Wild things in wild places: Is it safe to swim off Cape Cod beaches?

Dr. Gregory Skomal leaning over water to tag a white shark, all in the name of research. Photo by Wayne Davis.

By Daniel Merino
BU News Service

CAPE COD – It has been a busy and tragic summer on the beaches of Cape Cod. The usual dangers posed by strong currents, unexpected weather and lyme disease have taken a backseat to a much more primal threat.

Amateur video, eyewitness accounts and news stories have documented great white sharks on the Cape, in a large number of violent, captivating and eerily close-to-shore encounters in the recent months. The sharks may have visitors asking — “Is it safe to go in the water?”

If you plan on wading more than waist deep, the answer is likely no. The waters around Cape Cod are not places where you can swim or surf without a fear of sharks.

Great white shark sightings had become more and more common in the last few years on Cape Cod, but encounters with humans had been limited to just scary episodes and beach closures.

That changed on Aug. 15, 2018, when a swimmer was attacked off of Longnook Beach, barely escaping alive. On Sept. 15, a man boogie boarding at Newcomb Hollow Beach was attacked and died from his injuries. It was the first fatal attack in 80 years. 

Leslie Reynolds is Chief Ranger for the Cape Cod National Seashore and manages the emergency and lifesaving services for the park.

“This summer, 27 times, we closed the water to swimming for an hour, due to confirmed white shark sightings. Since 2013, the average every year has been 12 times,” she said in an interview that took place before the recent fatal attack.

So, what changed?

Simply put, these attacks are happening because there are far more white sharks in the area than in the recent past. While the exact number of individual sharks is not known, Dr. Gregory Skomal of Atlantic White Shark Conservancy is working on a study asking this exact question.

“It is safe to say [the population] numbers are in the hundreds. We have cataloged over 300 over the last four years.” That is a dramatic increase. Between 1962 and 1993, a total of only 36 sharks were tagged, with only two tags recovered.

But white sharks do not eat humans. As far as prey go, we are not that good for eating: all bones, no fat. Seals are what the white sharks are after, and seals have made a comeback in a big way out on the Cape.

Seals were hunted nearly to extinction along the east coast of the U.S. in the 19th and 20th centuries for their valuable pelts, as well as for meat and oil. But after the passage of the Marine Mammal Protection Act of 1972, which halted all seal hunting, populations of harbor and especially grey seals have rebounded to huge numbers.

“Forty years ago you couldn’t find a seal on the beaches of Cape Cod. And you couldn’t find a white shark either,” Dr. Skomal said. “We don’t know how many were here over the last forty years, but [the seals] were driven down to very low numbers, likely less than 10,000. That population now is thought to be in excess of 500,000.”

White sharks are selective predators. When they attack humans, it is almost always a case of mistaken identity, Dr. Skomal explained.

“When you go into water that is greater than waist depth [in Cape Cod], there is a very high probability that a shark is going to move through that area,” he said. “Then it’s just a statistical game: ‘what is the probability of a shark messing up and biting me?’ I just worry that one of these critters is gonna make a mistake.”

The Cape is a place of “wild things in wild places.” Reynolds gives this warning to people who decide to experience the beautiful nature of the National Seashore.

“We can give the public all the information to educate themselves, but that last decision is going to be made by the person entering the water. Take shark safety seriously,” she said.

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