"He must, so know the starfish and the student biologist who sits at the feet of living things, proliferate in all
directions. Having certain tendencies, he must move along their lines to the limit of their potentialities."

John Steinbeck - Log from the Sea of Cortez

Friday, June 4, 2010

How to be attacked by a shark

The beaches of Florida's Volusia County, particularly the stretch in and around Daytona Beach and New Smyrna Beach, are fairly infamous for the number of shark attacks that occur there. The vast majority are fairly inconsequential, although lethal attacks are certainly not unheard of. The Florida Museum of Natural History at the University of Florida maintains the International Shark Attack File in which they track shark attack records. Here you can see their compilation of Florida's 629 confirmed, unprovoked shark attacks between 1882 and 2009. Volusia County boasts 239 attacks, more than double the runner-up (which happens to be Brevard County, just to the south of Volusia). It's worth noting that none of the Volusia attacks have been lethal. In fact, only 13 of the total 639 have resulted in fatalities. The reason is that most of the sharks involved, and, in fact, most of the sharks found in nearshore waters are smaller species like spinners, blacktips, blacknoses, etc. You'll get the occasional tiger or bull, but they're few and far between. Still, shark attacks are a serious thing in Florida, where everything depends on tourism and tourism depends on water. And going in the water depends on, well, you know.

So, a group of researchers at UF combined the shark attack statistics with observational data gathered by staking out Volusia County beaches. The goal was to attempt to determine what factors play a role in shark attacks - what is it that makes people victims.

That's a great idea, and I certainly wouldn't put down research of this type. But let's cut through some of the chaff. We find out that most of the attacks are on young, white males, who are attacked most commonly on their legs. And most attacks occur on the weekend. I hope there's a little more analysis coming here. Because, thus far, you've told me that you've got a better chance of being attacked if you go in the water than if you don't.

There's more information, of course, and some of it has value. Attacks are more common in early morning and late afternoon than at mid-day. That may also reflect greater utilization by surfers as a result of higher waves, but it could also tell us something about activity patterns of the fish. Attacks are more likely at new moon and full moon. That could, again, be related to wave patterns and therefore surfing activity. More likely, it has to do with shark activity. Perhaps most intriguing, people wearing black and white swimsuits are attacked more than those wearing other combinations. Now, I haven't looked closely enough to judge whether there are simply more people wearing black and white swimsuits. I don't think that's the case. If it's not, then it suggests that the resulting contrast may make the victim more visible. That's a little troubling, when the prevailing argument for shark attacks in one of mistaken identity.

So, if the idea of being shark bait doesn't appeal to you, put on your green swimsuit and swim on the quarter moon in the middle of the day. And don't be a young white male. Otherwise, you're on your own.

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