WELLS, Maine (NEWS CENTER) -- A relaxing day at the beach turned tense quickly.

"The lifeguards came off the jetty and started whistling at everyone," says beach-goer Sarah Corcoran. "They called the surfers in and they finally told us everything that was going on."

The area was cleared as a precaution after a few people said they saw a shark near the Wells-Ogunquit line. Police say the initial report came from a paddleboarder who said a shark swam by that was at least 12 feet long.

Another person also saw a large creature in the water, but thought it was a basking shark, like the one pictured hear, which is big, but has no teeth and eats plankton.

"This time of year we do expect basking sharks to be around that close to shore. I don't think white sharks are going to be up here this early, but you never know," says Dr. James Sulikowski, a professor of Marine Science at the University of New England.

Dr. Sulikowski says white sharks sometimes venture into Maine waters, and are all over the Cape Cod region just south of us.

Our partners at NBC Boston say the first white shark of this year arrived in the Cape Cod area on June 2.

Dr. Sulikowski says Maine's cold water temperatures are not a deterrent for a white shark because it can control its own body temperature. He believes if a shark was seen here on Sunday, a basking shark is the most likely culprit, but beach-goers shouldn't be surprised if more white sharks are spotted in the future.

"White sharks will be moving up here in the next couple of years, if not sooner, and will have a larger presence mainly because there are a lot of seals around and their food source is increasing. So with an increasing food source, you are going to see more white sharks," says Dr. Sulikowski.

A notion that's not scaring off too many people -- Wells beach reopened Sunday afternoon, and crowds packed the shore and played in the water on Monday.