Lake Tana (also spelled T'ana, Amharic: ጣና ሀይቅ, Ṭana
Ḥäyq, T’ana Hāyk’; an older variant is Tsana, Ge'ez: ጻና
Ṣānā; sometimes called "Dembiya" after the region to the north of
the lake) is the source of the
Blue Nile and is the largest lake in
Ethiopia. Located in
Amhara Region in the north-western Ethiopian
Highlands, the lake is approximately 84 kilometers long and 66
kilometers wide, with a maximum depth of 15 meters, and an
elevation of 1,788 meters.
Lake Tana is fed by the Lesser Abay, Reb
and Gumara rivers. Its surface area ranges from 3,000 to
3,500 km², depending on season and rainfall. The lake level has
been regulated since the construction of the control weir where the
lake discharges into the Blue Nile. This controls the flow to the Blue
Nile Falls (Tis Abbai) and hydro-power station.
In 2015, the
Lake Tana region was nominated as UNESCO Biosphere
Reserve recognizing its national and international natural and
4 External links
Lake Tana in Ethiopia.
The Island Church on Lake Tana.
A local tour guide demonstrates how a stone is struck to signal meal
times at a monastery on Zege Peninsula.
Beginning of the
Blue Nile river by its outlet from Lake Tana.
Lake Tana was formed by volcanic activity, blocking the course of
inflowing rivers in the early
Pleistocene epoch, about 5 million years
The lake was originally much larger than it is today. Seven large
permanent rivers feed the lake as well as 40 small seasonal rivers.
The main tributaries to the lake are Gilgel Abbay (Little Nile River),
and the Megech, Gumara, and Rib rivers.
A resort hotel on
Lake Tana in Bahir Dar.
Lake Tana has a number of islands, whose number varies depending on
the level of the lake. It has fallen about 6 feet (1.8 m) in the
last 400 years. According to
Manoel de Almeida (a Portuguese
missionary in the early 17th century), there were 21 islands, seven to
eight of which had monasteries on them "formerly large, but now much
James Bruce visited the area in the later 18th
century, he noted that the locals counted 45 inhabited islands, but
stated he believed that "the number may be about eleven." A
20th-century geographer named 37 islands, of which he believed 19 have
or had monasteries or churches on them. Remains of ancient
Ethiopian emperors and treasures of the Ethiopian Church are kept in
the isolated island monasteries (including Kebran Gabriel, Ura Kidane
Mehret, Narga Selassie, Daga Estifanos, Medhane Alem of Rema, Kota
Maryam, and Mertola Maryam). On the island of
Tana Qirqos is a rock
shown to Paul B. Henze, on which he was told the Virgin Mary had
rested on her journey back from Egypt; he was also told that
Frumentius, who introduced
Christianity to Ethiopia, is "allegedly
buried on Tana Cherqos." The body of
Yekuno Amlak is interred in
the monastery of St. Stephen on Daga Island. Emperors whose tombs are
also on Daga include Dawit I, Zara Yaqob, Za Dengel, and Fasilides.
Other important islands in
Lake Tana include Dek, Mitraha, Gelila
Zakarias, Halimun and Briguida. The monasteries are believed to have
been built over earlier religious sites. They include the
fourteenth-century Debre Maryam, and the eighteenth-century Narga
Tana Qirqos (said to have housed the Ark of the Covenant
before it was moved to Axum), and Ura Kidane Mehret, known for its
regalia. A ferry service links
Bahir Dar with
Gorgora via Dek Island
and various lakeshore villages.
There is also
Zege Peninsula on the southwest portion of the lake.
Zege is the site of the Azwa Maryam monastery.
Great white pelicans on Lake Tana.
Lily pads floating near the shore on Lake Tana
Since there are no inflows that link the lake to other large waterways
and the main outflow, the Blue Nile, is obstructed by the Blue Nile
Falls, the lake supports a highly distinctive fish fauna, which
generally is related to species from the Nile Basin. About 70% of
the fish species in the lake are endemic. This includes one of only
two known cyprinid species flocks (the other, from
Lake Lanao in the
Philippines, has been decimated by introduced species), which consists
of fifteen relatively large, up to 1 m (3 ft 3 in)
Labeobarbus barbs. Eight of these are piscivorous and an
important prey is the small
Barbus tanapelagius, another endemic of
the lake. (B. humilis and B. pleurogramma also occur in Lake Tana, but
neither is endemic.) Other noteworthy endemic species are
Afronemacheilus abyssinicus, which is one of only two African stone
loaches, and the tana subspecies of the Nile tilapia.
Lake Tana supports a large fishing industry, mainly based on the
Labeobarbus barbs (formerly in genus Barbus),
Nile tilapia and
sharptooth catfish (a large catfish that is widespread in Africa).
According to the Ethiopian Department of Fisheries and Aquaculture,
1,454 tons of fish are landed each year at Bahir Dar, which the
department estimates are 15% of its sustainable amount.
Among other fauna, the lake supports relatively few invertebrates:
There are fifteen species of molluscs, including one endemic, and also
an endemic freshwater sponge. Numerous wetland birds, such as the
great white pelican and African darter, reside at Lake Tana. It is an
important resting and feeding ground for many
waterbirds. There are no crocodiles, but the African softshell
turtle has been recorded near the
Blue Nile outflow from the lake.
^ Statistical Abstract of Ethiopia. 1967–68.
^ "Lake Tana, source of the Blue Nile". Observing the Earth. European
Space Agency. 5 November 2004. Retrieved 4 November 2013.
^ Homepage of
Lake Tana Biosphere Reserve
^ a b https://link.springer.com/chapter/10.1007%2F978-1-4020-9726-3_9
^ a b c C.F. Beckham and G.W.B. Huntingford, Some Records of Ethiopia,
1593-1646, (series 2, no. 107; London: Hakluyt Society, 1954), p. 35
^ Paul B. Henze, Layers of Time: A History of
Ethiopia (New York:
Palgrave, 2000), p.73.
^ a b c d e f Freshwater Ecoregions of the World (2008). Lake Tana.
Archived 2011-10-05 at the Wayback Machine. Accessed 24 January 2012
^ a b de Graaf, Dejen, Sibbing and Osse (2000).
Barbus tanapelagius, A
New Species from
Lake Tana (Ethiopia): its Morphology and Ecology.
Environmental Biology of Fishes 59 (1): 1-9
^ de Graaf, Megens, Samallo, Sibbing (2007). ",Evolutionary origin of
Lake Tana's (Ethiopia) small
Barbus species: indications of rapid
ecological divergence and speciation," Animal Biology 57(1): 39-48
^ "Information on Fisheries Management in the Federal Democratic
Republic of Ethiopia", Food and Agricultural Organization (FAO),
^ Largen and Spawls (2010). The Amphibians and Reptiles of Ethiopia
and Eritrea. ISBN 978-3-89973-466-9
Wikimedia Commons has media related to Lake Tana.
Lake Tana Biosphere Reserve
Lake Tana project webpage of The Nature and Biodiversity Conservation
Union (NABU e.V.)
Lake Tana project at Aberystwyth University
Photographs of the lake
Unesco plan for Lake T'ana
Lake Tana and the Monasteries