Winter seal visitors along NH’s coast

Posted on January 19, 2023

By Ashley Stokes, Director of Marine Mammal Rescue, Seacoast Science Center 

Seacoast residents are accustomed to seeing harbor seals and their larger gray seal cousins along our rocky shores and sandy beaches during the warmer weather, but two more pinniped species visit New Hampshire during the winter.

Juvenile harp seal lying on its side with its mouth open
Juvenile harp seal

Harp seals and hooded seals, often of the juvenile age class, venture down to our region from the Arctic as temperatures plummet and snow starts to fall. These animals are born on pack ice in the Arctic and stay with their mothers for only a brief amount of time before learning to fend for themselves. 

Black and white striped adult harp seal facing to the right
Adult harp seal

The coats on these juvenile seals make them very easy to tell apart. Juvenile harp seals (referred to as ‘beaters’) are cream colored with varying brown spots. Adult harp seals have light gray fur with a black mask on their face and a curved black patch on their back. This black patch looks like a harp and is the source of the species’ common name. Adults are 5-6 feet long, weigh about 260 to 300 pounds, and have a robust body with a small, dog-like flat head and muzzle. They have a narrow snout and eight pairs of teeth in both the upper and lower jaws.

Juvenile harp seal with gray and cream fur and distinctive patches of black around its eyes
Juvenile hooded seal

Juvenile hooded seals (referred to as ‘bluebacks’) have a light colored belly and dark silvery-gray back, which almost has a deep blue hue in the right light. Both male and female adults have silver-gray fur with darker patches of different sizes and shapes across their bodies. Adult male hooded seals are about 8.5 feet long and weigh about 423 to 776 pounds, while females are about 6.5 feet long and weigh about 320 to 660 pounds. 

Juvenile hooded seal on a sandy beach with its mouth open and teeth bared
Juvenile hooded seal

Hooded seals are not social. They migrate and remain alone for most of the year except during mating season. They are more aggressive and territorial than other seal species and the pups have the shortest lactation period of any mammal, spending only three days with their mothers!

Both species have adapted to eat snow and ice to keep hydrated, but sometimes mistake sand and rocks for snow or ice. Harp and hooded seals are also known to “stress eat” by ingesting sand and small rocks when they become stressed by human presence or don’t feel well. Eating rocks and sand can quickly lead to impaction of the gastrointestinal tract, sometimes requiring surgery to fix, and can be fatal. This is why keeping a safe distance of at least 150 feet away is crucial for their health and well-being. This is the distance mandated by the federal Marine Mammal Protection Act. The public can help keep these animals safe by reporting any sightings to SSC Marine Mammal Rescue’s 24/7 reporting hotline at 603-997-9448.  

During the winter months, SSC’s marine mammal rescue team can be kept quite busy with these northern visitors, as it’s not uncommon for them to remain hauled out for days at a time. For the SSC Marine Mammal Rescue team, harp seal responses are far more common than hooded seal responses. As of the time this article was submitted, the team had not yet received any reports of ice seals being seen in the New Hampshire area, but the season could begin at any time! On average, the first ice seals will generally be reported in New Hampshire in mid-late January.

To learn more about Seacoast Science Center’s marine mammal wildlife conservation work, visit www.seacoastsciencecenter.org or check out the Marine Mammal Rescue program exhibit at the Center.

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Delayed opening today.

Seacoast Science Center will open at 11am today due to inclement weather.