Divers explore a cave near Walker's Cay. Photograph © Stephen Frink/CORBIS

Coral Vision
By Florence Williams

An inquisitive visitor learns that you need more than scuba gear or a snorkel to see underwater—to really see.

Beginning in the winter of 1983, a weird thing happened on coral reefs all over the western Atlantic: long-spined black sea urchins died a mass, sudden death. No one knows exactly why, but to this day, my snorkeling guide on Andros Island is very concerned about it. "Black sea urchins are the lawn mowers of the system," Jim Sollars explains in his West Country English accent. "They keep algae in check. Who's going to pick up the slack now? Ya see, love, everything is connected."

A few days ago I might have been surprised that a beefy former London constable and rugby player would get agitated over urchins. But this is the Bahamas, and I'm learning to accept paradox. For example, this island chain, so indelibly associated with cruise ships and casinos, hosts some of the world's least damaged coral reefs. The Bahamas extends far beyond Nassau and Freeport to 700 islands—many uninhabited—spread over 90,000 square miles of warm, largely shallow Atlantic. Andros is the largest.

From Sollars, I'm getting what most visitors here don't: the inside story on how reefs work. The connections that Sollars likes (almost as much as metaphors) are everywhere. Parrotfish, for example, depend on a host of small shrimp that crawl into their mouths to keep them clean ("dental hygienists," says Sollars). Crabs, vulturelike, help consume the reef's waste ("they're sanitation engineers, love"), and those much-touted white sands of the Bahamas are actually poop from coral-eating parrotfish, cleaned by sea cucumbers. This all helps explain why a suddenly missing link is cause for hand-wringing—algae has indeed begun overtaking some coral reefs—and why, in more polluted, populated places like the Florida Keys and the coasts of Brazil, the reefs are in big trouble.

I signed up for guided snorkel trips at Small Hope Bay Lodge because I wanted to learn about the reef—not just glimpse it as most of us tend to, like an exotic garden seen from a passing train. "A coral reef is like an art museum," as one biologist puts it. "You can still enjoy it if you don't know anything about art, but you'll like it better if you do."

Small Hope Bay provides guides trained by the Jean-Michel Cousteau Institute, which launched an Out Islands snorkeling program to boost tourism in the remote islands and send home happy snorkelers with the message that reefs are wonderful, endangered, and need our help. For $99, Small Hope's Cousteau package gives me three guided snorkel trips over two days, take-home field books, and a marine-ecosystem slide show. Sollars, with his long hair and rugby-remnant beer belly, is proving a worthy, if improbable, ambassador.

On the dive boat, Sollars regales my fellow snorkeler, a New York college administrator, and me: "I used to have three loves: rugby, beer, and women. Now I have a fourth: the coral reef." For Sollars, Cousteau training opened up a new world of understanding. "I never get bored here," he says. "If you look closely, you see the real beauty and complexity. You can look forever. It's like a fine wine. When you savor it slowly, the different layers, the fruits and what-have-you always reward your effort. Besides"—he grins—"underwater, fat men can fly."

And then he does, right off the stern. We jump after him. "Healthy corals have a coating, a thin slime layer," he warns, treading water. "If you touch it, you damage it." A touch can kill algae that live in the tiny coral polyps like pimentos in an olive. These beneficial, symbiotic algae, called zooxanthellae, process waste, create food, and help produce calcium carbonate, which builds up the reef over millennia. They also give the coral its rich, lively colors. If stressed, polyps may expel the algae, and the reef ends up looking like a sorry pile of limestone. You see this fate in parts of the Virgin Islands and Hawaii, where unknowing snorkelers stand on shallow reefs. In the Florida Keys, you can also see the effect of too much algae (whether from nutrient-rich pollution or the demise of algae grazers like urchins): fuzzy green and brown rocks.

Here, off Andros, what you see is like a chaotic forest, full of life. In his element, Sollars flutter-kicks through purple, green, and yellow coral shaped like antlers, cactuses, ferns. We follow, past schools of elegant yellowhead wrasse and blue tang. He swims over a stalk called pillar coral, takes a breath, and dives five feet, signaling us to follow. He puts his mask right up next to the golden pillars, without touching them, and points. Clumsily, we try to do the same. I can make out the rounded, olive-shaped polyps and their tiny hairlike tentacles. Then I bolt for the world of oxygen. Sollars stays down, motionless, observant, for several more long moments.

Diving with him demonstrates the striking difference that the Cousteau program can make. Earlier this week I had my first reef experience at Walker's Cay Hotel and Marina in the Abaco chain, northeast of here. Despite an emphasis on diving, Walker's Cay was one of many resorts that have dropped Cousteau, mainly because the program was poorly marketed; only eight of the original 23 hotels have stuck with it. "You're the first person who's ever called about it," I was told. Known as a place celebrities have come to relax and fish—Richard Nixon, Jack Nicklaus, John Elway—Walker's Cay on this weekend was catering to a rum-and-gasoline crowd; fishing yachts belched and revved their engines at the docks. Indoors, mounted marlins and other game fish dominated the decor.

I asked for a lesson there and was handed over—at no extra charge—to a deferential Bahamian named Tony Thomas. Thomas taught me how to relax my mouth around the silicon snorkel and how to clear my ears as we swam down below the surface. He took me to a shallow dive site called, fittingly, Aquarium. In bathtub-warm water, calm and clear, we floated above an enchanting, colorful forest of corals, each looking a lot like the names Thomas recited to me: brain coral, lettuce coral, staghorn, elkhorn. He pointed out yellow, folded fire coral, which appeared to this mountain-dweller like giant chanterelle mushrooms. We swam among slender trumpetfish and cornflake-flat angelfish, damselfish and sergeant majors, and heart-stoppingly colorful parrotfish.

Bobbing to the surface, I was ecstatic. "How did all this get here?" I asked. "How was the reef formed?"

Thomas laughed and gave a little shrug. He was long on fish and coral identification but short on big-picture ecology. Nor did he warn me about touching coral. Back on shore, only a few basic identification guides were for sale. More space was given over to the TV devoted to videos of Walker Cay's famous shark dive, set to groovy reggae and available for $40.

I checked out the shark dive next day. Divers watch from 20 feet away as dozens of nurse and reef sharks tear apart a suspended barrel of chum. For 20 bucks a trip, snorkelers can view the swirling shark-fest from above. Later, after gleefully swimming with dolphins and sharks on another dive-boat trip, I asked dive master Gary Adkison how much the resort tells guests about marine ecology, given its mind-blowing natural attractions. Adkison presents weekly talks about sharks and reef life but said, with some frustration: "The average boater wants to sit at the bar and doesn't want to learn that much about the reef. We can't force it down their throats."

At Walker's, the reef was entertaining. At Small Hope Bay Lodge, it became fascinating. The comfortably informal lodge, tucked into the mostly undeveloped eastern beaches of Andros, has only 20 rooms, no marina, no air-conditioning, no TVs. In the library are dog-eared issues of Bahamas Naturalist and a copy of "New and Notable Records of Bahamian Lepidoptera"—60 species of butterflies here! Although most visitors come to dive, Jeff Birch, the owner, welcomes snorkelers and encourages them to sign up for Cousteau. Last year, Small Hope won the Bahamas' annual ecotourism award.

At dinner, a rambling, social affair under the breezy sea-side palms, I sit with Martin and Susan Schauer from Los Alamos. It's their last night, and they look mighty blissed out. Martin, a physicist, takes a relaxed bite of conch fritter. "You know you're having a great vacation," he ruminates, "when you have no idea where your shoes are."

On my last day I go snorkeling on my own, armed with my post-Cousteau knowledge. I join the dive boat for a shallow dive at a spot called China Point, where I swim above the underwater topography that Sollars has explained for me earlier: branching corals—staghorn and elkhorn—found in shallow waters, and farther down, brain corals, whose shape presents lots of surface area so that the zooxanthellae can capture the dimmer sunlight at depth. Trained now to go slowly and look in unlikely places, I check out the underside of a billowing sheaf of sea fan. Bingo! There's a flamingo tongue—a delicate quarter-size snail decorated with postmodern tangerine droplets. Even the spectacular fish have more personality than before. A stoplight parrotfish lurks below me. Now I know I am seeing his most colorful (and sexually powerful) terminal phase, when he has changed gender from female. His teeth, fused into a virtual beak (hence his name), are adapted for munching coral to extract bits of algae.

After a lazy lunch on Small Hope's deck, I snorkel again, drifting just off the beach. Before long I'm right over an octopus, coiled in the shadows of a rock, as well as several delicate purple-tipped anemones, fat and rosy sea stars, and an immobile damselfish being cleaned by a small goby. I watch them for a long time. None of these treats, I'm sure, would I have noticed in my go-go days at Walker's Cay.

"I don't like carnival diving," Sollars had said when I told him about the shark frenzy. "Most of the life in the ocean is very, very small, love."

The information in this story was accurate at the time it was published, but we suggest you confirm all details before making travel plans.