130 Man Against Shark 



five, and many of those who are required to depend upon this preparation 

 for their personal safety do not have the necessary confidence in it." 



Shark experts at the conference even suggested that, since strong 

 stimuli generally repel and wesk ones attract, a dilute solution of a re- 

 pellent might actually have a reverse action and act as an attractant. 

 This was one of the many puzzling aspects of sharks and repellents which 

 led the experts to realize that research into a new kind of repellent was 

 not enough. The shark itself had to be studied, and attacks on men had 

 to be examined for clues to shark behavior. Thus, out of the quest for a 

 more effective repellent, the Shark Research Panel evolved. 



Perry Gilbert, the SRP chairman, decided to test Shark Chaser. "Al- 

 though 'Shark Chaser' performed admirably in various tests," he said, 

 "subsequent accounts of its effectiveness as a shark repellent by airmen 

 and skin-divers have been conflicting, and a re-evaluation and more 

 rigorous testing of this repellent is now needed." 



Gilbert, Michael Lerner, and Dr. Evelyn Shaw made the tests at the 

 Lemer Marine Laboratory, The tests, on Lemon and Dusky sharks, "sug- 

 gest that copper acetate may not be as repugnant to the sense of smell of 

 a dangerous shark as was originally believed," Gilbert reported. 



In the tests, a lure (usually fresh beef blood in a porous container), 

 suspended from a line on a long bamboo pole, was presented to sharks in 

 the experimental pens for 10 minutes. The sharks "readily" approached a 

 lure "through a cloud of copper acetate." But, when Shark Chaser was 

 used, "the sharks repeatedly avoided the lure." 



"This suggests," Gilbert said, "that possibly the 'Shark Chaser' dye 

 is more repellent to sharks than is the copper acetate . . . The value 

 of copper acetate as a shark repellent is open to serious question." 



Researchers are now trying to find a better shark repellent. They 

 are experimenting with many substances, such as the poison emitted by 

 the sea-cucumber. Until a better shark repellent is developed, the best 

 that can be said of the combination of copper acetate and nigrosine-type 

 dye is it sometimes seems to repel certain sharks under some conditions. 



Whether strung along a beach or on a skin-diver's weight belt, its 

 effectiveness may be conditioned not merely by its ingredients, but also 

 by the mood and hunger and type of shark that approaches. 



Captain Cousteau, the man who so rightly said that one can never 

 tell what a shark is going to do, once had an opportunity to try just about 

 every piece of advice that has ever been given on what to do when 

 approached by a shark. He and a companion, Frederick Dumas, were 

 skin-diving off the Cape Verde Islands when they were confronted by 

 three sharks, one of which seemed determined to attack them. 



Cousteau and Dumas flailed their arms, released bubbles from the 

 air tanks, yelled underwater, and released shark repellent. The shark came 

 ever closer. Finally, Cousteau banged the shark on the snout with his 



