Seal Movement Ecology and Health Research
We are using satellite tags to study gray and harbor seal movements to examine their use of the marine environment and the ecological drivers of their behavior.
What We Sample
Our goal is to capture seals for biological sampling and to deploy satellite tags. While we have primarily been attaching satellite tags to gray seals since 2019, we also work with our partners to deploy a small number of tags on harbor, harp, and hooded seals.
Why We Sample
We tag seals to understand their habitat use—at sea and on land—and to understand ecological drivers of behaviors such as foraging. Satellite tags provide information on seasonal movements throughout U.S. and Canadian waters as well as haul-out and diving behavior. Tagging data also records the amount of time seals are in the water—when they are not visible to observers during a survey. This underwater data helps researchers improve estimates of abundance.
We work closely with our academic, government, and non-government research partners to conduct captures and to collect and analyze tissue, antibody, and genetic samples from the animals. From these samples we gain information on:
- Health of the animals
- Presence of disease and contaminant loads in the wild population
- Animal’s diet
- Stock structure
How We Capture and Sample Animals
We capture animals on land or in the water using hand-held nets, bags, or seine nets. Land-based captures of gray seals typically occur in January during the pupping season, at pupping colonies in Massachusetts and Maine. The season and location for water-based captures of harbor and gray seals varies and depends on the distribution and accessibility of animals.
Sampling Methods
After we capture an animal, a team restrains it by hand—with or without sedation depending on the animal’s size. For each animal, the team collects:
- Weight
- Total length
- Hind- and fore-flipper lengths
- Girth
- Blood, tissue swabs, and skin samples
The team also attaches a green flipper tag to each hind flipper. The tag is labeled with the animal’s identification number and a Northeast Fisheries Science Center contact number in case the animal is seen again. When possible, the team glues a satellite tag to the animal’s fur at the base of the neck.
All research is conducted under appropriate permits, including:
- Marine Mammal Protection Act Research Permit
- Marine Mammal Health and Stranding Response Program Permit
- U.S. Fish and Wildlife Service Special Use Permit
- Atlantic Institutional Animal Care and Use Committee permit
Survey Gear and Technology
Satellite tags are designed to transmit data to our computers in near real-time via Argos satellites. The type of tag and its programming settings vary depending on the research questions being studied.
Deployment and Retrieval
The satellite tags we deploy on seals are typically not recovered. Tag batteries usually last about 5 to 6 months, but can transmit for up to about 1 year, depending on conditions. Transmissions stop when the animal molts and the tag falls off with its fur, the animal dies, or the tag battery fails.
Data Collection
Satellite tags can collect data on an animal’s location, dive depth, dive shape and duration, and haul-out behavior (i.e., the amount of time the animal may spend out of the water).
Our partners analyze blood and tissue samples for various factors that may affect the animal’s health. These analyses may include testing for evidence of or exposure to highly pathogenic avian influenza or phocine-distemper virus, as well as immune health and complete blood counts. We may also test samples for contaminants such as PCBs, pesticides, and per- and polyfluoroalkyl substances (PFAS)—also known as “forever chemicals.”
Data Use
The data we collect during this survey provide scientifically rigorous information and are used in a variety of ways, including:
- Marine Mammal Protection Act stock assessments
- Environmental assessments
- Fisheries bycatch analyses
- Public outreach and education
Access our Data
You can request publicly available satellite telemetry data by emailing Eleanor Heywood. You can view available data on the MoveBank data portal.
Who’s Involved
NOAA Scientists
Partners
- NOAA’s Marine Mammal Health and Stranding Response Program
- U.S. Fish and Wildlife Service
- Greater Atlantic Regional Fisheries Office
- Tufts University Cummings School of Veterinary Medicine
- University of Rhode Island
- University of Massachusetts
- University of Maine
- Dalhousie University
- Marine Mammals of Maine
- International Fund of Animal Welfare
- Atlantic Marine Conservation Society
- Marine Mammal Alliance Nantucket
- The Trustees of Reservations’ Coskata-Coatue Wildlife Refuge