Diverse and abundant megafauna documented at new Atlantic US Marine National Monument

The Northeast Canyons marine monument is a critical hotspot of biodiversity on the edge of the continental shelf where the shallow seas off of New England drop sharply into the deep waters of the northwestern Atlantic. In 2016, President Obama designated three underwater canyons that are deeper than the Grand Canyon, and four seamounts as tall as the Rockies, as the first American marine national monument in Atlantic waters. However in 2017, Secretary of the Interior Ryan Zinke recommended to President Trump that the Northeast Canyons and Seamounts either be downsized or eliminated. The exact nature of the recommendation has yet to be specified.

Given the great distance offshore, documenting the marine life there is a challenge. During the 4.5-hour aerial survey, the team spotted 169 bottlenose dolphins, 57 pilot whales, 44 Risso's dolphin's, 13 rare Sowerby's beaked whales, four sperm whales, and 44 other dolphins of various species. In two sightings, they saw a mixed group of up to 50 bottlenose dolphins and 30 pilot whales, but what intrigued the researchers most was that three groups of Sowerby's beaked whales were spotted at the water's surface, a rare occurrence given their marathon dive times

This is "extraordinary for such a small area," said Dr. Ester Quintana, the lead scientist on the Anderson Cabot Center aerial team, adding that they also observed basking sharks, the second largest species of shark in the world, and the strange, large, plankton-feeding Mola mola, or ocean sunfish.

The aerial sightings help researchers understand how the species are using the richly biodiverse monument waters and deep coral canyons at different times of year and for different purposes. "One of the reasons we do this work is that we are just discovering what's going on out there," said Dr. Scott Kraus of the Anderson Cabot Center. "This is an opportunity to see how animals use this habitat. No one has ever done this before."

This was the third in a series of aerial surveys of the monument that began in summer 2017, and the number of sightings by the scientists during this survey was higher than any other, nearly double the number of animals observed last fall.

"These surveys continue to show the incredible abundance of marine life in the Northeast Canyons and Seamounts Marine National Monument," said Kraus. "These sightings support the idea that this area is worthy of complete protection."

"This area was declared protected because it is a fragile ecosystem with a wide diversity of corals, deep water fishes, and invertebrates around these pristine canyons and seamounts that support a vast array of whales, dolphins, and large fish," Dr. Quintana said. "As new policies recommend opening more waters off the US coast to offshore drilling, it is incredibly important to have areas that remain protected."

She said the Northeast Canyons monument area is about one-tenth of one percent of all US ocean territorial waters. "Yet, the wildlife diversity we are seeing out there highlights the importance of preserving its ecological value," Dr. Quintana said.