Introduction to Clipperton Island
Clipperton Island, alternatively known as Clipperton Atoll and earlier as Clipperton’s Rock, is a 8.9 km² (3.4 sq mi) uninhabited French coral atoll located in the eastern Pacific Ocean. This is the sole French territory situated in the North Pacific. The distance from Paris, France to Clipperton Island is 10,675 km (6,633 mi). Papeete, French Polynesia, is 5,400 km (2,900 nmi) away while Acapulco, Mexico, is 1,280 km (690 nmi) distant.
Clipperton was first recorded by French merchant-explorers in 1711, and it was later considered as part of the French protectorate of Tahiti in 1858. Nonetheless, American guano miners started exploiting the island in the early 1890s. With increasing attention paid to the island, Mexico then staked its claim over the island in accordance with Spanish records from the 1520s that could describe the island.
In 1905, a small military colony was established by Mexico on the island, but during the Mexican Revolution, it became very rarely contacted with the mainland, most colonists died there, and the lighthouse keeper Victoriano Álvarez made an extremely short but brutal reign of “king” of the island. Eleven people survived and were rescued in 1917, after which Clipperton was deserted.
The dispute between Mexico and France over Clipperton was taken to binding international arbitration in 1909. Victor Emmanuel III, King of Italy, was appointed as the arbitrator and ruled in 1931 that the island belonged to France. However, until 1944, Clipperton remained largely uninhabited. In that year, the U.S. Navy established a weather station on the island to support its war efforts in the Pacific. France protested, and as concerns about Japanese activity in the eastern Pacific waned, the U.S. abandoned the site in late 1945.
Since the end of World War II, Clipperton has mainly been a destination for scientific expeditions to study the wildlife and marine life on the island, such as its major masked and brown booby colonies. Climate scientists and amateur radio DX-peditions have also visited the island. Development plans for the island to establish trade and tourism have been floated, but nothing has been implemented, and the island is still largely uninhabited except for periodic visits by the French navy.
Location
The coral island is situated at 10°18′N 109°13′W in the East Pacific, 1,080 km (583 nmi) southwest of Mexico, 2,424 km (1,309 nmi) west of Nicaragua, 2,545 km (1,374 nmi) west of Costa Rica, and 2,390 km (1,290 nmi) northwest of the Galápagos Islands in Ecuador. The nearest land is Socorro Island, about 945 km (510 nmi) to the northwest in the Revillagigedo Archipelago. The nearest French-owned island is Hiva Oa in the Marquesas Islands of French Polynesia.
Despite being geographically close to North America, Clipperton is sometimes considered one of the easternmost points of Oceania, especially because it is part of the French Indo-Pacific and shares a similar marine fauna with Hawaii and Kiribati’s Line Islands. The island is on the migration route for animals in the Eastern Tropical Pacific region. Clipperton is the only emerged portion of the East Pacific Rise and the only feature in the Clipperton fracture zone that breaks the ocean’s surface. Also, it is among the few islands in the Pacific that lack an underwater archipelagic apron.
The atoll is low-lying and largely barren, with some scattered grasses and a few clumps of coconut palms (Cocos nucifera). The land ring around the lagoon has an area of 1.7 square kilometers (0.66 sq mi) and an average elevation of 2 meters (6.6 ft).
Rising 29 metres (95 ft) on the southeast side is a small volcanic outcropping called Clipperton Rock (Rocher de Clipperton). It sits on the edge of a 3.7-square-kilometer (1.4 sq mi) reef that’s brimming with corals, partially exposed at low tide. In 2001, a geodetic marker was installed to check whether the land is rising or sinking.
Clipperton Rock forms the remains of the rim of the island’s now extinct volcano. This rock outcropping makes Clipperton not strictly a true atoll but rather a ‘near-atoll.’ The surrounding reef, together with the weather, renders landing on the island extremely problematic and anchoring offshore extremely risky for larger vessels. This fact has posed issues for American vessels since the 1940s.
Environment
Extensive study has been made on the environment of Clipperton Island. Recordings and sample collections first occurred in the 1800s. Recent studies in Clipperton Island have mostly revolved around climate science and migrating wildlife.
In 1997, the SURPACLIP oceanographic expedition, jointly conducted by the National Autonomous University of Mexico and the University of New Caledonia Nouméa, did extensive researches on the island. In 2001, French National Centre for Scientific Research geographer Christian Jost further carried out the studies of 1997 through the French Passion 2001 expedition, which dealt with the evolution of the ecosystem of Clipperton. In 2003, cinematographer Lance Milbrand spent 41 days on the island and documented the adventure for National Geographic Explorer. He also prepared an entire high-resolution GPS map of Clipperton for the National Geographic Society.
In 2005, Jean-Louis Étienne, an explorer, held a four-month scientific mission for the inventory of mineral, plant, and animal species. During this expedition, the researchers examined algae down to 100 meters (328 feet) deep and observed pollution. In 2008, sediment cores from the lagoon were taken by an expedition team from the School of Oceanography at the University of Washington for the analysis of climate change during the past millennium.
Lagoon
Clipperton is an atoll which is ring shaped and encloses a stagnant fresh water lagoon, measuring 12 km or 7.5 mi around, covering approximately 720 hectares or 2.8 square miles. The island is coral in the east Pacific. The lagoon is fish-less and shallow on most of its expanse, apart from some basins that plunge to depths as great as 43 to 72 meters (141 to 236 feet); there is an area called ‘Trou Sans Fond’ (‘the bottomless hole’), whose very bottom is characterized by acidic waters.
The waters are almost fresh at the top and highly eutrophic in nature. Beds of seaweeds cover as much as about 45 percent of the area of the lagoon. The rim of the atoll has an average width of 150 meters (490 feet), although it reaches up to 400 meters (1,300 feet) in the west and reduces to 45 meters (148 feet) on the northeast, where sea waves occasionally spill over into the lagoon. There are ten islets in the lagoon. Six of these are covered with vegetation, one of which includes the Egg Islands (les îles aux Œufs).
The lagoon was closed about 170 years ago, preventing seawater from entering, and a meromictic lake has formed. The bottom of the shallow parts of the lake is made up of eroded coral heads from when the lagoon was last connected to the ocean. On visits in 1897 and 1898, the depth at the center of the lagoon was recorded to be between two inches and two feet due to dead coral. The surface of the lagoon has a high concentration of phytoplankton, which vary slightly with the seasons.
As a result, the water columns are stratified and do not mix, and the lagoon remains with an oxic and brackish upper water layer and a deep sulfuric anoxic saline layer. At a depth of about 15 meters (49 feet), the water shifts, with salinity rising and both pH and oxygen levels quickly decreasing.
The deepest levels of the lagoon contain waters enriched with hydrogen sulfide, which prevents coral growth. Before the lagoon was sealed off from seawater, the environment was hospitable to coral and clams, and fossilized specimens of these objects can be found.
Studies of the water have found that microbial communities on the surface of the water are similar to other water samples around the world with deeper water samples showing a great diversity of both bacteria and archaea.
In 2005, a group of French scientists identified three dinoflagellate microalgae species in the lagoon: an abundant one known as Peridiniopsis cristata; Durinskia baltica, known to exist in previous times and locations but it was the first time it was seen on Clipperton; and Peridiniopsis cristata var. tubulifera, found nowhere else but at the island. Other than that, millions of isopods inhabit the lagoon and are said to cause painful stings.
Although some references have graded the lagoon water as not drinkable,[59] testimony from the crew of the tuna clipper M/V Monarch, stranded for 23 days in 1962 after their boat sank, shows otherwise. Their report shows that lagoon water, although “muddy and dirty,” was drinkable, although it did not taste very good.
Several of the castaways drank it, with no apparent ill effects.[60] Survivors of a Mexican military colony in 1917 (see below) indicated that they were dependent upon rain for their water supply, catching it in old boats.[60] American servicemen on the island during World War II had to use evaporators to purify the lagoon’s water.[32] Aside from the lagoon and water caught from rain, no freshwater sources are known to exist.
Climate
The island has a tropical oceanic climate; however, the average temperature ranges from 20–32 °C (68–90 °F), and the maximum can reach 37.8 °C (100.0 °F). The annual rainfall is about 3,000 to 5,000 millimetres (120 to 200 in) with the humidity level held mostly between 85 per cent and 95 per cent, and December to March happens to be the drier months. The southeast trade winds are the prevailing winds.
The rainy season takes place between May and October, and from April to September, tropical cyclones sometimes impact the region; however, such storms very frequently pass to the northeast of Clipperton. In 1997 Clipperton was in the path of the start of Hurricane Felicia, as well as Hurricane Sandra in 2015. Moreover, Clipperton has been exposed to several tropical storms and depressions, such as Tropical Storm Andres in 2003. Surrounding ocean waters are warm, pushed by equatorial and counter-equatorial currents and have seen temperature increases due to global warming.
Flora and fauna
In 1898, when Snodgrass and Heller visited the island, they mentioned ‘no land plant is native to the island.’ The recorded history was low grassy or suffrutescent (partially woody) flora dating back to the years 1711, 1825, and 1839. In 1958, Marie-Hélène Sachet reported that the vegetation presents a sparse cover of spiny grass and low thickets, a creeping plant (Ipomoea spp.), and stands of coconut palm. This low-lying herbaceous flora appears to be a pioneer in nature, and most of it is thought to be an introduced species.
Sachet suspected that Heliotropium curassavicum, and perhaps also Portulaca oleracea were originally native. Coconut palms and pigs introduced by guano miners in the 1890s were still extant in the 1940s. The largest coconut grove is Bougainville Wood (Bois de Bougainville) on the southwestern end of the island.
On the northwest side of the atoll, the most common plant species are Cenchrus echinatus, Sida rhombifolia, and Corchorus aestuans. These plants form a shrub cover up to 30 cm (12 in) in height, and are intermixed with Eclipta, Phyllanthus, and Solanum, as well as the taller Brassica juncea.
The islets in the lagoon are mainly vegetated with Cyperaceae, Scrophulariaceae, and Ipomoea pes-caprae. A peculiar characteristic of Clipperton is that its vegetation occurs as parallel rows of species, with dense rows of taller species alternating with the lower, open vegetation. The assumption here had been that such an arrangement had resulted from a trench-digging method employed by phosphate-gathering guano hunters.
The only land animals known to exist are two species of reptiles (the Pacific stump-toed gecko and the copper-tailed skink), bright-orange land crabs known as Clipperton crabs (Johngarthia oceanica, prior to 2019 classified as Johngartia planata), birds, and ship rats. The rats probably arrived when large fishing boats wrecked on the island in 1999 and 2000.
The pigs introduced in the 1890s reduced the crab population, which in turn allowed grassland to gradually cover about 80 per cent of the land surface. The elimination of these pigs in 1958, the result of a personal project by Kenneth E. Stager, caused most of this vegetation to disappear as the population of land crabs recovered. As a result, Clipperton is mostly a sandy desert with only 674 palms counted by Christian Jost during the Passion 2001 French mission and five islets in the lagoon with grass that the terrestrial crabs cannot reach.
A 2005 report by the National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center indicated that after the introduction of rats and their increased presence has led to a decline in both crab and bird populations, causing a corresponding increase in both vegetation and coconut palms. This report urgently recommended eradication of rats, which have been destroying bird nesting sites and the crab population, so that vegetation might be reduced, and the island might return to its ‘pre-human’ state.
In 1825, Benjamin Morrell reported finding green sea turtles nesting on Clipperton, but later expeditions have not found nesting turtles there, possibly due to disruption from guano extraction, as well as the introduction of pigs and rats. Sea turtles found on the island appear to have been injured due to fishing practices.[84] Morrell also reported fur and elephant seals on the island in 1825, but they too have not been recorded by later expeditions.
Birds are common on the island; Morrell noted in 1825: ‘The whole island is literally covered with sea-birds, such as gulls, whale-birds, gannets, and the booby.’ Thirteen species of birds are known to breed on the island and 26 others have been observed as visitors.
The island has been identified as an Important Bird Area by BirdLife International because of the large breeding colony of masked boobies, with 110,000 individual birds recorded. Observed bird species include white terns, masked boobies, sooty terns, brown boobies, brown noddies, black noddies, great frigatebirds, coots, martins (swallows), cuckoos, and yellow warblers. Ducks and moorhens have been reported in the lagoon.
The coral reef on the north side of the island includes colonies more than 2 metres (6.6 ft) high. The 2018 Tara Pacific expedition located five colonies of Millepora platyphylla at depths of 28–32 metres (92–105 ft), the first of this fire coral species known in the region. Among the Porites spp. stony corals, some bleaching was observed, along with other indications of disease or stress, including parasitic worms and microalgae.
The reefs that surround Clipperton have some of the highest concentration of endemic species found anywhere with more than 115 species identified. Many species are recorded in the area, including five or six endemics, such as Clipperton angelfish (Holacanthus limbaughi), Clipperton grouper (Epinephelus clippertonensis), Clipperton damselfish (Stegastes baldwini) and Robertson’s wrasse (Thalassoma robertsoni).
Widespread species around the reefs include Pacific creolefish, blue-and-gold snapper, and various species of goatfish. In the water column, trevallies are predominant, including black jacks, bigeye trevally, and bluefin trevally. Also common around Clipperton are black triggerfish, several species of groupers, including leather bass and starry groupers; Mexican hogfish; whitecheek, convict, and striped-fin surgeonfish; yellow longnose and blacknosed butterflyfish; coral hawkfish; golden pufferfish; Moorish idols; parrotfish; and moray eels, especially speckled moray eels. The waters around the island are an important nursery for sharks, particularly the white tip shark. Galapagos sharks, reef sharks, whale sharks, and hammerhead sharks are also present around Clipperton.
Three expeditions to Clipperton have collected sponge specimens, including U.S. President Franklin Roosevelt’s visit in 1938. Of the 190 specimens collected, 20 species were noted, including nine found only at Clipperton. One of the endemic sponges, collected during the 1938 visit, was named Callyspongia roosevelti in honor of Roosevelt.
In April 2009, Steven Robinson, a tropical fish dealer from Hayward, California, traveled to Clipperton to collect Clipperton angelfish. Upon his return to the United States, he described the 52 illegally collected fish to federal wildlife authorities as king angelfish, not the rarer Clipperton angelfish, which he intended to sell for $10,000. On 15 December 2011, Robinson was sentenced to 45 days of incarceration, one year of probation, and a $2,000 fine.
Environmental threats
During the night of 10 February 2010, the Sichem Osprey, a Maltese chemical tanker, ran aground en route from the Panama Canal to South Korea. The 170 m (558 ft) ship contained 10,513 metric tons (11,589 short tons) of xylene, 6,005 metric tons (6,619 short tons) of soybean oil, and 6,000 metric tons (6,600 short tons) of tallow. All 19 crew members were reported safe, and the vessel reported no leaks. The vessel was re-floated on 6 March and returned to service.
In mid-March 2012, the crew from the Clipperton Project noted the widespread presence of refuse, particularly on the northeast shore, and around the Clipperton Rock. Debris, including plastic bottles and containers, create a potentially harmful environment for the island’s flora and fauna. This trash is common to only two beaches (northeast and southwest), and the rest of the island is fairly clean. Other refuse has been left after the occupations by Americans 1944–1945, French 1966–1969, and the 2008 scientific expedition.
During a 2015 scientific and amateur radio expedition to Clipperton, the operating team discovered a package that contained 1.2 kilograms (2.6 lb) of cocaine. It is suspected that the package washed up after being discarded at sea. In April 2023, the Passion 23 mission by France’s Armed Forces in the Antilles and the surveillance frigate Germinal collected more than 200 kilograms (440 lb) of plastic waste from the island’s beaches along with a bale of cocaine.
The Sea Around Us Project estimates the Clipperton EEZ produces a harvest of 50,000 metric tons (55,000 short tons) of fish per year; however, because French naval patrols in the area are infrequent, this includes a significant amount of illegal fishing, along with lobster harvesting and shark finning, resulting in estimated losses for France of €0.42 per kilogram of fish caught.
As deep-sea mining of polymetallic nodules increases in the adjacent Clarion–Clipperton zone, similar mining activity within France’s exclusive economic zone surrounding the atoll may have an impact on marine life around Clipperton. Polymetallic nodules were discovered in the Clipperton EEZ during the Passion 2015 expedition.
The past
Discovery and early claims
There are several claims to the first discovery of the island. The earliest recorded possible sighting is 24 January 1521 when Portuguese-born Spanish explorer Ferdinand Magellan discovered an island he named San Pablo after turning westward away from the American mainland during his circumnavigation of the globe.
On 15 November 1528, Spaniard Álvaro de Saavedra Cerón discovered an island he called Isla Médanos in the region while on an expedition commissioned by his cousin, the Spanish conquistador Hernán Cortés, to find a route to the Philippines.
Although both San Pablo and Isla Médanos are considered to be possible sightings of Clipperton, the island was first charted by French merchant Michel Dubocage, commanding La Découverte, who arrived at the island on Good Friday, 3 April 1711; he was joined the following day by fellow ship captain Martin de Chassiron and La Princesse. The island was given the name Île de la Passion (‘Passion Island’) as the date of rediscovery fell within Passiontide. They drew up the first map of the island and claimed it for France.
In August 1825, American sea captain Benjamin Morrell made the first recorded landing on Clipperton, exploring the island and making a detailed report of its vegetation.
The common name for the island comes from John Clipperton, an English pirate and privateer who fought the Spanish during the early 18th century, and who is said to have passed by the island. Some sources claim that he used it as a base for his raids on shipping.
19th century
Mexican claim 1821–1858
After its declaration of independence in 1821, Mexico took possession of the lands that had once belonged to Spain. As Spanish records noted the existence of the island as early as 1528, the territory was incorporated into Mexico. The Mexican constitution of 1917 explicitly includes the island, using the Spanish name La Pasión, as Mexican territory. This would be amended on January 18, 1934, after the sovereignty dispute over the island was settled in favor of France.
El territorio nacional comprende el de las partes integrantes de la Federación y además el de las islas adyacentes en ambos mares. Comprende, asimismo, la isla de Guadalupe, las de Revillagigedo y la de la Pasión, situadas en el océano Pacífico.
The national territory includes that of the integral parts of the Federation and also that of the adjacent islands in both seas. It also includes the island of Guadalupe, Revillagigedo and La Pasión, located in the Pacific Ocean.
— Mexican Constitution of 1917
French claim (1858)
In April 1858, French minister Eugène Rouher reached an agreement with a Mr. Lockhard of Le Havre to claim oceanic islands in the Pacific for the exploitation of guano deposits. On 17 November 1858, Emperor Napoleon III formally annexed Clipperton as part of the French protectorate of Tahiti. Sailing aboard Lockhart’s ship Amiral, Ship-of-the-line Lieutenant Victor Le Coat de Kervéguen published a notice of this annexation in Hawaiian newspapers to further cement France’s claim to the island.
Guano mining claims (1892–1905)
In 1892, a claim on the island was filed with the U.S. State Department under the U.S. Guano Islands Act by Frederick W. Permien of San Francisco on behalf of the Stonington Phosphate Company. In 1893, Permien transferred those rights to a new company, the Oceanic Phosphate Company. In response to the application, the State Department rejected the claim, noting France’s prior claim on the island and that the claim was not bonded as was required by law. Additionally during this time there were concerns in Mexico that the British or Americans would lay claim to the island.
Despite the lack of U.S. approval of its claim, the Oceanic Phosphate Company began mining guano on the island in 1895. Although the company had plans for as many as 200 workers on the island, at its peak only 25 men were stationed there. The company shipped its guano to Honolulu and San Francisco where it sold for between US$10 and US$20 per ton. In 1897, the Oceanic Phosphate Company began negotiations with the British Pacific Islands Company to transfer its interest in Clipperton; this drew the attention of both French and Mexican officials.
On 24 November 1897, French naval authorities arrived on the Duguay Trouin and found three Americans working on the island. The French ordered the American flag to be lowered. At that time, U.S. authorities assured the French that they did not intend to assert American sovereignty over the island.
Weeks later, in December 13, 1897, Mexico sent the gunboat La Demócrata and a force of marines to assert its claim on the island, evicted the Americans, hoisted the Mexican flag, and drew an indignant protest from France. From 1898 to 1905, the Pacific Islands Company operated the Clipperton guano deposits under a concession agreement with Mexico. Mexico had laid a US$1.5 million claim in 1898 against the Oceanic Phosphate Company for guano shipped from the island between 1895 and 1897.
20th century
Mexican colonization (1905–1917)
In 1905, the Mexican government renegotiated its agreement with the British Pacific Islands Company, establishing a military garrison on the island a year later and erecting a lighthouse under the orders of Mexican President Porfirio Díaz. Captain Ramón Arnaud was appointed governor of Clipperton. At first, he did not want to accept the post considering it an exile from Mexico, but with the assurances that Díaz had chosen him personally to safeguard Mexican interests in the international tussle with France, he agreed. Also because Arnaud could speak English, French, and Spanish, it was said he would quite easily help to keep the territory in Mexico’s hands. He arrived on Clipperton as governor later that year.
By 1914 around 100 men, women, and children lived on the island, resupplied every two months by a ship from Acapulco. With the escalation of fighting in the Mexican Revolution, regular resupply visits ceased, and the inhabitants were left to their own devices.
The schooner Nokomis ran aground on Clipperton on 28 February 1914; with a still-seaworthy lifeboat, four crew members volunteered to row to Acapulco for assistance. Months later, the USS Cleveland came to rescue the crew. During that stay, the captain offered to take the survivors of the colony back to Acapulco; Arnaud refused thinking a resupply ship would soon arrive.
By 1917, all but one of the male inhabitants had died. Many had succumbed to scurvy, and others, including Arnaud, died attempting to sail after a passing ship to fetch help. Lighthouse keeper Victoriano Álvarez was the last man on the island, along with 15 women and children. Álvarez declared himself ‘king’, and launched a spree of rape and murder, before being assassinated by Tirza Rendón, his favorite victim. Just a few days after Álvarez was killed, four women and seven children, the last survivors, were taken aboard the U.S. Navy gunboat Yorktown on 18 July 1917.
Amateur radio DX-peditions
Clipperton has been a magnet for amateur radio groups over the years, considering its remoteness, permit requirements, history, and interesting environment. Other visits to the island included some radio operation, but major DX-peditions include FO0XB (1978), FO0XX (1985), FO0CI (1992), FO0AAA (2000), TX5C (2008), and TX5S (2024).
In March 2014, the Cordell Expedition, organized and led by Robert Schmieder, combined a radio DX-pedition using callsign TX5K with environmental and scientific investigations. The team of 24 radio operators made over 114,000 contacts, breaking the previous record of 75,000. The activity included extensive operation in the 6-meter band, including Earth–Moon–Earth communication (EME) or ‘moonbounce’ contacts.
The first DXA, a real-time satellite-based online graphic radio log web page, was also established. Any person with a browser could then view the radio activity. Scientific work done during the expedition included the first collection and identification of foraminifera and extensive aerial imaging of the island using kite-borne cameras. Two scientists from the University of Tahiti and a French TV documentary crew from Thalassa were part of the team.
In April 2015, Alain Duchauchoy, F6BFH operated from Clipperton using the callsign TX5P as part of the scientific expedition Passion 2015 on Clipperton Island. Research by Duchauchoy formed part of this expedition into early 1900s Mexican usage of the island.
