Ichaboe Island is a small rocky island off

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

's Diamond Coast. It is recognised by

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding ...

as an

Important Bird Area 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. IBA was developed and sites are identified by BirdLife Int ...

(IBAs) for its seabird breeding colonies.

Geography

There are twelve small islands on the Namibian coast between

Walvis Bay Walvis Bay ( en, lit. Whale Bay; af, Walvisbaai; ger, Walfischbucht or Walfischbai) is a city in Namibia and the name of the bay on which it lies. It is the second largest city in Namibia and the largest coastal city in the country. The c ...

and

Orange River The Orange River (from Afrikaans/Dutch: ''Oranjerivier'') is a river in Southern Africa. It is the longest river in South Africa. With a total length of , the Orange River Basin extends from Lesotho into South Africa and Namibia to the north ...

. Due to the Benguela Current, the seas on the west coast of southern Africa are some of the most productive in the world. The current flows north from the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...

and offshore winds drive the surface water away from the coast. Water rises from depths of hundreds of metres and at speeds of up to 12 m per minute bringing nutrients to the surface. A combination of sunlight and nutrients provide the conditions for

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Ph ...

which are the foundation for other life in the Benguela marine ecosystem. Feeding on the phytoplankton are

Zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

, which attract an abundance of shoaling

pelagic fish Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that do live on or near the bottom, and reef fish that are associated with coral reef ...

and is the reason why southern Africa is home to one of the richest seabird communities in the world. The islands off the west coast of southern Africa provide refuge from predators and

Cape gannet The Cape gannet (''Morus capensis'') is a large seabird of the gannet family, Sulidae. They are easily identified by their large size, black and white plumage and distinctive yellow crown and hindneck. The pale blue bill is pointed with fine ...

(''Morus capensis'') and

Cape cormorant The Cape cormorant or Cape shag (''Phalacrocorax capensis'') is a bird endemic to the southwestern coasts of Africa. It breeds from Namibia south to southern Western Cape. In the nonbreeding season, it may be found as far north as the mouth of t ...

s (''Phalacrocorax capensis'') are the region's most abundant seabirds with tens of thousands on the islands during the nesting season. The birds' guano also provide nutrients that flow back into the surrounding sea when large waves hit the island or when it rains. The guano enriches the rocky shore with carpets of seaweed grazed by goat's-eye limpets, which are predated by spiny starfish. Ichaboe Island is a 6.5 ha low-lying island, approximately 1.5 km off the Diamond Coast of Namibia and 48 km north of

Lüderitz Lüderitz is a town in the ǁKaras Region of southern Namibia. It lies on one of the least hospitable coasts in Africa. It is a port developed around Robert Harbour and Shark Island. The town is known for its colonial architecture, includi ...

. On the western side of the island is a reef which affords some protection from Atlantic waves, although sea spay covers the island during storms. The island was once covered in over 7 m of bird-droppings (

guano Guano (Spanish from qu, wanu) is the accumulated excrement of seabirds or bats. As a manure, guano is a highly effective fertilizer due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. G ...

), which was quarried in the 19th and 20th-centuries for sale as

manure Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the fertility of soil by adding organic matter and nutri ...

. The rocky ground is now entirely exposed and the eastern side has some sandy areas. Annual rainfall is less than 10 mm and coastal fog is frequent. Bird Life International recognizes Ichaboe Island along with other islands such as

Mercury Island :''not to be confused with the Mercury Islands of New Zealand'' Mercury Island is a small rocky island off The Diamond Coast, Namibia. Despite its small size it is recognised by BirdLife International and other global conservation groups as an I ...

and the nearby coast as an Important Bird Area for their seabird colonies.

History

In the early 19th-century Ichaboe and other islands of the South African coast witnessed the guano equivalent of the American gold rush. The island was once used for sealing and following a visit in 1828 by Captain Benjamin Morrell and the discovery of bird manure to depths of more than 7 m, the focus turned to the quarrying of guano. At one time more than 400 ships anchored off the island and shanty towns housed thousands of workers. Large-scale scraping and bagging of ′white gold′ began in 1843 and peaked two years later. The value was so great that competition was fierce, murder was committed over harvesting rights, and two British warships were despatched to restore order over what became known as the ′Great Guano War′. Britain took procession of the island on 21 June 1861. Guano has been taken off the island regularly, and for example in 1880 and 1881, Ichaboe Guano was claimed to be the ″richest and most fertilising guano imported into England″ containing 12 to 13%

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

and 27 to 30% guano

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phospho ...

s. The island was administered by the Cape Provincial Administration of South Africa and became a nature reserves in 1987. The islands were returned to Namibia in 1994 and are managed by the Ministry of Fisheries and Marine Resources (MFMR). Ichaboe, along with Mercury and Possession Islands, have permanent residents who partake in research and conservation of the seabirds. Scraping of guano continues with concessions granted during the 1980s and in 2000 a wall was put up around the perimeter of the island. The wall was built to prevent winds blowing the guano into the sea and has a few entry points for penguins’ to access the breeding areas.

Fauna

Ichaboe regularly supports over 50,000 seabirds of at least eight species and is consequently one of the most important and densely packed seabird breeding islands in the world. The island holds 65% of the world's

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

(''Phalacrocorax capensis''), despite the global population falling from 9,000 to less than 5,000 pairs over twenty years. Namibia has c. 4,000 pairs all told. The island is the most important location in the world for the

near-threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...

, crowned cormorant (''Phalacrocorax coronatus''), having 4% of the world's breeding population. Ichaboe also has large numbers of endangered

African penguin The African penguin (''Spheniscus demersus''), also known as Cape penguin or South African penguin, is a species of penguin confined to southern African waters. Like all extant penguins, it is flightless, with a streamlined body and wings stiff ...

(''Spheniscus demersus'') and the

bank cormorant The bank cormorant (''Phalacrocorax neglectus''), also known as Wahlberg's cormorant, is a medium-sized cormorant that is endemic to Namibia and the western seaboard of South Africa, living in and around coastal waters; it is rarely recorded mor ...

(''Phalacrocorax neglectus''), as well as the vulnerable

(''Morus capensis''). Smaller numbers of

kelp gull The kelp gull (''Larus dominicanus''), also known as the Dominican gull, is a gull that breeds on coasts and islands through much of the Southern Hemisphere. The nominate ''L. d. dominicanus'' is the subspecies found around South America, par ...

(''Larus dominicanus'') and

African oystercatcher The African oystercatcher or African black oystercatcher (''Haematopus moquini''), is a large charismatic wader resident to the mainland coasts and offshore islands of southern Africa. This near-threatened oystercatcher has a population of over ...

(''Haematopus moquini'') also breed. Thousands of

common tern The common tern (''Sterna hirundo'') is a seabird in the family Laridae. This bird has a circumpolar distribution, its four subspecies breeding in temperate and subarctic regions of Europe, Asia and North America. It is strongly migratory ...

(''Sterna hirundo'') and

black tern The black tern (''Chlidonias niger'') is a small tern generally found in or near inland water in Europe, Western Asia and North America. As its name suggests, it has predominantly dark plumage. In some lights it can appear blue in the breeding se ...

(''Chlidonias niger'') may roost on the island. Whales sighted off the island include the

humpback whale The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hump ...

(''Megaptera novaeangliae'') and

southern right whale The southern right whale (''Eubalaena australis'') is a baleen whale, one of three species classified as right whales belonging to the genus ''Eubalaena''. Southern right whales inhabit oceans south of the Equator, between the latitudes of 20 ...

(''Eubalaena australis''). The cetaceans include,

dusky dolphin The dusky dolphin (''Lagenorhynchus obscurus'') is a dolphin found in coastal waters in the Southern Hemisphere. Its specific epithet is Latin for "dark" or "dim". It is very closely genetically related to the Pacific white-sided dolphin, but ...

(''Lagenorhynchus obscurus''),

common bottlenose dolphin The common bottlenose dolphin or Atlantic bottlenose dolphin (''Tursiops truncatus'') is a wide-ranging marine mammal of the family Delphinidae. The common bottlenose dolphin is a very familiar dolphin due to the wide exposure it gets in captivi ...

(''Tursiops truncatus'') and the

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Heaviside's dolphin Heaviside's dolphin (''Cephalorhynchus heavisidii'') is one of four dolphins in the genus ''Cephalorhynchus''. The small cetacean is endemic to the Benguela ecosystem along the southwest coast of Africa. Taxonomy and evolution Nomenclature E ...

(''Cephalorhynchus heavisidii'').

References

{{Authority control Nature conservation in Namibia Geography of ǁKaras Region Guano trade Important Bird Areas of Namibia Islands of Namibia Lüderitz