Question: Lake Tana and Lake Sary-Chelek, are natural lakes?
Context: The Lake Tana Biosphere Reserve is located in the Amhara National Regional State approximately 563 km northwest of Addis Ababa in the north-western part of Ethiopia.  The biosphere reserve comprises Lake Tana, the largest lake in Ethiopia, the main source of the Blue Nile, which provides important ecosystem services.  The area is a hotspot of biodiversity, internationally known as an Important Bird Area and is of global importance for agricultural genetic diversity.  The area is characterized by an enormous heterogeneity of land uses and natural ecosystems. Sary-Chelek (also Sarychelek, Kyrgyz: Сарычелек) is a mountain lake located in Sary-Chelek Nature Reserve in Jalal-Abad Province in Western Kyrgyzstan.  It is north of Arkit (the park headquarters) at the eastern end of the Chatkal Range.  There are a number of smaller lakes in the area. Lake Tana (also spelled T'ana, Amharic: , "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. This is a list of natural lakes and reservoirs located fully or partially in the U.S. state of Washington.  Natural lakes that have been altered with a dam, such as Lake Chelan, are included as lakes, not reservoirs. Ura Kidane Mehret is a church of the Ethiopian Orthodox Church, located on the Zege peninsula in Lake Tana of Ethiopia.  It is part of the complex of the Convent of Mercy.  At least one author considers it the most attractive church in the Lake Tana region. Tana Qirqos (variantly spelled Tana Kirkos; also called Tana Chirqos or Tana Chirkos, etc.; Ge'ez: ጣና ቂርቆስ "ṭānā ḳīrḳōs", ጣና ጪርቆስ "ṭānā č̣īrḳōs") is an island in the eastern part of Lake Tana in Ethiopia, near the mouth of the Gumara River, having a latitude and longitude of .  It is considered a holy island, and only monks of the Ethiopian Church live there. Natural lakes in Bosnia and Herzegovina take 67.5 km², which is a little more than 0.12% of the total surface area of Bosnia and Herzegovina.  Buško Blato is the largest lake, its size being 56.7 km².  Blidinje lake is the largest natural mountain lake in Bosnia and Herzegovina, with surface area varying between 2.5 and 6 km², and Buško Blato lake with its size of 56.7 km² is the biggest artificial accumulation in Bosnia and Herzegovina; however it is forgotten that this lake was made from accumulation of water from the Buško Blato marshland, earlier natural slough and morass system.  The total size of all lakes is 1/10 as large as the world average.  Because of this, natural lakes in Bosnia and Herzegovina are not economically important. Bahir Dar Zuria (Amharic "Greater Bahir Dar Area") is one of the woredas in the Amhara Region of Ethiopia.  Part of the Mirab Gojjam Zone, this woreda is bordered on the south by Yilmana Densa, on the southwest by Mecha, on the northwest by the Lesser Abay River which separates it from Semien Achefer, on the north by Lake Tana, on the shores of Lake Tana situates the city and special zone of Bahir Dar, and on the east by the Abay River which separates it from the Debub Gondar Zone. Dengel Ber is a town in western Ethiopia.  Located on the south-western shore of Lake Tana in the Semien Gondar Zone of the Amhara Region, this town has a latitude and longitude of .  Access to this town includes track roads to both Shawra and Kunzela and weekly service by the Bahir Dar-Gorgora ferry on Lake Tana.  While the name of the town is indisputably Amharic, there is some disagreement over the meaning of its name: while "Pass of the Virgin" has been the most common interpretation since at least the days James Bruce visited Ethiopia, Huntingford and Beckingham state that it means "pass of "canna" plants". Zege Peninsula is located on the southern shore of Lake Tana in Ethiopia, and is situated at (11° 40’ to 11° 43’ N and 37 °19’ to 37 °21’ E).  It is 600 km northwest of Addis Ababa, the capital city of Ethiopia.  Lake Tana is the largest lake in Ethiopia, and is the source of the Blue Nile river.  Zege peninsula is attached to dry land on its western part.  As a place name, the word "zege" signifies a peninsula that encloses two rural qebele, the former monastery and Zägé town at the gate of the main land of the peninsula.  At present, Zegé is part of Bahir Dar city administration, and is 32 km from the main town, the capital of Amhara National Regional State.  The origin of the term "zegié" is somewhat obscure.  Informants from Ura Kidane miheret monastic church, one of the earliest church in the peninsula associated the term to Debra Zegag and Abba Nahom; where as some monks who were servants of Mähal Zegié Giyorgis attributed the term to Zengie (my shaft) and to Abun Betre Maryam, founder of Zegie monastery.  Still another church scholar, Aleqa Aynakulu Mersha, related the term to a name of a tribe called Zegie (Aleqa Aynekulu) 1955 E.C:466; Tadese Tamrat, 1994:954-959).  On the peninsula of Zege there are six Monastic churches, all established between the 14th and 17th centuries.
Answer: yes