SUMMERSIDE, P.E.I. -- A group of marine researchers says a young beluga whale is too attached to the Maritimes for his own good.

Nepi, who's estimated to be about four years old, was spotted in Summerside, P.E.I., in early December, much to the delight of a local diving class.

"We heard a whale, or what we thought was something blowing, and then this whale appeared," recalled Kimball Johnston, an instructor at Holland College's commercial diving program.

The group, which included Johnston and 11 students, thought the whale would swim away and keep his distance. Instead, Nepi hung around the divers for several hours.

"He started coming around and was more curious, and was diving amongst our divers, and kept getting closer and closer to the point where he was right up next to them and they could see him very, very clearly," he said.

Johnston, who's been diving for more than 20 years, said he's never seen a beluga so close to the Island.

While the students were excited to be in such close quarters with the whale, Johnston said they did not chase or entice Nepi to stay with them.

"We were there doing our thing and he was there doing his thing," he said. "We were just going about our business and he just kept intruding."

Robert Michaud, scientific director of the Quebec-based Group for Research and Education on Marine Mammals, says it's worrying to see a young beluga getting friendly with people while away from home -- especially when it's a repeat offender, like Nepi.

Michaud's group first came across the young whale in June 2017. After getting a call about a beluga being stuck in the mouth of the Nepisiguit River in Bathurst, N.B., the group coordinated a rescue that involved moving him to the St. Lawrence river in Quebec, near Cacouna.

Michaud said the rescue was an experiment.

"The St. Lawrence beluga population is declining, they're endangered, so we were wondering whether saving an animal would help recover the population," he said. "The animal was not too far from home, it was feasible, so we tried it."

The marine research group put a tag on Nepi so they could track him, but the mischievous whale managed to lose it after about 20 days.

A year after he went off the grid, Nepi was spotted by a wildlife photographer in Ingonish, N.S., and researchers managed to identify the whale by looking at the photographs.

Now that the beluga has popped up once again in P.E.I., Michaud said he's mystefied as to why Nepi finds the Maritimes so alluring.

"This young whale would be much better hanging around with others of his own kind in the St. Lawrence area. This is why we moved it back to Cacouna," he said. "The question is why he went back again. Is it the individual temper of this guy to be adventurous?"

When belugas get too close to boats and people, Michaud said, it can often lead to tragedy for the declining species.

Michaud said the Group for Research and Education on Marine Mammals hears of many cases in which a beluga got hit by a boat or struck by propellors and killed, which is why it's dangerous to allow them to get too close and encourage them to be fearless of people and their vessels.

"We don't see what's going on under our boat. So if we were fully aware, three dimensions around our boats, it might not be as dangerous," Michaud explained. "But when the animals are not cautious, when you move in reverse with your boat, then accidents happen. So we hope it won't happen with Nepi."

While most belugas live in the Arctic, their southernmost habitat is in the St. Lawrence Estuary: a critical habitat for belugas, which are protected under Canada's Species at Risk Act.

As of 2012, the St. Lawrence Estuary was home to an estimated 900 belugas -- though they say there could have been as many as 10,000 belugas in the estuary before 1885.

Michaud asked that anyone who sees a beluga farther south than the estuary tell the group so they can try to identify it, and added that while Nepi's wanderlust has marine experts concerned, he's hopeful the young whale will come back home.

"They're amazing navigators, they have the best underwater radar you can imagine," he said. "P.E.I. is a bit closer to the St. Lawrence than Nova Scotia, so there's reason to be hopeful. I cross my fingers for him."