Clipperton Island

Lore & Background

Clipperton was documented by French merchant-explorers in 1711 and formally claimed as part of the French protectorate of Tahiti in 1858. Despite this, American guano miners began working the island in the early 1890s. Mexico asserted a claim based on Spanish records from the 1520s and established a small military colony in 1905. During the Mexican Revolution, contact became infrequent, most colonists died, and lighthouse keeper Victoriano Álvarez instituted a short, brutal reign as 'king' of the island. Eleven survivors were rescued in 1917 and Clipperton was abandoned.

The dispute between Mexico and France was taken to binding international arbitration in 1909. Victor Emmanuel III, King of Italy, was chosen as arbitrator and decided in 1931 that the island was French territory. Despite the ruling, Clipperton remained largely uninhabited until 1944 when the U.S. Navy established a weather station; France protested, and the U.S. abandoned the site in late 1945. Since World War II, the island has primarily been a site for scientific expeditions studying wildlife and marine life, including significant masked and brown booby colonies, as well as climate science and amateur radio DX-peditions.

Reader's Guide

Clipperton Island's significance lies in its unique geography and history. It is the only coral island in the eastern Pacific and the only emerged part of the East Pacific Rise. The atoll completely encloses a stagnant freshwater lagoon that is devoid of fish, with a meromictic lake formed approximately 170 years ago when the lagoon closed off from the sea. The lagoon's water is almost fresh at the surface and highly eutrophic, with deep basins containing acidic, sulfur-rich water that prevents coral growth. The island's environment has been studied extensively, with expeditions such as SURPACLIP in 1997, the French Passion 2001 expedition, and a 2005 mission making a complete inventory of species. A 2008 expedition collected sediment cores to study climate change. The island hosts millions of isopods and unique dinoflagellate species, including Peridiniopsis cristata var. tubulifera, found only there. Despite plans for trade and tourism, the island remains mostly uninhabited, with periodic visits from the French Navy.

Did You Know?

• The lagoon is devoid of fish and has a spot known as Trou Sans Fond ('the bottomless hole') with acidic water at its base.
• The lagoon contains a unique dinoflagellate species, Peridiniopsis cristata var. tubulifera, found only on Clipperton.