Using both planes and unmanned aircraft systems (UAS), the National Oceanic and Atmospheric Administration’s (NOAA) Northeast Fisheries Science Center (NEFSC) – along with researchers from a variety of federal, state, academic and private organizations – is gathering data to determine how many gray seals there are in Northeastern waters.
The researchers are working on Muskeget Island off Nantucket, Mass. – the largest gray seal breeding and pupping colony in the U.S., says NOAA – and the Monomoy National Wildlife Refuge, an island near Chatham on Cape Cod, Mass.
According to NOAA, the aerial images will help document the number of pups on the breeding grounds, as well as pup distribution. The images can also document adult seals by providing data on brand marks or entanglements. Biological samples collected from weaned pups will reveal information about stock health, gray seal ecology and habitat use.
“We are using two types of unmanned aircraft systems, a fixed-wing system and a hexacopter, to take images of the populations, along with traditional aerial surveys using two different camera angles on the NOAA Twin Otter aircraft,” explains Kimberly Murray, coordinator of the seal research program at the NEFSC laboratory in Woods Hole, Mass.
“This approach provides four different views of the animals and should help us get a better estimate of gray seal abundance on the island and where the animals are in the pupping season process. It also allows us to evaluate the pros and cons of various technologies available to survey wildlife populations,” she says.
Two types of drones are being used – one from Duke University and the other from NOAA, which says both are operated at altitudes up to 400 feet.
“Duke’s fixed-wing eBee is ideal for surveying a large area and estimating seal density, while NOAA’s hexacopter, APH-22, is better at spot sampling and hovering over a location for more detailed study,” says Julian Dale, lead UAS engineer at Duke University’s UAS group in Beaufort, N.C. “We will be assessing the accuracy of UAS seal counts in comparison to images from the Twin Otter, which flies much faster and at an altitude of 750 feet.”
The fixed-wing eBee collects two types of imagery: traditional color photography to compare to the NOAA Twin Otter camera images and infrared/thermal imagery to detect animals that are difficult to see or that are within dense animal concentrations.
The NOAA Twin Otter aircraft is equipped with a standard side camera, as well as a bottom-mounted camera on loan from NOAA’s National Marine Mammal Laboratory.
Images from NOAA’s APH-22 hexacopter will also be evaluated for their utility as a census tool or for studying other features of the population, such as entanglements.
“This is the first time the APH-22 technology has been used to survey seal populations in the Northeast,” says the NEFSC’s Beth Josephson, one of the APH-22 pilots.
The scientific team comprises researchers from NOAA’s NEFSC and the National Marine Mammal Laboratory, Massachusetts Institute of Technology, Duke University, Mystic Aquarium, New England Aquarium, Marine Mammals of Maine, University of Connecticut, National Park Service, National Marine Life Center, Woods Hole Oceanographic Institution/Northwest Atlantic Seal Research Consortium, and the International Fund for Animal Welfare.
The team has a marine mammal scientific research permit issued by NOAA’s National Marine Fisheries Service to the Northeast Fisheries Science Center and a Monomoy National Wildlife Refuge special use permit to work on that island. The research was funded in part by the National Marine Fisheries Service Office of Science and Technology.