Habitat-based Marine Mammal Density Models for the U.S. Atlantic: Latest Versions

A Collaboration Led By Marine Geospatial Ecology Laboratory / Duke University

Collaborators: Northeast Fisheries Science Center/NOAA Fisheries, Southeast Fisheries Science Center/NOAA Fisheries, Dept. of Biology and Marine Biology, UNC Wilmington, Virginia Aquarium & Marine Science Center, Virginia Coastal Zone Management Program, Maryland Dept. of Natural Resources, Riverhead Foundation for Marine Research and Preservation, New Jersey Dept. of Environmental Protection, Woods Hole Oceanographic Institute, Center for Coastal Studies, Florida Fish and Wildlife Conservation Commission, New England Aquarium, Massachusetts Clean Energy Center, Bureau of Ocean Energy Management, Clearwater Marine Aquarium Research Institute, Georgia Dept. of Natural Resources, New York Dept. of Environmental Conservation, Tetra Tech, HDR

jason.roberts@duke.edu, tina.yack@duke.edu, phalpin@duke.edu


The Duke Marine Geospatial Ecology Laboratory leads an ongoing collaboration of federal, state, academic, and independent research organizations who pool scientific data and expertise to develop marine mammal species density models spanning the U.S. east coast and southeast Canada. The models estimate absolute density, rendered as maps of the number of individual animals per 100 km2, by statistically correlating sightings reported on shipboard and aerial surveys with oceanographic conditions. Since its initial publication in 2016, the project has expanded to utilize over 2.8 million linear kilometers of survey effort collected between 1992-2020, yielding density maps for over 30 species and multi-species guilds.

This page lists the latest available models and provides links to download their GIS files and documentation and explore them in an interactive online mapper. All of the models were most recently revised in spring 2022, as part of a comprehensive update developed for the U.S. Navy's Atlantic Fleet Training and Testing (AFTT) Phase IV Environmental Impact Statement. We are still developing detailed reports and updating the online mapper for these new models but have released them beforehand at the request of NOAA and other model users. We anticipate the reports will be complete by fall of 2022 and the online mapper will be ready by mid-summer 2022. To learn more about the modeling process, please see the 2016 publication. Feel free to contact us with questions (email jason.roberts@duke.edu).

This work was funded by the U.S. Navy to assist with complying with U.S. laws that require the Navy to assess the potential impacts to protected marine species resulting from military readiness activities. All marine mammals in the U.S. are protected under the Marine Mammal Protection Act (MMPA), and some marine species receive additional protection under the Endangered Species Act (ESA). As stipulated by the MMPA and ESA, information on the potential location and numbers of protected marine species is required in order to estimate how many animals might be affected by a specific activity. The Navy performs quantitative analyses to estimate the number of marine mammals and sea turtles that could be affected by at-sea training and testing activities. A key element of this quantitative impact analysis is knowledge of the abundance and concentration (density — the number of individual animals found per square kilometer of area) of the species in specific areas where those activities will occur.

Additional funding was provided by NOAA to further develop models of the North Atlantic right whale.

Model resolution and units

All models have a spatial resolution of 5 km. Model outputs are given as GIS-compatible raster files in an Albers Equal Area projection with a cell size of 5000x5000 m. The unit of density is individuals / 100 km2. To convert to individuals / 1 km2, divide the raster values by 100. To convert to individuals per grid cell, i.e. individuals / 25 km2, divide the raster values by 4.


Creative Commons LicenseThese files are © 2015-2022 by the Duke University Marine Geospatial Ecology Laboratory and licensed under a Creative Commons Attribution 4.0 International License. If you use them in a scientific publication or technical report, we kindly request that you cite our 2016 publication.

Latest Models

To download all models in a single zip file, click here (2 GB).

Modeled Taxon Scientific Name Version Released Links
Atlantic spotted dolphin Stenella frontalis 9 2022-06-20 DownloadMapperHistory
Atlantic white-sided dolphin Lagenorhynchus acutus 4 2022-06-20 DownloadMapperHistory
Blue whale Balaenoptera musculus 2 2022-06-20 DownloadMapperHistory
Clymene dolphin Stenella clymene 3 2022-06-20 DownloadMapperHistory
Common bottlenose dolphin Tursiops truncatus 6 2022-06-20 DownloadMapperHistory
Common minke whale Balaenoptera acutorostrata 10 2022-06-20 DownloadMapperHistory
Cuvier's beaked whale Ziphius cavirostris 7 2022-06-20 DownloadMapperHistory
Dwarf and pygmy sperm whales Kogia spp. 5 2022-06-20 DownloadMapperHistory
False killer whale Pseudorca crassidens 2 2022-06-20 DownloadMapperHistory
Fin whale Balaenoptera physalus 12 2022-06-20 DownloadMapperHistory
Fraser's dolphin Lagenodelphis hosei 2 2022-06-20 DownloadMapperHistory
Harbor porpoise Phocoena phocoena 6 2022-06-20 DownloadMapperHistory
Humpback whale Megaptera novaeangliae 11 2022-06-20 DownloadMapperHistory
Killer whale Orcinus orca 2 2022-06-20 DownloadMapperHistory
Melon-headed whale Peponocephala electra 2 2022-06-20 DownloadMapperHistory
Mesoplodont beaked whales Mesoplodon spp. 7 2022-06-20 DownloadMapperHistory
North Atlantic right whale Eubalaena glacialis 12 2022-02-14 DownloadMapperHistory
Northern bottlenose whale Hyperoodon ampullatus 2 2022-06-20 DownloadMapperHistory
Pantropical spotted dolphin Stenella attenuata 4 2022-06-20 DownloadMapperHistory
Pilot whales Globicephala spp. 7 2022-06-20 DownloadMapperHistory
Pygmy killer whale Feresa attenuata 1 2022-06-20 DownloadMapperHistory
Risso's dolphin Grampus griseus 5 2022-06-20 DownloadMapperHistory
Rough-toothed dolphin Steno bredanensis 3 2022-06-20 DownloadMapperHistory
Seals Phocidae spp. 5 2022-06-20 DownloadMapperHistory
Sei whale Balaenoptera borealis 10 2022-06-20 DownloadMapperHistory
Short-beaked common dolphin Delphinus delphis 5 2022-06-20 DownloadMapperHistory
Sperm whale Physeter macrocephalus 8 2022-06-20 DownloadMapperHistory
Spinner dolphin Stenella longirostris 2 2022-06-20 DownloadMapperHistory
Striped dolphin Stenella coeruleoalba 5 2022-06-20 DownloadMapperHistory
Unidentified beaked whales Ziphiidae spp. 7 2022-06-20 DownloadMapperHistory
White-beaked dolphin Lagenorhynchus albirostris 3 2022-06-20 DownloadMapperHistory

Retired Models

These models have been retired and replaced by more recent models listed above. They are retained here for reference purposes.

Modeled Taxon Scientific Name Version Released Links
Beaked whales Mesoplodon spp. and Ziphius cavirostris 4.4 2016-03-09 DownloadMapperHistory

The "Beaked whales" model is retired and no longer recommended for use. It was succeeded by three newer models: "Cuvier's beaked whale", "Mesoplodont beaked whales", and "Unidentified beaked whales". Following "Beaked whales" version 4.4 and its publication in Roberts et al. (2016), NOAA NEFSC and SEFSC contributed the AMAPPS surveys for use in updated models. In those surveys, NOAA undertook a concerted effort to boost the taxonomic precision of beaked whale sightings relative to prior surveys. Separately, the University of North Carolina, Wilmington team revisited all beaked whale sightings they collected since 2010 to try to fully identify them from photographs taken of each sighted group. These efforts collectively resulted in a large increase in sightings identified to the genus or species level, relative to unidentified sightings, as compared to sightings reported by the surveys used in version 4.4. This allowed us to split the "Beaked whales" guild modeled by version 4.4 into the three successor models that had higher taxonomic resolution.

Bryde's whale Balaenoptera edeni 1.3 2015-09-26 DownloadMapperHistory

The "Bryde's whale" model is retired and no longer recommended for use. The model relied on four ambiguous "Sei or Bryde's Whale" sightings from the 1990s, and estimated a mean abundance of 7 whales for the waters of the East Coast study area south of Cape Hatteras on the shelf and south of the Gulf Stream off the shelf. Subsequently, Rosel et al. (2021) reviewed multiple lines of evidence, including our model, and concluded that "Overall, the evidence to date indicates Bryde's whales are extremely rare in U.S. waters of the western North Atlantic." They pointed out that passive acoustic monitoring has not recorded whale call types associated with any type of Bryde's whale along the East Coast, but sei whales have been regularly recorded. Our conclusion is that the ambiguous sightings from the 1990s were most likely sei whales. Lacking any more recent possible evidence of Bryde's whales, and given the expert opinions of Rosel et al., we now believe Bryde's whale is effectively absent from our East Coast study area.

Conflict of Interest Statement

As acknowledged in our 2016 publication, U.S. Navy Fleet Forces Command is one of the principal funders of this modeling project. For the 2016 publication, the Navy was given the opportunity to suggest spatial, temporal, and taxonomical resolutions and a geographic extent that would facilitate the Navy’s use of the results in U.S. environmental regulatory processes. When the analysis was complete, the Navy was given opportunity to view preliminary results. Neither the Navy nor any other funder participated in the analysis of the data or the preparation of the manuscript. Since that publication, the Navy has continued to fund updates to the models under a similar arrangement.

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