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Lake Alaotra (Malagasy: farihin' Alaotra, [faˈrihin ˈaloʈʂə̥]; French: Lac Alaotra) is the largest lake in Madagascar, located in Alaotra-Mangoro Region and on the island's northern central plateau. Its basin is composed of shallow freshwater lakes and marshes surrounded by areas of dense vegetation.[3] It forms the center of the island's most important rice-growing region. It is a rich habitat for wildlife, including some rare and endangered species, as well as an important fishing ground. Lake Alaotra and its surrounding wetlands cover 7,223 square kilometres (2,789 sq mi), and include a range of habitats, including open water, reedbeds, marshes, and rice paddies. The lake itself covers 900 km2 (350 sq mi). Lake Alaotra was declared a wetland of international importance under the international Ramsar Convention on February 2, 2003.

Lake Alaotra
Lac Alaotra
seen from space
Lake Alaotra
Lac Alaotra
LocationMadagascar
Coordinates17.5°S 48.5°E / -17.5; 48.5
Primary inflowsAmbato River
Primary outflowsManingory River
Basin countriesMadagascar
Surface area900 km2 (350 sq mi)
Average depth0.60 m (2 ft 0 in)
Max. depth1.5 m (4 ft 11 in)
Water volumeapp. 0.945 km3 (0.227 cu mi)
Surface elevation750 m (2,460 ft)[1]
Ramsar Wetland
Official nameLe Lac Alaotra: Les Zones Humides et Bassins Versants
Designated9 September 2003
Reference no.1312[2]

The longfin tilapia (Oreochromis macrochir) was introduced into Lake Alaotra from the mainland in 1954 and proliferated quickly. By 1957, it provided 46% of the catch, perhaps because it was moving into an empty ecological niche as a phytophagous species.[4]

The fertile plain surrounding Lake Alaotra is Madagascar's most important rice-producing region. The hills surrounding the lake were formerly forested but have mostly been cleared for farmland in past decades. Severe erosion on these vulnerable hill slopes has caused considerable sedimentation of the lake, which is fast disappearing; the lake is now only 60 cm (24 in) deep during the dry season. Pressure to create more rice fields has also led locals to burn the reedbeds surrounding the lake. These reedbeds provide the sole habitat of the endemic Alaotra gentle lemur (Hapalemur griseus alaotrensis). The Alaotra gentle lemur is now limited to only 220 km2 (85 sq mi) of remaining reedbeds, and in recent years, its population rapidly declined by 60%, from about 7,500 individuals in 1994 to 3,000 in 2001, mostly from habitat loss, but also from hunting by local villagers.

The lake is the type locality of the butterfly Artitropa alaotrana and an important but increasingly threatened habitat for waterbirds, including the endangered Meller's duck (Anas melleri). Two waterbird species were endemic to northern Madagascar, the Madagascar pochard (Aythya innotata) and the Alaotra grebe (Tachybaptus rufolavatus). The Madagascar pochard is now critically endangered and no longer found on the lake, although very small numbers exist elsewhere. The Alaotra grebe was declared extinct in 2010. The area of the lake may have been its only habitat.[5]

The Ambato River provides the lake with water and also drains it. After 381 km, the river flows into the Indian Ocean.


References


  1. R. Battistini, G. Richard-Vindard (1972). Biogeography and Ecology in Madagascar, pp. 268–270. ISBN 978-94-015-7161-6
  2. "Le Lac Alaotra: Les Zones Humides et Bassins Versants". Ramsar Sites Information Service. Retrieved 25 April 2018.
  3. "Aythya innotata - Range & Habitat". Archived from the original on 2007-09-30. Retrieved 2006-12-24.
  4. C. Lévêque (1997). Biodiversity dynamics and conservation: the freshwater fish of tropical Africa. Cambridge University Press. p. 322. ISBN 0-521-57033-6.
  5. Lake Alaotra at BirdLife International



На других языках


[de] Lac Alaotra

Der Alaotra-See (frz. Lac Alaotra) ist der größte See auf Madagaskar.
- [en] Lake Alaotra

[es] Lago Alaotra

El lago Alaotra (en francés: Lac Alaotra) es el lago más grande de Madagascar, ubicado en la provincia de Toamasina, en la meseta central septentrional, al noroeste de Tamatave. Su cuenca está compuesta por lagos de agua dulce de poca profundidad y pantanos rodeados por densas áreas de vegetación.[1] Forma el centro de la más importante región de cultivo de arroz. Es un hábitat rico en fauna salvaje, algunas especies raras y en peligro, así como un importante territorio para pesca. El lago Alaotra y los humedales que lo rodean abarcan 7.225 km², e incluyen una diversidad de hábitats, incluyendo agua abierta, cañaverales, pantanos y arrozales. El lago en sí tiene una extensión de 900 km². El lago Alaotra fue declarado un sitio Ramsar como humedal de importancia internacional basándose en la convención de Ramsar el 2 de febrero de 2003.

[fr] Lac Alaotra

Le lac Alaotra est un lac de Madagascar situé dans la province de Tamatave (région Alaotra-Mangoro). À une altitude de 750 m, sa surface totale est de 43 000 ha dont 23 000 ha constitués de marais. Cette surface varie selon les saisons.

[it] Lago Alaotra

Il lago Alaotra è il maggiore lago del Madagascar.

[ru] Алаутра

Ала́утра[4][5] (Алаотра[6], малаг. Farihin' Alaotra[7]) — большое, но неглубокое озеро на востоке Мадагаскара. Крупнейшее на острове[1].



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