Monday’s fatal shark attack off Harpswell is the result of rebounding great white shark and seal populations along the Maine coast, experts say.

The attack on Julie Dimperio Holowach, 63, was the first fatal shark attack in the state’s history. A diver was attacked off Eastport in 2010, according to the Florida Museum’s International Shark Attack File, but he was not injured and fended off a porbeagle shark with his video camera.

Seal populations have grown since a 1972 law barred killing of marine mammals and white shark numbers have been rebounding for two decades as a result of a rule that said fishermen could no longer kill the fearsome predators, a shark expert based in Massachusetts said.

Gregory Skomal of the Massachusetts Division of Marine Fisheries dismissed speculation that warming water temperatures in the Gulf of Maine might be enticing more great whites to the state’s coastline.

He said the sharks always have been frequent visitors to Maine waters, but that growing seal populations might be drawing them closer to the shore. Seals are a favorite food of the great white, he said.

Tobey Curtis, fishery management specialist of the Atlantic Highly Migratory Special Management Division for the National Oceanic and Atmospheric Administration Fisheries, concurred with Skomal’s assessment.

“Understanding the effects of climate change on fish populations, including sharks, is an emerging area of study and a priority for NOAA Fisheries, (but) there is currently no evidence that white sharks or other species are spending more or less time near shore as a result of warming waters,” he said. “There is also no reason to suspect warming waters would bring more white sharks to the region; they are already there.”

Curtis said white sharks have been spotted in Maine for decades, particularly in the summer and fall months, and any lack of encounters with humans simply indicates that they are ignoring us and hunting their natural prey.

“Food availability, more than water temperature, influences where the sharks hang out during these seasons,” he said. “Locations with abundant seals, in particular, will more frequently attract white sharks.”

Seal populations were decimated in the 1950s and ’60s, but the 1972 Marine Mammal Protection Act barred the killing of marine mammals and the seal population has boomed all along the northeast coast as a result.

Great white sharks range as far north as Canada, said Skomal, who identified the shark involved in Monday’s attack as a great white by examining a tooth fragment that was recovered. It was clearly a great white, he said.

Shark populations off Cape Cod have grown dramatically, Skomal said, and, in shark terms, a trip to Maine is an easy journey. He said a great white could move from the coast of Massachusetts to Maine in a day.

“The occurrence of white sharks off the coast of Maine, that’s nothing new,” he said, but the numbers might be growing.

James Sulikowski, a professor with Arizona State University, said great white sharks generally populate the waters off New England from July to November when they head south. Sulikowski used to teach at the University of New England and still conducts research in New England.

Sulikowski said a seal was found Sunday off Phippsburg with a 19-inch shark wound that was likely the work of a great white. He said there were witness reports that Holowach was thrown into the air by the force of the attack and that, too, suggests a great white, although its not clear if it was the same shark that attacked the seal.

“Great whites are basically ambush predators” that swim below their prey and then attack with a sudden rush to the surface, Skomal said. Officials have said that Holowach was wearing a wet suit and the shark might have confused her with a seal, he said.

Sulikowski said he will be checking information on pingers that have been attached to some great whites to track their movements to see if they’ve been congregating off Maine. He and Skomal said a handful of sharks have been fitted with technology that allows researchers to track shark movements in real-time, but most have pingers that connect to offshore buoys and the data has to be downloaded on-site, so it’s only collected every few months.

Both experts said there are simple steps that people can take to avoid being in proximity with great whites, starting by not swimming in areas where seals congregate or large schools of fish are present.

They also urged swimmers to avoid wearing dark wet suits and shiny objects, such as jewelry, that might attract a shark’s attention. And, if officials say sharks have been spotted, stay out of the water, Sulikowski said.

“If you’re on a safari and you know there are lions around, you’re not going to go down to the watering hole,” he said.

 

Times Record Staff Writer Hannah LaClaire contributed to this report.