7/21/11

Lake Victoria

Lake Victoria is the seventh largest freshwater lake in world by volume and is situated on a high plateau between the Western and Eastern African Rift Valleys; 1,134 m above sea level. Lake Victoria is a part of tree nations: Kenya, Uganda and Tanzania and the lake is locally known as Victoria Nyanza as well. With its 68,870 square kilometres of surface area it is the largest lake on the African continent, the largest tropical lake in the world and the second largest freshwater lake on the planet in terms of surface area (only Lake Superior in North America is larger). From north to south, Lake Victoria stretches 337 kilometres and from east to west it is more than 240 kilometres wide. The lake has over 3200 kilometres of coastline that is filled with smaller and larger fisheries. Over 3,000 larger and smaller islands are found in Lake Victoria, such as the 84 Ssese Islands in Uganda which are popular tourist destinations. Lake Victoria is a comparatively shallow lake and reaches no further than 82 m and you can find numerous reefs located just below the surface. The outlet of Lake Victoria is called Victoria Nile and is situated to the north. This is the source of the White Nile, the longest branch of the Nile River. To the south, Lake Victoria is bordered by 90 m high cliffs, beyond which you will find the papyrus and ambatch swamps that forms the Kagera River delta. The Kagera River is one of the largest contributors of water to Lake Victoria and empties it self into the west side of the lake. One other main contributor is the Katonga River which is located north of the Kagera River. There are also many other smaller inlets from the surrounding region. 

Lake Victoria is famous for its abundance of fish and plays an imperative role in providing food for the millions that inhabit the region. It is today one of the most densely populated areas in the world and this has of course had a tremendous impact on the ecosystem. Several cities have been built right at the coast and many of the islands are also heavily populated. Pollution and over-fishing is not the only problems for Lake Victoria; the introduction of new species also poses a strong threat to the delicate natural balance. During the 1950 the large Nile Perch, Lates niloticus, was deliberately established in Lake Victoria since it is considered a good food source. The vigorous Nile Perch loved its new environment and managed to wipe out many endemic fish species. This caused disturbances in the whole ecosystem. Initially the fishermen experienced very good catches of Nile Perch, but the species is today over fished and the population has lessened significantly. In a way, this over fishing is not only bad since the over fishing of Nile Perch has caused several endemic species that were on the brink of extinction to increase their numbers. 

The first known records that mention this large African lake were made by Arab traders that were exploring the region in their search for gold, ivory and human slaves. The famous Al Adrisi map from the 1160s features an accurate picture of Lake Victoria and its surrounding tributaries. It also correctly depicts Lake Victoria as the source of the River Nile. The first Europeans to reach Lake Victoria were British explorers lead by John Hanning Speke in 1858. He was a part of an expedition searching for the source of the River Nile, since that would be important strategic knowledge for the British Colonial administration. John Hanning Speke decided to name the lake “Victoria” after the queen of the United Kingdom. One other prominent member of the expedition was Richard Francis Burton, but he was recovering from an illness and resting close to Lake Tanganyika when John Hanning Speke reached Lake Victoria. When Speke claimed the discovery for him self, Burton became outraged and a long lasting public quarrel commenced. One of the explorers who sat out to control the correctness of Speke's discovery was a certain Dr. Livingstone, later to be followed by Henry Morton Stanley.
time: 2:47 PM
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