Calm waters near the Cape Cod coast recently erupted in a display of predatory violence as a great white shark tore into a seal, and an onlooker on a boat captured the attack on video.
Peak shark season along coastal Massachusetts is typically August through October, but great white sharks still continue to cruise — and hunt — in coastal waters well into November, as this shark demonstrated on Nov. 7 near the southern tip of Monomoy Island, a sandy stretch of land that extends for 8 miles (13 kilometers) to the southwest of Chatham, Massachusetts.
Footage of the attack was shared in a tweet on Friday (Nov. 19) by the Atlantic White Shark Conservancy (AWSC), a shark conservation nonprofit. Two video clips were captured by a boater identified as R. Nossa, and the footage duration is 32 seconds; it shows a shark's dorsal fin briefly appearing above the surface of the water, accompanied by a lot of thrashing and a spreading pool of what appears to be blood.
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Even though we have passed peak season for white shark activity along the Cape Cod coast, it is important to note that white sharks are still in the area. Thank you to R. Nossa for sharing this footage that he took of a seal predation on 11/7 near the s. tip of Monomoy Island. pic.twitter.com/ltZtvzpAXWNovember 17, 2021
Because much of the attack took place at a distance and underwater, it's difficult to see exactly what's happening in the video, but AWSC representatives described the attack as "seal predation" in the tweet. The most common seals near Cape Cod are harbor seals (Phoca vitulina vitulina) and gray seals (Halichoerus grypus atlantica), which live there year-round. Great white sharks prey on both species, according to the Center for Coastal Studies in Provincetown, Massachusetts.
Great white sharks (Carcharodon carcharias) are one of the most widespread of living shark species. They inhabit coastal and offshore waters worldwide where sea-surface temperatures range from 45 to 81 degrees Fahrenheit (7 to 27 degrees Celsius), according to the ReefQuest Centre for Shark Research in Vancouver, Canada. The sharks are frequent visitors to the Cape Cod area, especially during the "peak season" months in the late summer and early fall, according to AWSC.
But in recent decades, conservation work protecting sharks and seals sparked population booms for predator and prey alike. This in turn has led to an uptick in shark sightings in New England waters, with some sharks venturing as close as 10 feet (3 meters) from the shore, Boston University representatives reported in September 2020.
"Seal populations are responding to conservation and showing up in areas where they used to be in the United States and Canada," Greg Skomal, a fisheries biologist at the Massachusetts Division of Marine Fisheries, said in the statement. "And the white shark population has been rebounding."
Recently, researchers found that great white sharks may attack people not because they have a taste for human flesh, but because they mistake humans for seals, Live Science previously reported. However, such attacks are rare, with just 57 cases of "unprovoked" bites — instances when a swimmer didn't interact with the shark prior to the attack — recorded worldwide in 2020, according to the Yearly Worldwide Shark Attack Summary published by the Florida Museum of Natural History's International Shark Attack File.
Of those unprovoked interactions, 10 were fatal, according to the 2020 summary.
Originally published on Live Science.
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Mindy Weisberger is a Live Science editor for the channels Animals and Planet Earth. She also reports on general science, covering climate change, paleontology, biology, and space. Mindy studied film at Columbia University; prior to Live Science she produced, wrote and directed media for the American Museum of Natural History in New York City. Her videos about dinosaurs, astrophysics, biodiversity and evolution appear in museums and science centers worldwide, earning awards such as the CINE Golden Eagle and the Communicator Award of Excellence. Her writing has also appeared in Scientific American, The Washington Post and How It Works Magazine.