Scientists can't lure shark from lagoon

WOODS HOLE -- More than a dozen scientists and fishermen using nets, electric currents, and even jets of water failed to coax a great white shark out of an island lagoon near Cape Cod yesterday.

The 1,700-pound fish had spent 10 days in the shallow lagoon, leading marine biologists to conclude it had become trapped and needed a push toward open water. In an all-day effort led by state fishery officials, the shark was nudged nearly out of the lagoon's mouth before nightfall forced the 15-person team to quit. Last night scientists were hoping the shark would take advantage of an overnight high tide to swim through a shallow, rocky area and sand bar that they believe she has been unwilling to cross.

"We are a little bit puzzled, but we are very hopeful," said Paul Diodati, commissioner of the Massachusetts Division of Marine Fisheries, who spent the day in one of the boats monitoring the shark.

While some scientists, after noticing the shark's fin listing to one side, are concerned it may be growing weak, Diodati said the female shark appeared healthy yesterday and not too agitated.

"The shark has moved, no one has been hurt, and she is not hurt," he said. "We'll be back tomorrow, but right now, it's up to her."

If the shark does manage to reach open sea, it will be a bittersweet moment for the legions of fans sprouting up in Falmouth, where tour operators have fielded calls from families from Illinois to Canada eager to pay a price to see the 14-footer.

"Of course we want to see it . . . but we want her to get out," said Barbara Kelly of New York, who was on vacation. "Everyone is rooting for her."

Scientists believe the shark entered the Naushon Island lagoon foraging for food and has been trapped since then by the shallows at its entrance.

While environmental police officers kept boat traffic away from the operation, the view from a helicopter revealed a tense situation with a shark clearly unwilling to leave. A pair of fishing nets were strung across the lagoon, restricting the shark to the portion closest to the exit channel. Over the course of the day, as the shark moved toward the channel, five fishermen repositioned the nets to hem in the fish closer and closer to open water. The nets will remain in position overnight.

Each time the gray-skinned shark began moving toward the end of the channel, she would stop, circle back, and try to inch her way back into the lagoon. Several times, scientists equipped with a pump and hose shot jets of water at her, at which point she would pause, then evade the jet by swimming below or around the boat and try to return to the lagoon.

To discourage the shark from returning to the lagoon, the rescue team attached electric shark-repellent pods to the float lines of the fishing nets hemming her in. But at least once she appeared to ignore the current and nudge the net blocking her way back to the lagoon.

"We think she senses the shoal and a lot of rocks, and that has a lot to do with" her not wanting to leave, said a weary Diodati, reached yesterday evening on a boat in the lagoon. "We did everything we wanted to accomplish today. It was a successful day."

If this latest attempt does not work, scientists may consider more dramatic means to move the shark, such as tranquilizing it or somehow towing it out. Authorities say they cannot ignore the shark because it could harm someone who gets too close -- a situation that appears possible given the number of curiosity seekers who tried to paddle up to it in kayaks before environmental police declared the lagoon off-limits.

Researchers are also eager to have the shark return to open water for the sake of science. State shark researchers were able to attach a satellite tag to the shark's tail that will track her location, depth, and temperature, the first such tag put on a great white in the North Atlantic. On April 1, the tag is designed to pop off and send researchers an account of the fish's whereabouts between now and April. So little is known about the mysterious sharks, any information is a bonus, scientists say.

Meanwhile, back at Woods Hole, a steady stream of tourists asked how they could see the shark, with many believing it was in the harbor. Although many were told that it was a 10-minute boat ride away -- and that they would not be allowed close enough to catch a glimpse -- a half-dozen boats of would-be spectators approached the rescue area anyway.

"It's been great," said Mike Ryan of charter boat company R&R Marine in Woods Hole, who has been taking tourists out to the area. "I think next year I'll hire a kid to put a fin on his back."

Beth Daley can be reached at bdaley@globe.com.