Our scientists spotted more than 1,200 individual animals and identified six species in just over one hour—including four elusive Cuvier’s beaked whales—during a recent aerial survey of the Northeast Canyons and Seamounts Marine National Monument before bad weather forced them to abort the rest of their flight.
Fieldwork can be challenging, especially if it involves planning around unpredictable weather. An aerial survey to the marine national monument was scheduled on June 28. The team, which included New England Aquarium scientists Dr. Ester Quintana and Orla O’Brien and two professional pilots, departed from Plymouth Municipal Airport at 10 a.m.
The trip to and from the monument, which is about 150 miles off the coast of Cape Cod, took approximately three hours. The offshore weather conditions were supposed to be excellent that day. However, just after starting the second of 10 tracklines, the survey had to be aborted due to a change in weather that included low, heavy clouds covering the study area.
This was very disappointing because the team had already recorded an unprecedented number of animals during the first hour on-site. Indeed, 1,252 individuals were spotted, including 1,036 common dolphins (Delphinus delphis,), 192 Risso’s dolphins (Grampus griseus), four Cuvier’s beaked whales (Ziphius cavirostris), three ocean sunfish (Mola mola), one unidentified shark, and a leatherback turtle (Dermochelys coriacea). Most of the animals were on the first trackline!
Cetacean (pink dots) and fish and turtle sightings (yellow dots) recorded during an aerial survey conducted on June 28, 2019. Tracklines (black) are designed to cover the monument area evenly. GOBW = Cuvier’s beaked whale (Ziphius cavirostris), GRAM = Risso’s dolphins (Grampus griseus), LETU = leatherback turtle (Dermochelys coriacea), OCSU = ocean sunfish (Mola mola), SADO = common dolphins (Delphinus delphis), and UNDO = unidentified dolphins.
One of the groups of common dolphins involved approximately 520 individuals spread over a few kilometers. This was an amazing sighting. From a thousand feet up in the air, all the team could see were splashes created by the multiple subgroups of dolphins quickly swimming north. Sightings of common dolphins occurred mainly in shallower waters (< 400 m).
Another sighting involved a group of 70 Risso’s dolphins accompanied by at least 10 calves. Interestingly, we did not see many calves in this survey, as we have during previous summer flights. All sightings of the Risso’s dolphins were in the deeper waters of the canyon (~500 – 1,500 meters).
Scientists spotted a pod of Risso’s dolphins seen from the air, including some calves.
The last sighting, which involved only four individuals, was equally exciting—the team spotted four elusive Cuvier’s beaked whales! Cuvier’s are hard to find because they live in deep water and spend only short periods at the surface to breathe. This sighting was surprising because the whales were just a couple of miles south of where the low clouds made survey conditions impossible. The group was at the edge of the Lydonia Canyon in deep waters (>1,300 m).
This was definitely a great day in spite of the weather conditions. The four beaked whales stayed for a few minutes at the surface and the team was able to take good photos. Those photos revealed that there were a couple of males in the group. Adult Cuvier’s, especially males, have a white dorsal region that usually extends from the face to back, and old males can appear almost all white. Some of the Cuvier’s pictured also have ochre-yellowish patches, presumably from diatoms, and distinct body scarring, which is consistent with mature males. Younger animals tend to be darker, distinctively paler below, and have rounded, more dolphin-like head.
The group of four Cuvier’s beaked whales was a surprising sight because the species spend so much time diving. On the right, they are about to dive again.
The team landed in Plymouth at approximately 3 p.m. and is monitoring the offshore forecast to plan another survey. We are hopeful that the weather conditions will improve and the team can examine the entire study area in one flight. Stay tuned!
This important work is made possible thanks to the generous support of the Conservation Law Foundation, National Ocean Protection Coalition, Natural Resources Defense Council, and Resources Legacy Fund.