The 40-second clip was first shared by local publication TAPInto; Long Beach Township Police Captain Kevin Mahon confirmed to the site the attack did take place, and that more than one shark had been spotted in the waters that morning.
While sharks will occasionally attack dolphins, they usually target the young or sick. Sharks are typically lone hunters while dolphins travel in pods, and will defend themselves as a pack if threatened.
Dolphins are also faster, smarter and more agile, and can seriously wound a shark by ramming it with their snouts.
There were unconfirmed reports that the dolphin attacked on Thursday had been struck and wounded by a boat propeller, and that the blood had attracted the predator.
While many species of shark call the waters off NJ home, attacks on humans are fairly rare, but they do happen: attacks had been averaging one every seven years, until two children were bitten on the same day in 2018.
The last fatal shark attack of New Jersey however was in 1926, according to the Shark Research Institute.
Shark attacks on Jersey Shore was also the subject of the aptly titled 2012 SyFy "Jersey Shore Shark Attack", in which Nicolina "Nooki" Santamaria, Gino "The Complication" Moretti and Joey Fatone must survive a series of deadly attacks.