Danger Island, Great Chagos Bank

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Coordinates: 06°23′00″S71°14′20″E / 6.38333°S 71.23889°E / -6.38333; 71.23889 (Danger Island)

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Danger Island on the western rim of the Great Chagos bank Danger Island ISS006-E-23425.jpg
Danger Island on the western rim of the Great Chagos bank

Danger Island is the westernmost and the southernmost island of the Great Chagos Bank, which is the world's largest coral atoll structure, located in the Chagos Archipelago in the Indian Ocean.

Great Chagos Bank island group

The Great Chagos Bank, in the Chagos Archipelago, about 500 km (310 mi) south of the Maldives, is the largest atoll structure in the world, with a total area of 12,642 km2 (4,881 sq mi). The atoll is administered by the United Kingdom through the British Indian Ocean Territory (BIOT).

Atoll Ring-shaped coral reef, generally formed over a subsiding oceanic volcano, with a central lagoon and perhaps islands around the rim

An atoll, sometimes called a coral atoll, is a ring-shaped coral reef including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. The coral of the atoll often sits atop the rim of an extinct seamount or volcano which has eroded or subsided partially beneath the water. The lagoon forms over the volcanic crater or caldera while the higher rim remains above water or at shallow depths that permit the coral to grow and form the reefs. For the atoll to persist, continued erosion or subsidence must be at a rate slow enough to permit reef growth upward and outward to replace the lost height.

Chagos Archipelago Archipelago in the Indian Ocean

The Chagos Archipelago or Chagos Islands are a group of seven atolls comprising more than 60 individual tropical islands in the Indian Ocean about 500 kilometres (310 mi) south of the Maldives archipelago. This chain of islands is the southernmost archipelago of the Chagos-Laccadive Ridge, a long submarine mountain range in the Indian Ocean.

Description

It is a 2 km (1.24 m) long and flat island with a maximum width of 400 m (1,312 ft), covered with tall coconut trees. Its name in all likelihood derives from the lack of a safe anchorage, which rendered every visit to this island dangerous for the ship and crew. [1] The closest land is Sea Cow Island, the southernmost of the Eagle Islands which lies 16 km (10 mi) to the NNE. [2]

Sea Cow Island

Sea Cow Island, also known as Île Vache Marine, is a round 18 ha island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory. It was named after the dugongs that were once abundant in the area, although they have since become regionally extinct. It is the smaller of the two islands in the Eagle Islands group on the western side of the atoll and forms part of the Chagos Archipelago strict nature reserve. It has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for brown noddies, of which 11,500 pairs were recorded in a 2004 survey.

Eagle Islands island group

Eagle Islands is a group of two islands in the Chagos Archipelago. They are located on the central-western rim of the Great Chagos Bank, which is the world's largest coral atoll structure.

History

There was never a permanent settlement on Danger Island, even at the time that the Chagos were inhabited (between the mid-18th and mid-20th centuries). However, occasionally plantation workers from other islands would be brought to this island to collect coconuts.

Plaque commemorating the Joint Services 1975 expedition to Danger Island Danger Island commemorative plaque.jpg
Plaque commemorating the Joint Services 1975 expedition to Danger Island

In 1975 there was an expedition to Danger Island by the Joint Services (JSDI). The expedition members were taken by RFA Resurgent to Eagle Islands and then by ketch and inflatable craft to Danger Island and to Three Brothers. The expedition made a topographical survey of the coral reef, an ecological survey of the corals on it and a study on the metabolism of the reef. [3] A reference collection of samples of the flora and fauna of the area was also undertaken. [4]

Ketch type of sailing boat

A ketch is a two-masted sailboat whose mainmast is taller than the mizzen mast, generally 40-foot or bigger. The name ketch is derived from catch. The ketch's main mast is usually stepped in the same position as a sloop.

Following the Strict Nature Reserves Regulations issued on 18 September 1998, Danger Island, including its territorial waters and the reef surrounding, became a Strict Nature Reserve. [5] [6]

Danger Island has also been identified as an Important Bird Area by BirdLife International. Birds for which the island is of conservation significance include red-footed boobies (3,500 breeding pairs) and brown noddies (11,000 pairs). [7]

Important Bird Area area recognized as being globally important habitat for the conservation of birds populations

An Important Bird and Biodiversity Area (IBA) is an area identified using an internationally agreed set of criteria as being globally important for the conservation of bird populations.

BirdLife International global partnership of conservation organisations that strives to conserve birds

BirdLife International is a global partnership of conservation organisations that strives to conserve birds, their habitats, and global biodiversity, working with people towards sustainability in the use of natural resources. It is the world's largest partnership of conservation organisations, with over 120 partner organisations.

Red-footed booby species of bird

The red-footed booby is a large seabird of the booby family, Sulidae. Adults always have red feet, but the colour of the plumage varies. They are powerful and agile fliers, but they are clumsy in takeoffs and landings. They are found widely in the tropics, and breed colonially in coastal regions, especially islands. The species faces few natural or man-made threats, although its population is declining it is considered to be a least-concern species by the International Union for Conservation of Nature (IUCN).

The 2012 Chagos Trust expedition landed on the island with some difficulty: it was necessary to swim from an inflatable offshore, and due to the strong undertow, not all were able to land. Those who got ashore reported good tree cover including hardwood trees, especially Pisonia, and a healthy bird community. In the water they explored a shallow bank of seagrass, hoping, but without success, to find dugongs. [8] The 2015 expedition visited the island, landing by the same method but with less difficulty, and reported red-footed and brown Boobys and two species of crab: ghost and sally lightfoot. They also reported turtle tracks and nest, and, in the water, good fish populations and some coral recovery following widespread coral death the previous year. [9] [10]

Related Research Articles

Diego Garcia British atoll in the Indian Ocean

Diego Garcia is an island of the British Indian Ocean Territory, an overseas territory of the United Kingdom. It is a militarised atoll just south of the equator in the central Indian Ocean, and the largest of 60 small islands comprising the Chagos Archipelago. It was first discovered by Europeans and named by the Portuguese, settled by the French in the 1790s and transferred to British rule after the Napoleonic Wars. It was one of the "Dependencies" of the British Colony of Mauritius until the Chagos Islands were detached for inclusion in the newly created British Indian Ocean Territory (BIOT) in 1965.

RFA <i>Gold Ranger</i> (A130)

RFA Gold Ranger (A130) was a fleet support tanker of the Royal Fleet Auxiliary which first served in World War II.

Peros Banhos archipelago

Peros Banhos, Pedro dos Banhos or Baixos de Pêro dos Banhos in old maps, is a formerly inhabited atoll in the Chagos Archipelago of the British Indian Ocean Territory. Île Yeye, located at the northeastern corner of the atoll, is the island of the Chagos Archipelago that is closest to the Maldives.

Geography of the British Indian Ocean Territory

The British Indian Ocean Territory (BIOT) is an archipelago of 55 islands in the Indian Ocean, located south of India. It is situated approximately halfway between Africa and Indonesia. The islands form a semicircular group with an open sea towards the east. The largest, Diego Garcia, is located at the southern extreme end. It measures 60 square kilometres (23 sq mi) and accounts for almost three-quarters of the total land area of the territory. Diego Garcia is the only inhabited island and is home to the joint UK-US naval support facility. Other islands within the archipelago include Danger Island, Three Brothers Islands, Nelson Island, and Peros Banhos, as well as the island groups of the Egmont Islands, Eagle Islands, and the Salomon Islands.

Salomon Islands island group

The Salomon Islands or Salomon Atoll is a small atoll of the Chagos Archipelago, British Indian Ocean Territory.

Three Brothers, Chagos island group

The Three Brothers are a group of three small coral islands 20 kilometres east of Eagle Islands along the central western rim of the Great Chagos Bank, which is the world's largest coral atoll structure, located in the Chagos Archipelago.

Egmont Islands Archipelago

The Egan Islands or Egan Atoll, also known as Six Iles, is an uninhabited atoll administered by the United Kingdom. They are one of the few emerged coral atolls that make up the Chagos Archipelago, British Indian Ocean Territory.

Nelsons Island island

Nelson Island or Nelsons Island or Legour Island is the northernmost and the easternmost island of the Great Chagos Bank, which is the world's largest coral atoll structure, located in the Chagos Archipelago in the Indian Ocean. The nearest neighbour is Île Boddam in the Salomon Islands.

Blenheim Reef island group

Blenheim Reef is a partly submerged atoll structure in the Chagos Archipelago, Indian Ocean. It includes the coral reef of Baxio Predassa in its southeastern rim, plus another completely submerged part. It is located in the northeastern part of the Chagos Archipelago. It measures almost eleven kilometres (north–south) by more than four kilometres (east–west), with a total area of 36.8 square kilometres, including the lagoon of 8.5 km², the difference being accounted for the mostly by the reef flat. Only on the eastern side, there are a few sand cays above the water. The largest of them is East Island, which is not quite 200 metres long and 70 metres wide. The other islands in the group are North, Middle and South. Only a few grasses grow on the island. The lagoon is up to 18 metres deep and encumbered with rock. The fringing coral reef has a wide passage in the southwest. The closest land is Takamaka Island in the Salomon Islands Atoll, about 20 kilometres to the southwest.

Benares Shoals mountain in Seychelles

Benares Shoals, or Benares Shoal, is a submerged coral reef, an isolated patch located at 5°15′S071°40′E, just 6 kilometres (3.7 mi) west-northwest of Île Pierre, the closest island of Peros Banhos atoll in the northern Chagos Archipelago. It measures about 3 kilometres (2 mi) east–west, with a width of about 700 metres (2,300 ft) and an area of 2 square kilometres (0.77 sq mi). The least depth at the western end is 4.5 metres (15 ft).

Wildlife of Maldives

The wildlife of Maldives includes the flora and fauna of the islands, reefs, and the surrounding ocean.

North Brother (Chagos Bank)

North Brother, also known as Île du Nord, is a round 6 ha coral island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory. It is one of the three islands in the Three Brothers group on the western side of the atoll, and forms part of the Chagos Archipelago strict nature reserve. It has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for 20,000 seabirds, notably Audubon's shearwaters of which 420 pairs were recorded in a 2004 survey.

Middle Brother (Chagos Bank) island in the British Indian Ocean Territory

Middle Brother, also known as Île du Milieu, is an 8-hectare coral island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory. It is one of the three islands in the Three Brothers group on the western side of the atoll, and forms part of the Chagos Archipelago strict nature reserve. It has been identified as an Important Bird Area by BirdLife International for its significance as a breeding site for seabirds, notably sooty terns, of which 12,500 pair were recorded in a 2004 survey.

South Brother (Chagos Bank) Coral island

South Brother, also known as Île du Sud, is a 23 ha coral island on the Great Chagos Bank atoll of the Chagos Archipelago in the British Indian Ocean Territory. It is one of the three islands in the Three Brothers group on the western side of the atoll, and forms part of the Chagos Archipelago strict nature reserve. It has been identified as an Important Bird Area by BirdLife International because of its significance as a breeding site for seabirds, including brown noddies and lesser noddies.

The Chagos Marine Protected Area, located in the central Indian Ocean in the British Indian Ocean Territory of the United Kingdom, is one of the world's largest marine protected areas, and one of the largest protected areas of any type on Earth. It was established by the British government on 1 April 2010 as a massive, contiguous, no-take marine reserve, it encompasses 640,000 square kilometres (250,000 sq mi) of ocean waters, including roughly 70 small islands and seven atolls of the Chagos Archipelago.

The geology of the British Indian Ocean Territory comprises the Chagos Archipelago—the above water portion of the Chagos Bank. Formed from hotspot volcanism, the Chagos Bank was separated from the Nazareth Bank, which is administered by Mauritius, 36 million years ago by activity on the Central Indian Ridge. Aside from plate boundaries, the region is one of the most seismically active and earthquakes have caused subsidence of some islands.

References

  1. Indian Ocean Pilot
  2. British Admiralty nautical chart 11000030 - 3 Chagos Archipelago, Scale 1:360 000
  3. Baldwin, EA (ed.) (1975), A report on the Joint Services Expedition to Danger Island in the central Indian Ocean, December 1974 to April 1975 Ministry of Defence Publication, London
  4. "Zoology collections - Natural History Museum". www.nhm.ac.uk.
  5. "Terrestrial Protected Areas". British Indian Ocean Territory. Retrieved 26 August 2018.
  6. "6: British Indian Ocean Territory" (PDF).
  7. "Danger Island, Chagos Bank". Important Bird Areas factsheet. BirdLife International. 2012. Archived from the original on 2007-07-10. Retrieved 2012-10-21.
  8. "February 2012 Expedition - Day 14 - Danger Island - Chagos Conservation Trust". chagos-trust.org.
  9. "2015 Darwin Science Expedition - Day 23 - Danger Island Coral Gardens and Rubble Beds - Chagos Conservation Trust". chagos-trust.org.
  10. "BIOT MPA Survey Expedition 2015 - Day 1 - Danger Island - Chagos Conservation Trust". chagos-trust.org.