UF researcher authors guide to link shark bites, species


Published: Tuesday, January 5, 2010 at 6:01 a.m.
Last Modified: Monday, January 4, 2010 at 10:53 p.m.

That ragged chunk bitten out of a surfboard or sea turtle now can be traced to the culprit.

George Burgess, director of the Florida Program for Shark Research and curator of the International Shark Attack File, authored a recent study that produced charts and a guide to link bite marks to the species of shark that left them.

The study, released Dec. 1, involved measuring shark jaws of specific species and averaging their size. Burgess and his team created a chart that plots the range within which a shark's jaw likely will fall. The resulting guide allows someone with a bite mark to compare its size to these charts, helping to identify the species of shark. The accuracy of the charts varies from species to species.

Burgess has been identifying shark bites for 25 years. Over time, he has acquired a sense for the look of shark bites. With this study, he has been able be more empirical - to "get it out of the feel stage and get it into a quantification stage," he said.

The size of a bite is revealing since some animals grow bigger than others, Burgess said. In the case of a very large bite, one can tell it did not come from a smaller species of shark.

Burgess also looks at the style.

"Attack patterns differ, leaving different bites," he said.

Burgess said the research was done to make it easier to prevent shark bites. By targeting a specific species, people can do more toward prevention.

In South Africa, netting is placed around beaches to keep sharks away from swimmers; knowing what size sharks are around those areas is important in choosing the size of the mesh in the net.

A variety of cables run along the bottom of the ocean, mostly for communication purposes. Sharks sometimes bite and ruin these cables, which are expensive to place. The owners of the cables are interested in determining which species are at fault so they can make a targeted effort at protecting the cables, Burgess said.

The victims of shark bites also want to identify the shark that bit them.

Sharks biting people is "very uncommon," Burgess said. Sharks account for, on average, four human fatalities a year worldwide. By comparison, 33 people were killed by lightning strikes in the U.S. in 2009, according to the National Weather Service.

Sharks bite about 60 to 65 people a year worldwide, Burgess said. The fatality rate from shark attacks has been dropping because of better medical treatment and faster response times, he said.

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