DNA Taken from Shark Tooth to Identify Type of Shark Responsible for Biting Two Teens in Waters off Long Island this SummerMarie Donlon | September 05, 2018
Following word that two teenagers were bitten within mere minutes of each other off the beaches of New York’s Fire Island this past July, officials sprung to action, hoping to dispel concerns that the waters were teeming with great white sharks ready to strike, à la the movie "Jaws."
Although great white sharks are commonly found off the end of Long Island, officials wanted to establish the type of shark responsible for biting swimmers.
As such, lifeguards removed “a chunk” of shark tooth from one of the teen’s wounds and officials sent the sample out to the International Shark Attack File at the Florida Museum of Natural History in Gainesville where shark bites have been tracked since 1958.
Although the tooth wasn’t large enough to compare to other shark teeth for matching purposes, researchers were able to extract a DNA sample from inside the tooth. From that DNA sample a small section was sequenced and then compared to DNA from 900 shark species found all over the world.
According to the results, at least one of the teens had been bitten by a sand tiger shark and not a great white shark as was rumored. Researchers also suspect that the second teen was bitten by the same type of shark — a type of shark not known for biting humans unless done by mistake as they pursue schools of fish in waters teeming with people.
Because almost 70% of the bites held in the shark attack file have gone unidentified, researchers urge more victims and rescuers to bag up debris from shark bite wounds for the purpose of developing an understanding of what sharks are most likely to attack and why.