Published: November 2005
Strange Terrain: Undersea Oddballs of Lembeh Strait
Predators erupt from volcanic sands, and delicate pygmy seahorses hide in plain sight in the strange world of Indonesia's Lembeh Strait.
Text and Photograph by David Doubilet

Think of a coral reef as Las Vegas: a glowing city of sexy fish flitting down boulevards of neon corals. Then imagine an undersea neighborhood that's more like the gritty desert beyond Vegas, where you run into quirky characters like the guy running the one-pump gas station, or the bar where people wait for aliens. That's Indonesia's Lembeh Strait.

Lying off the northeast tip of the island of Sulawesi,sheltered from the open ocean, the strait is at first glance an unwelcoming moonscape—plains of silt and black and gray volcanic sands stretching into murky gloom. Some divers call it the muck. There are no grand vistas, no teeming corals. But any place you put your hand, there is life, veiled in the sand or hiding in plain sight. You have to look closely, for many things are not what they seem. I stared for minutes at a sea fan before finding pygmy seahorses the size of my thumbnail clinging to the branches, their skin matching the color and texture of the sea fan's polyps. Another night a rare visitor drifted into the cove of Kungkungan Bay, camouflaged in a floating mass of sargassum weed. As the seaweed slowly broke apart, a golden sargassum frogfish emerged in mirror image under the lights of a pier.

In the shadow of volcanoes

At dusk the Lembeh Strait seems lit by fireflies as fishermen in outriggers use kerosene lanterns to attract baitfish for the tuna fishery far offshore. Sulawesi sits in the middle of the greatest concentration of coral reefs on the planet—a virtual coral Eden—so diving in Lembeh Strait can seem an ironic contrast. But this little-studied world between the reefs and the rain forests is also a rich environment. A deepwater upwelling in the Molucca Sea pushes a vital plankton broth south into the ten-mile-long (16.1 kilometers) strait, and rivers running down through Sulawesi's forests also add nutrients. Whale sharks and manta rays once cruised here, but they were fished out. With those attractions gone, divers and then scientists turned their attention to the bottom, and were astounded by the profusion of life. Yet the strait can't be called pristine. The port of Bitung has nearly 145,000 people, and the heavily traveled waters gather trash. Paradoxically, this has benefits: On the strait's otherwise featureless bottom, tires, bottles, cans, and old shoes all become some creature's habitat.