Study: Cape Cod sharks spend nearly half their time in shallow water


A shark was close off shore near Longnook Beach in Truro in 2018. David L. Ryan / Boston Globe, File

Cue the “Jaws” references.

Great white sharks visiting Cape Cod for some seal-shaped snacks spend almost half of their time in relatively shallow waters, according to a recent study led by researchers at the Atlantic White Shark Conservancy.

Tagging data, which was collected from 14 sharks in 2017, found that the sharks dawdled in depths under 15 feet 47 percent of the time — that’s near the shore, where swimmers and boogie boarders are most likely to float around.

“Although the overall risk posed to humans by white sharks is low, there is a high potential for overlap between white sharks and recreational water users off Cape Cod,” the researchers wrote.


The data also showed that the sharks were slightly more likely to stay closer to the shore at night during the new moon. The study, published in Wildlife Research, was the first to examine the vertical habitat use of white sharks off the Cape.

“White sharks are regularly spotted off our coastline during the summer and fall, the peak of Cape Cod’s tourist season, but until now we didn’t know just how much time they spent in shallow water close to shore,” lead author Megan Winton wrote in a release.

“People should be aware that white sharks are present along Cape Cod’s beaches during the summer and fall and proactively modify their behavior to reduce their risk,” CEO Cynthia Wigren wrote.


According to the Global Shark Attack File, there have been four unprovoked shark attacks documented in Massachusetts since 2012, including one fatal incident in September 2018. There was only one other fatal attack in the last century, in 1936.

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