Lake Tanganyika (Kirundi: Ikiyaga ca Tanganyika) is an African Great Lake, renowned for its impressive characteristics and biodiversity. It is shared among four countries-Tanzania, the Democratic Republic of the Congo (the DRC), Burundi, and Zambia-with Tanzania (46%) and the DRC (40%) possessing the majority of the lake.
Lake Tanganyika from space, June 1985
Key Facts About Lake Tanganyika
- It is the world's second-largest freshwater lake by volume.
- It is the second deepest lake in the world, after Lake Baikal in Siberia.
- It is the world's longest freshwater lake.
- It is the 6th largest lake by area.
Lake Tanganyika stores 4,500 cubic miles of water, covering an area of 12,700 square miles. The deepest point in the lake is 4,820 feet, and it averages a depth of 1,870 feet. The only lake greater than Lake Tanganyika is Lake Baikal in Siberia.
The lake is extremely clear, allowing you to see beneath the surface up to 20 metres. Somewhat remarkably, the temperature of Lake Tanganyika is uniform with the lower regions of the lake only a mere 3°C colder than the surface.
Geography and Hydrography
Lake Tanganyika is situated within the Albertine Rift, the western branch of the East African Rift, and is confined by the mountainous walls of the valley. It extends for 676 km (420 mi) in a general north-south direction and averages 50 km (31 mi) in width. The lake covers 32,000 km2 (12,000 sq mi), with a shoreline of 1,900 km (1,200 mi), a mean depth of 572 m (1,877 ft) and a maximum depth of 1,471 m (4,826 ft) (in the northern basin). The catchment area of the lake is 231,000 km2 (89,000 sq mi).
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Two main rivers flow into the lake, as well as numerous smaller rivers and streams. The one major outflow is the Lukuga River, which empties into the Congo River drainage. Precipitation and evaporation play a greater role than the rivers. The most important rivers that flow into the lake are the Malagarasi River (475 kilometers or 295 miles), the Ruzizi River (117 kilometers or 73 miles in length), and the Kalambo River.
The Kalambo River has the second highest waterfall in Africa, the Kalambo Falls (215 meters or 704 feet high).
The lake has a complex history of changing flow patterns, due to its high altitude, great depth, slow rate of refill, and mountainous location in a turbulently volcanic area that has undergone climate changes. Apparently, it has rarely in the past had an outflow to the sea. It has been described as "practically endorheic" for this reason.
The 3 Main Basins
Lake Tanganyika has 3 basins. The Kigoma basin in the North reaches a depth of 1,310 meters. It is separated by the middle basin by a broad sill that reaches a depth of 655 meters. The middle basin is separated by the Kipili basin in the South by another sill 700 meters in depth.
The lake is stratified and seasonal mixing generally does not extend beyond depths of 150 m (490 ft). The mixing mainly occurs as upwellings in the south and is wind-driven, but to a lesser extent, up- and downwellings also occur elsewhere in the lake. As a consequence of the stratification, the deep sections contain "fossil water". This also means it has no oxygen (it is anoxic) in the deeper parts, essentially limiting fish and other aerobic organisms to the upper part.
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Cichlids of Lake Tanganyika National Geographic
Flora and Fauna
Lake Tanganyika is home to at least 250 endemic species of cichlids, and undescribed species likely remain to be discovered. Almost all (roughly 98%) of the lake's cichlid species are found solely there, and nowhere else, thus making it a precious biological resource for the study of speciation and evolution. The cichlids of the African Great Lakes, including Tanganyika, represent the most diverse extent of adaptive radiation in vertebrates.
Tropheus moorii Kasanga
The open waters of the pelagic zone are dominated by four non-cichlid species: Two species of "Tanganyika sardine" (Limnothrissa miodon and Stolothrissa tanganicae) form the largest biomass of fish in this zone, and they are important prey for the forktail lates (Lates microlepis) and sleek lates (L. stappersii). Two additional lates are found in the lake, the Tanganyika lates (L. angustifrons) and bigeye lates (L.
A total of 83 freshwater snail species (65 endemic) and 11 bivalve species (8 endemic) are known from the lake. Among the endemic bivalves are three monotypic genera: Grandidieria burtoni, Pseudospatha tanganyicensis and Brazzaea anceyi. Many of the snails are unusual for species living in freshwater in having noticeably thickened shells and/or distinct sculpture, features more commonly seen in marine snails. They are referred to as thalassoids, which can be translated to "marine-like".
History and Exploration
This great African lake was first brought to the world’s attention in the mid 1800s by two English explorers named Richard Burton and John Speke. Their exploration was in pursuit of the source of the River Nile, arriving at the shores of Lake Tanganyika in February 1858. They eventually discovered that the Ruzizi River in the north, which they thought at the time to be the Nile, flowed into and not out of the lake.
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During World War I, several naval engagements were made between the British and Germans on the lake. The intention was to secure control of Lake Tanganyika, as it offered strategic importance.
Lake Tanganyika map
Economic Significance
Lake Tanganyika supports a major fishery, which provides 25-40% or c. 1 million people living around the lake are greatly dependent on the lake fish for protein. Fish from Lake Tanganyika is exported throughout the entire East Africa. The middle of the 1950s marked the beginning of commercial fishing on the lake, which had a great impact on pelagic fish species.
The lake is also an important trade route between riparian countries.
Ecological Concerns
Action must be taken in order to preserve the beauty of the lake, and its role as a source of life. Overfishing, combined with the use of destructive fishing gears, threaten to deplete the fish stocks in the lake.
Lake Tanganyika: Key Facts
| Feature | Data |
|---|---|
| Max. length | 673 km (418 mi) |
| Max. width | 72 km (45 mi) |
| Surface area | 32,900 km2 (12,700 sq mi) |
| Average depth | 570 m (1,870 ft) |
| Max. depth | 1,471 m (4,826 ft) |
| Basin countries | Burundi, DR Congo, Tanzania, and Zambia |
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