What’s behind the uptick in shark encounters?
There is an apparent uptick in shark/human encounters lately. Surfers were bitten near Reunion Island, Indian Ocean, and Wedge Island, Australia, late last month. Australia has had five recorded fatalities in the last ten months, far above the average. Beachgoers have spotted huge dorsal fins off Cape Cod where shark encounters decades ago were the original inspiration for Jaws, and off La Jolla. Large mako sharks were caught in LA and San Diego counties last month as well. So what’s going on? Are there more sharks, are there more people in the water, or are the iPhone-armed masses just better at spreading the news about the encounters? Surfline dug in to find out. – Ed.
As first posted on Surfline August 4, 2012.
Whoever says, "Fear of pain is worse than pain" never got attacked by a great white shark. A couple weeks ago (July 23rd) off France's Reunion Island, a large predator bit through the leg of 22-year-old surfer Alexandre Rassica just one hour after local beach monitoring for sharks had ceased. Nine days prior, 24-year-old surfer Benjamin Charles Linden was reportedly bitten in half off Wedge Island in Western Australia. His body hasn't been found.
The shark (a great white nicknamed "Brutus" by locals who estimated it between 16 and 24-feet) was never caught despite Western Australia Department of Fisheries efforts to install baited traps near the attack site. This was Western Australia's fifth recorded fatality in ten months.
A week before Linden's death off the U.S. East Coast, lifeguards and beachgoers spotted a 12- to 14-foot great white some 100-150 yards near Orleans, MA's, popular Nauset Beach in Cape Cod. A photograph of a huge dorsal fin trailing a kayaker went viral, prompted beach closures. That same day (July 7th) in Northern California, an estimated 18-foot great white allegedly bit through another fisherman's kayak near Pleasure Point, hurling him into the water unharmed before a nearby boater rescued him. A La Jolla Shores beach was also closed in early July when a lifeguard spotted a 12 to 15-foot great white cruising 50 yards from shore.
In an effort to separate fact from fiction in this insular age of Internet sensationalism, Surfline went right to the source, International Shark Attack File Director George Burgess, the Grand Poobah of ichthyology studies in this country. Incidentally, during the course of that 30-minute interview we received news of two more great white attacks, both non-fatal: one on a surfer at Streaky Bay off the west coast of South Australia on Tuesday; and one on a swimmer off Cape Cod on Monday.
Surfline: Has the Internet just made for better, quicker reporting of a phenomenon that really hasn't changed that much, or is something else going on?
George Burgess: Obviously, the advent of the Internet has made communication orders of magnitude better than what it was 20 years ago. Now people can report these instances in real time and, as a result, we're able to sort out errors very quickly. In the early days of the File everything was done by snail mail. You'd catch wind a year after an attack happened, try to find a victim on the other side of the world, and get to him sometime after that. Individual case investigation might go on five years. Now, it's not unusual to get a report fired in right after it happens. Just this morning, I got an email from a victim in Bali. I hadn't heard about it from the press or any scientific colleague. It was the victim himself who very likely hopped on Google and found us at the top. Of course, we've worked really hard in developing a network of observers and being proactive in talking to the media so they hopefully broadcast a levelheaded view of the situation.
What conclusions are you and your colleagues drawing from this current data?
Some changes in the numbers are above and beyond our reporting ability, and those are largely tied to increases in human population. We plot by decade, which smoothes out the curves from year to year. You get lots of variation based on the meteorological, oceanographic or economic situations involving humans. Looking at everything over a nice, even time period like a decade, you'll find that historically the number of shark attacks since 1900 has continued to rise. Human populations: same thing. Clearly, the major contributor to the number of attacks that occur each year is the amount of time humans are spending in the water.
That's sounds pretty obvious.
It is, in a "duh" sort of way. There are simply more of us than there are sharks, and we're flooding them out of their environment. We enter the sea pretty uniformly in very particular areas: shallow spots less than two meters in depth, which is a good place to be a shark. Bobbing around where they're trying to make a living, our activities can look a lot like the next fish. And looking at the growth in surfers' numbers, all this is fairly predictable.
Surfers are also traveling to more exotic waters. There's a reason that one spot's called "Skeleton Bay." There are literally carcasses everywhere.
Right, they're pushing the envelope and going places where locals say, "That's Shark Point. Don't surf there. That's where the big tigers hang out." But surfers are a fairly cocksure group who have great passion, so they're willing to accept the risks associated with the sport -- whether it's plowing their head into the bottom, breaking their neck, drowning or sharks.
So overfishing, cage attractions and shark-culling bans are all minor contributors?
Exactly. I just had another member of the media contact me about the 1916 attacks at Matawan Creek, NJ. We pulled all the files and read the old newspapers, and the conclusions and responses of the government at that time are not appreciably different than what they are today. Back then there were all kinds of strange theories about why these attacks were occurring -- the most common one being there aren't enough fish to eat, therefore sharks are eating humans; the precise argument we hear today. Now when there's a string of attacks like Western Australia and Reunion has seen over the last couple years, we look at what's going on in that particular area that led to the situation. More times than not we find environmental or human-related factors that changed at once, some event or combination of events that led to the increase. Once we find that, we take measures to reduce that risk, educate people to whatever was causing the problem, and therefore reduce those numbers. We had a similar situation in Recife, Brazil, in the 1990s. After enacting certain things as a result of our studies down there, those numbers took a big dive. While there will still always be attacks there, I don't think we'll see them occurring in one place at one time like we did before.
But West Oz, Reunion, those places have always been notorious for -- some would say synonymous with -- large, toothy predators aggravating otherwise idyllic lineups. Can you troubleshoot those areas?
Well, in Reunion we're not talking white sharks so much as other species, and those attacks are almost surely related to density of humans. That's most likely the backhanded compliment of a successful increase in tourism. With big airlines discovering smaller islands throughout the Indo-Pacific, we're suddenly seeing attacks in places we didn't formerly see them, like Togo and Tonga. A few years ago it was the Sharm el-Sheikh in Egypt -- an area that had blossomed into a tourist center and, sure enough, a series of bites followed. Albeit unusual, this was nevertheless bound to happen once there were enough people in the water.
Any connection between the Indian Ocean attacks and the ones here in America?
I don't think there's necessarily commonality from an environmental standpoint, but there is from a management standpoint. White shark populations have been down since the early 1900s, probably most directly related to the health of the large sea mammal population on both coasts, California and New England. The loss of sea mammals due to overfishing and habitat-loss resulted in these predators having to change their food strategy. Their numbers took a big dip once there wasn't enough high-energy food to go around, and the upswing in commercial fishing over that time period killed off a bunch, as well. As a result, the numbers I grew up with in the '60s -- the number of sharks, the number of attacks and our perception of how many were out there -- were artificially low.
Since the Endangered Species Act and other regulations have been put in place encouraging the growth of those marine mammal populations -- and protection given to the white shark through the National Marine Fisheries Service -- one would expect those numbers to rise to the point of "carrying capacity," evening themselves out based on available food and space. So I think we're seeing an increase in white shark populations, timed with a period when more people are doing sports that put them smack dab in the middle of preferred white shark habitat. They're looking for seals and sea lions at haul-out areas, and just the image of the board above is enough to get them excited. That's probably what's going on in Cape Cod -- a seal colony is re-growing, and heck if the white sharks aren't coming back. The situation in Western Australia is a little harder for me to understand without being there with my colleagues, but it's clear to me the area where these attacks are occurring is a passageway for whales. That's the key to the story there.
So basically, follow the mammals and you'll find the sharks. You know, since we've been speaking two more attacks have come across the AP wire.
Yes, we're investigating those now. I don't think we need to invoke global warming or anything for these particular animals. If you're going to take a chance in the sea, you must be willing to accept the consequence. But we all know surfers tend to be bigger risk-takers than others and often choose to ignore certain things for the sake of the experience. It all comes down to personal choice, like jumping out of an airplane with a piece of silk. People do it, people enjoy it, but once in a while somebody goes splat on the ground. When that happens, it's the jumper's fault because they accepted that risk. But in the case of shark attacks, the shark gets blamed. That's the only thing that bugs me: the shark always ends up taking the rap. Something I really appreciate, however, is virtually every surfer I've ever talked to or seen in the press who's been bit is always quick to say, "It's not the shark's fault. It's my fault...I'll be back out there, though."