Lake Victoria, or Victoria Nyanza (nēăn´zə, nī–), largest lake of Africa and the world's second largest freshwater lake, c.26,830 sq mi (69,490 sq km), E central Africa, on the Uganda-Tanzania-Kenya border. Lake Victoria (c.255 mi/410 km long and c.155 mi/250 km wide) occupies a shallow depression (c.250 ft/75 m deep) on the Equatorial Plateau (alt. 3,725 ft/1,135 m) between two arms of the Great Rift Valley. It has an irregular shoreline and many small islands. Numerous streams, including the Kagera River, feed Lake Victoria, which is one of the chief headwater reservoirs of the Nile; the Victoria Nile drains the lake to the north. At the Nalubaale (Owen Falls) and Kiira dams on the Victoria Nile the lake's waters are used to generate hydroelectricity. The lake basin is densely populated and intensely cultivated, and the lake is an important fishery, but fish stocks and diversity have declined since the 1980s as a result of overfishing and the introduction of the Nile perch. Control of the Migingo Islands and the surrounding fishing grounds has been a contentious issue between Uganda and Kenya in recent years. The lake has also suffered uncontrolled water hyacinth proliferation. Ships regularly call at lakeside towns, including Entebbe, Mwanza, Bukoba, and Kisumu. The first European to see Lake Victoria (originally called Ukerewe) was John Speke, the British explorer, in 1858; Henry Stanley explored the region in 1875.