MONTAUK - A shark expedition embarked on a three-week expedition around Long Island in an effort to gather data on the ecology and behavior of sharks in the Atlantic Ocean.

Researchers onboard the M/V Ocearch vessel believe great white sharks are using the South Shore as a breeding ground. Lead researcher Chris Fisher believes there's no danger to humans.

The Ocearch is 126-foot former Alaskan crab ship that uses a lift to take the sharks out of the water and onto the deck where they can conduct scientific research.

Team member Dr. Merry Camhi says the crew plans to attach a satellite tag the sharks' dorsal fins. Scientists say the study will help them understand sharks and maybe improve catches for fishermen.  

"We wanted to understand when they're here, why they're here, what habitats they're using, so we're using acoustic and satellite technology," says Dr. Camhi.

One of the vessel's first great successes was tagging great white shark "Mary Lee," who has acquired thousands of Twitter followers who watch her migrations.

The vessel left from Montauk, where it was anchored all day Thursday.