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 km,² 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.
* 1 Overview
* 2 Fauna
* 3 References
* 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
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
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) long,
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
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.
* ^ A B
* ^ 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 and note.
* ^ 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
* ^ 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):
* ^ "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