Not an orca, not a minke, but a finback, aquarium says

This screenshot from John Parisi's video shows the whale lunge feeding off Rockport's Halibut Point.

ROCKPORT — The two whales feeding off the coast of Halibut Point, caught on a video that went viral, are fin whales, according to a naturalist.

On Monday, Rockport native John Parisi shot a quick video of at least one whale sticking a fin out of the water before it submerged. In the video, which had which had 14,000 views on Facebook on Wednesday morning, the boaters off-screen exclaim they saw a "killer freakin' whale!"

After the video was posted, a debate broke out in its comment section: Is it actually an orca, or could it be a minke whale?

After viewing the video, Tony LaCasse, media relations director at the Boston Aquarium, agreed with a commenter that it was a minke. But wait.

After presstime Tuesday, LaCasse called the Times back.

Turns out the whale is in question is a finback whale, according to the New England Aquarium's head whale watch naturalist.

"Whenever fin whales lunge their half fluke, the tail fin, looks particularly tall," the naturalist told LaCasse. Lunge feeding is a technique used by baleen whales, which survive off of small fish. In attempt to maximize their catch, these whales rush schools of fish with an open mouth and gulp whatever they can get.

"Orcas are toothed whales, not baleen whales," said LaCasse. Fin and minke are baleen whales.

Finbacks, or fin whales as they also are called, "are the second longest whales in the world," LaCasse said. "They often are called 'greyhounds of the sea.'"

"We have lots of them that are here in the summer feeding, and they are probably the second most common whale seen aboard whale watches out of Gloucester after humpback whales," LaCasse said, adding they're usually not that exciting to watch.

"Generally all you see when they dive is this long arching backbone, or ridge," LaCasse said. "They don't show you their tail flukes doing their dive, and they don't breach often, if at all."

Watch Parisi's video here: tinyurl.com/rockportwhale.

Material from staff writer Michael Cronin was used in this report by Andrea Holbrook, who may be contacted at 975-675-2731 or aholbrook@gloucestertimes.com.