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When sharks attack!

June 22, 2009

A recent study in the Journal of Zoology suggests that great white sharks don’t attack their victims great-white-shark-1at random, but rather stalk them like a human serial killer.  Just the news that beach goers want to hear as they make plans for their summer vacations.

Temple Chemistry Professor John Williams has had a fascination with sharks since he was a young boy growing up in Western Australia.  And it has driven him to try to protect swimmers against shark attacks by using derivatives of cholesterol, the most common animal steroid, to make a class of compounds called mosesins and pavoninins that have been known to act as shark repellents.

“Every summer weekend when I was growing up, small planes would patrol up and down the coast looking for sharks,” he added. “Pilots could see the shark’s black outline against the light sandy bottom from the air. The pilots would relay the information to the lifeguards on the beach who would sound the siren warning swimmers to get out of the water. The lifeguards would row out in boats and scare the sharks away.”

Williams is trying to replicate a series of steroids from a particular species of fish that inhabits the Red Sea and South Pacific that have natural shark-repellent properties. He explains that the sharks need to ingest the compound so that it goes through their gills.

“Apparently, there is some receptor on the shark’s gills that reacts to the steroid,” he said. “This is how the fish does it in nature. When the fish feels threatened by the shark, it disperses the natural compound into the water and the trailing shark has to swim through it, tastes it as it ingests it, and then is repulsed by it.” He has been testing his compounds at the Bimini Biological Field Station Sharklab in the Bahamas.

Williams said that potentially, if successful, down the line these compounds could be something that could be added to sunscreen to help people ward off sharks in the water when swimming in the ocean. “Or for people who really feel scared swimming in the ocean, it could be put in a container that they wear around their waist, so when squeezed, the repellent would be released into the water around them, much like the fish does naturally,” he added.


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