WELLS – Town beaches reopened on Monday, a day after shark sightings prompted city officials to close beaches to swimming.

Wells Fire Chief Daniel Moore reopened the beaches after going out on the water to survey for sharks. A day earlier, a dead mako shark that was 3 to 4 feet long was discovered at the Wells Beach jetty, and two more sharks were spotted south of the jetty.

A theory is that warm water is drawing sharks close to shore to feed on smaller fish.

There are plenty of sharks in the Gulf of Maine, but they usually stay offshore to feed. There has never been a shark attack in Maine’s history, according to the University of Florida’s International Shark Attack File.

This isn’t the first time that Wells Beach has been closed because of sharks. Four years ago, the beach was closed for three days because of shark sightings.