Geospatial data obtained from the United States Navy included point shapefiles of valid sightings for all marine mammal targets and pre-calculated effort grids for each season. Sightings data were taken from NMFS-NEFSC Aerial Surveys, NMFS-NEFSC Shipboard Surveys, and the North Atlantic Right Whale Consortium Database. The validity of sightings was carefully screened and verified by United States Navy contractors before inclusion in the model. Invalid records were not included in the analysis. Sightings for each ten minute square were divided by the effort for each ten minute square to calculate Sightings Per Unit Effort (SPUE). SPUE was calculated for each target species, for each season, and for each ten minute square. Sightings Per Unit Effort (SPUE) was used to analyze areas of importance for the target marine mammal species in the Northwest Atlantic Marine Ecoregion: Where in the ecoregion has the species been consistently found over time? (persistence) Where in the ecoregion is the species consistently found in high abundances? (persistence weighted by abundance) The Nature Conservancy. (2010). Marine Mammals Sightings Per Unit Effort, 1979-2007. Northeast Ocean Data. Available at: http://purl.stanford.edu/pd288xz6366. Not to be used for navigation This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.