The Gulf of Maine has the most marine mammal diversity on the east coast, study finds

This map shows “mean species richness” – red indicates more species, and blue indicates fewer species. The white line represents the shelf-edge canyon. The analyses showed a gradient of higher to lower diversity from north to south and that the shelf-edge, canyons, and areas of likely upwelling support high diversity. (Society for Conservation Biology)

New research shows that ocean environments off New England contain the most diverse array of marine mammals to be found on the entire eastern seaboard. Lead scientist Brooke Hodge of the New England Aquarium says that the highest variety of mammals is found in and around giant underwater mountains and canyons.

In those areas, she says, cold, high-saline water carries nutrients from the deepest ocean toward the surface, powering a food chain that eventually leads to the mammals.

“The filter feeders — baleen whales — can feed on those small little animals. Then we have animals like beaked whales that are deep divers, squid eaters, and they like to go into those canyons off the shelf and dive deep, and that habitat helps support those types of animals as well. We also find things like dolphins and porpoise there,” Hodge said.

Areas such the Northeast Canyons and Seamounts Marine National Monument typify the kind of underwater structures that foster the highest mammal diversity, she says. Designated as a marine protected area by President Obama, the monument lies about 130 miles east of Cape Cod.

The study also found that along this side of the Continental Shelf, the Gulf of Maine — from Massachusetts to the mouth of the Bay of Fundy — carried the highest level of mammal diversity found on the east coast.