North Atlantic right whales spotted early in Cape Cod Bay

By Sarah N. Mattero, Globe Correspondent

Fifteen rare North Atlantic right whales were spotted feeding off Wellfleet today, the earliest sighting of the whales in Cape Cod Bay in nearly 30 years, the Provincetown Center for Coastal Studies announced.

“It is earlier than usual,” said Charles “Stormy” Mayo, director of right whale habitat studies at the center. “Our airplane is up right now circling them.”

With a population of 502, the North Atlantic right whale is one of the rarest baleen whale species. The whales historically appear in the bay from mid-January to early May. Last year, more than 200 of them were spotted off Cape Cod.

Two whales were accidentally discovered on Wednesday by the center’s disentanglement team , which was bringing a boat into a harbor for repairs. Fifteen more were seen by aerial researchers today. The spottings were the earliest observation of the population feeding in the bay in 27 years, Mayo said.

“They’re here because of food, there’s no question about that,” Mayo said, adding that the right whale feeds on the microscopic organism, zooplankton. “Cape Cod is a very rich place.”

Mayo suspects the whales are arriving earlier because of the Atlantic Ocean’s temperature changes. Last year, the ocean was measuring about 3 degrees warmer than average, which Mayo said is a significant increase.

“There’s a possibility, we can’t say for sure, that there’s somewhat of a change in this ecosystem,” he said. “Perhaps because of warmer conditions, they are coming in earlier.”

The center’s aircraft have been circling about 1,000 feet above the whales, taking photographs so the research team can identify them. The center’s researchers and aerial observers have found nearly two-thirds of the population in the past two years by using photographs of the unique, roughened patches of skin on their heads to identify the whales individually.

“If that area isn’t damaged,” Mayo said. “You can know the whale from above for a lifetime.”

Although the center has federal permits to approach the animals — it is illegal for those without permits to approach within 500 yards of a right whale — as well as permission to tag them, the center chooses not to, Mayo said.

“There’s strict control over them because they’re nearly extinct,” Mayo said. “The effort is to try and stay out of their lives as much as possible.”

The center works with many agencies, including the National Atmospheric and Oceanic Adminstration and the state’s Division of Marine Fisheries, to use the photographs taken to identify and track the whales in the population, study environmental stresses, and the overall health of the whale population, Mayo said.

They also work to figure out where the whales are traveling, how climate change can affect their capacity to find food.

“A lot of their remarkable story will be told right here in Cape Cod’s harbor,” Mayo said.