At low tide, cast a casual glance across the Merrimack River near Salisbury State Reservation, and you'll see lumpy black rocks covered with slippery rockweed. Look a little closer, and you'll see that the hefty clumps of gray and brown scattered over the rock are on the move.
These plump marine mammals make up our resident colony of harbor seals and gray seals, the two most common species along the Massachusetts seaboard. During the mid-19th century, folks attributed dwindling fish stocks to overabundant seal populations. The government sanctioned seal hunts in the Merrimack and elsewhere by paying a bounty for seal noses. Since then, seal populations have rebounded and created increased opportunities for seal watching right in our own backyard.
The diverse coastline of northern New England hosts about 15,000 harbor seals. While harbor seals remain the most numerous, the number of gray seals has increased tremendously within the past 30 years. Gray seals are native to the Canadian Maritimes, and in the past were rare winter wanderers into our region. In the late 1970s and early 1980s, only a handful of gray seals would be seen in Massachusetts waters, and mostly in the Nantucket Sound area. Recent surveys completed by the National Oceanic and Atmospheric Administration's Fisheries Service has found as many as 3,000 gray seals in that area.
While harbor seal pups are born in mid to late spring, gray seals are born in February. Imagine being a seal pup sliding suddenly from a 100-degree environment into the frigid February waters along the Massachusetts coast. Gray seals can grow to 8 feet and weigh up to 1,000 pounds. They have a distinctive "roman nose," giving them a horse-head appearance. The scientific name Halichoerus grypus is somewhat more elegant than the common meaning of "hook-nosed pig of the sea."
In October 1979, I was thrilled to actually find one young male gray seal that hauled out repeatedly on Plum Island. When leading whale watching expeditions from Newburyport in the late 1990s, I saw an occasional gray seal inside the Merrimack River, and it was always a special treat. However, last summer we visited a large colony of gray seals that we found at the Isles of Shoals, many of whom likely spent their winter in the Merrimack. These curious animals swam up to and beneath our skiff, providing some wonderful eye-to-eye encounters.
With all the excitement over the rising gray seal population, we can't overlook the beloved harbor seals. Known to biologists as Phoca vitulina meaning "sea dog," harbor seals range in length from 3 feet to 6 feet. They migrate north and south with the seasons. Also on the rise, their numbers have more than doubled since the early 1970s. Back then, it was rare to find seals in the Merrimack River or at the Isles of Shoals. Now, we see harbor seals here year-round.
Seal watching is a lot of fun. The best spots are along the Merrimack River stretch of Salisbury Beach State Reservation, where at low tide you can spy seals hauled out on the rocks. Remember that if you see one on the beach, it's likely just fine and you should leave it alone. Enjoy the sight from a safe distance. At high water, you may see seals along Plum Island or upriver along the central waterfront in Newburyport. You'll need a little patience and a decent pair of binoculars, but the rewards of seeing these sea dogs are many.
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Scott Mercer is a marine mammal expert, naturalist and educator. He serves on the board of directors of the Newburyport marine education organization BOAT CAMP. Visit www.boatcamp.org for more.
