Biologists contend that a rough triangle drawn from the Philippines to the western tip of New Guinea to the island of Bali and back encloses the richest concentration of coral reef species in the world. Into the very center of this teeming diversity of marine life - more than 3,000 species of fish, an amazing 75 genera of reef-building corals - reaches the crooked arm of Sulawesi's northern peninsula. With its rugged coastline and odd tangle of peninsulas, the Indonesian island of Sulawesi looks itself like a rare sea creature washed ashore. The island, famous in colonial days as The Celebes,...