Misplaced Pages

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19-579: It is one of the largest natural ports on the Atlantic coast of Africa and the only one in Mauritania. It is limited by the Cap Blanc (also known as Ras Nouadhibou ) headland on its western side. The bay opens towards the south and contains numerous shoals and extends from north to south for about 50 km, creating a bay about 43 km long and 32 km wide at the widest point. In French maps

38-442: A PVA is arrived at after repeating the environmental simulation thousands of times . Small populations are at a greater risk of extinction than larger populations due to small populations having less capacity to recover from adverse stochastic (i.e. random) events. Such events may be divided into four sources: MVP does not take external intervention into account. Thus, it is useful for conservation managers and environmentalists;

57-456: A colony structure. In the summer of 1997, two-thirds of its seal population were wiped out within two months, extremely compromising the species' viable population . While opinions on the precise causes of this epidemic remain divided (possible causes being a morbilivirus or a toxic algae bloom , ) the mass die-off emphasized the precarious status of a species already regarded as critically endangered throughout its range. While still far below

76-666: A minimum viable population (MVP) will depend on the population projection model used. A set of random (stochastic) projections might be used to estimate the initial population size needed (based on the assumptions in the model) for there to be, (for example) a 95% or 99% probability of survival 1,000 years into the future. Some models use generations as a unit of time rather than years in order to maintain consistency between taxa . These projections ( population viability analyses , or PVA) use computer simulations to model populations using demographic and environmental information to project future population dynamics . The probability assigned to

95-501: A population may be increased above the MVP using a captive breeding program or by bringing other members of the species in from other reserves. There is naturally some debate on the accuracy of PVAs, since a wide variety of assumptions are generally required for forecasting; however, the important consideration is not absolute accuracy but the promulgation of the concept that each species indeed has an MVP, which at least can be approximated for

114-413: A railway which runs 650 km from the mines to the port. The Bay of Nouadhibou is the final resting place of over 300 ships and one of the world's largest ship graveyards. This Mauritania location article is a stub . You can help Misplaced Pages by expanding it . Ras Nouadhibou Ras Nouadhibou ( Arabic : رأس نواذيبو ) is a 60-kilometre (37 mi) peninsula or headland divided by

133-487: Is defined as a group of interbreeding individuals in similar geographic area that undergo negligible gene flow with other groups of the species. Typically, MVP is used to refer to a wild population, but can also be used for ex situ conservation (Zoo populations). There is no unique definition of what constitutes a sufficient population for the continuation of a species, because whether a species survives will depend to some extent on random events. Thus, any calculation of

152-521: The São Tomé and Príncipe islands. These fishing activities have had a negative impact on wildlife and caused the disappearance or endangerment of many species of marine mammals and birds. The Spanish originally claimed the land from 20° 51' N (near Cap Blanc) to 26° 8' N (near Cape Bojador ) in 1885. This protectorate was governed from the Canary Islands in 1887. France would later claim

171-631: The border between Mauritania and Western Sahara on the African coast of the Atlantic Ocean . It is internationally known as Cabo Blanco in Spanish or Cap Blanc in French (both meaning "White Headland"). The headland forms the western limit of Dakhlet Nouadhibou Bay. It is divided between Mauritania and Western Sahara . On the western side lies the ghost town of La Güera ; on

190-611: The Atlantic Ocean along with the island of Gyaros in the eastern Mediterranean are the only places in the world where Mediterranean monk seals preserve the structure of a colony. In 1997, two-thirds of the colony died off, but there has been gradual recovery since. The Mediterranean monk seal 's ( Monachus monachus ) former range extended throughout the Northwest Atlantic Africa, Mediterranean and Black Sea , coastlines, including all offshore islands of

209-650: The Mediterranean, and into the Atlantic and its islands: Canary, Madeira , Ilhas Desertas , Porto Santo , as far west as the Azores . Vagrants could be found as far south as Gambia and the Cape Verde islands, and as far north as continental Portugal and Atlantic France. Today, the cape hosts the largest surviving single population of the species, and the only remaining site which still seems to preserve

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228-581: The Western Sahara. At a joint convention held in 1900, the French and Spanish settled the boundary, dividing the area between Spanish Sahara and French West Africa . Today, the same border separates Western Sahara from Mauritania . However, the western side is currently policed by Mauritania, as neither Morocco nor the Polisario Front occupies the area. A lighthouse was constructed on

247-480: The bay, which has required frequent drainage of the navigation channels. The bay of Nouadhibou is the most important economic and commercial area of Mauritania. It is the base of the Mauritanian fishing industry, as well as the route by which the iron ore from the mines of Zouérat is exported from the country. The iron ore arrives at the ore terminal of Point Central (located 10 kilometers south of Nouadhibou) by

266-484: The cape in 1910. Viable population Minimum viable population ( MVP ) is a lower bound on the population of a species, such that it can survive in the wild. This term is commonly used in the fields of biology , ecology , and conservation biology . MVP refers to the smallest possible size at which a biological population can exist without facing extinction from natural disasters or demographic, environmental, or genetic stochasticity . The term " population "

285-584: The desert coast of the Sahara, resulted from fishing activities carried out from the Canary Islands by Spanish fishermen, who also hunted and traded seal. The Spanish fished and whaled off the Sahara coast from Dakhla to Ras Nouadhibou from 1500 to the present, ranging from whaling humpback whales and likely North Atlantic right whales and whale calves, mostly in Cape Verde , the Guinea gulf in Annobón , and

304-535: The early 1997 count, numbers in this all-important location have since started a gradual recovery. Currently, the population in this location is estimated at 270 individuals, down from some 310 in 1997, but still the largest single colony by far. The threat of a similar incident that could wipe out the entire population remains. Portuguese sailing explorers first reached the location they called Cabo Branco in 1441. The Spanish interest in Western Africa , in

323-676: The eastern side, less than 1 mile (1.6 km) from the border, lies Mauritania's Nouadhibou (formerly Port Etienne). Although it is not the westernmost point of Africa, due to the Earth's tilt it is at least twice a year the last place in Africa where the sun sets. The headland has been designated an Important Bird Area (IBA) by BirdLife International because it supports significant populations of wintering waterbirdss , including ruddy turnstones , slender-billed and lesser black-backed gulls , and Caspian and Sandwich terns . Cabo Blanco in

342-400: The inner bay is known as Baie de l'Archimède and the wider bay as Baie du Lévrier . In addition to its geographical conditions, the bay of Nouadhibou has very favourable maritime conditions, given the absence of significant currents. The weather conditions also favour its use as a port as it is sheltered from winds and storms. The only unfavourable factor is the shallow sea depth in most of

361-501: The sake of conservation biology and Biodiversity Action Plans . There is a marked trend for insularity , surviving genetic bottlenecks , and r-strategy to allow far lower MVPs than average. Conversely, taxa easily affected by inbreeding depression –having high MVPs – are often decidedly K-strategists , with low population densities occurring over a wide range. An MVP of 500 to 1,000 has often been given as an average for terrestrial vertebrates when inbreeding or genetic variability

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