North Atlantic right whales arriving off Mass. coast

North Atlantic right whales are feeding and exploring in Cape Cod Bay.Center for Coastal Studies

Take heed — North Atlantic right whales are out there, feeding and exploring in Cape Cod Bay.

The Center for Coastal Studies in Provincetown said this week that researchers conducting aerial surveys spotted nine endangered right whales cruising through the waters. The sightings, the center said, are a sign of the “true beginning” of the 2016 right whale season off the state’s coast.

“Researchers have spotted individual right whales scattered throughout Cape Cod Bay since late November 2015, but numbers have increased dramatically in the last week,” the non-profit center said Sunday in a statement.

North Atlantic right whales are one of the most endangered ocean species. Only 526 are alive in the world, according to the Center for Coastal Studies.

The center is reminding recreational boat operators, swimmers, and aircraft pilots to keep a safe distance from the whales, since they are a federally protected species. It’s illegal to approach within 500 yards of a North Atlantic right whale, the organization said.

“This is really just an announcement to let people know that the rare animals have come in,” said Charles “Stormy” Mayo, director of right whale habitat studies at the center, in a telephone interview. “We see it about this time every year. We get the increases. It’s the beginning of the rise.”

There has been an increase in the number of North Atlantic right whales in Cape Cod Bay.Center for Coastal Studies

While the waters off Massachusetts are relatively deserted right now due to the cold weather, scientists expect to see an uptick in right whale sightings over the next two months — a “family reunion” of sorts — before the whales decamp for the summer.

“I would say this is fairly normal — a slow ramp-up in numbers and then typically a quick departure at the end of April or early May,” said Amy Knowlton, a research scientist with the New England Aquarium, in an e-mail.

In January, the National Oceanic and Atmospheric Administration announced plans to expand the “critical habitat” of the whales, which feed and congregate in Cape Cod Bay and the Gulf of Maine up to Canada. A portion of the population also migrates to the Georgia and Florida coasts for calving during colder seasons.

It’s a “mystery” where the whales that arrive in Cape Cod Bay in the spring come from, but experts suspect they are arriving from Georges Bank, an area between Cape Cod and Nova Scotia.

A critical habitat is defined as the areas where activities that are essential to the whales’ survival occur.

The new invisible boundaries go into effect at the end of the month, officials said.

“They are a lot rarer than tigers, and elephants, and other big-time animals. I think it’s an important thing to note every time this happens,” said Mayo. “Everyone who lives along the coastline is dealing with a nearly-extinct species. It’s a last-of-the-dinosaurs kind of thing.”