At first I thought it was a little shark, swimming curiously in to look at an intruder on this bare reef — a long white fish with angled fins and a sly way of swimming around behind you every time you turned to face it.

Spooked and slightly irritated, I waited for it to swim a bit too close, then hit the bastard right on top of the head, a sharp “whack!” with a closed fist. The impact felt sludgy and a little slimy but it had a result — the creature bolted hurriedly off to the west, toward deeper water.

Two other surfers were out, Timmy and Micah. I yelled out to ’em about the fish but they only half believed me. That is, until Micah started kicking and slapping at something under him. “God damn,” he yelped, “what is that?” Micah had a pair of goggles around his neck. “I wanna take a look at that thing,” said Timmy, and, sticking the goggles on, put his head underwater. “Whoaaa!” he gasped. “That thing is rad-looking!” Dude!!! It was indeed rad-looking. Two feet long, pointy pectoral fins set forward, sharp little tail, and wackiest of all, a large flattened surface across its skull — nothing to do with my savage blow, but some sort of inbuilt mechanism for something . . . then suddenly something about its shape, its whole act, clicked, and I realized . . . “It’s a remora! You know, a suckerfish … it glues itself onto sharks. It . . . thinks WE’RE sharks!”

My God, this creature was woefully mistaken. We weren’t sharks. We weren’t here to bite anyone. We were here to try to ride the north passes of the upper Tuamotu atolls — strange, silvery, windblown coral reef waves breaking around some of this planet’s bleakest and most weatherbeaten tropical coasts. And “coast” really is the word, for the Tuamotus are nothing but.

Pacific atolls are remnant islands — the ghosts of islands once shot up from the sea floor by volcanic action. Now, millions of years down the track, the volcanic energy is long past, and the islands are sunk back into the depths. But life doesn’t give up that easily, and the coral of those vanished islands’ ancient barrier reefs has hung in there, building its thin limey buttresses against the Pacific’s immense erosive pressure.

It’s about as oceanic a place as you’ll find: not so much a Mentawaian-style surfing Disneyland as an ancient ruin, a Polynesian Atlantis with its head barely above water, leaned on by the weight of tide and swell, scoured by trade winds, vanishing slowly, inexorably into the Pacific food chain.

Within the atolls lie shallow inland seas. Some are so broad you can’t see an opposite shore, and travel across by boat takes a day. Water between the inland seas and the Pacific is exchanged through reef passes, but since the demise of the central volcano and its coral-cutting freshwater runoffs, the passes have shrunk in number. Now, there’s sometimes only one left. That’s where you find the surf . . . — Nick Carroll