Marine scientists in Maine who read about three possible great white shark sightings over the weekend along the state’s southern coast said Monday that the sharks were more likely filter-feeding basking sharks.

In the most detailed of the three sightings, five friends who were fishing 26 miles out from Portland on Saturday evening reported seeing a shark several feet longer than their 22-foot boat. Another sighting was reported early Saturday afternoon about a mile off Moody Beach in Wells. The third sighting was reported by a diver off Old Orchard Beach on Saturday.

But James Sulikowski, a professor of marine sciences at the University of New England, said a great white shark measuring 25 feet is unheard of, and that what the fishermen saw Saturday evening was likely a harmless basking shark.

Unlike great whites – voracious predators widely known for their dagger-like teeth – basking sharks have only nubs of teeth and use their large mouths to take in and filter plankton and small fish from the water.

Sulikowski said there are many shark species in Maine’s waters, including porbeagle sharks, spiny dog fish, blue sharks, sand tigers, basking sharks, great whites and threshers.

“Maine is a pretty sharky area,” he said.

Shark fears have run high recently since two teenagers in North Carolina were severely injured in two separate shark attacks on June 14 in the same town. Media outlets reported the stories around the country, including a first-hand account from one of the shark attack victims afterward describing how the shark bit his arm off.

But Sulikowski’s message to Maine beachgoers, however, is to take a deep breath and “not be afraid.”

“There has never been an unprovoked shark attack in Maine, ever,” Sulikowski said. “You’ve got a better chance of being bitten by another human being than a shark.”

Adam Baukus, a research associate at the Gulf of Maine Research Institute in Portland, agreed that while it’s possible people saw great whites over the weekend, it’s not likely.

“It probably, more realistically, is a basking shark. They are more common,” Baukus said. “There are certainly more basking sharks to be seen.”

The average adult basking shark is about 25 feet long, while the average full-grown female great white shark is about 15 feet long, while males are usually about 12 feet long.

“Basking sharks are looking for big aggregations of plankton and small shrimp. They roam around quite a bit. They are a big animal and need quite a bit of food,” Baukus said.

Baukus saw a basking shark off Maine’s coast a week and a half ago and captured underwater video of the gentle giant while he was out on a research boat trip for the Casco Bay Aquatic Systems Survey to sample the area’s fisheries.

In the video Baukus used a pole to lower a camera underwater to capture up-close footage of the basking shark slowly swimming near them.

At the end of the video, Baukus looks into the camera to show his awed expression.

“This is my nervous excited smile,” he says to the camera.

Baukus said on Monday that even he was surprised at the size of the basking shark captured on the video.

“It’s big. You really don’t get a sense of how big they, the girth and the length, until you see one that close,” Baukus said. “I challenge anyone not to have their stomach drop.”

Lisa Kerr, a research scientist specializing in fisheries ecology at the Gulf of Maine Research Institute, sent an email to the institute staff on Monday morning in reaction to the news to distinguish between the fins of a great white shark and a basking shark.

Kerr shared a link with side-by-side photos of the sharks’ dorsal fins to show that a great white’s fin has a steeper angle and sharper tip compared to the more gradually sloping angle of the basking shark’s fin, which appears more rounded.

“It can be difficult to distinguish between basking shark and great white dorsal fins as the differences are subtle,” Kerr said in the email.

Kerr added in a phone interview on Monday afternoon that basking sharks can reach lengths of 40 feet, while even the largest great whites are less than half that length.

“It would be more common to see a basking shark than a great white, for sure,” she said.

The U.S. Coast Guard reported no further shark sightings since the three reports on Saturday.

The reported sightings came on the 40th anniversary of the first “Jaws” movie and as the Discovery Channel has begun promoting its annual “Shark Week” programming starting on July 5.