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Man Against Shark 



The dorsal fin of a Tiger shark ( Galeocerdo cuvieri ) parts the "bubble curtain" as the 

 shark passes through the bubbles, in tests showing the ineffectiveness of the "curtain" 

 as a shark barrier. The tests were conducted by Dr. Perry W. Gilbert, chairman of the 



Shark Research Panel. Courtesy, Dr. Perry W. Gilbert 



Two types of bubble fence tests were conducted in the pens. In 

 one, a bubble curtain was extended halfway across one pen. In the other, 

 a F-shaped curtain was arranged, with an 8-foot gap of quiet water at 

 the apex of the V so that both pens formed an 80-foot "fish trap." If 

 the F-shaped bubble curtain were effective, the sharks would be fun- 

 neled by it from one end of the pen, through the quiet-water gap, to the 

 other end of the pen. 



In all the tests, Gilbert used Tiger sharks, ranging in length from 5% 

 to 1 3 feet and weighing from 95 to 900 pounds. During the first 4-minute 

 period of the first test, two Tigers seemed to be turned away by the 

 bubble curtain that extended halfway across the pen. Ten Tigers passed 

 through the bubbles "seemingly undisturbed," according to Gilbert. 

 In a second 4-minute test, one Tiger appeared to be turned away and six 

 passed through the bubbles. 



In a 15-minute test using the F-shaped barrier which would theoreti- 

 cally funnel the sharks toward one end of the pen, the sharks "promis- 

 cuously swam back and forth through the bubble curtain." 



To confirm his findings, Gilbert tried a 26-hour test of the F-shaped 

 bubble curtain. Sharks passed through it in both directions, with the 

 number apparently increasing as they became accustomed to the cur- 

 tain's presence. During one 10-minute period in which a careful count 

 was taken of the number of times sharks passed through the bubbles, 

 the "fence" was breached 77 times. 



