This map shows the abundance of sperm whales, harbor porpoises, Atlantic white-sided dolphins, and striped dolphins in the spring and summer seasons. The species are sighted only when they surface, and therefore a low number or absence of sightings does not necessarily mean that they do not use an area.

Data Considerations

This map displays data from The Nature Conservancy’s Northwest Atlantic Marine Ecoregional Assessment (NAMERA), which utilizes effort-corrected sightings data 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. Sightings for each ten-minute square were divided by the survey effort for each ten-minute square to calculate Sightings per Unit Effort (SPUE). SPUE is an analysis technique designed to correct for survey effort and show the relative abundance of species in areas that are surveyed. While this map attempts to correct for survey effort, some areas were surveyed significantly less than others and therefore certainty in those areas is relatively limited. In addition, whales are only sighted when they surface. Therefore, low or no sightings in areas does not mean there is no whale activity. Please see metadata for more information on these datasets.


We are working to develop new maps that incorporate data from recent offshore surveys and other sources.

Support for Regional Ocean Planning

For information about how these data and maps are being developed with stakeholder input and used to support regional ocean planning, please visit the marine life page on the Northeast Regional Planning Body’s website.