Caught on camera: Great white shark feeding on whale carcass off Cape Cod

"We saw the fin come up after a couple of minutes," said Michelle Collins. "The shark then went and fed on the side of the whale's head."

The carcass of the minke whale was first spotted floating at the mouth of Boston Harbor on Thursday. Then on Sunday afternoon, word got out that a white shark was having it for lunch in Cape Cod Bay. The meal got mixed reaction from people on board a Captain John Whale watching boat.

"Of course they are coming out to see whales so we did, of course, we did have a couple of people upset that their first sighting was a dead whale but a lot more people were very excited," said Collins.

Grant Suchecki and Ryan Edmonds heard about the whale and went out curious to see what they'd find.

"I didn’t think we were going to see a shark, I just thought we were going to see a dead whale and bask in the glory of it but then a shark came out of nowhere and as you can see from the video it was actually pretty surprising and Duxbury, you usually see it off the Cape but you don’t expect to see something like that in Duxbury every day," said Edmonds.

"It was really weird at first but I'm like, this is really cool being able to see it because you don't see a great white every day," said Suchecki.

The sighting forced closure of the beach temporarily. A warning Edmonds says he now understands even more.

"Prior to this I used to be scared of sharks, and they would always tell me don’t be a baby they won’t be a baby they won’t come in the bay but I probably will be more alert when I go to the beach you see the signs but you don’t always think of it when you go swimming in the ocean," he said.

After biologists are done examining the carcass, the Duxbury Beach Reservation will determine how to dispose of it.