National Geographic News
Photo of a tiger shark in Hawaii.

A tiger shark (Galeocerdo cuvier) is pictured above. Hawaii has faced a spate of shark attacks on humans this year, raising safety concerns.

Photograph by Doug Perrine, Nature Picture Library/Corbis

Brian Handwerk

for National Geographic

Published December 3, 2013

A shark killed a fisherman off the Maui coast on Monday, Maui County Ocean Safety officials reported, when it bit his foot, which he had dangled over the side of his kayak.

The attack was the eighth near Maui and the thirteenth in Hawaiian waters this year—more than triple the 20-year average of about four unprovoked shark incidents each year.

Patrick Briney, the fisherman, was Hawaii's second shark attack fatality this year, following an August attack on a German snorkeler. Prior to 2013 there hadn't been a single fatal shark attack in Hawaii since 2004.

This year's attacks, on top of ten Hawaiian attacks last year, have people asking whether there's been a recent statistical anomaly or whether more shark attacks are Hawaii's new normal.

Yannis Papastamatiou, a marine biologist at the University of St. Andrews in Scotland, said it's nearly impossible to know what's behind the rise in attack numbers.

"The problem with shark bites is that the numbers are so low it's hard to do any type of statistical analysis," he said. "There may be something behind it. It may be due to natural fluctuations or chance.

"It's especially hard to answer with only one or two years of data," he continued. "If it would continue for years, we may be able to learn more." Hawaiian attacks spiked previously, during the 1990s, he said, before returning to previous levels.

Papastamatiou authored a recent seven-year tagging and tracking study of the migration patterns of tiger sharks in the Hawaiian Islands and uncovered a possible connection to attacks in the area, though that was not the focus of his study.

"We noted that there did seem to be a spike in shark bites during October, and that does overlap with the time of year when we now believe that there are pregnant female sharks coming down from the northwestern Hawaiian Islands to the main Hawaiian Islands, potentially to give birth," he said.

Data from the University of Florida's International Shark Attack File (ISAF) show that since 1926, the highest numbers of attacks around Hawaii took place in October, November, and December.

But Papastamatiou, previously at the University of Florida and the Florida Museum of Natural History, stressed that this correlation doesn't prove causation: "Whether one has anything to do with the other is very difficult to say."

Shark Attacks Around the World

Regardless of where in the world you swim, odds of becoming shark bait are very, very slim.

Using 2000 data as a typical example, the ISAF estimates that a person's odds of being bitten by a shark are about 1 in 11.5 million. (Related: "How Should We Respond When Humans and Sharks Collide?")

Worldwide, shark attack fatalities averaged between just four and five a year from 2001 to 2010.

The U.S. saw 53 shark attacks in 2012, according to the International Shark Attack File report, the most since 2000. But shark attack fatalities around the world remained flat, the authors found.

(By comparison, conservationists estimate that as many as 100 million sharks are killed every year in fisheries, primarily to feed Asia's appetite for shark fin soup.)

Still, shark attack numbers have slowly risen since 1900, according to ISAF statistics. That's because the growing human population has put many more people into the waters where sharks swim, experts say.

Learning exactly where and when those sharks swim in abundance might be one way to help keep people safe and explain why some attacks occur—including the recent spate in Hawaii.

Just 80 unprovoked attacks were recorded worldwide in 2012, according to the ISAF, even though people and sharks spent billions of hours sharing the water. While waters overall are statistically safe, ISAF director George Burgess said that some localities have developed problematic situations and are the site of repeated attacks, according to the press release announcing the report.

"What I've seen in all situations when there's been a sudden upswing in an area is that human-causative factors are involved," Burgess said in the release, "such as changes in our behavior, changes in our abundance, or an overt shark-attracting product of something that we're doing."

Shark attack variables—like weekend weather or the economy impacting the number of people in the water, or ocean conditions enticing sharks from one location to another—can change dramatically in the short term

That's why experts stress that studying attacks over the long term offers a much clearer picture of where human-shark problems lie, rather than looking at a short-term spike like the rise in Hawaiian attacks.

Gary Urtiaga
Gary Urtiaga

There is another reason I believe is responsible for the increase in shark attacks in Maui that I have yet to see stated anywhere.

It has to do with the dramatic increase in the Humpback Whale population that winters in Hawaiian waters every year. Given the enormous amount of afterbirth material as a result of the births of hundreds or even thousands of whales, this process provides a highly nutritious, easily digestible non-combative food source to migrating Tiger Sharks.

Couple this with more turbulent, lower visibility waters durring the winter months (whale birthing season) and a greater number of people in the water, you will see a continuation of these attacks. Common sense precautions such as staying out of murky water, especially at dusk or dawn, never swimming after a rain storm near a river mouth and always checking your surroundings prior to entering the water will help in lowering theses incidence.

Valley Isle Excursions
Valley Isle Excursions

I think there may be another reason.   Of course the usual suspects, like murky water will confuse the sharks but that is not unique to Maui. 

What is unique is a huge % increase in spearfishing along Maui's shores.  Most of the new people do not understand how, where and when to spearfish.  Many who are new to the sport are doing this right off the most populated beaches using rented gear. 

This type of fishing has always attracted sharks and that is why most who enjoy this sport do not fish in the same spot day after day.  

christina kriens
christina kriens

We were in Makena, Maui for five weeks this summer-arriving around July 20th.   Several days after our arrival there was a "Tropical Depression". In the aftermath of the storm there was a great deal of run-off from Up-Country whose force left a huge gash about 10-13 feet wide on "our" beach and a tons of debris in the ocean.  The debris seemed to consist of small pieces of wood and other plant life that had been dragged down the mountain with the run-off.  The ocean was extremely murky/cloudy for at least  7-8 days.  (This was disappointing but as I'm from New Jersey, I'm some-what accustomed to strange objects floating by in the ocean that are much more unappealing. )  A day or two following the storm, while playing in the ocean, we were approached by the Coast Guard on Jet Skies and ordered to get out of the water immediately.  There were also helicopters flying back and forth over the beach as they searched for the shark -very scary. We were told (rightly or not) that the uptick in the attacks was due to the extremely dirty water-that the sharks were confused by the murky water and had difficulty distinguishing their prey.  The accident with the German tourist occurred a mile or two up from where we stay-the same coast line-just a different beach.  There was also another attack while we were there but fortunately the man survived. The Islanders would routinely ignore the guard orders and re-enter the water only to be kicked out again upon their return.  We decided to hit the pool.

I warn my young son that we are visitors in the ocean-to respect it's power.  We stay closer to the shore  now.  It is not a hardship.  My heart goes out to the German girl and the Islander that were killed and all those injured.  I feel that "there but for the Grace of God..."  it could happen to any of us.  I will continue to visit each summer and than I will retire to this island that I love.

Vince Somoza
Vince Somoza

Ten times the people die every year from elephants sitting on them than die from shark attacks.

Chad Wasserman
Chad Wasserman

There may be a connection between the increasing populations of sea turtles and shark encounters. As a resident of Hawaii, I can confirm a huge increase in sea turtle numbers, also their food of choice, thankfully not humans!

Errol C Wong
Errol C Wong

There was another shark attack in August of this year off the coast of Maui.  A 20 year old German girl Jana Lutteropp was snorkeling and a shark took her arm off....she died.

DAVID Capettini
DAVID Capettini

This may be anecdotal, but Australians all tell you that shark fatalities and attacks are very rare: but they then show you their scar and tell you stories of the people they know who have been attacked. They are kind of like pit bull owners.

Bob Eppler
Bob Eppler

Of all people, fishermen should know that dangling things in the water may attract fish, and the bigger the bait the bigger the fish. After all, these are underlying principles of fishing. The fact that in this case it was a foot is unfortunate, but no surprise. 

Les McNalley
Les McNalley

Maybe because we're over-fishing and taking their food?

Jay Agnello
Jay Agnello

Mass migration of sharks have moved to the area. I didn't need 25 years of Marine Biology to explain that phenomenon. More sharks, more people, more attacks, pretty simple. I didn't have to clip a shark's penis, and jam a spike in his head with a camera, and shove a GPS up his a## to figure that out.


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