The Beauty of Lake Bunyonyi in Uganda and Lake Tanganyika in Burundi

Lake Bunyonyi lies in south western Uganda between Kisoro and Kabale close to the border with Rwanda. Located at 1,962 m above sea level, it is about 25 km long and 7 km wide. The depth of the lake is rumored to vary between 44 m and 900 m which if true would make the lake the second deepest in Africa.  Towns on its shores include Kyevu and Muko, while its 29 islands include Punishment Island and Bushara Island. It is a popular location for watersports and is known for the surrounding terraced hillsides. It is popular with both foreign and domestic tourists and there is a wide variety of tourist accommodation.

Its 29 islands are concentrated in the central part. These islands have few settlements; they are mostly used for tourist facilities and for a secondary and a primary school.

The temperature on the surface rises to 25 degrees Celsius. In the beginning of the 20th century, fish were introduced to the lake and in the 1930s fishing became profitable. Unfortunately in the 1960s the fish died massively as a result of a violent shallow mixing, likely caused by wind. Subsistence fishing prevailed in the lake, people mostly caught clarias species – the lake’s depth and stratification makes it difficult for the breeding of the common Ugandan species Nile Perch and Tilapia. Nevertheless, 300,000 Nile Tilapias and Clarias fish were released in the lake at the end of 2002. Also present in the lake are Mud fish, Cray fish and Mirrowcarp – and plenty of their predators, otters. The lake’s main center is Bufuka Village. The area’s inhabitants are from the Bakiga and the Batwa tribes.

Main islands

Punishment Island in Lake Bunyonyi

The Bakiga used to leave unmarried pregnant girls on this small island a lone to die of hunger or while trying to swim to the mainland. This was to educate the rest, to show them not to do the same. A man without cows to pay the bride wealth could go to the island and pick up a girl. The practice got abandoned in the first half of the 20th century. Although this practice has been abandoned, it is still possible to find women who were picked up from Punishment Island today.

Bushara Island

This island is the home of Lake Bunyonyi Development Company, an organization with strong links to Church of Uganda, the main church of the lake area. They use tourism to generate funds for several development projects around Bunyonyi. The island has many luxury tents, chalets, and also campsites for tourists to stay on. It is also possible to rent out canoes and sailboats with a view to paddling to one of the other islands.

The striking feature of the island is its forest, a demonstration of the most appealing attribute of the eucalyptus tree: an exceptionally fast growth rate. The hills around Bunyonyi used to feature many forests but overpopulation led to them being cut down to create land for agriculture needs.

Kyahugye Island

Kyahugye Island is the nearest to the mainland – a mere 5-minute boat ride away. It is surrounded by a 1-2m wide strip of reeds interspersed with papyrus. The Island has many tree species. The vegetation on the Island falls into four categories namely bush, open fallows, tree plantations and natural vegetation. The hilltop is flat and has been developed for tourists. There are chalets and campsites for accommodation, and a well-stocked bar and restaurant. From the top of the Island, there are spectacular views of the surrounding terraced hillsides, the calm waters of Lake Bunyonyi, and the neighboring Islands. On a clear day, Mt. Muhabura can be seen in the distance. Tourist activities like Nature walks, Birding walks, Dugout Canoe Treks, Community visits, Mountain Climbing, etc. can be organized. It is the only Island with wild animals which include the Impalas, Zebra, Water bucks, the Kobs and the only Debrasa Monkey. It also housed Lake Bunyonyi Eco Resort.

Bwama and Njuyeera (Sharp’s Island)

In 1921, an English missionary called Dr Leonard Sharp came to this part of Uganda and in 1931 established a leprosy treatment center on the then uninhabited Bwama island. A church, patient quarters (model villages) and a medical facility were built, while Sharp settled on Njuyeera Island (probably meaning ‘white cottage’, after the similarity of the doctor’s small white house to Sharp’s father’s house in Shanklin, now The White House Hotel). The rationale of the leprosy colony was that of ‘voluntary segregation’, where the provision of a happy community to live in would attract leprosy sufferers, so removing them from the communities where they might infect others. The buildings of the hospital are now used by a boarding secondary school which attracts students from the entire region. There is also a primary school but no village on the island.

Bucuranuka = Upside Down

People says that this island killed many people. About twenty were once brewing local sorghum beer there. An old woman was passing by and she said: “Can you give me some local beer?” They wrongly thought that she was a beggar they knew. They refused her: “Get lost, beggar! Get lost!!!” The old woman asked: “So you will not even give me a sip? Can I at least get somebody to take me to the mainland?” They answered: “Yes, because we are fed up with you!” They chose a young guy to take her over. When they reached the shore and the guy was just beginning to return, the island turned upside down. All died, only a chicken flew away and survived.

Lake Tanganyika

Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, in both cases, after only Lake Baikal in Siberia; it is also the world’s longest freshwater lake. The lake is divided among four countries – Tanzania, Democratic Republic of the Congo (DRC), Burundi, and Zambia, with Tanzania (46%) and DRC (40%) possessing the majority of the lake. The water flows into the Congo River system and ultimately into the Atlantic Ocean. The name apparently refers to “Tanganyika, ‘the great lake spreading out like a plain.

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 is the largest rift lake in Africa and the second largest lake by volume in the world. It is the deepest lake in Africa and holds the greatest volume of fresh water, accounting for 18% of the world’s available fresh water.

The enormous depth and tropical location of the lake can prevent ‘turnover’ of water masses, which means that much of the lower depths of the lake are so-called ‘fossil water’ and are anoxic (lacking oxygen).  Two main rivers flow into the lake, as well as numerous smaller rivers and streams (whose lengths are limited by the steep mountains around the lake). There is one major outflow, the Lukuga River, which empties into the Congo River drainage.

The major river flowing into the lake is the Ruzizi River, formed about 10,000 years ago, which enters the north of the lake from Lake Kivu. The Malagarasi River, which is Tanzania’s second largest river, enters the east side of Lake Tanganyika. The Malagarasi is older than Lake Tanganyika and, before the lake was formed, directly drained into the Congo River.

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 lake’s connection to the sea is dependent on a high water level allowing water to overflow out of the lake through the Lukunga into the Congo.

Due to the lake’s tropical location, it suffers a high rate of evaporation. Thus it depends on a high inflow through the Ruzizi out of Lake Kivu to keep the lake high enough to overflow. This outflow is apparently not more than 12,000 years old, and resulted from lava flows blocking and diverting the Kivu basin’s previous outflow into Lake Edward and then the Nile system, and diverting it to Lake Tanganyika. Signs of ancient shorelines indicate that at times Tanganyika may have been up to 300 m lower than its present surface level, with no outlet to the sea. Even its current outlet is intermittent and may not have been operating when first visited by Western explorers in 1858.

The lake may also have at times had different inflows and outflows: inward flows from a higher Lake Rukwa, access to Lake Malawi and an exit route to the Nile have all been proposed to have existed at some point in the lake’s history.

Islands

There are several islands in Lake Tanganyika. The most important of them are Kavala Island (The Democratic Republic of the Congo) Mamba-Kayenda Islands (The Democratic Republic of the Congo), Milima Island (The Democratic Republic of the Congo), Kibishie Island (The Democratic Republic of the Congo), Mutonowe Island (Zambia) and Kumbula Island (Zambia)

Lake Tanganyika is considered the oldest of the East African lakes, and has the most morphologically and genetically diverse groups of cichlids. This lake also has the largest number of endemic cichlid genera of all African lakes. Almost all (98%) of the Tanganyikan cichlid species are endemic to the lake, and Lake Tanganyika is thus an important biological resource for the study of speciation in evolution. Among the non-cichlid fish, 59% of the species are endemic. Lake Tanganyika is the most diverse extent of adaptive radiation.

Among Rift Valley lakes, Lake Tanganyika far surpasses all others in terms of crustacean and freshwater snail richness (both in total number of species and number of endemics). For example, the only other Rift Valley Lake with endemic freshwater crabs is Lake Kivu with two species.