A large number of whales is visiting the waters off New England, and the group includes an unusually high number of an endangered species, said scientists who study the animals.

A research flight made 161 sightings of seven different species of whale on May 25 south of Martha’s Vineyard and southeast of Nantucket, officials with the National Oceanic and Atmospheric Administration said Thursday. The sightings included 93 of sei whales, and that is one of the highest concentrations of the rare whale during a single flight, the agency said.

Other highlights included two orcas - an uncommon sight off New England - one of which was toting a tuna in its mouth, NOAA said. There were also endangered North Atlantic right whales as well as humpback, fin, minke and sperm whales, the agency said.

The sightings do not necessarily represent 161 individual whales, because observers could be sighting the same animal more than once, said Teri Frady, the chief of research communications for the NOAA’s Northeast Fisheries Science Center. However, the observers clearly reported “a lot of whales,” Frady said.

“It is not unusual that there are a lot of whales in the area this time of year. But since we do not survey every day, or in the same areas every time we fly, catching such a large aggregation with such a variety of species on one of our flights is the exception rather than the rule,” Frady said.

Observers logged three sightings of the North Atlantic right whale, which has been the subject of new proposed fishing and shipping regulations in an attempt to protect it from extinction. There are less than 360 of the whales left on Earth, scientists have said.

The large whale group appeared in an area that is “increasingly important as year-round core habitat for North Atlantic right whales and other large whale species,” said Gib Brogan, campaign director with conservation group Oceana. The whales are “swimming in harms way” until the U.S. finalizes strict rules to protect them from collisions with large ships and entanglement in commercial fishing gear, he said.

“Oceana is concerned about the protection of these whales from vessel strikes and entanglements, the two leading causes of death for large whales in the U.S. Atlantic,” Brogan said.