Protected Areas and World Heritage Programme

NAME Clipperton Island

LOCATION 10°18°'N, 109°13°'W; in the East Pacific, 1,300 km from the Pacific coast of Mexico, 2,800 km from Hawaii and 5,200 km from Tahiti.

AREA 600 ha.

ALTITUDE Sea level to 5 m (volcanic plug 29 m).

OVERVIEW An isolated "near atoll" with a completely enclosed lagoon; the only atoll in the East Pacific east of Ducie (Pitcairn Islands). The lagoon is of considerable limnological interest, and the fauna and flora are of biogeographical interest on account of their Indo-Pacific and American relationships.

PHYSICAL FEATURES Clipperton Island is an egg-shaped "near atoll" with a completely enclosed lagoon oriented northwest-southeast. The atoll rim consists of a narrow band of rock generally 100-200 m wide, but reaching 400 m wide in the west and narrowing to 45 m in the northeast where waves occasionally spill over into the lagoon. There is a small volcanic plug covered with lichens and guano at the southeast end of the island. The island is surrounded by a reef flat exposed at low tide. The closed lagoon has permanently deoxygenated water; there is a strong halocline, and the waters are highly eutrophic and almost fresh at the surface. The climate is tropical oceanic. Northeasterly trade winds predominate, but are replaced occasionally in the summer by tropical storms and sometimes cyclones from the southeast.

ECOLOGICAL FEATURES Higher plants and algae are reported to be abundant in the lagoon. The island is largely covered with scrub vegetation, but there are a few coconut palms.

LAND TENURE French Government.

CONSERVATION MEASURES TAKEN None.

CONSERVATION MEASURES PROPOSED The island is to be legally protected by the French Government, but this is expected to take some time to implement. Visits by tuna fishermen should be prohibited. It has been recommended that the island be protected as a natural laboratory for scientific studies.

LAND USE Phosphate was worked from 1898 to 1917, but the island is now uninhabited although it is sometimes visited by U.S. tuna fishermen. Meteorological stations have occasionally been set up on the island. Access is difficult because of the heavy oceanic swell.

DISTURBANCES AND THREATS Coconuts were planted in 1897. Introduced pigs were destroyed in 1958 to prevent a decline in seabird populations. There is a possibility that a permanent meteorological and/or satellite observation post could be set up on the island. This would be likely to have a major effect on the atoll. There is also a proposal to open up the lagoon in order to build a port.

HYDROLOGICAL AND BIOPHYSICAL VALUES The closed lagoon is of particular interest as a model for modern formation and sedimentation of phosphate and carbonate diagensis. Apatite has been discovered in the intertidal modern deposits along the shore.

SOCIAL AND CULTURAL VALUES None known.

NOTEWORTHY FAUNA The lagoon supports an impoverished invertebrate fauna. Breeding seabirds include a frigatebird (Fregatasp.), two boobies (Sulaspp.), two noddies (Anousspp.) and two terns (Sternaspp.). Other fauna includes the lizard Emoia cyanuraand the crab Geocarcinus planatus/.

NOTEWORTHY FLORA No information.

SCIENTIFIC RESEARCH AND FACILITIES A number of scientific expeditions have visited the islands; these are listed by Sachet (1958) and UNEP/IUCN (1988). Studies of the invertebrate fauna of the lagoon are listed in UNEP/IUCN (1988).

MANAGEMENT AUTHORITY AND JURISDICTION The island is under the authority of the Governor of French Polynesia.

REFERENCES Sachet (1958); UNEP/IUCN (1988).

REASONS FOR INCLUSION 1a, 2b. Clipperton is one of the least altered island systems in the Pacific. The fauna and flora consist of an unusual assemblage including both Panamic (American) and Indo-Pacific forms.

SOURCE UNEP/IUCN (1988).