Too large for its surroundings, like a barracuda in a bathtub, the massive fish crisscrossed a narrow inlet here Tuesday, its telltale dorsal fin leaving a jagged wake on the still water.
Almost 30 years after the movie "Jaws" -- filmed a few miles to the south on Martha's Vineyard -- left a generation of beachgoers wondering whether it was safe to go back in the water, the 14-foot, 2,000-pound great white shark was spotted here a week ago.
It has since stirred up a ruckus by patrolling the shallow, pond-size shoal sometimes within feet of the shore, leaving scientists puzzled as to why it came and when it will return to the open sea.
Word of the creature's arrival spread across New England from Woods Hole, a small town on Cape Cod's southwestern coast that is home to a renowned oceanographic institute and just a 10-minute boat ride from the animal's temporary home.
Gawking boaters and shark fans came in droves from as far away as Canada for a rare chance to view the legendary predator up close. Despite a soupy fog and light rain Tuesday, few left disappointed.
"It was just spectacular," said Johanna Flacks, 34, a lawyer and self-proclaimed amateur shark enthusiast upon returning from a one-hour round-trip viewing guided by a local fisherman. "My adrenaline is still going. I don't want to leave the dock."
Marine experts here said that while they initially shared the public's enthusiasm, they are now hoping -- for the shark's well-being and the safety of local residents -- that it goes away soon.
Last week a state biologist attached a tracking device to the fish, which will help scientists better understand its migration patterns. At first boaters were allowed uninhibited into the inlet, but harbor police now permit people to watch the fish only from behind a 10-foot-wide sandbar.
"You had them going out there in little rubber boats, or kayaks, which is probably not a good idea," said Dan McKiernan, deputy director of the Massachusetts Division of Marine Fisheries. "It's been pretty calm so far, but it's still a great white. And all the boats around could be harmful to the shark."
Naushon is an unspoiled, privately owned enclave in the Elizabeth Islands archipelago, whose only structures are the stately slate-colored vacation homes owned by members of the Forbes clan, one of New England's oldest and wealthiest families.
On Tuesday marine biologists filmed the shark's movements with an underwater camera as it circled the channel, occasionally arching its massive frame up out of the water, while a handful of gasping spectators looked on. Its head always stayed below the surface.
Notorious for their occasional attacks on swimmers and surfers, great whites usually prefer warmer climes to the frigid waters off New England. The last fatal attack in this state occurred in 1936, when a child was mauled while swimming in Buzzards Bay, near Mattapoisett -- just across the Cape Cod Canal on the Massachusetts mainland.
McKiernan theorizes that the newly arrived shark chased one of the plentiful local schools of striped bass or bluefish, or even a seal, into the inlet and is now discouraged from leaving because fish are in ready supply and the only passageways back to the ocean are about three feet deep at low tide.
With higher than usual tides expected because of a full moon, officials are hoping the deeper water will help the shark venture back to sea.
Because the water here is too cold for the shark to live year-round, scientists are considering how to coax it away if it does not leave. Suggestions have poured in from around the world, said Ann Dunnigan, who works in the visitor information center at the oceanographic institute.
An Australian diver offered his services to swim the fish back through the channel.
"One mother from Nantucket e-mailed a suggestion from her 4-year-old son," Dunnigan said. "He thought we should get a big crane to lift it out of the water and deposit it somewhere else."
But in Woods Hole, where the shark has given new life to a sometimes slow fall tourist season, residents said they hope it sticks around for a while. As might be expected with fish stories, its reputed size has grown with its exposure.
"There is no way that thing is less than 17 feet," said Steve Murphy, who works in a rigging shop at the oceanographic institute, after he and two colleagues took a motorboat to see the shark during their lunch break Tuesday. "I've been on the water my whole life and never seen anything like that."
Mike Ryan, who grew up in Woods Hole and owns a charter fishing and tour boat company, estimated that he has shuttled more than 300 people out to see the great white since Friday. The shallow water makes small boats a must, so he and his crew have led 10 daily, six-person trips on a 22-foot dinghy. He charges $100 per journey.
"It has been quite a windfall for us," he said.
Over the weekend several hundred people lined up on the small marina, including one man who wore a shark emblazoned T-shirt and whose license plate read "Jaws75," said Matt Lundberg, who works for Ryan.
There was some pushing and shoving, Lundberg said, and many people were turned away for lack of space.
" 'Jaws' scared people away from the water," Lundberg, 20, said. "This thing is having the opposite effect."