WELLS — A fisherman thought he saw a shark swimming around the Wells town jetty Wednesday, causing police and Maine Marine Patrol agents to search the water and lifeguards to keep a close eye from the town beach Thursday.

No other sightings were reported and no warnings were issued to swimmers.

Someone fishing off the jetty reported seeing a large fish with a dorsal fin about 5:30 p.m. Wednesday. “He believed it was a shark. It looked like it was hunting,” said Wells police Sgt. Kevin Chabot.

Wells police and the Marine Patrol searched the area in boats late Wednesday, while others looked from shore.

“After about two hours of looking … we stopped,” Chabot said.

Lifeguards kept a close eye on the waters around the beach Thursday but again saw no evidence of a shark or anything that might look like one, he said.

Members of the public are encouraged to report shark sightings near the beach by calling 646-9354.

Shark sightings are unusual but not unheard of around Maine beaches.

“There are all kinds of sharks in the water, but they are typically off the coast. … To see one 300 feet from the shore is an abnormality,” Chabot said.

A string of confirmed shark sightings at Wells Beach and around the jetty in August 2002 became a major tourist attraction, with people going to the beach to try to see sharks estimated to be 12 feet long.

In 2006, the beach was closed after a dead mako shark 3 to 4 feet long was found at the jetty, and other sharks were spotted in the water.

On the other hand, lifeguards and police often check reported shark sightings and find something else instead.

Last year at this time, what appeared to be shark fins were spotted 30 to 50 yards off Wells Beach and lifeguards told bathers to get out of the surf. The fins turned out to belong to ocean sunfish, a large, odd-looking but docile species.

“We had a report earlier this week of a shark in the water and the lifeguard investigated it and deteremined it was a log,” Chabot said. “In this case, we never found anything.”

According to the International Shark Attack File maintained by the Florida Museum of Natural History, there has only been one documented shark attack in Maine since 1670, and no fatal attacks. That compares to 663 attacks and 11 fatal attacks off Florida during the same period.