Record sighting: 33 critically endangered whales seen in Cape Cod Bay

A gathering of critically endangered whales in Cape Cod Bay over the weekend appears to have set a new monthly record.

The Center for Coastal Studies says observers on a plane spotted 33 North Atlantic right whales on Saturday, which is believed to be the most an aerial survey has ever recorded on a single day in January.

The whales were behaving a bit differently than what researchers are used to for this time of year.

"Most of our sightings in December and early January have been of animals in what we call surface active groups, but almost all of the whales on Saturday's flight were observed in shallow subsurface feeding," aerial observer Ryan Schosberg said in a statement.

The center said there were two notable sightings among the nearly three-dozen whales. One was a seldom-spotted male known as EgNo 1050, who is estimated to be at least 45 years old and has only been seen one other time in the past 15 years. The other was a calf that was seen for the first time ever last year in Cape Cod Bay.

There are estimated to be 384 right whales in the world after a few years of "slow growth" for the species population, the New England Aquarium said last fall. 

The biggest threat to the whales are vessel strikes and entanglement in fishing lines. In December, a 3-year-old male frequently seen in New England waters was found severely entangled off the coast of Georgia, and scientists say he may not survive.