A great white shark was sighted attacking a seal off the coast of Cape Cod in the Stellwagen Bank National Marine Sanctuary about 5 miles off the coast. The sighting occurred on Saturday morning by the crew and passengers on a vessel operated by Dolphin Fleet Whale Watch, an event that was captured on video by company employee Michelle Silva. In a matter of minutes, the shark surfaced and gorged itself on the seal.

It was the first white shark sighting of the season in the northwest Atlantic, according to the Atlantic White Shark Conservancy on Cape Cod and the New England Aquarium in Boston. The shark was estimated to be about 12 feet long.

The sight of a great white shark sighting off the coast of Cape Cod is a sure sign that summer is fast approaching. A growing number of these top predators have been seen near Cape Cod, the only northwest Atlantic white shark aggregation site, feeding on the recovering seal population. While the sharks pose little threat to humans, experts have warned beachgoers and boaters to be mindful of their presence, as bites on humans have been known to occur.

“It serves as a reminder to beachgoers and boaters to be mindful of the presence of these ocean animals,” said John Chisholm, an adjunct scientist in the New England Aquarium’s Anderson Cabot Center for Ocean Life.

For many of the roughly 150 passengers aboard the Dolphin Fleet Whale Watch vessel that witnessed the attack, the sight of the great white shark feeding was an incredible and awe-inspiring experience they would not soon forget. Biologist Andrea Spence has described the shark feeding that occurred over the weekend as “very rare.” Sharks are infrequently seen by whale watching boats.