Science: Sharks Don't Like It

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The seiner Angle and Florence, out of Gloucester, Mass., was about to bag a school of mackerel. The boat towed the net, buoyed and weighted, around the milling fish. Next step was to close the "purse" and haul the mackerel aboard.

Just then a school of hungry sharks, unusually active off New England this year, spotted the netful of fish. They charged toward the seine, prepared to tear it to bits. But suddenly they changed their minds, turned tail and swam away.

The sharks had been deeply offended. A boat had towed two cloth bags full of the Navy's new shark repellent all around the net. The concoction's smell was so revolting to the sharks that they lost interest in the mackerel.

The Navy's shark-discourager was developed to protect men struggling in shark-infested waters. Its inventors knew that sharks are repelled by a dead and decaying shark. An extract of rotten shark proved even more effective. Eventually, the active substance so offensive to sharks turned out to be a chemical which people don't mind. A black dye was added to the brew, just to give the sharks a good visual scare.

Last week the Navy's shark-scat was a red-hot topic in Gloucester. Other fishermen, following the Angle and Florence, tried it with success. But Skipper Philip Nicastro of the Serafina N. claimed that one impetuous shark ate a whole bag of the stuff without apparent damage. One possible explanation: shark-scat (like some strong cheeses) offends the nose and eyes, but not the stomach.