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SHOALS OF TIME.

Are we witnessing the extinction of the world's coral reefs?

All day we've been observing the surgeonfish, which the Tahitians call maroa and the French call chirurgien zebre, streaming over the outer-reef slopes in tightly knit single files. Now, in the final hour of daylight, scores of these fish meet and coalesce into banners of yellow-and-blue, flowing gaudily over the contours of the coral toward the edge of Tiputa Pass. Here the mission of the fish unfolds as they bunch into agitated crowds of ten or twenty individuals, the groups rising above the reefs, swarming and butting one another in a chaos of seeming cross-purposes.

Stimulated by the onset of a moonless night in the South Pacific, the surgeonfish cluster, rise, bump, then drop back to the reef, disperse, circle, regroup, rise again. A dozen times they practice, each round taking them higher into the water column, farther from the safety of the coral. Finally the foreplay culminates in what scientists call spawning and what the French divers I'm with charmingly refer to as lovemaking. A pair of surgeonfish detach from the crowd and explode upward in an impossibly fast arc, at the apex of which the pair eject their sperm and eggs into the open water in a burst of milky smoke. The two fish never break stride, shooting back down to the reef at speeds nearly unrecordable by the human eye. Other pairs follow. Meanwhile the ejaculated white puff balls hang in the water, seemingly still but in fact riotously mobilized as the chemistry of conception begins, sperm seeking eggs with only a moment for the micro-journey to succeed before the gametes are caught up in the monstrous outflow of water from Tiputa Pass and carried out to sea.

Motoring back to land, against a sunset as soft and mutable as a watercolor, we reach the dock and begin to disassemble and rinse our gear. My fellow divers have blissful expressions on their faces. It's always this way. It doesn't matter who they are, or the location of the reef; but in this case, today, as we return from Tiputa Pass at Rangiroa Atoll in French Polynesia, the faces are those of two young Frenchmen. Both guide here professionally, spending nearly a majority of their lives underwater. If anyone would be jaded it would rightfully be them. But quite the opposite has happened. The reef has caught these tough young men in its spell and rendered them, for this moment, as beatific as angels.

It's rare in the wild to see what is essentially the moment of conception. Yet what we say about it is trivial. Incroyable, eh? Formidable. Still, the mood is joyful and relieved, as if we've conquered some summit and survived. The French divers are happy that their day's work went well and they were able to show me this secret, I'm pleased that I'll have it to write about. Back in my bungalow I check my underwater slate, anxious to transcribe its notes into my journal, then laugh to discover that there's only a single exclamation point marked on it.

Such is the paradox of the reef: a world that feels purely and extravagantly sensual yet, in reality, happens mostly outside our own sensory realm. Designed for the land, we smell nothing underwater, taste only the metallic twang of compressed air, see poorly, and are reduced to nondirectional hearing; in effect, we're disabled. Nor can we talk. Without language, I believe that human divers revert to an older state of mind in which thoughts are processed nonverbally. So the dive you've just made tends to be felt rather than accurately remembered, and the little plastic slate that you've dutifully carried underwater with you for note-taking reveals only doodles or strange hieroglyphs, made more difficult to decipher by the fact that the pencil marks (supposedly erasable by scrubbing with beach sand) never really do come clean, leaving you to contend with the ghostly outlines of all your previous, equally enigmatic dives. This is the struggle, or at least my struggle, working underwater: how to comprehend and then translate the otherworldly marvels to the world topside.

French Polynesia, which includes Tahiti, comprises more than one hundred islands sorted into five archipelagoes that taken together cover an area of the South Pacific larger than Western Europe. Rangiroa, part of the Tuamotu Archipelago, is the second-largest atoll on earth, enclosing a 400-square-mile lagoon within a bracelet of low, sandy islands called motus. Because of its geography, Rangiroa has one of the most dynamic reef systems anywhere.

Only two navigable passes pierce its 48-mile circlet, and so the changing of the tides produces an extraordinary phenomenon of pressures and counter-pressures as seawater pours into the lagoon or rapidly escapes it. At these times Tiputa Pass is transformed into a maelstrom, inflow and outflow colliding in 15-foot-high standing waves, which spin off whirlpools that appear underwater as snaky tornadoes of blinding sediment. The French call this phenomenon the mascaret, and the surgeonfish use its power to launch their fertilized eggs, the zygotes, on the first stage of their life journey.

No human diver can survive immersion into the mascaret, so we dive at its edges, where the noise of the riptide rumbles beneath the brighter soundtrack of the sea, the snapping, clicking, rasping, buzzing, squealing, and grunting of fish, shrimp, clams, and corals at work. For these creatures, the waxing and waning of the mascaret is an external force akin to a respiratory system, an enormous set of oceanic lungs that four times a day take a mighty inhale, hold it briefly in the slack tide, then release it again in a rush of exhalation. In this way the sea is enriched: huge loads of organic matter emptying out of the lagoon to nourish the outer reef slopes, immeasurable quantities of clear water from the open sea rushing back to refresh it.

Yann Hubert is guiding the way. I've worked with him in years past and am familiar with his yogilike presence underwater. Simply put, he's the best diver I've ever seen--a complete contrast to his topside persona, which tends toward fidgety boredom, chain-smoking, and amusing himself with incomprehensibly profane and colloquial French jokes. But down here he's a master, breathing so rarely, so delicately, that fish sidle up to him as if he were not like the rest of us intruders from another world. I believe I understand his secret: total compliance with the environment. Rather than challenge the currents, he remains still, using the minimum angulation of body or fins to move. Even so, when I surreptitiously check the air gauge on his tank at the end of several dives, I'm stunned to see that he doesn't consume enough air to sustain human life.

This morning we descend through a tightly packed shoal of sea bream, or perche d'or, who rest in the shade cast by our Zodiak, then down beyond them, through a phalanx of batfish, steely and triangular as arrowheads. Yann drifts off to my left, light as a falling leaf, through the center of a silvery cyclone, thousands of barracuda riding one another's tails in a lazy vortex of their own making. Far below, the coral appears, mottling the sandy bottom in deepening shades of blue. Large animals drift over it: a manta ray sailing the edge of the current; ghostly schools of gray reef sharks drifting in a state of near sleep, hundreds of them packed shoulder to shoulder, shoaling like lowly sardines. This is their chief defense against even larger predators such as great hammerhead or tiger sharks.

One of the effects of the mascaret is to telescope habitats inside Tiputa Pass so that the creatures of the deep come here and mingle alongside the life of the shallows. It's difficult to know where to look: to focus out to the depths, where the big animals dwell, or into the reef, where a metropolis of small life clambers through skyscrapers of coral. Occasionally something demands your attention by appearing suddenly from the edges of your peripheral vision. A white trumpetfish drifts past, long, narrow, positively un-fishlike. It travels in the manner of its species, vertically in the water, head down, large eyes circling around at me, not alarmed but likewise interested. We study each other.

Suddenly it blushes. Bright aquamarine stains its pale head, purple blossoms into its body. It drifts to a stop alongside an identically colored backdrop: purple coral head bedecked with a flock of blue-green chromis fish. There it hovers, confident in its masquerade, awaiting the opportunity to dart in and with a jerk of its tubular body vacuum up the one chromis too slow, foolish, or forgetful to survive this day. I lie on the bottom, awaiting the outcome, rolling gently back and forth in the surge from the surface ... until Yann appears, silent in the near absence of his scuba bubbles, startling me with a touch on my arm and pointing to a stonefish the size of a football only a few inches from my knee. It takes me a moment to see it: a strange, nearly invisible creature that appears exactly like an algae-encrusted piece of coral rubble. Yet this fish carries enough venom in its dorsal spines to kill me. Yann picks up a real piece of coral rubble and places it gently on top of the stonefish, then points again, out to where the trumpetfish is drifting off with the tail of a chromis wriggling in its mouth.

These atolls of the Tuamotu Archipelago, crammed with the tense energies of life and death, are the end products of tiny coral animals, countless trillions of individuals, most no bigger than ants, living and feeding, reproducing and dying, over the course of millions of years. French Polynesia's reefs are formed in conjunction with shield volcanoes rising from hot spots on the seafloor. Yet long after the volcanoes themselves are extinct, after their islands have eroded and then subsided under their own weight back into the sea, the corals remain on their fossilized flanks, an exoskeleton of sorts, holding up all that remains of the land--the ring of sandy strips, or motus, formed by wave-borne debris tossed upon the barrier reef.

Corals are among the simplest of invertebrate animals, composed of little more than a hollow tube, the gastric cavity, surrounded by a fringe of stinging tentacles with which they capture prey. Reef-building corals secrete external limestone skeletons--the coral rock--pockmarked with tiny depressions where each individual animal--the polyp--resides. Related polyps are connected by living tissue through which they share digested food. Generation after generation of new corals grow atop the limestone skeletons of dead corals, until a reef is formed. Although the growth is incremental, less than one inch per year, the colonies can live a thousand years or more. Measurements in some Pacific atolls show the skeletons of dead corals stretching nearly a mile below the living reef.

In this way, working together, depositing up to 880 tons of limestone per acre per year, coral colonies construct the largest architecture on the planet. Australia's Great Barrier Reef has grown to 92,000 square miles, bigger than anything humans have ever built. Visible from space, it has conceivably already informed distant, alien intelligences that this planet harbors life.

Although many of the 6,000 species of corals and anemones are solitary polyps, or colonies of soft corals, or those that build flat calcium-carbonate formations in the seemingly inhospitable waters of the Arctic and Antarctic, the story of coral reefs occurs in the narrow band of equatorial water at the 21 [degrees] C isotherm, where the delicate balance between sunlight, temperature, salinity, nutrients, and gases meets the exacting requirements of the tiny coral animals.

Part of the corals' finicky needs comes from the fact that they rarely live alone. During most dives, as you drift over landscapes of brain, elkhom, star, and flower corals, you see only the skeletons of the animals. The polyps themselves are dormant and retracted throughout the hours of sunshine while the work of the reef is accomplished by single-celled plants, the microscopic dinoflagellates known as zooxanthellae that live within each coral polyp. Ordinarily, more than 6.5 million zooxanthellae inhabit each square inch of coral, and in return for this safe home these algae contribute the by-products of their photosynthesis: oxygen for the corals' respiration, carbohydrates for their food, and the alkalinity necessary for the animals to secrete their aragonite skeletons, the backbone of the reef itself. Incidentally, the zooxanthellae are also the source of the corals' brilliant colors.

The results of this marriage of plant and animal are phenomenal, and their symbiosis greatly affects the nature of the world's oceans, binding up roughly half the calcium that enters the sea each year and then depositing (along with each atom of calcium) a molecule of carbon dioxide, for a total of perhaps 1.5 trillion pounds of carbon dioxide per year. The corals' calcium carbonate production (part of their skeleton-building) is considered a likely mediator of atmospheric [CO.sub.2], and therefore makes this collaboration between plant and animal a contributor to the stability of our atmosphere.

Reefs are also wellsprings of biodiversity. Despite their small range (240,000 square miles, or only 0.1 percent of the earth's surface), the reefs constructed by corals and their zooxanthellae are home to as many as 9 million species of plants and animals, or at least one quarter of all marine life. Yet because they are a place where the plant and animal kingdoms wed, and in a sense procreate, coral reefs actually foster the process of evolution, creating not only new species but entirely new genera, or even families, of life.

Altered by climate and sea-level changes, cyclones, tsunamis, earthquakes, and volcanoes, reefs are also the recordkeepers of the sea. Those built by scleractinian corals (our present reef builders) chronicle the last 245 million years; earlier reef builders, cyanobacteria and sponges, record billions of years before that. The history of these ancient reefs is not contiguous but rather one of fits and starts, explosions of life followed by long reef-less epochs. In fact, throughout time reefs have suffered extinctions, or near extinctions, including one about a million years in advance of the better-known mass extinctions of terrestrial lifeforms such as dinosaurs, raising doubts about the meteor-impact theories.

But whatever the meaning of the demise of reefs, the geologic record seems to indicate that there is a predilection on our planet toward the emergence of reefs, toward having something in the sea that builds habitats of such enormity and opportunity that much other life evolves around them. Older than the prairies or flowering plants, coral reefs have suffered and survived enormous changes in our planet's past. Yet today they are experiencing challenges not just from one front, but from a multitude of them--pollution, sedimentation, overfishing, rapid global climate change--which have combined to destroy a quarter of the world's reefs. Remaining reefs are in such great peril that governments are preparing for the contingency that millions of island residents might need to be relocated. Despite their consequences, these assaults on the reefs (which are the ripple effects of our own species' evolution into the most catastrophic extinction agent of all time) are largely shrouded from our eyes, occurring in the mysterious underwater realm where few people understand or, it seems, care what happens.

It can take years of experience to begin to see even a small part of all that the reef has to offer. And see is about all we can do, though there is a wealth of other information adrift in the sea from electromagnetic fields, subsonic noise, subtle changes in water pressure, and chemical tastes and smells. The ocean's residents possess an array of specialized organs without terrestrial equivalent that enable them to read the signals hidden to me: the smell of a fish's anxiety, the taste of water just filtered through a sponge, the sound of a whale calling hundreds of miles away.

But if you're observant you can use the reef's inhabitants to augment your senses. The hump-head wrasse, which the French call Napoleon, is an imposing fish up to five feet long, with an overhanging forehead, thick lips, and a blue body overlaid with squiggly patterns of green-and-yellow that look like the insides of a circuit board. This design is most striking around his eyes and, as with so many reef fishes, continues right into his eyeballs. He is a stately, easygoing fellow whose leisured life invariably allows him enough free time to greet you on your visits. Follow him and you'll find things you might not see, the cleaning station over there in the cool water under the parasol of a large plate coral, where he rests for a few moments while an army of small, daintily colored shrimp crawl inside his lips, under his eyelids, around his undulating caudal fins. They work like fiends, tiny claws picking away who knows what and frenetically conveying it to their mouths. The humphead hovers in a state akin to meditation. Only now and then he flinches, and the shrimp somersault off into midwater. Someone pinched him too hard. Never mind. He won't hold it against them; he waits patiently until they come back aboard and resume their body work.

One of the Frenchmen diving with me is a young marine biologist who's spending a year stationed on Rangiroa. He tells me that the large Napoleon begins its life as a tiny, completely transparent larva floating among the zooplankton of the pelagic zone--the open ocean beyond the coral reef. He's filled with that mixture of enthusiasm and disdain that marks young scientists, enthusiasm at the wonders of nature, disdain at having to explain them to me. So, I ask, just as with the surgeonfish, the Napoleon's parents met and spawned at the edge of a pass on an outgoing tide? He shrugs, of course.

The pelagic zone, where the surgeonfish and the Napoleon begin their lives, doesn't appear vitally connected to coral reefs. It's deep, monotonously blue, and empty by reef standards. From the surface you can look down and see nothing more than shafts of silvery sunlight converging a hundred feet below you. Many divers and much science shun this world because of its seeming impenetrability. But around mid-ocean islands such as those of French Polynesia the pelagic zone comes close to land, arriving suddenly at volcanic slopes, marching up them, then crashing ashore on barrier reefs.

For the denizens of the reef, including many of the corals themselves, this nearby open ocean is a nursery ground, a nearly limitless realm where their fertilized eggs go to hatch. Why exactly they go there is still not understood. Safety certainly is not a prerequisite, since mortality for larval reef fish in the open sea approaches 100 percent. Whatever the reason, the pelagic zone is where most eggs go, where they hatch into larvae, and where they then join the legions of zooplankton.

If you dive in the pelagic zone--or, rather, if you don't dive but, like most everything else here, stop and drift--you can see some of these plankton. By hanging under the surface, remaining still, then refocusing your eyes to a distance just beyond the tip of your nose, a world of new creatures suddenly emerges, translucent things with peculiar winglike fins and pulsing combs of cilia that refract light into tiny rainbows. Nearly invisible, these tiny beings sail the currents of the globe, countless trillions of them drifting in ranks spaced as perfectly as divine geometry. Then, as you observe, some of these ethereal beings collide with you, yet there's no sensation of touch, as if you've arrived in a fairy realm.

But there's even more that you can't see. The fields of the sea are rich beyond measure, densely populated not only with these zooplankton but also with phytoplankton, the single-celled plantlike organisms that form the basis of the entire marine food web. And it's not just the well-known dinoflagellates and diatoms but entire ecosystems of newly discovered species: the ultraplankton, who, at 40 millionths of an inch in size, are today counted at 3 million individuals per ounce of sunlit seawater and may account for 70 percent of all the photosynthesis in the world's oceans; the even smaller heterotrophic bacteria, which help the ultraplankton to manufacture and consume carbohydrates and carbon dioxide on a scale science can't yet imagine; and preying upon them genetically, tinier things still, recently discovered viruses known as bacteriophages, which reach astonishing population densities of 3 billion per ounce of ocean water. Taken altogether, the recent discovery of this micro-ecosystem is akin to finding the elusive dark matter of the universe.

Extending ever smaller, deeper, broader, and richer, the pelagic zone begins to embrace the properties of infinity. As I pause here, watching the largest of the small sail by, I remind myself that little of what is bathing me and buoying me is actually water; it's almost all life.

For the fertilized eggs of the surgeonfish and all the other pelagic spawners, this planktonic realm is a phenomenal feeding ground in which to spend their youth (all nine to a hundred days of it, depending on their species), grazing and hunting. Perhaps, as some scientists propose, reef fish might be more accurately characterized as pelagic animals, with their coral-dwelling adult life simply the final phase of it.

In their youth, sailing through the bottomless blue of the pelagic zone, the fishes of the coral reef take on extraordinary forms. Most are tiny, only 0.2 to 2 inches in length, and completely transparent. Many have long decorative spines trailing above and below them, no fins at all, and gigantic eyes that dwarf underdeveloped bodies.

This afternoon I'm acquainting myself with them not in the open sea but in an air-conditioned French biological station on the island of Moorea, a ninety-minute flight southwest of Rangiroa. A photographic library of these creatures is loaded into Vincent Dufour's computer here at CRIOBE (Centre de Recherches Insulaires et Observatoire de l'Environnement). One photo of his interests me particularly. It's the juvenile form of Ostracion cubicus, the yellow boxfish, or momoa afata in Tahitian. In adulthood this animal will have, as its name implies, a boxlike body enclosed in fused, bony plates. But in its youth it looks like a tiny yellow gumdrop, gaily polka-dotted in blue, with huge yellow-and-blue eyes and small transparent fins. How could such a tiny morsel of life navigate its way across ocean currents to return to an island, possibly the same island where it was spawned?

In the deep ocean, Vincent says, drifting, swimming weakly, hunting, and avoiding hunters, the tiny yellow boxfish and all the others like it grew, changed, and then, with the single-mindedness of salmon, returned to a home on the coral reef they've never seen before.

In fact, at this moment they're swarming in the waters outside Moorea's barrier reef. Tiny boxfish, surgeonfish, poisson dragon, iihi, nohu, Cephalopholis argus, Centropyge flavissimus--all the fishes named in all the different languages. They mass by species, sorting out their own identities, even though most are as small and invisible in the water as contact lenses.

Above them huge Antarctic swells roll toward the islands. Below them the stony corals of the reef's outer slope hunker down to withstand the surge. Ahead lies the barrier reef, the natural buffer between sea and lagoon. At its summit sits the most inhospitable zone of all, an impossible place where combers repetitively curl, break, then retreat: the algal ridge. Built by encrusting red seaweeds and cemented into place under the extreme forces of surf and sunlight, it is the final, seemingly insurmountable obstacle between the baby fish and the sanctuary of Moorea's inner lagoon.

The young fish are anticipating the moonless night to come, as restless and skittery as flocks of birds preparing to migrate. They will not travel through one of Moorea's passes, as too many predators are assembled there. Instead, as Vincent's doctoral research uncovered, they choose what seems a suicidal option. After nightfall, despite having never done anything of the kind before, they will gather under the humped back of a wave, ride up its powerful rise, then down its thunderous landfall, and surf across the algal ridge.

It's a trip that would likely kill you or me. Even now, snorkeling in Moorea's Irihonu Pass on a relatively calm day, I can see the power of these waves. From underwater they lift, then curl, forming beautiful, mercury-bright cylinders that barrel-roll up the barrier reef toward the algal ridge. The larger swells rear and corkscrew, appearing from underwater to pull themselves inside out until they've drawn to their full height, at which point they throw themselves onto the algal ridge, exploding in billows of blinding white bubbles. It's difficult to imagine the tiny fish, delicate as flower petals, surviving such a journey. Yet they do, and once inside the lagoon they swim in search of reef patches on which to settle. Because the best sites are already commanded by adult fish, the newcomers are relegated to less desirable areas.

I've discovered one such place alongside a crumbling rock jetty inside Moorea's lagoon. Apparently there's too much boat traffic here for the larger fishes and also too many human fishers; but for the new arrivals it's perfect, the disintegrating cement of the pier porous with hidey-holes, the bottom strewn with old tires, PVC pipes, soft-drink bottles, shoes. Amid this human detritus is everything you could ever hope to see on the big reef at a fraction of its normal size. A black-spotted moray eel no bigger than my pinkie finger snakes out of a chip in the dock. A squadron of spotted eagle rays, each smaller than my outstretched hand, cruises the will of the pier, their striking designs of white circles on black backs flexing with each wing stroke. Inside an eight-ounce can that once held jus d'ananas (and exactly mimicking its colors) lives a tiny yellow-and-white octopus, pale and translucent as a ghost.

All the fishes are here, too, most no bigger than dimes but already, within just a few days of settling on the reef, having blossomed into their adult color patterns: a huehue, the tiny pufferfish whose radiating lines of green-and-orange eye makeup give it a look of happy surprise; a miniature bird wrasse, its long beak probing a red sponge in search of even smaller crustaceans.

Occasionally an adult of something or other swims through, amplifying the illusion that I've arrived in a watery Lilliput. A giant moray eel startles me with its six-foot size and its unexpected daytime excursion from its home cave. I find myself diving to the bottom for cover, then laughing at such an overreaction. The fish, however, have no doubts. All the bright clouds of them have vanished into the honeycomb of Tjunk around the dock.

The most remarkable of all Vincent Dufour's photographs is of a pair of his own outstretched hands cupping a wriggling treasure of about fifty of these jewellike young fish. They're all there, instantly recognizable in their adult patterns: butterflyfish, triggerfish, angelfish, pufferfish, boxfish, surgeonfish.

This photo, displayed in Vincent's press kit, describes the premise behind his new venture, which marks his own personal migration from science to environmentalism, via the unusual path of commerce. He's returned to Moorea from his home in France to launch an enterprise called AquaFish Technology. Since his return, CRIOBE has undergone a small-scale building boom. He's expanded an old storehouse, transforming it into a bright clean series of rooms now filled with racks for aquariums of various sizes, sinks, sorting tables, pumps, filters. Upstairs, two small bedrooms will house his staff, the young men and women eagerly awaiting the chance to nanny the baby fish. Outside, the foundation is laid for two much larger tanks, and the ground nearby is littered with pieces of Vincent's own creation, the keystone to his whole enterprise, a tubular steel contraption he calls a crest net. Once mounted on top of the barrier reef it will collect virtually all the little fish that surf across at that point.

Since there's no immediate hope of breeding reef fish in captivity (because, at the moment, there's no way to re-create the conditions of a mascaret), Vincent will leapfrog that obstacle; he will capture the little fish as they return to the reef and raise them in the 3,500 cubic feet of aquariums under construction at CRIOBE. As one of perhaps only ten people on earth who can identify these postlarval fish species, he'll be able to separate them into quarantine tanks where the carnivorous species will not consume the herbivorous ones. There he'll domesticate them, tailoring their food supply so they won't nibble away and destroy the home aquarist's expensive decorative corals.

The worldwide trade in aquarium fish--currently worth $200 million per year and fueled mostly by demand among home aquarists in the United States, Europe, and Japan--is badly in need of transformation. The collection methods are brutal. Using poisons, primarily sodium cyanide, poor people destroy entire ecosystems in order to capture the few stunned fish surviving on the perimeters. The sodium cyanide begins to kill corals and fish within thirty seconds of contact. A handful of fish at the outermost edge of the destruction, disabled but not dead, are then collected by hand.

With each purchase of a lionfish or butterflyfish, the home aquarist, obliviously or uncaringly, funds this devastation. But if Vincent's plan works he'll be able to offer an alternative. Better yet, his technology is low-impact and relatively cheap, with the potential for installation in poor countries throughout the tropical world.

I question him about something bothering me, though, the impact of removing the newly arriving fish from the lagoon. I know that 90 percent of these youngsters are destined to die within a few days of settling there, but aren't they destined to die inside the stomach of some larger, hungry reef fish who depends upon them? He admits that his enterprise may not be up to the standards of deep ecologists, but his crest nets will be mounted on only a small portion of the entire perimeter of the barrier reef. Of the two to four pounds of tiny fish captured each night, another ten to thirty tons will surf daily into Moorea's lagoon, without getting caught.

Vincent hopes to move beyond the aquarium trade and eventually to wrestle with the problem of the live-reef food-fish trade, whereby living fish, particularly grouper and the large Napoleon, are shipped to pricey restaurants throughout Hong Kong, China, and Singapore. There they swim in aquariums while diners point out the individual they would like to eat, which is then fished out of the tank and steamed alive. Before the Asian economic crisis live fish in Hong Kong cost 800 percent more than frozen fish, and the favorites (which perversely enough are endangered species) fetched up to $82 per pound. The supreme delicacy, a plate of nothing more than the thick lips of the Napoleon, sold for as much as $225. At its height this hunt destroyed an estimated 25,000 tons of fish yearly. Vincent also plans to raise fish for local consumption in French Polynesia, where most of the heavily populated islands are overfished. I've seen evidence of this myself, since commercial flights to and from the outer islands of the Tuamotus make frequent stops at remote atolls. All aboard the plane get out, stretch their legs, and watch as coolers full of reef fish are loaded aboard, bound for the restaurants and hotels of Tahiti, Moorea, and Bora Bora, whose lagoons and reefs can no longer supply the locals' own needs. But according to Vincent's plan, one small net (no bigger than a desktop) will collect 4,000 baby groupers in one night's net set--fish that he will then rear to adulthood, providing food for twenty-two people for an entire year.

Aquariums like his, established in poor countries such as the Philippines, also could help end the most destructive of all fishing practices--the blast fishery. In this, fish for local consumption are collected with explosives: beer-bottle bombs filled with dynamite, or homemade fertilizer/kerosene mixes. The explosions kill fish at the epicenter by destroying their swim bladders, incapacitating those on the perimeters. Incidentally, the blasts also reduce the reefs to rubble, from which they may never recover.

By raising captive fish, Vincent will also address the problem of ciguatera, a serious and growing health problem among fish-eating people in the tropics. Wild fish are infected by eating poisonous dinoflagellates. The poison then spreads through the food web from herbivorous to carnivorous fishes to people, until today most of the tropical oceans are affected both on the reefs and in the pelagic zone. Human symptoms of ciguatera include diarrhea, vomiting, dizziness, muscle weakness, numbness in the mouth and extremities, inversion of the senses (hot feels cold), and paralysis. Bad cases may last for weeks; severe cases can be fatal.

Ciguatera flourishes on damaged reefs where the corals are dying and being replaced by algal (seaweed) turf, a definition that applies to more and more of the world's reefs each year. In Moorea, where each morning I snorkel off the beach outside my fare, or bungalow, the signs are ominous. Here the fringing reef inside the lagoon is akin to a great city on the verge of collapse. The skeletons of huge plate corals, killed in the cyclones spawned by the 1982-83 El Nino, lie broken, tilted on their sides or toppled upside down, as if chandeliers had fallen from on high. Thick mats of yellowy fibrous algal turf, ropy as old cobwebs, coat the debris. In between, vast stretches of barren sand prettily decorated with nothing more than dancing hexagonals of sunlight creep up to and over the petrified remains of dead cowrie shells, a moray eel strangled in fishing line, the empty gaping maws of giant clams. There are still lovely things too, dense schools of herbivores, convict surgeonfish, cerulean damselfish, goldtail demoiselles, humbug dascyllus. But here, in microcosm, is an example of the kinds of things that can go wrong when reefs and humans come together. To begin with, the island is becoming a bedroom community for nearby Tahiti and its capital, Papeete. People fed up with traffic on the colonial-era road system are flocking to Moorea, building houses here, then commuting back to work on Tahiti aboard fast ferries that make the trip in twenty minutes. Unfortunately, Moorea (as for all of French Polynesia and most of the tropical world) has no sewage treatment, and so the human waste from these new residents eventually leaches from septic systems into the lagoon, where it acts as a powerful fertilizer, energizing the growth of the algal mat that first smothers the living corals and then fosters the explosion of ciguatera.

Just as with the wonders of the reef, most of its troubles are also beyond our direct sensory experience. As you hover above an enormous yellow anemone, marveling at the way its resident colony of clownfish dart in and out of the dancing arms of its poisonous tentacles, can you judge the effects of the Jet Ski that just tore by overhead; of the fuel that leaks from its engine; of the impact of its noise pollution on marine life, which depends on sound for offense or defense; of the inevitable collisions with coral at low tide and the surface fish left like roadkill in its wake? Or, for instance, how can we really understand the outcome of decisions made half a world away in France that award citizens there tax breaks for investing in development schemes, for which there may be no need in French Polynesia, or else no means of support, such as an adequate water supply?

Under assault from pollution, coastal development, agricultural runoff, overpopulation, and overfishing, the world's reefs are exhibiting their vulnerability in many ways. Each year new coral diseases are identified--black-band disease, white-band, yellow-band, red-band, patchy necrosis, white pox, and on and on--perhaps caused, frighteningly enough, by the desertification of Africa, by huge volumes of dust in the atmosphere dropping viral and fungal spores into the weakened seas.

Furthermore, as the global climate changes, sea temperatures throughout the tropics are rising above 30 [degrees] C--the critical threshold at which the plant and animal marriage of coral and zooxanthellae dissolves. Under stress (including that of higher temperatures) corals expel their zooxanthellae, rendering the reef a ghostly white. Bleached corals suffer from a lack of proteins, lipids, and carbohydrates, which undermines their skeleton-building and reproductive cycles. Although they may survive a few months like this, the divorce from their plant partners eventually leads to necrosis of the coral tissues. The dead reef is soon invaded by massive algal blooms, and thereafter by those who shelter in the dead coral skeleton, or those who graze on the plant life--the mollusks, sponges, sea urchins, and herbivorous fishes who, taken together, form a bio-erosive army, one acting with such efficiency that the reef is quickly converted to sediment.

Although ancient corals did live in warmer seas, those living on earth today cannot adapt as quickly as climatic changes are occurring. In the last two decades, worldwide coral bleaching events associated with higher seawater temperatures have destroyed reefs across entire ocean basins. The 1991 bleaching event led to the death of 25 percent of all Acropora corals surrounding French Polynesia. The 1997-98 El Nino killed 70 percent of all corals in the Indian Ocean from Africa to India. The reefs of the Galapagos Islands have yet to show signs of recovery, seventeen years later, from the widespread coral bleaching event of 1982-83. The status of the world's reefs from the Caribbean to the Red Sea is similarly dire.

For the people who live alongside coral reefs, the effects are devastating. A 1997 study struggled to estimate the annual value of the world's coral reefs by factoring in four types of benefits: consumptive uses of reefs, such as coral mining, fisheries, and shellfisheries; nonconsumptive uses, such as tourism and recreation; indirect use values, including the way coral reefs protect coastlines and serve as fish nurseries; and option values, something you will pay some amount of money to save now because it may yield value in the future. The total yearly value they arrived at was $375 billion.

Whatever the true economic worth of coral reefs, there can be no doubt that in their absence the poor people of the tropics will become poorer. Barrier reefs, as their name implies, form a stronghold between the land and the sea, protecting people and their homes from the onslaughts of typhoons. While reefs buffer the coast from storms, they also, obviously, suffer the effects, and too many storms in rapid succession can ruin even healthy reefs. French Polynesia experiences severe cyclones only during El Nino years. Flying into the atoll of Manihi, I saw firsthand how storm waves had battered the motus with hunks of coral the size of school buses, destroying fully half of the airstrip we had just landed on. Underwater the trouble became even more obvious, as Manihi's reefs, first bleached and dying due to El Nino's warmer waters, were afterward utterly destroyed by its massive storms. Most scientists now agree that the increasing frequency of El Nino events is tied to human-induced global warming.

Without coral to keep them afloat, atoll islands eventually disappear altogether, a fate dangerously near for the people of the Maldives--an archipelago of 1,200 atolls in the Indian Ocean so badly hit by the 1997-98 coral bleaching that virtually all coral life here has died. Without reefs, many fishes and shellfishes disappear, leaving people hungry and malnourished. Even if Vincent Dufour's dream comes true and aquariums appear on all these impoverished coastlines, without a sustainable population of adult fish, the moonless nights will come and go without spawners, until the last little fish

surfs across and then no more, ever again, for Vincent or anyone else to catch.

As we burn more fossil fuels, causing global temperatures to increase, sea levels also rise. Because zooxanthellae rely on photosynthesis, corals can grow only in the uppermost membrane of water inside the sunlit zone. A similar great flooding at the end of the Ice Age 10,000 years ago demonstrated that while some reefs grew fast enough to keep up with rising sea levels, others did not. Those that failed were presumably already too stressed from sedimentation, nutrient loading, or changing temperatures--the same problems plaguing virtually all reefs today.

Meanwhile, the ultraviolet light now pouring in (particularly to the southern hemisphere) through the ozone holes above the planet's poles not only stresses corals enough for them to bleach but also kills phytoplankton and the delicate fish larvae in the pelagic zone. Losing this, the true nursery ground of the sea, has profound ramifications for the entire global food web, both marine and terrestrial, and for all the people in the world, including you and me, who yearly utilize more than 100 million tons of food from it.

I have dinner with Michael Poole, an American friend and a marine biologist with CRIOBE, who's lived and worked in Moorea for more than a decade. He, his Tahitian wife, Mareva, and their sons, Temoana and Tearenui, live in an old house on the northeast tip of Moorea, where the barrier reef comes to within sixty feet of their beach. Here they can relax in the evenings and watch as courting groups of humpback whales travel by, and again in the mornings, as spinner dolphins, Michael's primary animals of study, return from their nighttime feeding grounds in the pelagic zone to the safety of the lagoon.

This evening we chat, drink wine, shuck shrimp, and listen to the ceaseless swoosh and thunder of waves breaking and retreating, on the reef. Mareva reminisces about her childhood, when her father used to catch all the pretty lagoon fishes in the water just offshore of their fare. These fishes are hard to find now. She and Michael discuss the fact that their sons have never even eaten some of them, little goatfish, for instance, which Mareva claims have too many bones in them for Michael, a Westerner, to safely eat. Michael strenuously disagrees. He grew up in hot, watery places from Florida to Bermuda and knows how to eat fish. Not these fish, says Mareva. You have to be born eating them. Michael counters that she can't eat a chicken nearly as well as he can, doesn't know how to pick those bones clean. They laugh, they're charming, the cultural divide, you suspect, an endless source of wonder and periodic exasperation to them.

It's difficult to comprehend the magnitude of threats facing the world's reefs, and here, over this pleasant dinner, we discuss the smaller troubles, the ones intimate to Michael and Mareva's daily life. In Mareva's girlhood fishing was a community activity, with each family member inheriting a valued role. Michael describes how on his first meeting Mareva's family he was sent out with her and a sister to the reef at low tide, each with a bucket and small tool to glean mollusks for the meal. Although Michael worked hard, clambering on the slippery surfaces, inexpertly prying clams from their holdfasts, when he returned to shore his bucket held a meager prize of only half a dozen, while Mareva's and her sister's were overflowing--proving to him the value of her skills.

In traditional Tahitian society the coral reef was a source of social stability, awarding everyone a job that was generally fun as well as rewarding. Although many Tahitians still reef-glean, the rules are changing. Mareva says that once there was an etiquette, an unspoken understanding that the part of the reef nearest your own dwelling was your reef, not to be exploited by others without an invitation. Nowadays, not only does the ferry deliver new residents to Moorea; it also brings hordes of weekenders from Tahiti, the Sunday fishermen, the spearfishermen, the Jet Skiers, the gleaners, altering both the lifestyle and the community of the island.

The next morning Michael points out a small protest under way in the lagoon, a dozen or so outrigger canoes, fishing skiffs, and plastic dinghies tied together offshore, all bedecked with beach umbrellas and packed tightly with Mooreans. They've tethered themselves to a yellow dredger, which is about to begin pumping sand from around the lagoon to replenish the beachfront lost during the construction of a new Outrigger hotel. The Mooreans are upset; this is their sand, and its loss will undermine their own beaches and further degrade their reefs. They're determined to prevent the dredger from operating, and have enlisted a contingent of supporters onshore to hold up signs handwritten in French and Tahitian for passing motorists to see: DON'T TOUCH OUR SAND; THINK OF OUR CHILDREN.

It's a tiny demonstration, yet as the days go by it makes the local newspapers and the television news, partially owing to the tenaciousness of the protesters, the feeling that, ensconced in their small boats, cheerily trading picnic food back and forth, slipping in and out of the water to cool off, they might--rather happily--stay there forever. Meanwhile the hotel continues its noisy construction of a long line of over-water bungalows that stretches far out into the lagoon, ruining the neighborhood views and disrupting the natural waterflows so that all the beaches in the area will continue to erode, with or without the dredger.

To me, the protest seems both sad and hopeful: sad because the territorial government nearly always chooses to accept token fines in lieu of environmental compliance; hopeful because I can feel that this small gathering of people might spawn something that will grow, spread, and someday come back in force.

In the midday heat, when shops and businesses close their shutters and most Mooreans retreat for a nap, the protesters have slumped down under the thwarts of their dinghies, the only sign they're still there the occasional hand reaching over the side for a flick of cooling water. At this time even the fish seek relief from the sun, and snorkeling out to the middle of the lagoon I find the underside of a diving platform crowded with pufferfish, rabbitfish, Moorish idols, lemonpeel angelfish, and a pair of teardrop butterflyfish. All are assembled here in the shade, to the jingling accompaniment of the platform's mooring chain, a hypnotic underwater chime driven by lazy waves at the surface. The fish face headfirst into the current, pedaling against it with the rotation of their pectoral fins, as if dozens of fans were silently whirring.

The only large motion in this sleepy environment is that of a fish that the French call perroquet brule, after the Tahitian name paati paapaa auahi, or burnt parrotfish. Dark yellowish-orange flanks do make this species look burnt, perhaps sunburnt; and as if to prevent more of this it's also trying to get into the shadow of the dive platform, but to no avail. In order to approach, it needs to bypass a large lavender-colored Pocillopora coral, from which a squadron of dusky damselfish, drab charcoal-colored fish many times smaller than the parrotfish, emerge and repeatedly drive it away. Earlier, I watched them evict an emperor angelfish, a spectacular beauty with a black mask edged in neon blue, who expressed his annoyance by making a loud drumming noise as he retreated. Earlier still, they came after me, nipping my fingers so that I had to swim by with my hands tucked into my armpits. One astonishingly bold individual even swam up to the faceplate of my mask, bouncing off it in a paroxysm of pique so startling that I found myself swatting at it.

I first met these oddly pugnacious fish some years ago when filming the work of an American biologist, Mary Gleason. A small woman with a fluid graceful diving style, she possessed the keen eye and patience needed to decipher some of the reef's best-camouflaged secrets. For three years she set ceramic tiles on Moorea's lagoon floor, periodically collecting them for study under the microscope where she could count and measure the tiny colonies of corals that settled there. After the first field season she noticed a pattern emerging; by the end of the study she'd discovered that three times as many young corals survived if they happened to settle inside damselfish territories.

Today, hovering with the fish in the shade of the dive platform, I can clearly see the reason why; by aggressively driving off all other fishes, these damselfish protect the young corals just getting started. The perroquet brule they're currently mobbing, for instance, would otherwise linger here, excavating algae from the seafloor and with its sharp beak incidentally consuming infant coral colonies. Yet, as I know from Mary's study, the little damselfish aren't defending the corals, only their own landholdings, the gardens known as algal lawns or algal turf growing in fields they've cleared between the pillars of coral.

Perfectly tended, these lawns are a neat monoculture of filamentous red algae, the fish having meticulously weeded out unwanted plants such as sargassum and turbinaria (which also happen to be the main beneficiaries of untreated sewage, and therefore a bane to the overall reef). Working day and night, these tiny farmers drive off herbivorous fishes that eat their gardens. They harass carnivorous species, which steal the egg clutches the male damselfish are currently brooding. In fact, they remove all marauders, including sea urchins, which they carry off gingerly by the spines. In the years of Mary's study, when Moorea's reefs had been badly battered by the 1982-83 El Nino cyclones, only the corals inside damselfish territories were beginning to recover--and are still recovering far faster today.

As a visitor to the coral world, you might happen upon a damselfish colony, see little more than a gathering of unspectacular strangely aggressive fish, and quickly swim on in search of something friendlier. Yet in the accumulated tasks of their daily lives, in their obsessive industry, these damselfish play a critical role in the regeneration of reefs. Remembering something Mary told me, I swim to the Pocillopora coral, braving the wrath of the damselfish to untie the pencil from my underwater slate and drop it into the center of their algal lawn. A buzz ripples through the colony; the fish actually look offended. One individual darts in, grabs the litter in its mouth, then carries it away to drop onto the open sand well clear of the coral head before swimming back to join the twenty or so other damselfish angrily facing me down.

Mary's study--tiny by any measure--is itself an indicator of the state of our knowledge of the world's reefs. While it's difficult for an individual diver to perceive even a small corner of the coral realm, it's still more difficult for us to understand what's happening globally. Because reefs occur mostly in poor countries, in nearly inaccessible locations, they're studied only sketchily. Much of what we know about their health comes not from scientists but from the scattered reports of dive operators, yachtsmen, and fishermen. Satellite images tell something more, but most of what's happening to them is still veiled by the vast mirrored surface of the sea.

To the ancient Tahitians, the ocean around them was a cosmos as grand and mysterious as the sky, where gods lived not in the clouds but in the lagoon. This focus--so different from our own--may yet prove prescient. For while in recent years the world's attention has focused on rain forests (and coral reefs are frequently described as the rain forests of the sea), I would argue that coral reefs are greater than rain forests if for no other reason than that they are far more powerful arbiters of life both in the sea and on the land. The reefs and the oceans they help stock are the chemical engine driving the planet, stabilizing our climate, refreshing the air we breathe, making the rain that feeds the rivers and lakes and waters the crops upon which we depend. This water world and its most fertile core, the reefs, are the continuing cradle of life on earth.

As reefs decline, there is some comfort in the long geological history of our planet, the knowledge that life comes and goes, arises and changes, on a schedule that has been extremely violent even in our absence. If the geologic record teaches us anything, it is that, with or without either our help or our hindrances, the earth's reefs will vanish, and then re-emerge again, as long as the sun delivers its rays and the waters flow. Whatever role we might play in the next great extinction will surely have less effect on the tenacious re-emergence of reef builders than it will have on us. Reefs, we know, can survive without us. The opposite may not be true.

Julia Whitty's last story for Harper's Magazine, "A Tortoise for the Queen of Tonga," won an O. Henry Award. A collection of short stories by the same name will be published by Houghton Mifflin, as will a novel, The Hunger of Stone.
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Title Annotation:coral reef preservation in the South Pacific
Author:Whitty, Julia
Publication:Harper's Magazine
Geographic Code:80OCE
Date:Jan 1, 2001
Words:8884
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