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Great white sharks swimming closer to US shorelines: Why? (+video)

Daniel B. WoodThe Christian Science Monitor

"Just when you thought it was safe to go back in the water...."

A full 37 years after this movie-ad line helped make “Jaws” the biggest cinematic hit of its time, it still makes beachgoers pause. Along with the pulsing music and images of a fin slicing the ocean surface – from kid pranksters or a real shark – the line is once again being trotted out by officials on both the East and West Coasts at the height of beachgoing season because of real-life shark visitations.

An 18-foot great white shark buzzsawed through the front end of a kayak about 400 yards from Pleasure Point off Santa Cruz July 7. And the town of Chatham, a Cape Cod resort, has barred swimming within 300 feet of seals, known to be a key delectation for hungry sharks. The Cape Cod Shark Hunters, which conducts research with scientists from the Massachusetts Division of Marine Fisheries and the Woods Hole Oceanographic Institute, reported two shark sightings July 3, and three other great whites the week before.

The danger, however, is very slight, say a host of researchers, who are using the incidents to remind the public of its fascination with the ocean predator – and to shift the spotlight to mankind’s global abuse of the species.

“The public loves to fear the idea of sharks and so the media play it up big time because they know it sells newspapers and can be used by broadcasters to tease news features endlessly,” says George Burgess, head ichthyologist at the Florida Museum of Natural History in Gainesville, who has studied sharks for over 30 years. The facts are that sharks almost never attack humans. From 1953 to 2011 there were only 103 verified great white shark attacks in California, with 12 fatalities. Worldwide, last year, there were only five fatalities, says Mr. Burgess, who publishes statistics about sharks.

But Burgess and others say that the opportunity is perfect to harness the attention to man’s treatment of sharks, which is to kill 40 million to 70 million annually. A huge percentage of that is unintentional, as sharks are caught in the nets of tuna and swordfish operations. But a significant portion is also the result of huge demand – especially in Asian countries – for the health food supplements made from shark oil and fins. Using his calculator, Burgess quickly comes up with the ratio of 14 million to 1 – sharks killed by man vs. men killed by sharks.

His conclusion: “We don’t want to sound callous at all to those who have died, because our hearts do very much go out to the families of victims – but statistically, sharks are a nonproblem, especially if you consider their hundreds of millions of hours in the sea.”

All this said, there are several reasons why the human/shark interface is making the news more in recent weeks than in previous beachgoing seasons:

More and more people are visiting beaches and venturing further from shore than in the past, using kayaks, surfboards, and windboards. Shark encounters are much more easily and commonly captured as images and videos on cell phones, which make their way to the Internet via YouTube and to local broadcast news shows hungry for summer features. And the summer season is precisely when migrating sharks come to land after months at sea, so sightings are much more common.

“There is most definitely a seasonal pattern to this,” says Sal Jorgensen, senior researcher at the Monterrey Bay Aquarium. “This increased concern could be an uptick in sightings because more people are there to see them.” He says the sharks stay about 1,000 miles offshore in an area dubbed, affectionately, the “white shark café” for about six months a year and then beeline straight for the Baja Peninsula. The annual migration takes about three weeks of swimming at the high speed of about 50 miles per day.

“We know because they swim that fast and in a straight line, that they haven’t had time to hunt to eat a lot and thus are very hungry when they arrive,” he says.

But he adds that the recent incident at Pleasure Point was mischaracterized as an attack: A man fishing from his kayak in about 40 feet of water just outside a kelp bed was knocked from the kayak by the shark's bump to the vessel’s backside.

“I looked at the pictures of bite marks on the kayak and it was merely what a dog might do to some object when curious about it – nip at it with the only means it has,” says Mr. Jorgensen.

He says probably too much was made in the press about the teeth left in the kayak.

“Kayaks are not edible and so the shark just toyed with it and left,” he says.

He urges beachgoers and swimmers on both coasts to simply remember to just not do something stupid.

“Common sense should prevail when swimming in waters known to be frequented by dangerous sharks,” says George Benz, professor of Marine Biology at Middle Tennessee State University in Murfreesboro, Tenn. “In the case of the Cape Cod situation ... people should avoid swimming nearby seals. This type of common sense is really no different from a person not getting on an airplane with a broken wing.”

Chris Lowe, a professor of Marine Biology at California State University, Long Beach, says that while recent fatal shark attacks in Southern California and Mexico have many people concerned about going to the beach again, beachgoers need to put things in perspective.

“These are really, really rare events. While it’s truly unfortunate, I don’t really think people have much to worry about. The chances of someone being bitten by a shark in Southern California are so small that in many ways, it’s an unrealistic worry."