How common are sharks in Maine’s coastal waters? Here’s what experts say

Sightings are more common on Cape Cod, but that may have more to do with people than sharks.

Boats are seen in Casco Bay on Bailey Island. Julie Dimperio Holowach, 63, of New York City, was swimming off of the coast of Bailey Island died Monday afternoon after an apparent shark attack. It was the first ever recorded in Maine, but experts say sharks have long been known to visit the waters off the state's coast.Jessica Rinaldi/Globe Staff

Shark attacks like the one that claimed the life of a 63-year-old woman swimming in a cove off the coast of Maine on Monday are unheard of in the state, officials said. But the presence of great white sharks along the rocky shores that border Maine’s quaint coastal communities has long been clear, according to experts.

“We have records going back hundreds of years that the white shark is quite commonly documented in the Gulf of Maine,” said Greg Skomal, a senior scientist with the Massachusetts Division of Marine Fisheries. “That’s historically documented and demonstrated by our tagging data.”

Skomal, a leading expert on great white shark activity in the region, said people tend to think of Cape Cod as being the northern-most feeding grounds for great white sharks, since it’s typically where sightings and predations are reported by the general public and the media — especially during the busy summer months.

But they travel much farther than that, he said, often using Cape Cod as “a rest stop on a major highway, as they move into northern parts” in search of seals, their preferred food source.

Massachusetts Division of Marine Fisheries Shark Specialist Greg Skomal.Josh Reynolds

“Some stay around Cape Cod and feed. Others will stop by for varying amounts of time and keep moving into the Gulf of Maine where there’s ample amounts of seals,” he said. “It’s not a new phenomenon that white sharks are along the Maine coast.”

He said part of the reason people may not hear about the presence of great whites near the Maine shoreline quite as often is because there are fewer people there, and they tend to be more spread out than those who flock to the popular beaches of Cape Cod each season.

“The Gulf of Maine isn’t as densely populated as the coastline of Massachusetts, so when sharks attack and kill seals, maybe not so many people see them happen,” he said. “These reports of attacks on seals — they do come to us, we do see it. But they aren’t as frequent as off the coast of Cape Cod where they are reported quite routinely.”

What is rare, however, are attacks on people.

“Obviously, this type of issue is certainly new to Maine,” Patrick Keliher, commissioner of the Maine Department of Marine Resources said at a press conference Tuesday.

Skomal said while experts don’t know “what’s going on in the brain of the shark,” the fatal incident off of Bailey Island could have been the result of mistaken identity.

“In this case, that shark made a mistake,” Skomal said. “It was likely feeding on seals in that area or along the coastline of Maine and interpreted the behavior of this poor individual as being similar to a seal to the extent that it initiated a predatory sequence.”

Skomal said there’s no empirical evidence to suggest that the presence of sharks off the coast of Maine has anything to do with a changing climate, and the sharks are not “going North more.”

“I understand that reaction, I really do, but that’s not the case,” he said. “Remember, climate change is a relatively recent phenomenon, and we’ve got plenty of records showing that white sharks move up to these northern latitudes in the summer.”

Skomal said as both the population of seals and great white sharks continue to rebound due to increased protections, the likelihood of seeing more of the apex predators along the Maine coastline is possible.

“As the population becomes a healthy population, you’re going to see it venturing into these higher latitudes where it has historically gone,” he said.