CHATHAM, Mass., July 28 (UPI) -- A naturalist looking for basking sharks to tag found and tagged a great white shark off a Massachusetts beach resort, officials say.

Catherine Williams, a spokeswoman for the Massachusetts Marine Fisheries, said Gregg Skomal saw the great white Tuesday afternoon near Chatham on Cape Cod, the Boston Globe reported. The electronic tag he attached may remain in place until February, transmitting information about the shark's movements.

Stuart Smith, the Chatham harbormaster, said there have been a number of shark sightings this summer, many of them from commercial fishermen, who are considered more reliable than beachgoers when it comes to sharks.

Great whites can grow to be more than 20 feet long and have a fearsome reputation. But attacks on humans are unusual and fatal ones even rarer.

Basking and whale sharks are even larger. But both feed on plankton like the largest whales.

Smith said swimmers have been advised to be cautious and told to stay at least 300 feet away from seals, the favorite prey of the largest great whites.