WRECKING THE REEFS

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The underwater structures at the center of this concern are, in fact, built by live animals. Corals--fingertip- to hand-size creatures that stick together to form large colonies--use the carbon and calcium in seawater to build their hard, exterior skeletons. Over time, the stony material accumulates, giving colonies of coral their signature shapes. Some corals, for example, form big round heads that resemble a giant cauliflower, while others assume elongate shapes reminiscent of skyscrapers. As impressive as cities, mature reefs may be thousands of years old, extend for hundreds of miles and shelter thousands upon thousands of species--making them one of the most genetically diverse ecosystems on sea or land.

Modern reef-building corals are descendants of organisms that first appeared in the fossil record 225 million years ago. These ancient carnivores, cousins of sea anemones and jellyfish, boast stinging cells and tentacles for stunning and capturing prey. But while corals have survived the onset of major ice ages and variations in sea level of hundreds of feet, there are limits to the conditions they can tolerate. For example, they cannot build reefs in water colder than 60[degrees] F or in murky depths. They live in symbiotic relationships with colonies of tiny algae called zooxanthellae that depend on the sun for photosynthesis. Unfortunately, the fact that they gravitate toward sunlit shallows has made reefs easy targets for plunder.

Nowhere in the world have they been subject to more abuse than in the Philippines, says University of the Philippines marine scientist Edgardo Gomez. According to environmentalists, a staggering 90% of the archipelago's 13,000 sq. mi. of reef is dead or deteriorating. Among other things, Philippine reefs are being buried by tons of soil that washes from deforested tracts of land. They are also being damaged by pollution that seeps from factories, farm fields and sewers. But above all they are being destroyed by too much fishing.

The destructive cycle of overfishing began when coastal villagers started stripping nearshore reefs of giant clams, groupers and other large fish. Then the fishermen upped their productivity by a novel but frighteningly destructive practice: blasting the reefs with dynamite and scooping up the dead fish. Now they have adopted what may be the most insidious fishing method of all. Sustained by hoselike "hookahs" and portable air compressors, Philippine divers are hunting down big reef fish, stunning them with cyanide and hauling them to the surface alive. The practice allows traders to supply Chinese restaurants with the live fish their affluent customers covet. Meanwhile, the 330,000 lbs. of cyanide the divers dump onto living corals each year is poisoning the reefs.