Habitat suitability maps for harbour porpoises in the North Sea–Baltic Sea transition zone from 1997 to 2022

The dataset includes 6 layers showing modelled habitat suitability for harbour porpoises (Phocoena phocoena) across the North Sea–Baltic Sea transition zone over a 25-year period (1997–2004; 2005-2012; 2013-2022) during winter (Nov–Apr) and summer (May–Oct). Habitat suitability was estimated using the maximum entropy (MaxEnt) algorithm, based on satellite tag data of 111 individuals and a range of dynamic and static environmental conditions as predictor variables. Habitat suitability models and maps were developed by researchers of the Department of Ecoscience, Aarhus University to quantify potential spatiotemporal changes in the overlap between suitable habitats and an existing network of 62 MPAs dedicated to harbour porpoise protection. The habitat suitability rasters can inform effective design of forthcoming MPAs under the EU Biodiversity Strategy for 2030. Harbour porpoise habitat suitability layers cover a seascape area of 70,145 km2. Habitat suitability layers are available for the periods: 1997–2004; 2005-2012; 2013-2022 and for both winter (Nov–Apr) and summer (May–Oct). All layers are projected using the EEA reference grid (ETRS89-LAEA Europe, EPSG:3035), have a 1x1 km spatial resolution (cell size) and a spatial extent of 4275000, 4545000, 3415000, 4105000 (xmin, xmax, ymin, ymax). Habitat suitability values (probabilities) range between 1 and 0 with values closer to 1 indicating habitat being highly suitable for harbour porpoises while values closer to 0 indicate habitat that is poorly suitable for harbour porpoises. Location data underlying the habitat suitability models were collected from 111 harbour porpoises tracked over the period 1997–2022 as part of a long-term satellite telemetry monitoring program in Denmark. Location and meta data are freely available at Zenodo (https://doi.org/10.5281/zenodo.13968991). Harbour porpoise habitat suitability layers were produced as part of the projects: GES4SEAS (grant agreement no. 101059877) and OBAMA-NEXT (101091642))