Shark Repelling Research
In the early 1990's off the coast of Southern California in the Catalina Channel, the research vessel Discovery bobs in the gentle sea swell. Its captain, the late shark researcher Dr. Donald Nelson directs his research assistants from Cal State Univ. @ Long Beach in the art of loading a bait container on the stern swim-step.
The researchers are using mackerel filets to draw in their research subjects, blue sharks. These sharks are employed like laboratory rats in the researcher's quest to test the effectiveness of various formulas of liquid shark repellent solutions.
Also on board is biologist Dr. Samuel Gruber, from the University of Miami, a veteran shark expert who has synthesized a variety of liquid detergent-like fluids which attempt to mimic a natural defense toxin emitted by a small fish found in the Red Sea called the Moses Sole. This chemical defense acts on a predator's gills, kind of like mace, temporarily robbing the aquatic attacker of oxygen, compelling the predator to flee the area and flush its gills in order to breathe again. No permanent harm is done to the sharks, yet they sense danger, leave the area and do not return; thus fitting the ideal definition of a shark repellent!
The shark repellent being synthesized by Dr. Gruber is highly effective and is being designed to meet four parameters.
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Effectively repel sharks.
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The repelling material must not harm the person using it; the detergent acts on gills, and since humans lack gills no harm is done.
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The repellent cannot harm the environment (it biodegrades).
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As a future product, the material must have a long shelf life (unlike the natural toxin derived from the Moses Sole that quickly deteriorates and becomes ineffective).
Blue sharks are ideal for this research, since they fit the parameters of a top predator. They are potentially dangerous to humans in certain situations, and have been known to attack victims of air and sea disasters. Yet blue sharks are relatively calm compared to other sharks and can be worked with under baiting situations where divers are swimming in the ocean with blood and chum present.
Underwater cameraman Bill Macdonald was called upon to document how sharks react to the various repellent solutions. Working without a shark cage or protective suit, Macdonald swam around the test zone and filmed the repelling action. Once he saw how effective the repellent was, Bill felt more confident and swam up and placed his camera nearly inside the shark's mouth while the frenzied shark was feeding on the chum served up by the researchers, just as the repellent was being administered. The result documented the "immediate" effect of Dr. Gruber's formula.
Researchers are now working on reducing the total amount of repellent needed to be effective, this will reduce the size of the applicator so it can be conveniently attached to life vests.
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