A first: Great whites tagged off Mass.

BOSTON -- Massachusetts officials are using high-tech tags to track the movements of two great white sharks near Cape Cod -- the first time the fish have ever been tagged in the Atlantic Ocean.

The electronic tag uses satellite technology to record the travels of the sharks, allowing scientists to better understand their migratory patterns.

The sharks were spotted Saturday by scientists investigating sightings off Monomoy Island in Chatham. Officials say a harpooner tagged them with help from a state shark expert.

Sharks are common in Cape waters during summer, though great white sharks are relatively rare around New England.

State officials have warned area swimmers to be on the lookout for sharks this weekend, and state environmental police are patrolling the area as a precaution.