BOSTON (CBS) – For the first time this year, biologists have detected a great white shark off the coast of Cape Cod.

On Tuesday, May 28th, the 13-foot female was detected near Monomoy Island. The shark was tagged by the Division of Marine Fisheries in 2011 and returned last summer.

Researchers believe the sharks are attracted to Massachusetts coastal waters due to the growing population of gray seals that migrate here annually. Researchers from OCEARCH tagged sharks that have since been tracked as far south as Florida.

Officials advise swimmers to avoid swimming at dawn or dusk, stay close to the shore and avoid areas where seals congregate.

Last year, a man swimming in the water off Ballston Beach in Truro was attacked by a great white shark. The man suffered severe cuts on both legs.