A pilot in a small helicopter hovering above a research vessel off Chatham, MA today spotted a large Great White rapidly closing in on a diver who was swimming near a the boat.

"I saw a shark going real slow about a quarter-mile away, Breen said, and then when the diver jumped in, all of a sudden, I saw the shark head right for the boat, going from about 2 knots to 10 to 15 knots in an instant.

The shark definitely smelled something, Breen said. Their sensory perception is unbelievable. The shark was only about 100 feet [away] when they pulled the diver out."

He radioed the crew on the boat to get the diver out - right away. The diver, attached to a tether, was pulled out.

Later, the same pilot witnessed another shark move within 100 yards of a surfer at a nearby beach.

As of Thursday, five individual Great Whites have been spotted within a mile of Chatham, MA on the south east corner of Cape Cod, two of which have been tagged. Annually home to throngs of summer bathers, these beach-goers have been kept out of the water via closing by local lifeguards and state authorities.

This unprecedented level of White Shark activity has swimmers nervous and shark researches elated. "The White Shark is poorly understood in this ocean...in the Atlantic it remains very rare. This is an opportunity to fill in those gaps," said a state marine life biologist.

For more on this story check out the story on Boston.com