After nearly seven hours on a plane on Sunday, two New England Aquarium research scientists had hit a lull in their search for marine mammals in the waters south of Nantucket and Martha’s Vineyard. They thought their day was almost done when one of them saw some splashing.
Not exactly sure what they were seeing, the scientists, Orla O’Brien and Katherine McKenna, began to circle the area. Upon closer inspection, they were surprised to see two killer whales swimming side by side. Then they spotted a third. Then a fourth.
“It’s the type of thing that jolts you,” Ms. O’Brien said.
Ms. O’Brien was tasked with taking photos, and she was worried she wouldn’t get a good shot of the underwater creatures. Fortunately, they popped up long enough for her to capture the moment.
She said that she and Ms. McKenna typically saw humpback whales, North Atlantic right whales and minke whales. Sightings of killer whales, or orcas, however, are rare for the East Coast.
“This kind of sighting generates a lot of attention because killer whales are very charismatic, striking and beautiful,” Ms. O’Brien said. “It’s fun to share this with people, but it’s not necessarily something we see all the time or something I expect to see going forward — just a really lucky day.”
What made the sighting even more remarkable was that it was the second time that a killer whale was spotted off the New England coast that day.
Chris Simon was among a small crew aboard a fishing boat, the Simon Sez, in the waters off Provincetown, Mass., when he saw a fin larger than those of most of the whales and dolphins he typically encounters.
“As we got closer, I was like, ‘Oh my god, this is once-in-a-lifetime experience that many people will never get to see,’” Mr. Simon said. “We were just in awe.”
A video of the whale that Mr. Simon posted on Instagram drew more than 100 comments. One commenter said it was a “dream” to see an orca up close, while others identified the whale as Old Thom, an orca who is known to travel alone and is occasionally spotted in the Cape Cod area.
One reason these sightings are so rare is that the population of killer whales in the northwest Atlantic Ocean is so small, Ms. O’Brien said.
It’s unclear if there ever was a significant population of killer whales in the northwest Atlantic, said Andrew Trites, the director of the marine mammal research unit at the University of British Columbia.
He said the more recent sightings could be tied to rebounding seal and shark populations along the Eastern Seaboard. Killer whales are known to feed off both, he said.
“Almost everything is connected to food,” Mr. Trites said.
“Whether the presence of one and now four is the sign of a recovery or comeback is yet to be seen,” he said. But, he added, “I suspect it is probably related to the recovery of seal populations and white sharks as well.”