Samuel Gruber squints in the harsh Caribbean sun as he leans over the edge of the boat. He scans the ocean surface, counting sharks. One of his lab assistants is tossing chum -- pieces of dead fish -- into the water to attract the sharks.
It is working.
"Go! Go! Go!" yells Gruber. The tube in his hands squirts a yellowish liquid at a shark as it approaches a piece of fish meat.
The shark darts away, abandoning the meat.
"That shark is outta here!" yells chemist Eric Stroud excitedly as he watches the impact of his latest concoction. "This one's looking promising. The fish don't mind the chemical at all, but the shark won't go through it."
Here in the blue Caribbean waters two miles off the coast of the Bahamian island of Bimini, the scientists are working to develop what could be the world's first effective shark repellent. They call it A-2.
It was Stroud, a New Jersey chemist and pharmaceutical consultant, who began the project back in the summer of 2001. That was the "Summer of the Shark," when stories of shark bites dominated a slow news summer. Stroud wondered what could be done to prevent such attacks.
"There were anecdotes," he says, "there were fishermen and they would be cited here and there as lore that a dead shark, a decayed shark, seemed to keep other sharks away."
And so Stroud set out to artificially reconstitute the essence of dead shark -- his very own perfume, designed to repel rather than attract.
"It was a very smelly process," he says, laughing. "It was collecting a lot of dead sharks from piers around New Jersey, fish markets, steaks, whatever I could get my hands on and letting them rot and looking at the chemicals at all different levels of decay."
As Stroud refined the chemicals he enlisted the help of two other scientists. Engineer Mike Herrmann developed the testing machinery: pumps and syringes and compressed air guns, all cobbled together from the local hardware store. And then they found Gruber, known as "Doc" to his students and co-workers. Gruber, a biologist, is the University of Miami's shark expert. He operates the Bimini Biological Field Station, the shark research lab that is the home base for the A-2 research.
In the knee-deep waters in front of the Field Station, Stroud and Herrmann and several others are preparing for another test of A-2. A lab assistant has brought a baby lemon shark -- no more than a foot long -- out of a cage in the water. Stroud is tinkering with several bottles of liquid, each a different mixture of the components of A-2. He is searching for the right blend and the right concentration.
"Three, two, one, dose!" says Stroud as he squirts a syringe in the face of the sleeping baby shark. Within seconds the shark jolts awake and struggles to get away.
"That's pretty good for a repellent," says Stroud. "It could be sharper. So I'm going to run that again and see if she's responsive."
This is not the first time scientists have tried to develop an effective shark repellent. There was an earnest effort during World War II, when fighter pilots were constantly crashing into the ocean. The U.S. Navy developed the "shark chaser," a pressed cake of copper acetate. Its inventors hoped it would mimic the effects of the ink an octopus squirts as a defense against predators.
Gruber says the science was flawed, but it probably comforted the pilots.