August 2012

A Happy Haul

Cape Cod Life  /  August 2012 / ,

Writer: Donna Scaglione

A surging seal population takes up residence off Truro

seal population

Courtesy of the Provincetown Center for Coastal Studies

The line of hulking creatures along the J-shaped sandbar just off High Head Beach in Truro is at first deceiving: Their round, shiny bodies are reminiscent of large, dark rocks, giving the peninsula the look of Maine’s rugged coast rather than Cape Cod’s sandy shore. But when the wind dies down, the rocks can be heard moaning. Those rocks, it turns out, are gray seals.

“It’s just fascinating to sit and listen,” says Sue Moynihan, chief of interpretation and cultural resources management for the Cape Cod National Seashore. “There are all these vocalizations they are making, and we really don’t know what they mean.” When visitors step closer to the shore, the seals swimming by themselves stop their acrobatics to stare. Their heads are the size of a horse’s, their eyes black.

This is at least the fifth year that seals have congregated off Truro. Jeremy Point off Wellfleet, Chatham Harbor, South Monomoy Island, and Muskeget Island off Nantucket are also home to gray seal haul-outs, but for humans, the Truro gathering spot is probably the least remote, making it a popular place to observe seals in their element.

In the fall of 2007, the Provincetown Center for Coastal Studies took notice of “bottling” seals off Head of the Meadow Beach. Around 60 to 70 gray seals appeared to be hanging vertically in the water, something they do when they are resting. Throughout that fall the seals were regularly sighted in the area. The following May, dozens returned to haul out onto the J-bar, recounts Lisa Sette, a biologist with the PCCS. Since then, the seals have returned each year to different haul-outs between Head of the Meadow and High Head beaches from late May until the fall—or whenever a storm obliterates the J-bar.

The sandy haul-out—so-named because seals “haul” themselves out of the water and rest after feeding—is formed by ocean currents. Some years, the Truro site has had a deep-water “trough” surrounding it; this year it’s attached to the beach, making it a peninsula but still offering seals the protection they need from predators that threaten from the land and sea.

“They’re resting,” explains Sette, who has been studying the seals off Truro since 2008. “Some are still molting (shedding their coat and growing a new one), and that is a stressful time for them. If they are wounded, they may haul out to heal as well. It’s basically their way of resting and healing.”

seal population

Photo Courtesy of National Park Service

Early this summer, about 200 to 300 animals populated the haul-out, according to Sette, but as many as 600 may come. Mostly gray seals gather at the haul-out, although some smaller harbor seals are also seen there. Gray seals live year-round in Cape waters, while harbor seals mainly appear in large numbers late summer through spring. (The majority of adult harbor seals travel to the coasts of New Hampshire and Maine to have their pups and breed in the summer.)

Gray seals in southeastern Massachusetts waters now number more than 15,000, according to Gordon Waring, a research fishery biologist for NOAA Northeast Fisheries Science Center in Woods Hole. But that wasn’t always the case. For years, the seals—the bane of commercial and recreational fishermen because of their taste for prized fish—had bounties on their heads. In fact, as recent as the 1980s, gray seals were a rare sight around the Cape and islands, Waring says. “The perception of seals from Europe was basically carried over to the colonies—that they were a nuisance, competition for fish, vermin,” Waring says. “There were all kinds of descriptions for them.”

According to the July 2009 issue of the Northeast Naturalist, a quarterly journal of natural history, Massachusetts and Maine paid bounties for seals during the 19th and 20th centuries. Researchers estimate that 72,284 to 135,498 seals were killed between 1888 and 1962, “probably enough to account for regional declines in seal populations,” they wrote. “Larger numbers of bounties were paid where there were more seals and a higher human population.”

The end of the bounties and the passage of the Marine Mammal Protection Act in 1972 helped bring the seal populations back. Today, Moynihan directs the CCNS Seal Education Team, a group of 15 docents staffing the haul-out this summer to protect the seals and educate an enthusiastic public. The program was put in place in 2010 when the haul-out, also attached to land that year, grew in popularity, with as many as 200 people visiting at low tide. “That presented a dilemma for us because, on the one hand, it presented a fantastic educational opportunity, but on the other hand, we had a situation where the people were getting too close to the seals because they could walk out to them,” she says.

And though these creatures may no longer have to count humans among their enemies, there is one predator that is not going away: the great white shark. Around 2004, Dr. Greg Skomal, a marine biologist and shark expert from the Massachusetts Division of Marine Fisheries, started noticing a subtle increase in the number of sightings mainly on the eastern end of Cape Cod and adjacent to seal colonies, despite a decline in fishing. The increase is “heavily correlated with the rebound of the gray seal population,” he says.

In fact, two years ago, a beachgoer not far from the current Truro haul-out captured terrifyingly graphic photos of a great white successfully attacking a gray seal. “We’re monitoring that seal haul-out,” he says. “We know in 2010 there was an actual eyewitness account of a shark attack and killing of a seal in that area . . . That tells us, yes, at least one white shark has taken notice of those seals in that area.”

Since 2009, Skomal has tagged 18 great whites in Cape waters, tracking their movements with a network of acoustic receivers placed off the coastline. In June 2012, two electronic detections were made off Chatham, and although acoustic receivers are close to the Truro haul-out, no detections had been made as of late June, he says. “But that doesn’t mean sharks don’t go there.”

Donna Scaglione is a freelance writer living in Falmouth.