News Page Seventy Nine
Researchers may have found shark repellent.
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{below}Reseachers test a shark repellent on a lemmon shark in South Bimini, Bahamas. Scientitst spent decades developing similiar chemicals
San Jun, Puerto Rico, Excited by the scent of blood a dozen sharks dart about in a frenzy as a researcher dips a pole in the sea and squirts out a clear, yellowish substance. WIthin seconds, the sharks jerk their snouts away and vanish. Researches say they finally have found a potent repellent to drive away sharks, after testing off Bikini island in the Bahamas. It's a goal that has eluded scientist for decades.
If proven effective, the repellent one day might protect divers, surfers and swimmers. But researchers say that would require much more study. First they hope it can protect sharks, in decline worldwide because of over fishing, by reducing the numbers caught needlessly by long time commercial fishermen. "you introduce this chemical, and they all leave," said lead researcher Eric Stored, a 30 year od chemical engineer from Oak Ridge, N.J. "it works very, very well."
The repellent, called a-2 because it west the second recipe tried, is derived from extracts of dead sharks that Strode gathered at New Jersey fish markets and piers. Fishermen and scientists have long noted that sharks stay away if they smell a dead shark. "We have something that really works, but research remains," said Samuel Gruber, a University of Miami marine biologist and shark expert who is helping conduct test at the Bimini Biological Field Station.
Tests have found the repellent effective on four species: the Caribbean reef, black nose, nurse and lemon sharks. Studies are needed on other species such as the great white, mako and oceanic whitetip. Gruber said the repellent seems to carry a chemical messenger that triggers a light reaction. e said more studies are needed to pinpoint the active molecule among a dozen or so.
A dose of 4 fluid ounces is enough to scare away feeding sharks, Strout said, keeping them away from a fish head for two hours with just a few drops with just a few drops per minute. In contrast, sharks didn't respond to a red did in control tests. The researchers presented tier work in May during a meeting of the American Society of Ichthyologists and Herpetolgists in Norman, Okla. Films of their test captured images of sharks splashing the surface as the turn to flee.
They hope to make a slow dissolving repellent for use in baits and fishing nets, and to guard equipment on submarines and oil exploration vessels that sharks have damaged in the past. The repellent, though nontoxic, is apparently so disagreeable to sharks that it can revive them from semi consciousness. Some species slip into a hypnotic state if turned belly up , and tests found that the repellent brought captive sharks out of the trance.
Repellent research began in World War II, when the U.S. Navy created "Shark Chaser" for sailors and downed pilots. Mixed with black dye, it was made of copper acetate, which scientists thought would smell like a rotting shark. Studies later showed it wasn't that effective. A promising find came in 1972, when University of Maryland shark expert Eugenie Clark discovered that a Red Sea Fish, the Moses sole secreted a milky substance that repelled sharks.
The finding soon cased a stir, and soon the maker's of Copper tone suntan lotion contracted Clark, hoping to market it. She said she discouraged them, saying initial research couldn't back up such a use. YEars of study by Gruber and other followed. In the end, though, there repellent derived from the sole wasn't practical, because it had to be squirted into a sharks mouth to be effective.
Clark, who at 82 still works at Mote Marine Laboratory in Sarasota, Fla., said the latest findings could be a welcome way to reduce accidental killing of sharks, although she is skeptical of human use, saying few would be carrying the repellent at the rare moment it's needed ."It's be happy to see someone body work it out, but I don't see it as a practical solution," she said.
Anti shark items on the market now include cages, steel mesh suits and a device called the Shark SHield, which when worn by divers or surfers emits an electric field. The devices Australlian Maker acknowledges it can't guarantee total effectiveness. In most cases, the danger of attack is extremely slight. The International Shark Attack File, at the Florida Museum of Natural History, recorded 55 unprovoked attacks worldwide last year, including four deaths.
Stroud got the idea to pursue a repellent after several 2001 shark attacks drew widespread attention, including one that nearly killed an 8 year old boy near Pensacola Florida. Stroud and engineer Mike Herrmann do lab work in a New Jersey warehouse, relying on donations of less than $500,000 from two private benefactors. They have a patent pending and are starting a company, Shark Defense Inc., to eventually market the repellent.
By Ian James/The Associate Press
Michael Herrmann/The Associate Press Took the above Picture.
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