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Lake Victoria

Lake Victoria is one of the African Great Lakes. With a surface area of approximately 59,947 km2 (23,146 sq mi),[6][7] Lake Victoria is Africa's largest lake by area, the world's largest tropical lake,[8] and the world's second-largest fresh water lake by surface area after Lake Superior in North America.[9] In terms of volume, Lake Victoria is the world's ninth-largest continental lake, containing about 2,424 km3 (1.965×109 acre⋅ft) of water.[7][10] Lake Victoria occupies a shallow depression in Africa. The lake has an average depth of 40 m (130 ft) and a maximum depth of 80–84 m (262–276 ft).[7][10][11] Its catchment area covers 169,858 km2 (65,583 sq mi).[12] The lake has a shoreline of 7,142 km (4,438 mi) when digitized at the 1:25,000 level,[13] with islands constituting 3.7% of this length.[14]

Lake Victoria
Lake Victoria partially obscured by clouds taken on the International Space Station
Lake Victoria
LocationAfrican Great Lakes
Coordinates1°S 33°E / 1°S 33°E / -1; 33Coordinates: 1°S 33°E / 1°S 33°E / -1; 33
Native name
Primary inflowsKagera River
Primary outflowsWhite Nile
Catchment area169,858 km2 (65,583 sq mi)
229,815 km2 (88,732 sq mi) basin [1]
Basin countriesBurundi, Kenya, Rwanda, Tanzania, and Uganda[1]
Max. length359 km (223 mi)[2]
Max. width337 km (209 mi)[2]
Surface area59,947 km2 (23,146 sq mi)[3]
Average depth41 m (135 ft)[3]
Max. depth81 m (266 ft)[3]
Water volume2,424 km3 (582 cu mi)[3]
Shore length17,142 km (4,438 mi)[3]
Surface elevation1,135 m (3,724 ft)[4]
Islands985 (Ukerewe Island, Tanzania;Ssese Islands,[3] Uganda; Maboko Island, Kenya)[5]
Settlements
1 Shore length is not a well-defined measure.
Victoria Nyanza. The black line indicates Stanley's route.

The lake's area is divided among three countries: Kenya occupies 6% (4,100 km2 (1,600 sq mi)), Uganda 45% (31,000 km2 (12,000 sq mi)), and Tanzania 49% (33,700 km2 (13,000 sq mi)).[15]

Though having multiple local language names (Dholuo: Nam Lolwe; Luganda: 'Nnalubaale; Kinyarwanda: Nyanza; also Ukerewe),[16][17] the lake was renamed after Queen Victoria by the explorer John Hanning Speke, the first Briton to document it in 1858, while on an expedition with Richard Francis Burton.[18][19] The lake is home to many species of fish which live nowhere else, especially cichlids. Invasive fish, such as the Nile perch, have driven many endemic species to extinction.

Geology

 
Topographical map of Lake Victoria

Geologically, Lake Victoria is relatively young at about 400,000 years old. It was formed when westward-flowing rivers were dammed by an upthrown crustal block.[20] During the Miocene era, what is now the catchment area of the lake was on the western side of an uplifted area that functioned as a continental divide, with streams on the western side flowing into the Congo River basin and streams on the eastern side flowing to the Indian Ocean. As the East African Rift System formed, the eastern wall of the Albertine Rift (or Western Rift) rose, gradually reversing the drainage towards what is now Lake Victoria. The opening of the main East African Rift and the Albertine Rift downwarped the area between them as the rift walls rose, creating the current Lake Victoria basin.[21]

During its geological history, Lake Victoria went through changes ranging from its present shallow depression, through to what may have been a series of much smaller lakes.[14] Geological cores taken from its bottom show Lake Victoria has dried up completely at least three times since it formed.[20] These drying cycles are probably related to past ice ages, which were times when precipitation declined globally.[20] Lake Victoria last dried out about 17,300 years ago, and it refilled 14,700 years ago[22] as the African humid period began.[23]

Hydrology and limnology

Lake Victoria receives 80 percent of its water from direct rainfall.[14] Average evaporation on the lake is between 2.0 and 2.2 metres (6.6 and 7.2 ft) per year, almost double the precipitation of riparian areas.[24] Lake Victoria receives its water additionally from rivers, and thousands of small streams. The Kagera River is the largest river flowing into this lake, with its mouth on the lake's western shore. Lake Victoria is drained solely by the Nile River near Jinja, Uganda, on the lake's northern shore.[25] In the Kenya sector, the main influent rivers are the Sio, Nzoia, Yala, Nyando, Sondu Miriu, Mogusi, and Migori.

 
Lake Victoria and the Great Rift Valley

The only outflow from Lake Victoria is the Nile River, which exits the lake near Jinja, Uganda. In terms of contributed water, this makes Lake Victoria the principal source of the longest branch of the Nile. However, the most distal source of the Nile Basin, and therefore the ultimate source of the Nile, is more often considered to be one of the tributary rivers of the Kagera River (the exact tributary remains undetermined), and which originates in either Rwanda or Burundi. The uppermost section of the Nile is generally known as the Victoria Nile until it reaches Lake Albert. Although it is a part of the same river system known as the White Nile and is occasionally referred to as such, strictly speaking this name does not apply until after the river crosses the Uganda border into South Sudan to the north.

The lake exhibits eutrophic conditions. In 1990–1991, oxygen concentrations in the mixed layer were higher than in 1960–1961, with nearly continuous oxygen supersaturation in surface waters. Oxygen concentrations in hypolimnetic waters (i.e. the layer of water that lies below the thermocline, is noncirculating, and remains perpetually cold) were lower in 1990–1991 for a longer period than in 1960–1961, with values of less than 1 mg per litre (< 0.4 gr/cu ft) occurring in water as shallow as 40 metres (130 ft) compared with a shallowest occurrence of greater than 50 metres (160 ft) in 1961. The changes in oxygenation are considered consistent with measurements of higher algal biomass and productivity.[26] These changes have arisen for multiple reasons: successive burning within its basin,[27] soot and ash from which has been deposited over the lake's wide area; from increased nutrient inflows via rivers,[28] and from increased pollution associated with settlement along its shores.[29]

Between 2010 and 2022 the surface area of Lake Victoria increased by 15%[30] flooding lakeside communities.[31]

Bathymetry

 
Lake Victoria bathymetric model[32]

The lake is considered a shallow lake considering its large geographic area with a maximum depth of approximately 80 metres (260 ft) and an average depth of 40 metres (130 ft).[33] A 2016 project digitized ten-thousand points and created the first true bathymetric map of the lake.[32] The deepest part of the lake is offset to the east of the lake near Kenya and the lake is generally shallower in the west along the Ugandan shoreline and the south along the Tanzanian shoreline.[32]

Native wildlife

Mammals

Many mammal species live in the region of Lake Victoria, and some of these are closely associated with the lake itself and the nearby wetlands. Among these are the hippopotamus, African clawless otter, spotted-necked otter, marsh mongoose, sitatunga, bohor reedbuck, defassa waterbuck, cane rats, and giant otter shrew.[34]

Reptiles

Lake Victoria and its wetlands has a large population of Nile crocodiles, as well as African helmeted turtles, variable mud turtles, and Williams' mud turtle.[35] The Williams' mud turtle is restricted to Lake Victoria and other lakes, rivers, and swamps in the upper Nile basin.[35]

Cichlid fish

 
Unlike many other Lake Victoria cichlids, Haplochromis nyererei remains common.[36] Compared to several other cichlids, its eyes are particularly sensitive to light, especially red, which is less affected by the decrease in water clarity caused by eutrophication than short wavelength colors[37]

Lake Victoria formerly was very rich in fish, including many endemics, but a high percentage of these became extinct since the 1940s.[38] The main group in Lake Victoria is the haplochromine cichlids (Haplochromis sensu lato) with more than 500 species, almost all endemic,[22][39][40] and including an estimated 300 that still are undescribed.[41] This is far more species of fish than any other lake in the world, except Lake Malawi.[42] These are the result of a rapid adaptive radiation in the last circa 15,000 years.[22][39][43] Their extraordinary diversity and speed of evolution have been the subjects for many scientists studying the forces that drive the richness of life everywhere.[39][44] The Victoria haplochromines are part of an older group of more than 700 closely related species, also including those of several smaller lakes in the region, notably Kyoga, EdwardGeorge, Albert, and Kivu.[22][39]

Most of these lakes are relatively shallow (like Victoria) and part of the present-day upper Nile basin. The exception is Lake Kivu, which is part of the present-day Congo River basin, but is believed to have been connected to Lakes Edward and Victoria by rivers until the uplifting of parts of the East African Rift.[22] This deep lake may have functioned as an "evolutionary reservoir" for this haplochromine group in periods where other shallower lakes in the region dried out, as happened to Lake Victoria about 15,000 years ago.[22] In recent history only Lake Kyoga was easily accessible to Victoria cichlids, as further downstream movement by the Victoria Nile (to Lake Albert) is prevented by a series of waterfalls, notably Murchison. In contrast, the Owen Falls (now flooded by a dam) between Victoria and Kyoga were essentially a series of rapids that did not effectively block fish movements between the two lakes.[45]

 
Haplochromis thereuterion survives in low numbers.[46] Initially feared extinct, when rediscovered it had changed habitat (from near surface to rocky outcrops) and feeding behavior (from surface insects to insect larvae)[47]

The Victoria haplochromines are distinctly sexually dimorphic (males relatively brightly colored; females dull),[48] and their ecology is extremely diverse, falling into at least 16 groups, including detritivores, zooplanktivores, insectivores, prawn-eaters, molluscivores and piscivores.[44] As a result of predation by the introduced Nile perch, eutrophication and other changes to the ecosystem, it is estimated that at least 200 species (about 40 percent) of Lake Victoria haplochromines have become extinct,[40][44][49] including more than 100 undescribed species.[41] Initially it was feared that this number was even higher, by some estimates 65 percent of the total species,[50] but several species that were feared extinct have been rediscovered after the Nile perch started to decline in the 1990s.[44][51] Several of the remaining species are seriously threatened and additional extinctions are possible.[52] Some species have survived in nearby small satellite lakes,[51] have survived in refugias among rocks or papyrus sedges (protecting them from the Nile perch),[53] or have adapted to the human-induced changes in the lake itself.[44][49] Such adaptions include a larger gill area (adaption for oxygen-poor water), changes in the feeding apparatus, changes to the eyes (giving them a better sight in turbid water)[37][44] and smaller head/larger caudal peduncle (allowing faster swimming).[54] The piscivorous (affected by both predation and competition from Nile perch[55]), molluscivorous and insectivorous haplochromines were particularly hard hit with many extinctions.[44] Others have become extinct in their pure form, but survive as hybrids between close relatives (especially among the detritivores).[40][44] The zooplanktivores have been least affected and in the late 1990s had reached densities similar to, or above, the densities before the drastic declines, although consisting of fewer species and often switching their diet towards macroinvertebrates.[37][44] Some of the threatened Lake Victoria cichlid species have captive "insurance" populations in zoos, public aquaria and among private aquarists, and a few species are extinct in the wild (only survive in captivity).[56][57][58][59][60]

Before the mass extinction that has occurred among the lake's cichlids in the last 50 years, about 90 percent of the native fish species in the lake were haplochromines.[38] Disregarding the haplochromines, the only native Victoria cichlids are two critically endangered tilapia, the Singida tilapia or ngege (Oreochromis esculentus) and Victoria tilapia (O. variabilis).[61][62]

In 1927–1928 Michael Graham conducted the first ever systematic Fisheries Survey of Lake Victoria. In his official report of the expedition, Graham wrote that "The ngege or satu Tilapia esculenta, is the most important food fish of the lake, whether for native or non-native consumption. No other fish equals it in the quality of the flesh. It is convenient size for trade, travels well and is found in much greater numbers than other important fish, such as semutundu (Luganda), Bagrus sp.".[63] Furthermore, Graham noted that the introduction of the European flax gill net of 5 inch mesh had undoubtedly caused a diminution in the number of ngege in those parts of the Kavirondo Gulf, the northern shore of the lake, the Sesse Islands and Smith's Sound which are conveniently situated close to markets.[63] Survey catches in 1927–28 included several Haplochromis species that are now thought to be extinct, including: Haplochromis flavipinnis, Haplochromis gowersii, Haplochromis longirostris, Haplochromis macrognathus, Haplochromis michaeli, Haplochromis nigrescens, Haplochromis prognathus.

As well as being due to the introduction of Nile Perch, the extinction of cichlids in the genus Haplochromis has also been blamed on the lake's eutrophication. The fertility of tropical waters depends on the rate at which nutrients can be brought into solution. The influent rivers of Lake Victoria provide few nutrients to the lake in relation to its size. Because of this, most of Lake Victoria's nutrients are thought to be locked up in lake-bottom deposits.[14][64] By itself, this vegetative matter decays slowly. Animal flesh decays considerably faster, however, so the fertility of the lake is dependent on the rate at which these nutrients can be taken up by fish and other organisms.[64] There is little doubt that Haplochromis played an important role in returning detritus and plankton back into solution.[65][66][67] With some 80 percent of Haplochromis species feeding off detritus, and equally capable of feeding off one another, they represented a tight, internal recycling system, moving nutrients and biomass both vertically and horizontally through the water column, and even out of the lake via predation by humans and terrestrial animals. The removal of Haplochromis, however, may have contributed to the increasing frequency of algal blooms,[28][66][67] which may in turn be responsible for mass fish kills.[28]

Other fish

The non-cichlid native fish include African tetras (Brycinus), cyprinids (Enteromius, Garra, Labeo, Labeobarbus, Rastrineobola and Xenobarbus), airbreathing catfish (Clariallabes, Clarias and Xenoclarias), bagrid catfish (Bagrus), loach catfish (Amphilius and Zaireichthys), silver butter catfish (Schilbe intermedius), Synodontis squeaker catfish, Nothobranchius killifish, poeciliids (Aplocheilichthys and Micropanchax), the spiny eel Mastacembelus frenatus, elephantfish (Gnathonemus, Hippopotamyrus, Marcusenius, Mormyrus, Petrocephalus, and Pollimyrus), the climbing gourami Ctenopoma muriei and marbled lungfish (Protopterus aethiopicus).[68]

At a genus level, most of these are widespread in Africa, but the very rare Xenobarbus and Xenoclarias are endemic to the lake, and the common Rastrineobola is near-endemic.[68]

Crustaceans

Four species of freshwater crabs are known from Lake Victoria: Potamonautes niloticus is widespread in the lake and P. emini has been recorded from the vicinity of Bukoba in Tanzania, but both are also found elsewhere in Africa.[69][70] The last were first scientifically described in 2017 and very little is known about them: P. entebbe is only known from near Entebbe (the only known specimen was collected in 1955 and it is unknown if it was in or near the lake) and P. busungwe only at Busungwe Island in the northwestern part of the lake. The latter likely is the smallest African freshwater crab with a carapace width up to about 1.6 cm (0.6 in), although P. kantsyore of Kagera River, and Platythelphusa maculata and P. polita of Lake Tanganyika are almost as small.[71]

The only shrimp/prawn is Caridina nilotica,[72] which is common and widespread in Lake Victoria.[44]

Molluscs

Lake Victoria is home to 28 species of freshwater snails (e.g., Bellamya, Biomphalaria, Bulinus, Cleopatra, Gabbiella, and Melanoides), including 12 endemic species/subspecies.[73][74] There are 17 species of bivalves (Corbicula, Coelatura, Sphaerium, and Byssanodonta), including 6 endemic species/subspecies.[73][75] It is likely that undescribed species of snails remain. Conversely, genetic studies indicate that some morphologically distinctive populations, traditionally regarded as separate species, may only be variants of single species.[41] Two of the snail genera, Biomphalaria and Bulinus, are intermediate hosts of the parasite that causes bilharzia (schistosomiasis). Human infections by this parasite are common at Lake Victoria.[76] This may increase as a result of the spread of the invasive water hyacinth (an optimum snail habitat),[77] and the loss of many snail-eating cichlids in the lake.[78]

Spiders

Evarcha culicivora is a species of jumping spider (family Salticidae) found only around Lake Victoria in Kenya and Uganda. It feeds primarily on female mosquitos.[79]

Fisheries

 
Fishers and their boats on the shore of Lake Victoria

Lake Victoria supports Africa's largest inland fishery (as of 1997).[80] Initially the fishery involved native species, especially tilapia and haplochromine cichlids, but also catfish (Bagrus, Clarias, Synodontis and silver butter catfish), elephantfish, ningu (Labeo victorianus) and marbled lungfish (Protopterus aethiopicus).[81][82] Some of these, including tilapia and ningu (Labeo victorianus), had already declined in the first half of the 20th century due to overfishing.[44][83] To boost fishing, several species of non-native tilapia and Nile perch were introduced to the lake in the 1950s. Nevertheless, the natives continued to dominate fisheries until the 1970s where their decline meant that there was a strong shift towards the non-native Nile tilapia (now 7 percent of catches), non-native Nile perch (60 percent) and the native Lake Victoria sardine (30 percent).[44][82] Because of its small size, the abundant open-water Lake Victoria sardine only supported minor fisheries until the decline of other natives.[82] At the peak in the early 1990s, 500,000 tonnes (490,000 long tons; 550,000 short tons) of Nile perch were landed annually in Lake Victoria, but this has declined significantly in later years.[44]

Environmental issues

A number of environmental issues are associated with Lake Victoria and the complete disappearance of many endemic cichlid species has been called the "most dramatic example of human-caused extinctions within an ecosystem".[52]

Invasive fish

Starting in the 1950s, many species have been introduced to Lake Victoria where they have become invasive and a prime reason for the extinction of many endemic haplochromine cichlids.[38] Among the introductions are several tilapias: redbreast (Coptodon rendalli), redbelly (C. zillii), Nile (Oreochromis niloticus) and blue-spotted tilapias (O. leucostictus).[44][82][84] Although these have contributed to the extinction of native fish by causing significant changes to the ecosystem, outcompeted natives and (in the case of the Nile tilapia) possibly hybridized with the highly threatened native tilapias, the most infamous introduction was the large and highly predatory Nile perch (Lates niloticus).[38][44][82]

 
The Nile perch was introduced to Lake Victoria for fishing, and can reach up to 2 m (6.6 ft) and 200 kg (440 lb).[85]

As early as the 1920s, it was proposed to introduce a large pelagic predator such as the Nile perch to improve the fisheries in the lake. At the same time it was warned that this could present a serious danger to the native fish species and required extensive research into possible ecological effects before done.[84] These warnings primarily concerned the native tilapia O. esculentus, as the smaller haplochromine cichlids (despite playing an important role in local fisheries) were regarded as "trash fish" by the colonial government.[84] In the following decades, the pressure to introduce the Nile perch continued, as did warnings about the possible effects of doing it.[84] The first introduction of Nile perch to the region, done by the Uganda Game and Fisheries Department (then part of the colonial government) and local African fish guards, happened upstream of Murchison Falls directly after the completion of the Owen Falls Dam in 1954. This allowed it to spread to Lake Kyoga where additional Nile perch were released in 1955, but not Victoria itself.[84] Scientists argued that further introduction should wait until research showed the effect of the introduction in Kyoga, but by the late 1950s, Nile perch began being caught in Lake Victoria.[84] As the species was already present, there were few objections when more Nile perch were transferred to Victoria to further bolster the stock in 1962–63.[84]

The origin of the first Victoria introductions in the 1950s is not entirely clear and indisputable evidence is lacking. Uganda Game and Fisheries Department (UGFD) officials denied that they were involved, but circumstantial evidence suggests otherwise and local Africans employed by UGFD have said that they introduced the species in 1954–55 under the directive of senior officials.[84] UGFD officials argued that Nile perch must have spread to Lake Victoria by themselves by passing through the Owen Falls Dam when shut down for maintenance, but this is considered highly unlikely by many scientists.[84] The Nile perch had spread throughout the lake by 1970.[44] Initially the population of the Nile perch was relatively low, but a drastic increase happened, peaking in the 1980s, followed by a decline starting in the 1990s.[44]

Due to the presence of the Nile perch, the natural balance of the lake's ecosystem has been disrupted. The food chain is being altered and in some cases, broken by the indiscriminate eating habits of the Nile perch. The subsequent decrease in the number of algae-eating fish allows the algae to grow at an alarming rate, thereby choking the lake. The increasing amounts of algae, in turn, increase the amount of detritus (dead plant material) that falls to the deeper portions of the lake before decomposing. As a by-product of this the oxygen levels in the deeper layer of water are being depleted. Without oxygen, any aerobic life (such as fish) cannot exist in the deeper parts of the lake, forcing all life to exist within a narrow range of depth. In this way, the Nile perch has degraded the diverse and thriving ecosystem that was once Lake Victoria. The abundance of aquatic life is not the only dependent of the lake: more than thirty million people in Tanzania, Kenya and Uganda rely on the lake for its natural resources.

Hundreds of endemic species that evolved under the special conditions offered by the protection of Lake Victoria have been lost due to extinction, and several more are still threatened.[86] Their loss is devastating for the lake, the fields of ecology, genetics and evolution biology, and more evidently, for the local fisheries. Local fisheries once depended on catching the lungfish, tilapia, carp and catfish that comprise the local diet. Today, the composition and yields of such fish catches are virtually negligible. Extensive fish kills, Nile perch, loss of habitat and overfishing have caused many fisheries to collapse and many protein sources to be unavailable at the market for local consumption. Few fisheries, though, have been able to make the switch to catching the Nile perch, since that requires a significant amount of capital resources.[87]

Water hyacinth invasion

 
A hyacinth-choked lakeshore at Ndere Island, Lake Victoria, Kenya.

The water hyacinth has become a major invasive plant species in Lake Victoria.

The release of large amounts of untreated wastewater (sewage) and agricultural and industrial runoff directly into Lake Victoria over the past 30 years has greatly increased the nutrient levels of nitrogen and phosphorus in the lake "triggering massive growth of exotic water hyacinth, which colonised the lake in the late 1990s".[88][89] This invasive weed creates anoxic (total depletion of oxygen levels) conditions in the lake inhibiting decomposing plant material, raising toxicity and disease levels to both fish and people. At the same time, the plant's mat or "web" creates a barrier for boats and ferries to maneuver, impedes access to the shoreline, interferes with hydroelectric power generation, and blocks the intake of water for industries.[88][90][91][92][93] On the other hand, water hyacinth mats can potentially have a positive effect on fish life in that they create a barrier to overfishing and allow for fish growth, there has even been the reappearance of some fish species thought to have been extinct in recent years. The overall effects of the water hyacinth, however, are still unknown.[90][94]

Growth of the water hyacinth in Lake Victoria has been tracked since 1993, reaching its maxima biomass in 1997 and then declining again by the end of 2001.[90] Greater growth was observed in the northern part of the lake, in relatively protected areas, which may be linked to current and weather patterns and could also be due to the climate and water conditions, which are more suitable to the plants growth (as there are large urban areas to the north end of the lake, in Uganda).[93] The invasive weed was first attempted to be controlled by hand, removed manually from the lake; however, re-growth occurred quickly. Public awareness exercises were also conducted.[93] More recently, measures have been used such as the introduction of natural insect predators, including two different water hyacinth weevils and large harvesting and chopping boats, which seem to be much more effective in eliminating the water hyacinth.[93][95][96][97] A green power plant that uses harvested water hyacinth (but also can use other degradable waste) was constructed in Kisumu County in 2013. In addition to the biogas it produces, its by-product can be used as fertilizer.[41]

Other factors which may have contributed to the decline of the water hyacinth in Lake Victoria include varying weather patterns, such as El Niño during the last few months of 1997 and first six months of 1998 bringing with it higher levels of water in the lake and thus dislodging the plants. Heavy winds and rains along with their subsequent waves may have also damaged the plants during this same time frame. The plants may not have been destroyed, instead merely moved to another location. Additionally, the water quality, nutrient supply, temperature, and other environmental factors could have played a role. Overall, the timing of the decline could be linked to all of these factors and perhaps together, in combination, they were more effective than any one deterrent would have been by itself.[93] The water hyacinth is in remission and this trend could be permanent if control efforts are continued.[98]

Pollution

 
Population density around Lake Victoria

Pollution of Lake Victoria is mainly due to discharge of raw sewage into the lake, dumping of domestic and industrial waste, and fertiliser and chemicals from farms.

The Lake Victoria basin, while generally rural, has many major centres of population. Its shores are dotted with key cities and towns, including Kisumu, Kisii, and Homa Bay in Kenya; Kampala, Jinja and Entebbe in Uganda; and Bukoba, Mwanza, and Musoma in Tanzania. These cities and towns are also home to many factories that discharge some chemicals directly into the lake or its influent rivers. The set up of small beaches and local authorities around the lake lack proper sewage treatment facilities allowing pollutants to find their way into the water.[99][100] Large parts of these urban areas also discharge untreated (raw) sewage into the river, increasing its eutrophication that in turn is helping to increase the invasive water hyacinth.[101] Increased logging and act of deforestation has led to environmental degradation around the region reducing the absorption of polluting chemicals and deteriorating the water quality.[102]

Environmental data

As of 2016, an environmental data repository exists for Lake Victoria.[103] The repository contains shoreline, bathymetry, pollution, temperature, wind vector, and other important data for both the lake and the wider Basin.

History and exploration

 
Bismarck Rock

The first recorded information about Lake Victoria comes from Arab traders plying the inland routes in search of gold, ivory, other precious commodities, and slaves.

 
The lake as seen from the shores of the Speke Resort in Kampala, Uganda

The lake existed and was known to many Africans in the catchment area who left no written records long before it was sighted by a European in 1858 when the British explorer John Hanning Speke reached its southern shore while on his journey with Richard Francis Burton to explore central Africa and locate the Great Lakes. Believing he had found the source of the Nile on seeing this "vast expanse of open water" for the first time, Speke named the lake after Queen Victoria. Burton, who had been recovering from illness at the time and resting further south on the shores of Lake Tanganyika, was outraged that Speke claimed to have proved his discovery to have been the true source of the Nile River, which Burton regarded as still unsettled. A very public quarrel ensued, which not only sparked a great deal of intense debate within the scientific community of the day, but also much interest by other explorers keen to either confirm or refute Speke's discovery.[104]

In the late 1860s, the famous Scottish explorer and missionary David Livingstone failed in his attempt to verify Speke's discovery, instead pushing too far west and entering the River Congo system instead.[105] Ultimately, the Welsh-American explorer Henry Morton Stanley, on an expedition funded by the New York Herald newspaper, confirmed the truth of Speke's discovery, circumnavigating the lake and reporting the great outflow at Ripon Falls on the lake's northern shore.

Nalubaale Dam

The only outflow for Lake Victoria is at Jinja, Uganda, where it forms the Victoria Nile. The water for at least 12,000 years has drained across a natural rock weir. In 1952, engineers acting for the government of Colonial Uganda blasted out the weir and reservoir to replace it with an artificial barrage to control the level of the lake and reduce the gradual erosion of the rock weir. A standard for mimicking the old rate of outflow called the "agreed curve" was established, setting the maximum flow rate at 300 to 1,700 cubic metres per second (392–2,224 cu yd/sec) depending on the lake's water level.

In 2002, Uganda completed a second hydroelectric complex in the area, the Kiira Hydroelectric Power Station, with World Bank assistance. By 2006, the water levels in Lake Victoria had reached an 80-year low, and Daniel Kull, an independent hydrologist living in Nairobi, Kenya, calculated that Uganda was releasing about twice as much water as is allowed under the agreement,[106] and was primarily responsible for recent drops in the lake's level.

Water use

Many towns and cities are reliant on Victoria for their water supplies, for farming and other uses.[107]

Lamadi water scheme

The Lamadi water scheme is a water and sanitation project that serves Mwanza and the satellite towns of Lamadi, Misungwi, Magu, Bukoba, and Musoma on the bank of Lake Victoria.  European Investment Bank started the project in 2013 with the aim of protecting the environmental health of the lake, through improved water and sanitation to the towns whose pollution is part of the degradation of the lake. The project aims to provide safe drinking water for an estimated one million people and improved sanitation for 100 000 people. Sediment and suspended solids are filtered out using sand, which acts like a sieve. The water is then ready to be chlorinated or treated in another way. The sand filtration helps reduce water-borne diseases and is based on the use of the local environment.[108]

Transport

Since the 1900s, Lake Victoria ferries have been an important means of transport between Uganda, Tanzania, and Kenya. The main ports on the lake are Kisumu, Mwanza, Bukoba, Entebbe, Port Bell, and Jinja. Until 1963, the fastest and newest ferry, MV Victoria, was designated a Royal Mail Ship. In 1966, train ferry services between Kenya and Tanzania were established with the introduction of MV Uhuru and MV Umoja. The ferry MV Bukoba sank in the lake on 21 May 1996 with a loss of between 800 and 1,000 lives, making it one of Africa's worst maritime disasters.[109] Another tragedy occurred recently on 20 September 2018 that involved the passagers ferry MV Nyerere from Tanzania that caused the deaths of over 200 people.[110]

On 6 November 2022, Lake Victoria was the site of a commercial passenger aircraft crash. Precision Air Flight 494 an ATR 42–500 carrying 39 passengers and four crew, crashed while approaching Bukoba Airport, resulting in 19 fatalities.[111][112]

See also

References

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External links

  • Decreasing levels of Lake Victoria Worry East African Countries
  • New Scientist article 13 October 2008 at the Wayback Machine on Uganda's violation of the agreed curve for hydroelectric water flow.
  • Dams Draining Lake Victoria 10 March 2012 at the Wayback Machine
  • A Naturalist on Lake Victoria, with an Account of Sleeping Sickness and the Tse-tse Fly (1920). T.F. Unwin Ltd, London; Biodiversity Archive
  • Video of Lake Victoria
  • Institutions of the East African Community:

lake, victoria, other, places, with, same, name, disambiguation, african, great, lakes, with, surface, area, approximately, africa, largest, lake, area, world, largest, tropical, lake, world, second, largest, fresh, water, lake, surface, area, after, lake, sup. For other places with the same name see Lake Victoria disambiguation Lake Victoria is one of the African Great Lakes With a surface area of approximately 59 947 km2 23 146 sq mi 6 7 Lake Victoria is Africa s largest lake by area the world s largest tropical lake 8 and the world s second largest fresh water lake by surface area after Lake Superior in North America 9 In terms of volume Lake Victoria is the world s ninth largest continental lake containing about 2 424 km3 1 965 109 acre ft of water 7 10 Lake Victoria occupies a shallow depression in Africa The lake has an average depth of 40 m 130 ft and a maximum depth of 80 84 m 262 276 ft 7 10 11 Its catchment area covers 169 858 km2 65 583 sq mi 12 The lake has a shoreline of 7 142 km 4 438 mi when digitized at the 1 25 000 level 13 with islands constituting 3 7 of this length 14 Lake VictoriaLake Victoria partially obscured by clouds taken on the International Space StationLake VictoriaLocationAfrican Great LakesCoordinates1 S 33 E 1 S 33 E 1 33 Coordinates 1 S 33 E 1 S 33 E 1 33Native nameNam Lolwe Dholuo Nnalubaale Luganda Nyanza Kinyarwanda Nyanza Viktoria Swahili Primary inflowsKagera RiverPrimary outflowsWhite NileCatchment area169 858 km2 65 583 sq mi 229 815 km2 88 732 sq mi basin 1 Basin countriesBurundi Kenya Rwanda Tanzania and Uganda 1 Max length359 km 223 mi 2 Max width337 km 209 mi 2 Surface area59 947 km2 23 146 sq mi 3 Average depth41 m 135 ft 3 Max depth81 m 266 ft 3 Water volume2 424 km3 582 cu mi 3 Shore length17 142 km 4 438 mi 3 Surface elevation1 135 m 3 724 ft 4 Islands985 Ukerewe Island Tanzania Ssese Islands 3 Uganda Maboko Island Kenya 5 SettlementsBukoba Tanzania Mwanza Tanzania Musoma Tanzania Kisumu Kenya Kendu Bay Kenya Homa Bay Kenya Kampala Uganda Entebbe Uganda Jinja Uganda1 Shore length is not a well defined measure Victoria Nyanza The black line indicates Stanley s route The lake s area is divided among three countries Kenya occupies 6 4 100 km2 1 600 sq mi Uganda 45 31 000 km2 12 000 sq mi and Tanzania 49 33 700 km2 13 000 sq mi 15 Though having multiple local language names Dholuo Nam Lolwe Luganda Nnalubaale Kinyarwanda Nyanza also Ukerewe 16 17 the lake was renamed after Queen Victoria by the explorer John Hanning Speke the first Briton to document it in 1858 while on an expedition with Richard Francis Burton 18 19 The lake is home to many species of fish which live nowhere else especially cichlids Invasive fish such as the Nile perch have driven many endemic species to extinction Contents 1 Geology 2 Hydrology and limnology 3 Bathymetry 4 Native wildlife 4 1 Mammals 4 2 Reptiles 4 3 Cichlid fish 4 4 Other fish 4 5 Crustaceans 4 6 Molluscs 4 7 Spiders 5 Fisheries 6 Environmental issues 6 1 Invasive fish 6 2 Water hyacinth invasion 6 3 Pollution 6 4 Environmental data 7 History and exploration 8 Nalubaale Dam 9 Water use 9 1 Lamadi water scheme 10 Transport 11 See also 12 References 13 External linksGeology Edit Topographical map of Lake Victoria Geologically Lake Victoria is relatively young at about 400 000 years old It was formed when westward flowing rivers were dammed by an upthrown crustal block 20 During the Miocene era what is now the catchment area of the lake was on the western side of an uplifted area that functioned as a continental divide with streams on the western side flowing into the Congo River basin and streams on the eastern side flowing to the Indian Ocean As the East African Rift System formed the eastern wall of the Albertine Rift or Western Rift rose gradually reversing the drainage towards what is now Lake Victoria The opening of the main East African Rift and the Albertine Rift downwarped the area between them as the rift walls rose creating the current Lake Victoria basin 21 During its geological history Lake Victoria went through changes ranging from its present shallow depression through to what may have been a series of much smaller lakes 14 Geological cores taken from its bottom show Lake Victoria has dried up completely at least three times since it formed 20 These drying cycles are probably related to past ice ages which were times when precipitation declined globally 20 Lake Victoria last dried out about 17 300 years ago and it refilled 14 700 years ago 22 as the African humid period began 23 Hydrology and limnology EditLake Victoria receives 80 percent of its water from direct rainfall 14 Average evaporation on the lake is between 2 0 and 2 2 metres 6 6 and 7 2 ft per year almost double the precipitation of riparian areas 24 Lake Victoria receives its water additionally from rivers and thousands of small streams The Kagera River is the largest river flowing into this lake with its mouth on the lake s western shore Lake Victoria is drained solely by the Nile River near Jinja Uganda on the lake s northern shore 25 In the Kenya sector the main influent rivers are the Sio Nzoia Yala Nyando Sondu Miriu Mogusi and Migori Lake Victoria and the Great Rift Valley This paragraph needs additional citations for verification Please help improve this article by adding citations to reliable sources in this paragraph Unsourced material may be challenged and removed Find sources Lake Victoria news newspapers books scholar JSTOR June 2017 Learn how and when to remove this template message The only outflow from Lake Victoria is the Nile River which exits the lake near Jinja Uganda In terms of contributed water this makes Lake Victoria the principal source of the longest branch of the Nile However the most distal source of the Nile Basin and therefore the ultimate source of the Nile is more often considered to be one of the tributary rivers of the Kagera River the exact tributary remains undetermined and which originates in either Rwanda or Burundi The uppermost section of the Nile is generally known as the Victoria Nile until it reaches Lake Albert Although it is a part of the same river system known as the White Nile and is occasionally referred to as such strictly speaking this name does not apply until after the river crosses the Uganda border into South Sudan to the north The lake exhibits eutrophic conditions In 1990 1991 oxygen concentrations in the mixed layer were higher than in 1960 1961 with nearly continuous oxygen supersaturation in surface waters Oxygen concentrations in hypolimnetic waters i e the layer of water that lies below the thermocline is noncirculating and remains perpetually cold were lower in 1990 1991 for a longer period than in 1960 1961 with values of less than 1 mg per litre lt 0 4 gr cu ft occurring in water as shallow as 40 metres 130 ft compared with a shallowest occurrence of greater than 50 metres 160 ft in 1961 The changes in oxygenation are considered consistent with measurements of higher algal biomass and productivity 26 These changes have arisen for multiple reasons successive burning within its basin 27 soot and ash from which has been deposited over the lake s wide area from increased nutrient inflows via rivers 28 and from increased pollution associated with settlement along its shores 29 Between 2010 and 2022 the surface area of Lake Victoria increased by 15 30 flooding lakeside communities 31 Bathymetry Edit Lake Victoria bathymetric model 32 The lake is considered a shallow lake considering its large geographic area with a maximum depth of approximately 80 metres 260 ft and an average depth of 40 metres 130 ft 33 A 2016 project digitized ten thousand points and created the first true bathymetric map of the lake 32 The deepest part of the lake is offset to the east of the lake near Kenya and the lake is generally shallower in the west along the Ugandan shoreline and the south along the Tanzanian shoreline 32 Native wildlife EditMammals Edit Many mammal species live in the region of Lake Victoria and some of these are closely associated with the lake itself and the nearby wetlands Among these are the hippopotamus African clawless otter spotted necked otter marsh mongoose sitatunga bohor reedbuck defassa waterbuck cane rats and giant otter shrew 34 Reptiles Edit Lake Victoria and its wetlands has a large population of Nile crocodiles as well as African helmeted turtles variable mud turtles and Williams mud turtle 35 The Williams mud turtle is restricted to Lake Victoria and other lakes rivers and swamps in the upper Nile basin 35 Cichlid fish Edit Unlike many other Lake Victoria cichlids Haplochromis nyererei remains common 36 Compared to several other cichlids its eyes are particularly sensitive to light especially red which is less affected by the decrease in water clarity caused by eutrophication than short wavelength colors 37 Lake Victoria formerly was very rich in fish including many endemics but a high percentage of these became extinct since the 1940s 38 The main group in Lake Victoria is the haplochromine cichlids Haplochromis sensu lato with more than 500 species almost all endemic 22 39 40 and including an estimated 300 that still are undescribed 41 This is far more species of fish than any other lake in the world except Lake Malawi 42 These are the result of a rapid adaptive radiation in the last circa 15 000 years 22 39 43 Their extraordinary diversity and speed of evolution have been the subjects for many scientists studying the forces that drive the richness of life everywhere 39 44 The Victoria haplochromines are part of an older group of more than 700 closely related species also including those of several smaller lakes in the region notably Kyoga Edward George Albert and Kivu 22 39 Most of these lakes are relatively shallow like Victoria and part of the present day upper Nile basin The exception is Lake Kivu which is part of the present day Congo River basin but is believed to have been connected to Lakes Edward and Victoria by rivers until the uplifting of parts of the East African Rift 22 This deep lake may have functioned as an evolutionary reservoir for this haplochromine group in periods where other shallower lakes in the region dried out as happened to Lake Victoria about 15 000 years ago 22 In recent history only Lake Kyoga was easily accessible to Victoria cichlids as further downstream movement by the Victoria Nile to Lake Albert is prevented by a series of waterfalls notably Murchison In contrast the Owen Falls now flooded by a dam between Victoria and Kyoga were essentially a series of rapids that did not effectively block fish movements between the two lakes 45 Haplochromis thereuterion survives in low numbers 46 Initially feared extinct when rediscovered it had changed habitat from near surface to rocky outcrops and feeding behavior from surface insects to insect larvae 47 The Victoria haplochromines are distinctly sexually dimorphic males relatively brightly colored females dull 48 and their ecology is extremely diverse falling into at least 16 groups including detritivores zooplanktivores insectivores prawn eaters molluscivores and piscivores 44 As a result of predation by the introduced Nile perch eutrophication and other changes to the ecosystem it is estimated that at least 200 species about 40 percent of Lake Victoria haplochromines have become extinct 40 44 49 including more than 100 undescribed species 41 Initially it was feared that this number was even higher by some estimates 65 percent of the total species 50 but several species that were feared extinct have been rediscovered after the Nile perch started to decline in the 1990s 44 51 Several of the remaining species are seriously threatened and additional extinctions are possible 52 Some species have survived in nearby small satellite lakes 51 have survived in refugias among rocks or papyrus sedges protecting them from the Nile perch 53 or have adapted to the human induced changes in the lake itself 44 49 Such adaptions include a larger gill area adaption for oxygen poor water changes in the feeding apparatus changes to the eyes giving them a better sight in turbid water 37 44 and smaller head larger caudal peduncle allowing faster swimming 54 The piscivorous affected by both predation and competition from Nile perch 55 molluscivorous and insectivorous haplochromines were particularly hard hit with many extinctions 44 Others have become extinct in their pure form but survive as hybrids between close relatives especially among the detritivores 40 44 The zooplanktivores have been least affected and in the late 1990s had reached densities similar to or above the densities before the drastic declines although consisting of fewer species and often switching their diet towards macroinvertebrates 37 44 Some of the threatened Lake Victoria cichlid species have captive insurance populations in zoos public aquaria and among private aquarists and a few species are extinct in the wild only survive in captivity 56 57 58 59 60 Before the mass extinction that has occurred among the lake s cichlids in the last 50 years about 90 percent of the native fish species in the lake were haplochromines 38 Disregarding the haplochromines the only native Victoria cichlids are two critically endangered tilapia the Singida tilapia or ngege Oreochromis esculentus and Victoria tilapia O variabilis 61 62 In 1927 1928 Michael Graham conducted the first ever systematic Fisheries Survey of Lake Victoria In his official report of the expedition Graham wrote that The ngege or satu Tilapia esculenta is the most important food fish of the lake whether for native or non native consumption No other fish equals it in the quality of the flesh It is convenient size for trade travels well and is found in much greater numbers than other important fish such as semutundu Luganda Bagrus sp 63 Furthermore Graham noted that the introduction of the European flax gill net of 5 inch mesh had undoubtedly caused a diminution in the number of ngege in those parts of the Kavirondo Gulf the northern shore of the lake the Sesse Islands and Smith s Sound which are conveniently situated close to markets 63 Survey catches in 1927 28 included several Haplochromis species that are now thought to be extinct including Haplochromis flavipinnis Haplochromis gowersii Haplochromis longirostris Haplochromis macrognathus Haplochromis michaeli Haplochromis nigrescens Haplochromis prognathus As well as being due to the introduction of Nile Perch the extinction of cichlids in the genus Haplochromis has also been blamed on the lake s eutrophication The fertility of tropical waters depends on the rate at which nutrients can be brought into solution The influent rivers of Lake Victoria provide few nutrients to the lake in relation to its size Because of this most of Lake Victoria s nutrients are thought to be locked up in lake bottom deposits 14 64 By itself this vegetative matter decays slowly Animal flesh decays considerably faster however so the fertility of the lake is dependent on the rate at which these nutrients can be taken up by fish and other organisms 64 There is little doubt that Haplochromis played an important role in returning detritus and plankton back into solution 65 66 67 With some 80 percent of Haplochromis species feeding off detritus and equally capable of feeding off one another they represented a tight internal recycling system moving nutrients and biomass both vertically and horizontally through the water column and even out of the lake via predation by humans and terrestrial animals The removal of Haplochromis however may have contributed to the increasing frequency of algal blooms 28 66 67 which may in turn be responsible for mass fish kills 28 Other fish Edit The non cichlid native fish include African tetras Brycinus cyprinids Enteromius Garra Labeo Labeobarbus Rastrineobola and Xenobarbus airbreathing catfish Clariallabes Clarias and Xenoclarias bagrid catfish Bagrus loach catfish Amphilius and Zaireichthys silver butter catfish Schilbe intermedius Synodontis squeaker catfish Nothobranchius killifish poeciliids Aplocheilichthys and Micropanchax the spiny eel Mastacembelus frenatus elephantfish Gnathonemus Hippopotamyrus Marcusenius Mormyrus Petrocephalus and Pollimyrus the climbing gourami Ctenopoma muriei and marbled lungfish Protopterus aethiopicus 68 At a genus level most of these are widespread in Africa but the very rare Xenobarbus and Xenoclarias are endemic to the lake and the common Rastrineobola is near endemic 68 Crustaceans Edit Four species of freshwater crabs are known from Lake Victoria Potamonautes niloticus is widespread in the lake and P emini has been recorded from the vicinity of Bukoba in Tanzania but both are also found elsewhere in Africa 69 70 The last were first scientifically described in 2017 and very little is known about them P entebbe is only known from near Entebbe the only known specimen was collected in 1955 and it is unknown if it was in or near the lake and P busungwe only at Busungwe Island in the northwestern part of the lake The latter likely is the smallest African freshwater crab with a carapace width up to about 1 6 cm 0 6 in although P kantsyore of Kagera River and Platythelphusa maculata and P polita of Lake Tanganyika are almost as small 71 The only shrimp prawn is Caridina nilotica 72 which is common and widespread in Lake Victoria 44 Molluscs Edit Lake Victoria is home to 28 species of freshwater snails e g Bellamya Biomphalaria Bulinus Cleopatra Gabbiella and Melanoides including 12 endemic species subspecies 73 74 There are 17 species of bivalves Corbicula Coelatura Sphaerium and Byssanodonta including 6 endemic species subspecies 73 75 It is likely that undescribed species of snails remain Conversely genetic studies indicate that some morphologically distinctive populations traditionally regarded as separate species may only be variants of single species 41 Two of the snail genera Biomphalaria and Bulinus are intermediate hosts of the parasite that causes bilharzia schistosomiasis Human infections by this parasite are common at Lake Victoria 76 This may increase as a result of the spread of the invasive water hyacinth an optimum snail habitat 77 and the loss of many snail eating cichlids in the lake 78 Spiders Edit Evarcha culicivora is a species of jumping spider family Salticidae found only around Lake Victoria in Kenya and Uganda It feeds primarily on female mosquitos 79 Fisheries Edit Fishers and their boats on the shore of Lake Victoria Main article Fishing on Lake Victoria Lake Victoria supports Africa s largest inland fishery as of 1997 80 Initially the fishery involved native species especially tilapia and haplochromine cichlids but also catfish Bagrus Clarias Synodontis and silver butter catfish elephantfish ningu Labeo victorianus and marbled lungfish Protopterus aethiopicus 81 82 Some of these including tilapia and ningu Labeo victorianus had already declined in the first half of the 20th century due to overfishing 44 83 To boost fishing several species of non native tilapia and Nile perch were introduced to the lake in the 1950s Nevertheless the natives continued to dominate fisheries until the 1970s where their decline meant that there was a strong shift towards the non native Nile tilapia now 7 percent of catches non native Nile perch 60 percent and the native Lake Victoria sardine 30 percent 44 82 Because of its small size the abundant open water Lake Victoria sardine only supported minor fisheries until the decline of other natives 82 At the peak in the early 1990s 500 000 tonnes 490 000 long tons 550 000 short tons of Nile perch were landed annually in Lake Victoria but this has declined significantly in later years 44 Environmental issues EditA number of environmental issues are associated with Lake Victoria and the complete disappearance of many endemic cichlid species has been called the most dramatic example of human caused extinctions within an ecosystem 52 Invasive fish Edit Starting in the 1950s many species have been introduced to Lake Victoria where they have become invasive and a prime reason for the extinction of many endemic haplochromine cichlids 38 Among the introductions are several tilapias redbreast Coptodon rendalli redbelly C zillii Nile Oreochromis niloticus and blue spotted tilapias O leucostictus 44 82 84 Although these have contributed to the extinction of native fish by causing significant changes to the ecosystem outcompeted natives and in the case of the Nile tilapia possibly hybridized with the highly threatened native tilapias the most infamous introduction was the large and highly predatory Nile perch Lates niloticus 38 44 82 The Nile perch was introduced to Lake Victoria for fishing and can reach up to 2 m 6 6 ft and 200 kg 440 lb 85 As early as the 1920s it was proposed to introduce a large pelagic predator such as the Nile perch to improve the fisheries in the lake At the same time it was warned that this could present a serious danger to the native fish species and required extensive research into possible ecological effects before done 84 These warnings primarily concerned the native tilapia O esculentus as the smaller haplochromine cichlids despite playing an important role in local fisheries were regarded as trash fish by the colonial government 84 In the following decades the pressure to introduce the Nile perch continued as did warnings about the possible effects of doing it 84 The first introduction of Nile perch to the region done by the Uganda Game and Fisheries Department then part of the colonial government and local African fish guards happened upstream of Murchison Falls directly after the completion of the Owen Falls Dam in 1954 This allowed it to spread to Lake Kyoga where additional Nile perch were released in 1955 but not Victoria itself 84 Scientists argued that further introduction should wait until research showed the effect of the introduction in Kyoga but by the late 1950s Nile perch began being caught in Lake Victoria 84 As the species was already present there were few objections when more Nile perch were transferred to Victoria to further bolster the stock in 1962 63 84 The origin of the first Victoria introductions in the 1950s is not entirely clear and indisputable evidence is lacking Uganda Game and Fisheries Department UGFD officials denied that they were involved but circumstantial evidence suggests otherwise and local Africans employed by UGFD have said that they introduced the species in 1954 55 under the directive of senior officials 84 UGFD officials argued that Nile perch must have spread to Lake Victoria by themselves by passing through the Owen Falls Dam when shut down for maintenance but this is considered highly unlikely by many scientists 84 The Nile perch had spread throughout the lake by 1970 44 Initially the population of the Nile perch was relatively low but a drastic increase happened peaking in the 1980s followed by a decline starting in the 1990s 44 Due to the presence of the Nile perch the natural balance of the lake s ecosystem has been disrupted The food chain is being altered and in some cases broken by the indiscriminate eating habits of the Nile perch The subsequent decrease in the number of algae eating fish allows the algae to grow at an alarming rate thereby choking the lake The increasing amounts of algae in turn increase the amount of detritus dead plant material that falls to the deeper portions of the lake before decomposing As a by product of this the oxygen levels in the deeper layer of water are being depleted Without oxygen any aerobic life such as fish cannot exist in the deeper parts of the lake forcing all life to exist within a narrow range of depth In this way the Nile perch has degraded the diverse and thriving ecosystem that was once Lake Victoria The abundance of aquatic life is not the only dependent of the lake more than thirty million people in Tanzania Kenya and Uganda rely on the lake for its natural resources Hundreds of endemic species that evolved under the special conditions offered by the protection of Lake Victoria have been lost due to extinction and several more are still threatened 86 Their loss is devastating for the lake the fields of ecology genetics and evolution biology and more evidently for the local fisheries Local fisheries once depended on catching the lungfish tilapia carp and catfish that comprise the local diet Today the composition and yields of such fish catches are virtually negligible Extensive fish kills Nile perch loss of habitat and overfishing have caused many fisheries to collapse and many protein sources to be unavailable at the market for local consumption Few fisheries though have been able to make the switch to catching the Nile perch since that requires a significant amount of capital resources 87 Water hyacinth invasion Edit Main article Water hyacinth in Lake Victoria A hyacinth choked lakeshore at Ndere Island Lake Victoria Kenya The water hyacinth has become a major invasive plant species in Lake Victoria The release of large amounts of untreated wastewater sewage and agricultural and industrial runoff directly into Lake Victoria over the past 30 years has greatly increased the nutrient levels of nitrogen and phosphorus in the lake triggering massive growth of exotic water hyacinth which colonised the lake in the late 1990s 88 89 This invasive weed creates anoxic total depletion of oxygen levels conditions in the lake inhibiting decomposing plant material raising toxicity and disease levels to both fish and people At the same time the plant s mat or web creates a barrier for boats and ferries to maneuver impedes access to the shoreline interferes with hydroelectric power generation and blocks the intake of water for industries 88 90 91 92 93 On the other hand water hyacinth mats can potentially have a positive effect on fish life in that they create a barrier to overfishing and allow for fish growth there has even been the reappearance of some fish species thought to have been extinct in recent years The overall effects of the water hyacinth however are still unknown 90 94 Growth of the water hyacinth in Lake Victoria has been tracked since 1993 reaching its maxima biomass in 1997 and then declining again by the end of 2001 90 Greater growth was observed in the northern part of the lake in relatively protected areas which may be linked to current and weather patterns and could also be due to the climate and water conditions which are more suitable to the plants growth as there are large urban areas to the north end of the lake in Uganda 93 The invasive weed was first attempted to be controlled by hand removed manually from the lake however re growth occurred quickly Public awareness exercises were also conducted 93 More recently measures have been used such as the introduction of natural insect predators including two different water hyacinth weevils and large harvesting and chopping boats which seem to be much more effective in eliminating the water hyacinth 93 95 96 97 A green power plant that uses harvested water hyacinth but also can use other degradable waste was constructed in Kisumu County in 2013 In addition to the biogas it produces its by product can be used as fertilizer 41 Other factors which may have contributed to the decline of the water hyacinth in Lake Victoria include varying weather patterns such as El Nino during the last few months of 1997 and first six months of 1998 bringing with it higher levels of water in the lake and thus dislodging the plants Heavy winds and rains along with their subsequent waves may have also damaged the plants during this same time frame The plants may not have been destroyed instead merely moved to another location Additionally the water quality nutrient supply temperature and other environmental factors could have played a role Overall the timing of the decline could be linked to all of these factors and perhaps together in combination they were more effective than any one deterrent would have been by itself 93 The water hyacinth is in remission and this trend could be permanent if control efforts are continued 98 Pollution Edit Population density around Lake Victoria Pollution of Lake Victoria is mainly due to discharge of raw sewage into the lake dumping of domestic and industrial waste and fertiliser and chemicals from farms The Lake Victoria basin while generally rural has many major centres of population Its shores are dotted with key cities and towns including Kisumu Kisii and Homa Bay in Kenya Kampala Jinja and Entebbe in Uganda and Bukoba Mwanza and Musoma in Tanzania These cities and towns are also home to many factories that discharge some chemicals directly into the lake or its influent rivers The set up of small beaches and local authorities around the lake lack proper sewage treatment facilities allowing pollutants to find their way into the water 99 100 Large parts of these urban areas also discharge untreated raw sewage into the river increasing its eutrophication that in turn is helping to increase the invasive water hyacinth 101 Increased logging and act of deforestation has led to environmental degradation around the region reducing the absorption of polluting chemicals and deteriorating the water quality 102 Environmental data Edit As of 2016 an environmental data repository exists for Lake Victoria 103 The repository contains shoreline bathymetry pollution temperature wind vector and other important data for both the lake and the wider Basin History and exploration Edit Bismarck Rock The first recorded information about Lake Victoria comes from Arab traders plying the inland routes in search of gold ivory other precious commodities and slaves The lake as seen from the shores of the Speke Resort in Kampala Uganda The lake existed and was known to many Africans in the catchment area who left no written records long before it was sighted by a European in 1858 when the British explorer John Hanning Speke reached its southern shore while on his journey with Richard Francis Burton to explore central Africa and locate the Great Lakes Believing he had found the source of the Nile on seeing this vast expanse of open water for the first time Speke named the lake after Queen Victoria Burton who had been recovering from illness at the time and resting further south on the shores of Lake Tanganyika was outraged that Speke claimed to have proved his discovery to have been the true source of the Nile River which Burton regarded as still unsettled A very public quarrel ensued which not only sparked a great deal of intense debate within the scientific community of the day but also much interest by other explorers keen to either confirm or refute Speke s discovery 104 In the late 1860s the famous Scottish explorer and missionary David Livingstone failed in his attempt to verify Speke s discovery instead pushing too far west and entering the River Congo system instead 105 Ultimately the Welsh American explorer Henry Morton Stanley on an expedition funded by the New York Herald newspaper confirmed the truth of Speke s discovery circumnavigating the lake and reporting the great outflow at Ripon Falls on the lake s northern shore Nalubaale Dam EditMain article Nalubaale Power Station The Nalubaale Hydroelectric Power Station in Njeru Uganda The only outflow for Lake Victoria is at Jinja Uganda where it forms the Victoria Nile The water for at least 12 000 years has drained across a natural rock weir In 1952 engineers acting for the government of Colonial Uganda blasted out the weir and reservoir to replace it with an artificial barrage to control the level of the lake and reduce the gradual erosion of the rock weir A standard for mimicking the old rate of outflow called the agreed curve was established setting the maximum flow rate at 300 to 1 700 cubic metres per second 392 2 224 cu yd sec depending on the lake s water level In 2002 Uganda completed a second hydroelectric complex in the area the Kiira Hydroelectric Power Station with World Bank assistance By 2006 the water levels in Lake Victoria had reached an 80 year low and Daniel Kull an independent hydrologist living in Nairobi Kenya calculated that Uganda was releasing about twice as much water as is allowed under the agreement 106 and was primarily responsible for recent drops in the lake s level Water use EditMany towns and cities are reliant on Victoria for their water supplies for farming and other uses 107 Lamadi water scheme Edit The Lamadi water scheme is a water and sanitation project that serves Mwanza and the satellite towns of Lamadi Misungwi Magu Bukoba and Musoma on the bank of Lake Victoria European Investment Bank started the project in 2013 with the aim of protecting the environmental health of the lake through improved water and sanitation to the towns whose pollution is part of the degradation of the lake The project aims to provide safe drinking water for an estimated one million people and improved sanitation for 100 000 people Sediment and suspended solids are filtered out using sand which acts like a sieve The water is then ready to be chlorinated or treated in another way The sand filtration helps reduce water borne diseases and is based on the use of the local environment 108 Transport EditMain article Lake Victoria ferries Since the 1900s Lake Victoria ferries have been an important means of transport between Uganda Tanzania and Kenya The main ports on the lake are Kisumu Mwanza Bukoba Entebbe Port Bell and Jinja Until 1963 the fastest and newest ferry MV Victoria was designated a Royal Mail Ship In 1966 train ferry services between Kenya and Tanzania were established with the introduction of MV Uhuru and MV Umoja The ferry MV Bukoba sank in the lake on 21 May 1996 with a loss of between 800 and 1 000 lives making it one of Africa s worst maritime disasters 109 Another tragedy occurred recently on 20 September 2018 that involved the passagers ferry MV Nyerere from Tanzania that caused the deaths of over 200 people 110 On 6 November 2022 Lake Victoria was the site of a commercial passenger aircraft crash Precision Air Flight 494 an ATR 42 500 carrying 39 passengers and four crew crashed while approaching Bukoba Airport resulting in 19 fatalities 111 112 See also Edit Lakes portal Africa portal Geography portal Kenya portalDarwin s Nightmare KishandaReferences Edit a b Hamilton Stuart Salisbury University 2016 Basin Lake Victoria Watershed inside vector polygon 2015 Data Set Harvard Dataverse doi 10 7910 DVN Z5RMYD a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help a b Hamilton Stuart Salisbury University 2016 Shoreline Lake Victoria vector polygon 2015 Data Set Harvard Dataverse doi 10 7910 DVN PWFW26 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help a b c d e f Hamilton Stuart 2018 Lake Victoria Statistics from this Dataverse Data Set Harvard Dataverse doi 10 7910 DVN FVJJ4A a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Database for Hydrological Time Series of Inland Waters DAHITI Victoria Lake retrieved 20 April 2017 For a comprehensiwe list of these islands see sw Ziwa Viktoria Stuart Hamilton 5 October 2016 Shoreline Lake Victoria vector polygon 2015 Data Set Harvard Dataverse doi 10 7910 dvn pwfw26 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help a b c Stuart Hamilton 13 November 2018 Lake Victoria Statistics from this Dataverse Data Set Harvard Dataverse doi 10 7910 dvn fvjj4a a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Saundry Peter Lake Victoria Lake Victoria Encyclopaedia Britannica a b Stuart Hamilton Taabu Anthony Munyaho Noah Krach Sarah Glaser 17 May 2018 Bathymetry TIFF Lake Victoria Bathymetry raster 2017 V7 Data Set Harvard Dataverse doi 10 7910 dvn soeknr a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help United Nations Development and Harmonisation of Environmental Laws Volume 1 Report on the Legal and Institutional Issues in the Lake Victoria Basin United Nations 1999 page 17 Stuart Hamilton 12 November 2017 Basin Lake Victoria Watershed inside vector polygon 2015 Harvard Dataverse Data Set doi 10 7910 dvn z5rmyd Hamilton Stuart 11 October 2016 Shoreline Lake Victoria vector line 2015 LakeVicFish Dataverse Data Set Harvard Dataverse doi 10 7910 dvn 5y5ivf a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help a b c d C F Hickling 1961 Tropical Inland Fisheries London Longmans J Prado R J Beare J Siwo Mbuga amp L E Oluka 1991 A catalogue of fishing methods and gear used in Lake Victoria UNDP FAO Regional Project for Inland Fisheries Development IFIP FAO RAF 87 099 TD 19 91 En Rome Food and Agricultural Organization The Victoria The Land the Races and their Customs with Specimens of Some of the Dialects World Digital Library 1899 Archived from the original on 29 May 2016 Retrieved 18 February 2013 Lake Ukerewe nTZ An Information Resource for Northern Tanzania David Marsh Retrieved 17 October 2020 Alberge Dalya 11 September 2011 How feud wrecked the reputation of explorer who discovered Nile s source The Guardian Retrieved 29 December 2013 Moorehead Alan 1960 Part One Chapters 1 7 The White Nile Harper amp Row ISBN 978 0 06 095639 4 a b c John Reader 2001 Africa Washington DC National Geographic Society pp 227 28 ISBN 978 0 7922 7681 4 Ouma J P B M 1970 Fluvial Differentiation in the Basin of Lake Victoria Journal of Hydrology New Zealand 9 2 221 223 JSTOR 43944206 a b c d e f Verheyen Salzburger Snoeks Meyer 2003 Origin of the Superflock of Cichlid Fishes from Lake Victoria East Africa Science 300 5617 325 329 Bibcode 2003Sci 300 325V doi 10 1126 science 1080699 PMID 12649486 S2CID 84478005 deMenocal Peter Ortiz Joseph Guilderson Tom Adkins Jess Sarnthein Michael Baker Linda Yarusinsky Martha January 2000 Abrupt onset and termination of the African Humid Period Quaternary Science Reviews 19 1 5 347 361 Bibcode 2000QSRv 19 347D doi 10 1016 S0277 3791 99 00081 5 ISSN 0277 3791 Simeon H Ominde 1971 Rural economy in West Kenya In S H Ominde ed Studies in East African Geography and Development London Heinemann Educational Books Ltd pp 207 29 ISBN 978 0 520 02073 3 vanden Bossche J P Bernacsek G M 1990 Source Book for the Inland Fishery Resources of Africa Issue 18 Volume 1 Food and Agriculture Organization United Nations p 291 ISBN 978 92 5 102983 1 Retrieved 4 January 2016 R E Hecky F W B Bugenyi P Ochumba J F Talling R Mugidde M Gophen L Kaufman 1994 Deoxygenation of the deep water of Lake Victoria East Africa Limnology and Oceanography 39 6 1476 81 Bibcode 1994LimOc 39 1476H doi 10 4319 lo 1994 39 6 1476 JSTOR 2838147 R E Hecky 1993 The eutrophication of Lake Victoria Verhandlungen der Internationale Vereinigung fur Limnologie 25 39 48 doi 10 1080 03680770 1992 11900057 a b c Peter B O Ochumba David I Kibaara 1989 Observations on blue green algal blooms in the open waters of Lake Victoria Kenya African Journal of Ecology 27 1 23 34 doi 10 1111 j 1365 2028 1989 tb00925 x Environmental and Social Management Framework ESMF PDF World Bank Document Early Warning System March 2018 Retrieved 26 May 2020 Keriako Tobiko 2021 Rising Water Levels in Kenya s Rift Valley Lakes Turkwel Gorge Dam and Lake Victoria PDF Government of Kenya and UNDP Archived from the original PDF on 28 April 2022 Retrieved 16 March 2022 Baraka Carey 17 March 2022 A drowning world Kenya s quiet slide underwater The Guardian Retrieved 17 March 2022 a b c Hamilton Stuart Munyaho Anthony Taabu Krach Noah Glaser Sarah 17 May 2018 Bathymetry TIFF Lake Victoria Bathymetry raster 2016 LakeVicFish Dataverse Data Set Harvard Dataverse doi 10 7910 dvn soeknr a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help LV Bathy faculty salisbury edu Retrieved 24 October 2016 Kingdon J 1997 The Kingdon Guide to African Mammals Academic Press Limited London ISBN 0 12 408355 2 a b Spawls Howell Drewes and Ashe 2002 A Field Guide to the Reptiles of East Africa Academic Press London ISBN 0 12 656470 1 Witte F de Zeeuw M P Brooks E 2016 Haplochromis nyererei IUCN Red List of Threatened Species 2016 e T60668A97125826 doi 10 2305 IUCN UK 2016 1 RLTS T60668A97125826 en Retrieved 14 January 2018 a b c Witte Msuku Wanink Seehausen Katunzi Goudswaard Goldschmidt 2000 Recovery of cichlid species in Lake Victoria an examination of factors leading to differential extinction Reviews in Fish Biology and Fisheries 10 2 233 41 doi 10 1023 a 1016677515930 S2CID 39566440 a b c d Witte Goldschmidt Goudswaard Ligtvoet van Oijen Wanink 1992 Species extinction and concomitant ecological changes in Lake Victoria Netherlands Journal of Zoology 42 2 3 214 32 doi 10 1163 156854291X00298 a b c d Meier Marques Mwaiko Wagner Excoffier Seehausen 2017 Ancient hybridization fuels rapid cichlid fish adaptive radiations Nature Communications 8 14363 Bibcode 2017NatCo 814363M doi 10 1038 ncomms14363 PMC 5309898 PMID 28186104 a b c DeWeerdt S 28 February 2004 Dark secret of the lake New Scientist Retrieved 26 March 2017 a b c d Sayer C A L Maiz Tome and W R T Darwall 2018 Freshwater biodiversity in the Lake Victoria Basin Guidance for species conservation site protection climate resilience and sustainable livelihoods Cambridge UK and Gland Switzerland IUCN doi 10 2305 IUCN CH 2018 RA 2 en Turner Seehausen Knight Allender Robinson 2001 How many species of cichlid fishes are there in African lakes Molecular Ecology 10 3 793 806 doi 10 1046 j 1365 294x 2001 01200 x PMID 11298988 S2CID 12925712 J C Stager T C Johnson 2008 The late Pleistocene desiccation of Lake Victoria and the origin of its endemic biota Hydrobiologia 596 1 5 16 doi 10 1007 s10750 007 9158 2 S2CID 42372016 a b c d e f g h i j k l m n o p q Lowe McConnell R 2009 Fisheries and cichlid evolution in the African Great Lakes progress and problems Freshwater Reviews 2 2 131 51 doi 10 1608 frj 2 2 2 S2CID 54011001 McClanahan T and T P Young 1996 East African Ecosystems and Their Conservation pp 201 06 ISBN 978 0 19 510817 0 Witte F de Zeeuw M P Brooks E 2010 Haplochromis thereuterion IUCN Red List of Threatened Species 2010 e T185857A8492470 doi 10 2305 IUCN UK 2010 3 RLTS T185857A8492470 en Retrieved 14 January 2018 Steeves G Haplochromis thereuterion Cichlid Forum Retrieved 28 March 2017 Rijssel Moser Frei Seehausen 2018 Prevalence of disruptive selection predicts extent of species differentiation in Lake Victoria cichlids Proceedings of the Royal Society B Biological Sciences 285 1871 1871 doi 10 1098 rspb 2017 2630 PMC 5805951 PMID 29367400 a b van Rijssel Witte 2013 Adaptive responses in resurgent Lake Victoria cichlids over the past 30 years Evol Ecol 27 2 253 67 doi 10 1007 s10682 012 9596 9 S2CID 2291741 Goldschmidt Witte Wanink 1993 Cascading Effects of the Introduced Nile Perch on the Detritivorous Phytoplanktivorous Species in the Sublittoral Areas of Lake Victoria Conservation Biology 7 3 686 700 doi 10 1046 j 1523 1739 1993 07030686 x a b IUCN Red Lists Geographic Patterns Eastern Africa Retrieved 25 March 2017 a b Fiedler P L and P M Kareiva editors 1998 Conservation Biology For the Coming Decade 2nd edition pp 209 10 ISBN 978 0 412 09661 7 Chapman Chapman Chandler 1996 Wetland ecotones as refugia for endangered fishes Biological Conservation 78 3 263 70 doi 10 1016 s0006 3207 96 00030 4 Zeeuw Westbroek van Oijen Witte 2013 Two new species of zooplanktivorous haplochromine cichlids from Lake Victoria Tanzania ZooKeys 256 1 34 doi 10 3897 zookeys 256 3871 PMC 3650828 PMID 23717179 McGee Borstein Neches Buescher Seehausen Wainwright 2015 A pharyngeal jaw evolutionary innovation facilitated extinction in Lake Victoria cichlids Science 350 6264 1077 79 Bibcode 2015Sci 350 1077M doi 10 1126 science aab0800 PMID 26612951 Yirka B 27 November 2015 Study shows evolution does not always mean more diversification Phys org press release Retrieved 28 March 2017 Leveque C 1997 Biodiversity Dynamics and Conservation The Freshwater Fish of Tropical Africa p 358 ISBN 978 0 521 57033 6 Steeves G New to the hobby Haplochromines Cichlid Forum Retrieved 28 March 2017 Rizza D Looking At Victoria Cichlids Conscientious Aquarist Magazine Retrieved 28 March 2017 McAndrews R and D I Warmolts 25 May 2015 Progress in breeding freshwater fish Boston Aquarium Society Retrieved 14 April 2017 Twongo T K Bayona J D R amp Hanssens M 2006 Oreochromis esculentus IUCN Red List of Threatened Species 2006 e T15457A4587658 doi 10 2305 IUCN UK 2006 RLTS T15457A4587658 en Retrieved 14 January 2018 Twongo T K Bayona J D R amp Hanssens M 2006 Oreochromis variabilis IUCN Red List of Threatened Species 2006 e T15458A4587788 doi 10 2305 IUCN UK 2006 RLTS T15458A4587788 en 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March 2017 Cumberlidge N 2009 Freshwater Crabs and Shrimps Crustacea Decapoda of the Nile Basin Chapter 27 pp 547 61 in Dumony H J editor The Nile Origin Environments Limnology and Human Use Monographiae Biologicae Vol 89 Springer New York ISBN 978 1 4020 9726 3 Cumberlidge N 2016 Potamonautes emini IUCN Red List of Threatened Species 2016 e T44523A84352263 doi 10 2305 IUCN UK 2016 3 RLTS T44523A84352263 en Retrieved 14 January 2018 Cumberlidge N Clark P F 2017 Description of three new species of Potamonautes MacLeay 1838 from the Lake Victoria region in southern Uganda East Africa Brachyura Potamoidea Potamonautidae European Journal of Taxonomy 371 1 19 doi 10 5852 ejt 2017 371 Goudswaard K Witte F Wanink J H 2006 The shrimp Caridina nilotica in Lake Victoria East Africa before and after the Nile perch increase Hydrobiologia 563 1 31 44 doi 10 1007 s10750 005 1385 9 S2CID 40935454 a b Seddon M Appleton C Van Damme D Graf D 2011 Darwall W Smith K Allen D Holland R Harrison I Brooks E eds Freshwater molluscs of Africa diversity distribution and conservation The Diversity of Life in African Freshwaters Under Water Under Threat An Analysis of the Status and Distribution of Freshwater Species Throughout Mainland Africa pp 92 119 ISBN 978 2 8317 1345 8 Brown D 1994 Freshwater snails of Africa and their medical importance 2nd edition ISBN 0 7484 0026 5 Mwambungu J A 2004 The diversity of benthic molluscs of Lake Victoria and Lake Burigi Tanzania Journal of Science 30 1 21 32 doi 10 4314 tjs v30i1 18384 Senthilingam M 9 February 2016 The snails spreading fever across Africa CNN Retrieved 16 May 2018 Chege N 1995 Lake Victoria A Sick Giant PDF People amp the Planet Archived from the original PDF on 17 May 2018 Retrieved 16 May 2018 Pomerantz J 19 September 2015 Haplochromine Cichlids of Lake Victoria ecologycenter us Retrieved 16 May 2018 Nelson Ximena J Jackson Robert R Sune Godfrey 2005 Use of Anopheles Specific Prey Capture Behavior by the Small Juveniles of Evarcha culicivora a Mosquito Eating Jumping Spider The Journal of Arachnology 33 2 541 548 doi 10 1636 05 3 1 ISSN 0161 8202 JSTOR 4129852 S2CID 55244513 Kim Geheb 1997 The Regulators and the regulated fisheries management options and dynamics in Kenya s Lake Victoria Fishery PhD thesis University of Sussex Lake Victoria Fisheries Organization 2016 Lake Victoria Fisheries An introduction Archived from the original on 15 September 2016 Retrieved 27 March 2017 a b c d e Njiru Waithaka Muchiri van Knaap Cowx 2005 Exotic introductions to the fishery of Lake Victoria What are the management options Lakes amp Reservoirs Research and Management 10 3 147 55 doi 10 1111 j 1440 1770 2005 00270 x FishBase team RMCA amp Geelhand D 2016 Labeo victorianus IUCN Red List of Threatened Species 2016 e T60318A47182908 doi 10 2305 IUCN UK 2016 3 RLTS T60318A47182908 en Retrieved 14 January 2018 a b c d e f g h i Pringle R M 2005 The Origins of the Nile Perch in Lake Victoria BioScience 55 9 780 787 Froese Rainer Pauly Daniel eds 2017 Lates niloticus in FishBase March 2017 version Breitinger Jan C 24 November 2021 A Lake to Serve The Exploration Modification and Degradation of Lake Victoria 1920s to 1960s The Journal of Imperial and Commonwealth History 50 1 144 184 doi 10 1080 03086534 2021 1985212 S2CID 244667637 Retrieved 22 July 2022 Nile Perch and the Future of Lake Victoria Archived from the original on 11 January 2015 Retrieved 11 January 2015 a b Luilo G B August 01 2008 Lake Victoria water resources management challenges and prospects a need for equitable and sustainable institutional and regulatory frameworks African Journal of Aquatic Science 33 2 105 13 Muli J Mavutu K Ntiba J 2000 Micro invertebrate fauna of water hyacinth in Kenyan waters of Lake Victoria International Journal of Ecology and Environmental Science 20 281 302 a b c Kateregga E amp Sterner T January 01 2009 Lake Victoria Fish Stocks and the Effects of Water Hyacinth Journal of Environment amp Development 18 1 62 78 Mailu A M G R S Ochiel W Gitonga and S W Njoka 1998 Water Hyacinth An Environmental Disaster in the Winam Gulf of Lake Victoria and its Control pp 101 05 Gichuki J Guebas F Dahdouh Mugo J Rabour C O Triest L Dehairs F 2001 Species inventory and the local uses of the plants and fishes of the Lower Sondu Miriu wetland of Lake Victoria Kenya Hydrobiologia 458 99 106 doi 10 1023 A 1013192330498 S2CID 34576879 a b c d e Albright T P Moorhouse T G amp McNabb T J January 1 2004 The Rise and Fall of Water Hyacinth in Lake Victoria and the Kagera River Basin 1989 2001 Journal of Aquatic Plant Management 42 73 84 Jager J Bohunovsky L Radosh L amp Sustainability Project 2008 Our planet How much more can earth take London Haus Ochiel G S A M Mailu W Gitonga and S W Njoka 1999 Biological Control of Water Hyacinth on Lake Victoria Kenya pp 115 18 Mallya G A 1999 Water hyacinth control in Tanzania pp 25 29 United Nations Environment Programme amp Belgium 2006 Africa s lakes Atlas of our changing environment Nairobi Kenya UNEP Crisman T L Chapman Lauren J Chapman Colin A amp Kaufman Les S 2003 Conservation ecology and management of African fresh waters Gainesville University Press of Florida Toxic dump The poisons killing lake Victoria Daily Nation Retrieved 18 February 2020 Nantaba Florence Wasswa John Kylin Henrik Palm Wolf Ulrich Bouwman Hindrik Kummerer Klaus January 2020 Occurrence distribution and ecotoxicological risk assessment of selected pharmaceutical compounds in water from Lake Victoria Uganda Chemosphere 239 124642 Bibcode 2020Chmsp 239l4642N doi 10 1016 j chemosphere 2019 124642 ISSN 0045 6535 PMID 31521936 S2CID 202581465 Water Hyacinth Re invades Lake Victoria Image of the Dat NASA 21 February 2007 Odhiambo Harold Scientists raise concerns over pollution of Lake Victoria The Standard Retrieved 18 February 2020 LakeVicFish Dataverse dataverse harvard edu Retrieved 27 May 2020 Speke John Hanning Dictionary of National Biography London Smith Elder amp Co 1885 1900 Kenya Africa Lake Victoria in Kenya Jambo Kenya Network Archived from the original on 17 June 1997 Retrieved 14 July 2008 Fred Pearce 9 February 2006 Uganda pulls plug on Lake Victoria New Scientist 2538 12 Archived from the original on 13 October 2008 Retrieved 2 September 2017 Lake Victoria Size Map Countries amp Facts Encyclopedia Britannica Retrieved 24 August 2020 Development Solutions Creative flow European Investment Bank Retrieved 24 August 2020 Harris Edward 29 September 2002 Diver s recover 180 bodies from Africa s worst ferry disaster Panama City News Herald Panama city Florida p 8 Retrieved 6 April 2018 via Newspaperarchive com The tragedy was one of Africa s deadliest maritime disasters On May 21st 1996 at least 500 people died in the sinking of the MV Bukova on Lake Victoria Ferry tragedy More than 200 feared dead in Tanzania The East African Retrieved 18 February 2020 Mukhtar Idris Said Moorhouse Lauren Madowo Larry 6 November 2022 19 dead after commercial aircraft crashes into Lake Victoria in Tanzania CNN Retrieved 6 November 2022 Dausen Nuzulack 6 November 2022 Passenger plane crashes into Lake Victoria in Tanzania 19 dead Reuters Retrieved 6 November 2022 External links Edit Wikimedia Commons has media related to Lake Victoria Wikisource has the text of a 1911 Encyclopaedia Britannica article about Lake Victoria Decreasing levels of Lake Victoria Worry East African Countries New Scientist article Archived 13 October 2008 at the Wayback Machine on Uganda s violation of the agreed curve for hydroelectric water flow Dams Draining Lake Victoria Archived 10 March 2012 at the Wayback Machine A Naturalist on Lake Victoria with an Account of Sleeping Sickness and the Tse tse Fly 1920 T F Unwin Ltd London Biodiversity Archive Video of Lake Victoria Institutions of the East African Community Lake Victoria Fisheries Organisation Retrieved from https en wikipedia org w index php title Lake Victoria amp oldid 1150167437, wikipedia, wiki, book, books, 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