In 1994 at Flagler Beach, a quaint stretch of sand on Florida's Palm Coast, a shark attacked a 21-year-old surfer named Jeff Weakley. He survived with lacerations on his foot and a mystery that would not be resolved for another 24 years. In the fall, when Weakley chanced on an article on scientists using DNA to identify sharks that attacked humans, the case was finally closed.
It was about the same time I took the tooth out of my foot. "
" It was about the same time I took the tooth out of my foot, "Weakley says Inverse . [1
He tracked Naylors hold down, "curious to see if they could use the same DNA process on my sample."
Normally, Naylor uses this technique to estimate evolutionary relationships between different sharks, understand their population structure, and reconstruct their historical demographics – "as is done by companies like 23 and me for humans." In a 2015 study PNAS they used it on archival shark samples during a century-old. Unlike the tooth, these samples were carefully preserved by a museum, not within a surfer's foot.
The team's success says Lei, "made us realize that the techniques we use can be more powerful and generally usable than we originally thought."
I suspect it had been a blacktip shark bite, and it was satisfying to learn the truth. "
In the database, dental DNA had a clear fight: Carcharhinus limbatus better known as blacktip shark. First, the team was skeptical of the result, fearing that they had accidentally polluted the sample, but the DNA they sequenced was consistent with DNA from other degraded tissues and did not bring a signature suggesting pollution. "Also," Naylor points out, "the sequence perfectly matched the one of the most abundant species from Flagler County, where Jeff had been bitten 24 years earlier. "
After 24 years, Weakley's suspicions were confirmed." was satisfying to learn sandhe
DNA is becoming increasingly useful in identifying sharks behind human attacks and pointing to particular populations to be monitored. As for shark attacks themselves, they appear to be increasing – but not because sharks seem to be any testies than normal.
A PLOS One study published in February showed, using the pigs data from the Florida Natural History Museum's International Shark Attack File, that shark attack rates have doubled over the past 20 years in highly populated areas. The authors concluded that the sharks were not more hostile, but that more visitors flocked to beaches.
Still, beach guests should be aware of the preventive measures recommended by experts such as Naylor. "Make sense," he calls. It means following beach rules, not swimming at dawn or dusk, and avoiding swimming alone.
Another useful tip is to pay attention to strange activity among other sea creatures: "Get out of the water if you see large forest of deciduous hippopotamus in shallow water," he says. "It is most likely that they will be chased by a predator like a jack or a shark, and you will not get in the way of this interaction."
All these years later, Weakley has no hard feelings about the shark and continues to surf. The goat in his foot is gone, its content is now an important addition to the sharks' science annals.
"How do I feel? I continue to wonder about the results of modern science," says Weakley. "I feel happy to think maybe I've made a contribution."
Shark attacks are rare, but when they arise, they create significant media, public and other interests. The aftermath of an attack has the potential to influence the public attitudes to sharks and political decisions to limit shark attacks and conservation. After an attack, the media often brings interest in determining the sharks involved. This information can meet curiosity, complete medical and case records and inform shark attack limitation strategies. However, it is not an easy task to determine the identity of the responsible species.