The Sukuma are a Bantu ethnic group from the southeastern African Great Lakes region. They are the largest ethnic group in Tanzania and North Western Uganda, with an estimated 10 million members or 16 percent of the country's total population. Sukuma means "north" and refers to "people of the north." The Sukuma refer to themselves as Basukuma (plural) and Nsukuma (singular). They migrate from North Western Uganda to Tanzania to keeping animals and agriculture activities.
157-576: The Sukuma live in northwestern Tanzania on or near the southern shores of Lake Victoria , and various areas of the administrative districts of the Mwanza , southwestern tip of Mara Region , Simiyu Region and Shinyanga Region . The northern area of their residence is in the Serengeti Plain. Sukuma families have migrated southward, into the Rukwa Region and Katavi Region , encroaching on
314-604: A Nyamwezi people who had moved northwestward to escape Mirambo 's raids with the result that game and tsetse re-occupied the deserted area. Unyanyembe, the most important kingdom of the Nyamwezi, centered on Tabora and obtained its meat supplies from the Sukuma. By 1892, however, the herds of cattle began to decline due to rinderpest and tsetse fly , and while two-thirds of German East Africa became unsuitable for cattle, and cattle in general probably did not recover until after
471-556: A few species are extinct in the wild (only survive in captivity). 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. 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 ). In 1927–1928 Michael Graham conducted
628-502: A few species are extinct in the wild (only survive in captivity). 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. 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 ). In 1927–1928 Michael Graham conducted
785-459: 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. 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. Ultimately,
942-400: 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. 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. Ultimately,
1099-498: A holistic view the world as interconnected with all living things, natural and supernatural. The Sukuma are one of many ethnic groups who use animals in their traditional medicine, also known as "zootherapy." Like other African groups including the Eswatini Inyangas and Bight of Benin, many believe that traditional medicines derived from animals are more effective than Western-style medicine . Plants and animals have been
1256-519: A maximum depth of 80–81 m (262–266 ft). Its catchment area covers 169,858 km (65,583 sq mi). The lake has a shoreline of 7,142 km (4,438 mi) when digitized at the 1:25,000 level, with islands constituting 3.7% of this length. The lake's area is divided among three countries: Tanzania occupies 49% (33,700 km (13,000 sq mi)), Uganda 45% (31,000 km (12,000 sq mi)), and Kenya 6% (4,100 km (1,600 sq mi)). The lake
1413-519: A maximum depth of 80–81 m (262–266 ft). Its catchment area covers 169,858 km (65,583 sq mi). The lake has a shoreline of 7,142 km (4,438 mi) when digitized at the 1:25,000 level, with islands constituting 3.7% of this length. The lake's area is divided among three countries: Tanzania occupies 49% (33,700 km (13,000 sq mi)), Uganda 45% (31,000 km (12,000 sq mi)), and Kenya 6% (4,100 km (1,600 sq mi)). The lake
1570-797: A result of the spread of the invasive water hyacinth (an optimum snail habitat), and the loss of many snail-eating cichlids in the lake. 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. Lake Victoria supports Africa's largest inland fishery (as of 1997). 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 ). Some of these, including tilapia and ningu ( Labeo victorianus ), had already declined in
1727-745: A result of the spread of the invasive water hyacinth (an optimum snail habitat), and the loss of many snail-eating cichlids in the lake. 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. Lake Victoria supports Africa's largest inland fishery (as of 1997). 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 ). Some of these, including tilapia and ningu ( Labeo victorianus ), had already declined in
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#17327937215081884-613: 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, and was primarily responsible for recent drops in
2041-408: 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, and was primarily responsible for recent drops in
2198-491: 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. 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
2355-428: 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. 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
2512-583: 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
2669-583: 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
2826-436: Is Caridina nilotica , which is common and widespread in Lake Victoria. Lake Victoria is home to 28 species of freshwater snails (e.g., Bellamya , Biomphalaria , Bulinus , Cleopatra , Gabbiella , and Melanoides ), including 12 endemic species/subspecies. There are 17 species of bivalves ( Corbicula , Coelatura , Sphaerium , and Byssanodonta ), including 6 endemic species and subspecies. It
2983-436: Is Caridina nilotica , which is common and widespread in Lake Victoria. Lake Victoria is home to 28 species of freshwater snails (e.g., Bellamya , Biomphalaria , Bulinus , Cleopatra , Gabbiella , and Melanoides ), including 12 endemic species/subspecies. There are 17 species of bivalves ( Corbicula , Coelatura , Sphaerium , and Byssanodonta ), including 6 endemic species and subspecies. It
3140-566: Is Africa's largest lake by area, the world's largest tropical lake, and the world's second-largest fresh water lake by surface area after Lake Superior in North America. In terms of volume, Lake Victoria is the world's ninth-largest continental lake , containing about 2,424 km (1.965 × 10 acre⋅ft) of water. Lake Victoria occupies a shallow depression in Africa. The lake has an average depth of 40 m (130 ft) and
3297-583: 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.,
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#17327937215083454-472: 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.,
3611-465: 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
3768-414: 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
3925-460: 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 . Though having multiple local language names ( Swahili : Ukerewe ; Dholuo : Nam Lolwe ; Luganda : 'Nnalubaale ; Kinyarwanda : Nyanza ), the lake was renamed after Queen Victoria by the explorer John Hanning Speke ,
4082-410: 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 . Though having multiple local language names ( Swahili : Ukerewe ; Dholuo : Nam Lolwe ; Luganda : 'Nnalubaale ; Kinyarwanda : Nyanza ), the lake was renamed after Queen Victoria by the explorer John Hanning Speke ,
4239-690: Is in remission and this trend could be permanent if control efforts are continued. 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
4396-634: Is in remission and this trend could be permanent if control efforts are continued. 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
4553-453: 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. 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. This may increase as
4710-453: 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. 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. This may increase as
4867-426: Is near-endemic. 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. 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
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5024-426: Is near-endemic. 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. 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
5181-645: Is sometimes used for the Sukuma area. The name "Sukuma" literally means "north," but it has become a term of ethnic identification. The Nyamwezi and Sukuma region lies between 2°10′ and 6°20′ S and 31°00′ and 35°00′ E. The Nyamwezi "home" area is in the Tabora Region and western Shinyanga Region, and Sukumaland lies to the north and east, covering the eastern Shinyanga Region and the Mwanza Region. There has been much population movement in and beyond these areas, and members of both groups have also settled on
5338-795: Is spread out among small farm plots and sparse vegetation. As with the Nyamwezi , all members of the five groups in Greater Unyamwezi identified themselves as Wanyamwezi to those outside of the "greater" area, but among themselves use Sukuma. They call themselves "Sukuma" (Northerners) when speaking to Nyamwezi, but use Nyamwezi when speaking to anyone else. The groups can be called the Nyamwezi–Sukuma complex, for, while never united, they were very closely related in attitude and way of life. Like most of their neighbors, they were an ethnic group divided into many smaller groups. Some claim they were
5495-533: Is the legal and illegal trafficking of wild animals for pets. There are also weak policies for regulating the census of endangered animals. Traditional healers do not pose as big of a threat to conservation efforts as commercial hunters do. Unlike the latter group, traditional hunters and medicine men only hunt what they need. Other than medicinal purposes, the Sukuma people use animal resources for things such as decoration and clothing. For example, animal skins are used for house decoration and bags. Relationships between
5652-629: The Brachystegia - Isoberlinia association; these areas are often called miombo country, after one of these trees. Lower areas of grass and thornbush steppe are also common, and in Sukumaland there are large tracts of park steppe interspersed with baobabs . Lake Victoria Lake Victoria is one of the African Great Lakes . With a surface area of approximately 59,947 km (23,146 sq mi), Lake Victoria
5809-485: The African humid period began. Lake Victoria receives 80 percent of its water from direct rainfall. 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. 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
5966-431: The African humid period began. Lake Victoria receives 80 percent of its water from direct rainfall. 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. 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
6123-525: 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. Many towns and cities are reliant on Lake Victoria for their water supplies, for farming and other uses. The Lamadi water scheme is
6280-399: 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. Many towns and cities are reliant on Lake Victoria for their water supplies, for farming and other uses. The Lamadi water scheme is
6437-443: The hippopotamus , African clawless otter , spotted-necked otter , marsh mongoose , sitatunga , bohor reedbuck , defassa waterbuck , cane rats , and giant otter shrew . 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 . The Williams' mud turtle is restricted to Lake Victoria and other lakes, rivers, and swamps in
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6594-443: The hippopotamus , African clawless otter , spotted-necked otter , marsh mongoose , sitatunga , bohor reedbuck , defassa waterbuck , cane rats , and giant otter shrew . 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 . The Williams' mud turtle is restricted to Lake Victoria and other lakes, rivers, and swamps in
6751-465: The First World War, large valuable herds of cattle were retained by the Sukuma who were then still able to escape any great social change by exploiting the herds economically. Sukuma tradition suggests that famine did become more common towards the end of the nineteenth century, leaving conservative Sukuma blaming religious innovation for the natural disasters and expecting regular sacrifices for
6908-666: 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 in Kazeh (near present-day Tabora ), 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
7065-495: 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 in Kazeh (near present-day Tabora ), 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
7222-468: The Nile perch, since that requires a significant amount of capital resources. 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
7379-468: The Nile perch, since that requires a significant amount of capital resources. 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
7536-582: 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. 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. As the species was already present, there were few objections when more Nile perch were transferred to Victoria to further bolster
7693-466: 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. 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. As the species was already present, there were few objections when more Nile perch were transferred to Victoria to further bolster
7850-450: The Owen Falls Dam when shut down for maintenance, but this is considered highly unlikely by many scientists. The Nile perch had spread throughout the lake by 1970. 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. Due to the presence of the Nile perch, the natural balance of the lake's ecosystem has been disrupted. The food chain
8007-450: The Owen Falls Dam when shut down for maintenance, but this is considered highly unlikely by many scientists. The Nile perch had spread throughout the lake by 1970. 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. Due to the presence of the Nile perch, the natural balance of the lake's ecosystem has been disrupted. The food chain
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#17327937215088164-586: The Sukuma and their non-Nyamwezi neighbors, the Tatoga , were generally good and they did not regard each other as enemies, as they were mutually dependent on one another. The Tatoga needed the grain of the Sukuma while the Sukuma needed the cattle and the highly regarded rainmaking diviners of the Tatoga (the Tatoga were considered the very best at this important and highly specialized activity). The Maasai , however, were considered enemies. The Tatoga–Sukuma relationship
8321-778: The Sukuma. For this reason, up until the time of the dissolution of the chieftain system, all chiefs and major headmen represented themselves as Taturu even though they were now within the Sukuma area. The Nyamwezi (also called Dakama, or people of the South) and Sukuma (also called people of the North) are two closely related ethnic groups that live principally in the region to the south of Lake Victoria in west-central Tanzania. When using ethnic names, they describe themselves as "Banyamwezi" (sing. Munyamwezi) and "Basukuma" (sing. Musukuma) respectively; they refer to their home areas as "Bunyamwezi" or " Unyamwezi ," and as "Busukuma." The term "Sukumaland"
8478-474: The Tatoga (Taturu) were their leaders and chiefs when they migrated from the north; the Taturu were the cattle herders and needed open plains for their cattle and moved into the greater Serengeti area. The Sukuma were left closer to the big Nyanza (Lake Victoria), cleared the forests and became the agriculturalists. Even then, when the Taturu moved out toward the plains, they left Taturu administrators to "rule" over
8635-419: The basis for Sukuma medicine for centuries; however, nowadays plant medicines are used more. The Sukuma people use a system of naming that allows them to distinguish animals according to their medical purposes. Healers organize faunal medicines by first taking a list of known diseases and their symptoms, then making another list of plants, animals, and their healing properties. Within the communities, healers are
8792-582: The coast and elsewhere. Sukuma and members of other groups, such as the Tutsi and the Sumbwa, are often found in Nyamwezi villages, but Sukuma villages are ethnically more homogeneous. Sukuma took over the Geita area of Mwanza Region during the colonial period, and they have expanded farther west since then. They have also moved down into Nzega District and the neighboring Igunga District , and some have migrated into
8949-462: The colonial government. In the following decades, the pressure to introduce the Nile perch continued, as did warnings about the possible effects of doing it. 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
9106-403: The colonial government. In the following decades, the pressure to introduce the Nile perch continued, as did warnings about the possible effects of doing it. 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
9263-575: The complete disappearance of many endemic cichlid species has been called the "most dramatic example of human-caused extinctions within an ecosystem". 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. Among the introductions are several tilapias : redbreast ( Coptodon rendalli ), redbelly ( C. zillii ), Nile ( Oreochromis niloticus ) and blue-spotted tilapias ( O. leucostictus ). Although these have contributed to
9420-575: The complete disappearance of many endemic cichlid species has been called the "most dramatic example of human-caused extinctions within an ecosystem". 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. Among the introductions are several tilapias : redbreast ( Coptodon rendalli ), redbelly ( C. zillii ), Nile ( Oreochromis niloticus ) and blue-spotted tilapias ( O. leucostictus ). Although these have contributed to
9577-544: The current Lake Victoria basin . 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. Geological cores taken from its bottom show Lake Victoria has dried up completely at least three times since it formed. These drying cycles are probably related to past ice ages , which were times when precipitation declined globally. Lake Victoria last dried out about 17,300 years ago, and it refilled 14,700 years ago as
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#17327937215089734-544: The current Lake Victoria basin . 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. Geological cores taken from its bottom show Lake Victoria has dried up completely at least three times since it formed. These drying cycles are probably related to past ice ages , which were times when precipitation declined globally. Lake Victoria last dried out about 17,300 years ago, and it refilled 14,700 years ago as
9891-423: The detritivores). 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 . Some of the threatened Lake Victoria cichlid species have captive "insurance" populations in zoos, public aquaria and among private aquarists, and
10048-423: The detritivores). 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 . Some of the threatened Lake Victoria cichlid species have captive "insurance" populations in zoos, public aquaria and among private aquarists, and
10205-488: The drier months. The year can be broadly divided into a rainy season, from about November until April, and a dry season the rest of the year. Average annual rainfall is about 75 centimetres (30 in) for most of the Sukuma area, and about 90 centimetres (35 in) for Unyamwezi, but there is much variation from year to year and from place to place. Across the region, there is a regular sequence of soil and vegetation zones. The upper levels are dry woodland typified by trees of
10362-422: The ecosystem, it is estimated that at least 200 species (about 40 percent) of Lake Victoria haplochromines have become extinct, including more than 100 undescribed species. Initially it was feared that this number was even higher, by some estimates 65 percent of the total species, but several species that were feared extinct have been rediscovered after the Nile perch started to decline in the 1990s. Several of
10519-422: The ecosystem, it is estimated that at least 200 species (about 40 percent) of Lake Victoria haplochromines have become extinct, including more than 100 undescribed species. Initially it was feared that this number was even higher, by some estimates 65 percent of the total species, but several species that were feared extinct have been rediscovered after the Nile perch started to decline in the 1990s. Several of
10676-480: The end of 2001. 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). The invasive weed was first attempted to be controlled by hand, removed manually from
10833-427: The end of 2001. 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). The invasive weed was first attempted to be controlled by hand, removed manually from
10990-418: 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 ). As early as the 1920s, it was proposed to introduce a large pelagic predator such as the Nile perch to improve
11147-418: 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 ). As early as the 1920s, it was proposed to introduce a large pelagic predator such as the Nile perch to improve
11304-450: The feeding apparatus, changes to the eyes (giving them better sight in turbid water) and smaller head/larger caudal peduncle (allowing faster swimming). The piscivorous (affected by both predation and competition from Nile perch ), molluscivorous and insectivorous haplochromines were particularly hard hit with many extinctions. Others have become extinct in their pure form, but survive as hybrids between close relatives (especially among
11461-450: The feeding apparatus, changes to the eyes (giving them better sight in turbid water) and smaller head/larger caudal peduncle (allowing faster swimming). The piscivorous (affected by both predation and competition from Nile perch ), molluscivorous and insectivorous haplochromines were particularly hard hit with many extinctions. Others have become extinct in their pure form, but survive as hybrids between close relatives (especially among
11618-486: The fertility of the lake is dependent on the rate at which these nutrients can be taken up by fish and other organisms. There is little doubt that Haplochromis played an important role in returning detritus and plankton back into solution. 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
11775-486: The fertility of the lake is dependent on the rate at which these nutrients can be taken up by fish and other organisms. There is little doubt that Haplochromis played an important role in returning detritus and plankton back into solution. 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
11932-487: The first Briton to document it in 1858, while on an expedition with Richard Francis Burton . 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. 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
12089-433: The first Briton to document it in 1858, while on an expedition with Richard Francis Burton . 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. 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
12246-492: 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. ". Furthermore, Graham noted that
12403-492: 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. ". Furthermore, Graham noted that
12560-406: The first half of the 20th century due to overfishing . 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
12717-406: The first half of the 20th century due to overfishing . 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
12874-514: The first true bathymetric map of the lake. 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. 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
13031-402: The first true bathymetric map of the lake. 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. 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
13188-401: 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. 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
13345-401: 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. 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
13502-474: The household or chiefdom ancestors. As with all Nyamwezi, the Sukuma, being agriculturalists, ridged their fields to accommodate the fertile but rather arid region. At the same time they had herds, having acquired them from the Tatoga people, but since "mixed" farming was practiced they were not considered pastoralists. Sukumaland also contained and used iron deposits, re-exporting some 150,000 iron hoes to Tabora. The Sukuma believe in spirit possession and have
13659-458: The inland routes in search of gold , ivory , other precious commodities, and slaves . 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
13816-404: The inland routes in search of gold , ivory , other precious commodities, and slaves . 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
13973-521: The intake of water for industries. 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. Growth of the water hyacinth in Lake Victoria has been tracked since 1993, reaching its maxima biomass in 1997 and then declining again by
14130-521: The intake of water for industries. 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. Growth of the water hyacinth in Lake Victoria has been tracked since 1993, reaching its maxima biomass in 1997 and then declining again by
14287-411: 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. 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. On 6 November 2022, Lake Victoria
14444-411: 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. 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. On 6 November 2022, Lake Victoria
14601-547: 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. By itself, this vegetative matter decays slowly. Animal flesh decays considerably faster, however, so
14758-547: 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. By itself, this vegetative matter decays slowly. Animal flesh decays considerably faster, however, so
14915-805: 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. 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
15072-622: 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. 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
15229-406: 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. 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
15386-406: 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. 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
15543-411: The lake in the late 1990s". 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
15700-411: The lake in the late 1990s". 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
15857-473: 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. 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. Increased logging and act of deforestation has led to environmental degradation around
16014-473: 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. 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. Increased logging and act of deforestation has led to environmental degradation around
16171-405: The lake's level. 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
16328-405: The lake's level. 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
16485-515: The lake's western shore. Lake Victoria is drained solely by the Nile River near Jinja, Uganda, on the lake's northern shore. In the Kenya sector, the main influent rivers are the Sio , Nzoia , Yala , Nyando , Sondu Miriu , Mogusi , and Migori . 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
16642-409: The lake's western shore. Lake Victoria is drained solely by the Nile River near Jinja, Uganda, on the lake's northern shore. In the Kenya sector, the main influent rivers are the Sio , Nzoia , Yala , Nyando , Sondu Miriu , Mogusi , and Migori . 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
16799-496: The lake's wide area; from increased nutrient inflows via rivers, and from increased pollution associated with settlement along its shores. Between 2010 and 2022 the surface area of Lake Victoria increased by 15% flooding lakeside communities. 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). A 2016 project digitized ten-thousand points and created
16956-496: The lake's wide area; from increased nutrient inflows via rivers, and from increased pollution associated with settlement along its shores. Between 2010 and 2022 the surface area of Lake Victoria increased by 15% flooding lakeside communities. 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). A 2016 project digitized ten-thousand points and created
17113-449: The lake; however, re-growth occurred quickly. Public awareness exercises were also conducted. 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. A green power plant that uses harvested water hyacinth (but also can use other degradable waste)
17270-449: The lake; however, re-growth occurred quickly. Public awareness exercises were also conducted. 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. A green power plant that uses harvested water hyacinth (but also can use other degradable waste)
17427-634: 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. These changes have arisen for multiple reasons: successive burning within its basin, soot and ash from which has been deposited over
17584-634: 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. These changes have arisen for multiple reasons: successive burning within its basin, soot and ash from which has been deposited over
17741-404: 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
17898-404: 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
18055-459: The native Lake Victoria sardine (30 percent). Because of its small size, the abundant open-water Lake Victoria sardine only supported minor fisheries until the decline of other natives. 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. A number of environmental issues are associated with Lake Victoria and
18212-459: The native Lake Victoria sardine (30 percent). Because of its small size, the abundant open-water Lake Victoria sardine only supported minor fisheries until the decline of other natives. 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. A number of environmental issues are associated with Lake Victoria and
18369-436: The ones who direct what and how each animal will be used. For example, pangolins are believed to be a sign for a good harvest year, so healers will sell pangolin scales to protect crops. Because snakes and porcupines are a danger to people and crops in Sukumaland, medicine men and healers captured them to be used as entertainment. There is little information on the Sukuma tribes' use of animals in their medicine because most of
18526-462: 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
18683-462: 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
18840-540: 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. The water hyacinth
18997-540: 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. The water hyacinth
19154-570: 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
19311-450: 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
19468-577: The region dried out, as happened to Lake Victoria about 15,000 years ago. 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
19625-457: The region dried out, as happened to Lake Victoria about 15,000 years ago. 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
19782-403: The region reducing the absorption of polluting chemicals and deteriorating the water quality. As of 2016, an environmental data repository exists for Lake Victoria. The repository contains shoreline, bathymetry, pollution, temperature, wind vector, and other important data for both the lake and the wider Basin. The first recorded information about Lake Victoria comes from Arab traders plying
19939-403: The region reducing the absorption of polluting chemicals and deteriorating the water quality. As of 2016, an environmental data repository exists for Lake Victoria. The repository contains shoreline, bathymetry, pollution, temperature, wind vector, and other important data for both the lake and the wider Basin. The first recorded information about Lake Victoria comes from Arab traders plying
20096-598: The region, notably Kyoga , Edward – George , Albert, and Kivu . 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 . This deep lake may have functioned as an "evolutionary reservoir" for this haplochromine group in periods where other shallower lakes in
20253-531: The region, notably Kyoga , Edward – George , Albert, and Kivu . 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 . This deep lake may have functioned as an "evolutionary reservoir" for this haplochromine group in periods where other shallower lakes in
20410-403: The remaining species are seriously threatened and additional extinctions are possible. Some species have survived in nearby small satellite lakes, have survived in refugias among rocks or papyrus sedges (protecting them from the Nile perch), or have adapted to the human-induced changes in the lake itself. Such adaptions include a larger gill area (adaption for oxygen-poor water), changes in
20567-403: The remaining species are seriously threatened and additional extinctions are possible. Some species have survived in nearby small satellite lakes, have survived in refugias among rocks or papyrus sedges (protecting them from the Nile perch), or have adapted to the human-induced changes in the lake itself. Such adaptions include a larger gill area (adaption for oxygen-poor water), changes in
20724-647: The research that has been done on the medicinal practices of this tribe has been plant based. A study was conducted in the Busega District of Tanzania, an area comprising the Serengeti Game Reserve and Lake Victoria , to determine which faunal resources healers use to treat illnesses within the community. Many of the traditional medicines, referred to as dawa, are no longer practiced, as many Sukuma tribe members rely more on Western-style medicine. The biggest threat to conservation in Tanzania
20881-439: The southern highland areas of Tanzania, and even into Zambia. These Sukuma movements have stemmed from political factors, such as colonial cattle-culling policies, and from local overcrowding and deteriorating soil conditions. The two areas form a large and undulating tableland, most of it at elevations between 1,150 and 1,275 metres (3,773 and 4,183 ft). There are several rivers in the region, but most of them do not flow during
21038-422: The spiny eel Mastacembelus frenatus , elephantfish ( Gnathonemus , Hippopotamyrus , Marcusenius , Mormyrus , Petrocephalus , and Pollimyrus ), the climbing gourami Ctenopoma muriei and marbled lungfish ( Protopterus aethiopicus ). 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
21195-422: The spiny eel Mastacembelus frenatus , elephantfish ( Gnathonemus , Hippopotamyrus , Marcusenius , Mormyrus , Petrocephalus , and Pollimyrus ), the climbing gourami Ctenopoma muriei and marbled lungfish ( Protopterus aethiopicus ). 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
21352-515: The stock in 1962–63. 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. UGFD officials argued that Nile perch must have spread to Lake Victoria by themselves by passing through
21509-515: The stock in 1962–63. 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. UGFD officials argued that Nile perch must have spread to Lake Victoria by themselves by passing through
21666-483: The territory of the Pimbwe . These Sukuma have settled outside Pimbwe villages. The Sukuma land is mostly a flat, scrubless savannah plain between 910 and 1,220 metres (3,000 and 4,000 ft) elevation. Twenty to forty inches (51 to 102 cm) of rain fall from November to March. High temperatures range from 26 to 32 °C (79 to 90 °F) while lows at night seldom drop below 15 °C (59 °F). The population
21823-411: The two lakes. The Victoria haplochromines are distinctly sexually dimorphic (males relatively brightly colored; females dull), and their ecology is extremely diverse, falling into at least 16 groups, including detritivores , zooplanktivores , insectivores , prawn-eaters, molluscivores and piscivores . As a result of predation by the introduced Nile perch , eutrophication and other changes to
21980-411: The two lakes. The Victoria haplochromines are distinctly sexually dimorphic (males relatively brightly colored; females dull), and their ecology is extremely diverse, falling into at least 16 groups, including detritivores , zooplanktivores , insectivores , prawn-eaters, molluscivores and piscivores . As a result of predation by the introduced Nile perch , eutrophication and other changes to
22137-426: The upper Nile basin. Lake Victoria formerly was very rich in fish, including many endemics, but a high percentage of these became extinct since the 1940s. The main group in Lake Victoria is the haplochromine cichlids ( Haplochromis sensu lato ) with more than 500 species, almost all endemic, and including an estimated 300 that still are undescribed . This is far more species of fish than any other lake in
22294-426: The upper Nile basin. Lake Victoria formerly was very rich in fish, including many endemics, but a high percentage of these became extinct since the 1940s. The main group in Lake Victoria is the haplochromine cichlids ( Haplochromis sensu lato ) with more than 500 species, almost all endemic, and including an estimated 300 that still are undescribed . This is far more species of fish than any other lake in
22451-756: 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 , which may in turn be responsible for mass fish kills . 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 ),
22608-756: 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 , which may in turn be responsible for mass fish kills . 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 ),
22765-403: 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
22922-403: 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
23079-811: 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
23236-420: 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
23393-416: The world's largest tropical lake, and the world's second-largest fresh water lake by surface area after Lake Superior in North America. In terms of volume, Lake Victoria is the world's ninth-largest continental lake , containing about 2,424 km (1.965 × 10 acre⋅ft) of water. Lake Victoria occupies a shallow depression in Africa. The lake has an average depth of 40 m (130 ft) and
23550-431: The world, except Lake Malawi . These are the result of a rapid adaptive radiation in the last circa 15,000 years. Their extraordinary diversity and speed of evolution have been the subjects for many scientists studying the forces that drive the richness of life everywhere. The Victoria haplochromines are part of an older group of more than 700 closely related species, also including those of several smaller lakes in
23707-431: The world, except Lake Malawi . These are the result of a rapid adaptive radiation in the last circa 15,000 years. Their extraordinary diversity and speed of evolution have been the subjects for many scientists studying the forces that drive the richness of life everywhere. The Victoria haplochromines are part of an older group of more than 700 closely related species, also including those of several smaller lakes in
23864-646: Was centered on cultural and economic exchange, while the Sukuma–Maasai connection was centered on fear and hatred, for cattle were the only thing the Maasai wanted from the Sukuma, believing that God had granted the Maasai all the cattle in the world. However, it is still possible that some peaceful relationships did exist. The Sukuma were very selective in what they assimilated, just as the Nyamwezi were; they were able to assimilate others but were unable to assimilate themselves into other societies. One Sukuma myth states that
24021-429: 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. The only shrimp/prawn
24178-429: 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. The only shrimp/prawn
24335-474: Was constructed in Kisumu County in 2013. In addition to the biogas it produces, its by-product can be used as fertilizer . 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
24492-412: Was constructed in Kisumu County in 2013. In addition to the biogas it produces, its by-product can be used as fertilizer . 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
24649-419: 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. Lake Victoria Lake Victoria is one of the African Great Lakes . With a surface area of approximately 59,947 km (23,146 sq mi), Lake Victoria is Africa's largest lake by area,
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