Most of us think of starfish as fairly benign, peaceful ocean dwellers, but in fact the poisonous crown-of-thorns variety devours endangered coral reefs. Certainly many other factorsamong them overfishing, pollution, typhoons, snorkelers and global warmingthreaten the fragile reefs that many other sea critters call home. But the situation is dire: an estimated 27 percent of the world's coral reefs have already been destroyed, according to the Global Coral Reef Monitoring Network, and an estimated 40 percent will vanish by 2010 without better management. Thus, scientists have sought ways to thwart the hungry starfish from doing their part. Unfortunately, tactics such as poisoning, harpooning or isolating the animals have not been successful.

Some researchers are attempting to develop means for controlling starfish populations by way of introducing disease and predators. But in the meantime, Daisuke Uemura and his colleagues at Nagoya University in Japan have come up with a kinder approach: they have identified two active chemicals in sea urchins that appear to lure the five-armed menaces away from their coral feasts. The chemists described the attractantsarachidonic acid and a-linolenic acidyesterday at the 2000 International Chemical Congress of Pacific Basin Societies. Both unsaturated fatty acids drew only a small number of starfish in an initial trial, but Uemura feels the results are promising because they represent proof of principle. "Although we can't save all the coral reefs in the world from destruction," he says, "our research is useful for saving some of them."