-North-Atlantic Frontal Zone Ecologically or Biologically Significant marine Area and Important Bird and Biodiversity Area. The OSPAR Commission 2023 amended the delineation of the NACES MPA boundary based on the addendum submitted by the Portuguese Republic in 2017 to the Commission on the Limits of the Continental Shelf regarding the establishment of the outer limits of the Portuguese continental shelf. This change was not retroactively implemented in the revised nomination proforma, however a layer for the proposed extended shelf boundary has been included here. This database also compiles multiple published and previously unpublished layers based on a mixture of modelled and ground-truthed data. The geodiversity layers include features such as abyssal plains, ridges and seamounts, as well as multibeam data from the iAtlantic "IceDivA2" cruise (2021), which includes detailed bathymetry of the Mount Doom seamount that was discovered during the expedition. The unique oceanography and global climatology of the region can be visualised from layers on percentage of eddy coverage and mean bottom eddy kinetic energy as well as chlorophyll a concentration. The biology of the region can be explored in the OBIS species diversity layer, seabird stopovers and wintering areas, whale movements including sightings from the DY080 cruise (2017), bluefin tuna corridors, mesopelagic fish catches, modelled habitat suitability for black and scleractinian corals, and cephalopod, zooplankton and phytoplankton sample stations. The anthropogenic activities of the area can be mapped in the form of oil and gas well sites, shipping lanes, and Global Fishing Watch apparent fisheries effort activity data (excluding bottom trawling activity). In total the dataset includes 64 layers from over 40 sources, available as either an ESRI shapefile (.shp), GeoTIFF (.tif), Geodatabase (.gdb), Gridded data (.grd) or netCDF (.nc). An explanatory text (.txt) has been provided along with layers where further description on the contents or use of the layer is needed. The layers are ordered based on boundaries (1-8), geodiversity (9-24), oceanography and global climatology (25-31), biology (32-57) and anthropogenic activities (58-64). Where possible, attribute tables contain further information related to the spatial layer such as species name, fauna counts, eddy characteristics, and so on. This dataset was created using QGIS 3.36 Maidenhead with the aim of supporting the ongoing management and monitoring of the NACES MPA in the context of a changing ocean.

Acknowledgements: Thanks to Jannos Hennicke, Richard Emmerson, Michail Georgios Papadoyannakis, Eirik Drabløs Pettersen, Alice Belin, Pia Norling, Dominic Pattinson, Lena Avellan, Emily Corcoran and Barbara Middleton for their support throughout the revisions process. Also, thanks to the collaborators participating in the identification of the NACES MPA (listed in Annex 1 of the revised nomination proforma: https://www.ospar.org/documents?v=51436).