Last Monday's shark attack off Truro's Ballston Beach – the first in 76 years on Cape Cod – set off a media furor and horrified beachgoers along the storied Massachusetts peninsula that attracts millions of vacationers every summer.
It may also force the hordes that crowd the Cape's beaches to relearn a lesson lost for decades when seals had all but disappeared from the New England coasts – that swimming among shark's prey is very dangerous.
Lifeguards were on high alert, hundreds of spurious dorsal fin sightings were reported and airborne spotters scanned the offshore swells for great white sharks, the prime suspect in the attack on Chris Myers, 50.
More than 300,000 grey seals, and their vulnerable pups, now live on the Cape – a population 30 times the nadir in the 1960s – and the return of the seals has attracted a return, inshore, of great white sharks.
"The reason the great white sharks are coming closer to shore in the Cape Cod area, specifically on the eastern shore, is because of the growing grey seal population," said Greg Skomal, a Massachusetts marine biologist.
Mr. Myers and his 16-year-old son were swimming several hundred metres offshore, close to known seal colonies, when something bit his lower legs.
Meanwhile harried Massachusetts tourism officials were battling to prevent a single attack morphing into a nightmare marketing scenario of sinister fins slicing the waters off Cape Cod.
"Not to downplay the nasty experience the bitee has had but there are sharks in the ocean," said Betsy Wall, executive director of the Massachusetts Office of Travel and Tourism. "There's a lot of signs and notices about where it is safe to swim and where it is not. People should stay away from seals."
Mr. Myers, 50, who is expected to make a full recovery from deep gashes that required more than 40 stitches to close, apparently got the message.
"Maybe people need to be a little more careful than I was," he told Good Morning America, his lower legs still heavily bandaged. "Don't be an easy meal."
"It's the summer news doldrums and nothing tops a shark attack for media excitement," said George Burgess, director of the Florida Program for Shark Research who also maintains the International Shark Attack File at the University of Florida. "It's a hot-button issue and not just because of the movie Jaws," he said.
"When humans disregard the rules … such as going in the water with seals in the area," there will be attacks, he said.
Great whites, while hardly the ferocious, man-eating terrors depicted in Steven Spielberg's 1975 horror-thriller Jaws, are dangerous and have been sighted with greater frequency in recent years off Cape Cod as seal populations have re-established themselves.
Seals, along with sea birds, fish and dolphins are routinely eaten by the great white, which can exceed five metres in length and weigh more than two tonnes.
Seal-hunting sharks like to lurk just offshore to attack as the seals leave or return to the beach, especially where the bottom drops off suddenly, Mr. Burgess said. "It's a bad idea to swim there."
Shark attacks on humans are statistically rare; fatal attacks vanishingly so. In 2011, a typical year, just roughly 120 attacks were verified worldwide, of which only 17 were fatal. By comparison, an estimated 100 people die every year from jellyfish stings. The last, and unconfirmed, fatal shark attack in Canada was off Nova Scotia in August, 1891.
"But ultimately, the sharks are in their realm, … we are the intruders," said Rob Mottice, a shark expert and marine biologist at the Tennessee Aquarium in Chattanooga, Tenn. "There will always be a handful of attacks," he said. "Sharks attack because they mistake humans for something else. Whatever we do won't change that."