Porolithon gardineri, and Caulerpa racemosa. Fauna The atoll is populated by several species of birds, fish, and reptiles. In the lagoon, sparse, living coral can be found; the dominant species is Montipora bilaminata (family Acroporidae). Most of the coral in the lagoon is dead, presumed to have been killed by influxes of cold water. Birds Though no terrestrial birds are found on the atoll, Ducie Island is known for the seabirds that breed there. Birds that have been recorded nesting on the atoll include the red-billed tropicbird, red-tailed tropicbird, white tern, great frigatebird, masked booby, and red-footed booby. Wintering bristle-thighed curlews have been recorded as well. A number of tern species, including the sooty tern, blue noddy, brown noddy, lesser noddy, and white tern have been recorded, as have several members of the family Procellariidae: Kermadec petrel, Trindade petrel, Murphy's petrel, and Christmas shearwater. The island is particularly important for Murphy's petrel, as more than 90% of its world population breeds on Ducie. Around 3,000 pairs of Christmas shearwaters, about 5% of the world's total population, can be found on the island too. Meanwhile, the red-tailed tropicbirds and white terns that breed on Ducie are around 1% of the world population of each species. Phoenix petrels, which previously inhabited the atoll, apparently disappeared between the Whitney expedition in 1922 and the 1991–92 Pitcairn Scientific Expedition. The island has been identified by BirdLife International as an Important Bird Area (IBA), principally for its colonies of Murphy's, herald, and Kermadec petrels, and Christmas shearwaters. Fish In the lagoon there are around 138 fish species, which also inhabit southeastern Oceania, the Western Pacific, and the Indian Ocean. The lagoon is noted for its poisonous fish and dangerous sharks. The yellow-edged lyretail, the blacktip grouper, and the greasy grouper are known to cause ciguatera poisoning. The lagoon is also inhabited by Galápagos sharks and the whitetip reef shark. The Galápagos shark is dangerous to humans, while the whitetips are seldom aggressive unless provoked. Five species are found exclusively around the Pitcairn Islands: Sargocentron megalops (a species of squirrelfish), the spiny butterflyfish, the Henderson triplefin (a species of threefin blenny), an unnamed species of Alticus (a genus of combtooth blenny), and an unnamed species of Ammodytes (a genus of sand lance). Terrestrial vertebrates Lizards that inhabit the island include the white-bellied skink (Emoia cyanura), photographed by E. H. Quayle during an expedition in 1922, and