WELLS – Wells police have asked beachgoers to be on the lookout for sharks, after two basking sharks spotted Sunday prompted officials to close a local beach for about 30 minutes.

The sharks were seen about 25 feet from shore. People at the beach were never in any danger, said Lt. Gregory Stone of the Wells Police Department.

They were spotted at around 10:15 a.m. on the Atlantic Avenue side of Wells beach, and left the area around 12:15 p.m.

Basking sharks usually swim in deeper, open water. They spend their summers off the New England and Canadian coasts, and travel south to the mid-Atlantic states in the winter.

Adults can reach more than 30 feet in length. They are vegetarian filter feeders, eating plankton, not people, but have been known to defend themselves if provoked or disturbed.

In Maine, shark sightings are rare, and there has never been a confirmed shark attack anywhere on the state’s coast, according to the University of Florida’s International Shark Attack File.

Shark species that frequent the Gulf of Maine include mako sharks, porbeagle sharks and blue sharks, along with threshers and whites.

Makos, porbeagles, threshers and blues can be a threat to humans, along with great whites, which are rarely seen off Maine’s shores.