68-494: Many, see text Haplochromis is a ray-finned fish genus in the family Cichlidae . It has been used as the default " wastebin taxon " for Pseudocrenilabrinae cichlids of the East African Rift , and as such became the "largest" fish "genus". Many of these cichlids are popular aquarium fishes; like similar Haplochromini they are known as "haplos" , "happies" or "haps" among aquarium enthusiasts. The genus
136-487: A few years before their demise, and additional ones were only known or suspected to exist, but never properly studied or described. While the stocks of those species that survived are in many cases recovering, the lake ecosystem has changed irrevocably. The entire trophic web has been observed to be upset. But still, evolution runs its course: those Lake Victoria Haplochromis species that still exist are in many cases adapting to new food sources, and in time, speciation
204-459: A free-swimming larval stage. However other patterns of ontogeny exist, with one of the commonest being sequential hermaphroditism . In most cases this involves protogyny , fish starting life as females and converting to males at some stage, triggered by some internal or external factor. Protandry , where a fish converts from male to female, is much less common than protogyny. Most families use external rather than internal fertilization . Of
272-527: A genus level, six species of Chrysichthys catfish are only found in the Tanganyika basin where they live both in shallow and relatively deep waters; in the latter habitat they are the primary predators and scavengers. A unique evolutionary radiation in the lake is the 15 species of Mastacembelus spiny eels, all but one endemic to its basin. Although other African Great Lakes have Synodontis catfish, endemic catfish genera and Mastacembelus spiny eels,
340-496: A greater role than the rivers. At least 90% of the water influx is from rain falling on the lake's surface and at least 90% of the water loss is from direct evaporation. The major river flowing into the lake is the Ruzizi River , formed about 10,000 years ago, which enters the north of the lake from Lake Kivu . The Malagarasi River , which is Tanzania's second largest river, enters the east side of Lake Tanganyika. The Malagarasi
408-571: A precious biological resource for the study of speciation and evolution . The cichlids of the African Great Lakes , including Tanganyika, represent the most diverse extent of adaptive radiation in vertebrates. Some of the endemic species do occur slightly into the upper Lukuga River (Lake Tanganyika's outflow), but any further distribution into the Congo River basin is stemmed purely by geography and chemistry—Tanganyika's lake environment
476-726: A trait still present in Holostei ( bowfins and gars ). In some fish like the arapaima , the swim bladder has been modified for breathing air again, and in other lineages it have been completely lost. The teleosts have urinary and reproductive tracts that are fully separated, while the Chondrostei have common urogenital ducts, and partially connected ducts are found in Cladistia and Holostei. Ray-finned fishes have many different types of scales ; but all teleosts have leptoid scales . The outer part of these scales fan out with bony ridges, while
544-587: Is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of skin supported by radially extended thin bony spines called lepidotrichia , as opposed to the bulkier, fleshy lobed fins of the sister class Sarcopterygii (lobe-finned fish). Resembling folding fans , the actinopterygian fins can easily change shape and wetted area , providing superior thrust-to-weight ratios per movement compared to sarcopterygian and chondrichthyian fins. The fin rays attach directly to
612-667: Is an African Great Lake . It is the second-largest freshwater lake by volume and the second deepest , in both cases after Lake Baikal in Siberia . It is the world's longest freshwater lake. The lake is shared among four countries— Tanzania , the Democratic Republic of the Congo (the DRC), Burundi , and Zambia —with Tanzania (46%) and the DRC (40%) possessing the majority of the lake. It drains into
680-424: Is deeper than any other cichlid known. Some of the deepwater genera (e.g., Bathybates , Gnathochromis , Hemibates and Xenochromis ) have been caught in places virtually devoid of oxygen, and how they are able to survive there is unclear. Tanganyika cichlids are generally benthic (found at or near the bottom) and/or coastally. No Tanganyika cichlids are truly pelagic and offshore, except for some of
748-540: Is divided into the infraclasses Holostei and Teleostei . During the Mesozoic ( Triassic , Jurassic , Cretaceous ) and Cenozoic the teleosts in particular diversified widely. As a result, 96% of living fish species are teleosts (40% of all fish species belong to the teleost subgroup Acanthomorpha ), while all other groups of actinopterygians represent depauperate lineages. The classification of ray-finned fishes can be summarized as follows: The cladogram below shows
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#1732855744528816-482: Is far more stable and consistent than the rapids and fast-flowing sections of the Congo River. Additionally, Lake Tanganyika's water is alkaline and of a higher pH (which the cichlids prefer), containing a higher calcium and mineral content than the Congo's acidic , sediment -rich waters, which collect much organic detritus from the surrounding rainforests . In areas of the Congo away from rapids or whitewater ,
884-680: Is hardly surprising that the genus has a large number of junior synonyms . Most referred to small or monotypic genera that were once considered distinct, but are now included in Haplochromis again, if only to wait for a major review of their status. Synonyms are: Sometimes other genera listed above are also synonymized. Ray-finned fish Actinopterygii ( / ˌ æ k t ɪ n ɒ p t ə ˈ r ɪ dʒ i aɪ / ; from actino- 'having rays' and Ancient Greek πτέρυξ (ptérux) 'wing, fins'), members of which are known as ray-finned fish or actinopterygians ,
952-482: Is highly doubtful, as they may just be distinct lineages of Haplochromis or other haplochromines. That nonwithstanding, Haplochromini genera to which some former "Haplochromis" have been removed are in particular: Some other Pseudocrenilabrinae were also – mainly by early authors – included in Haplochromis , though they are not members of its tribe . These are: With all the taxonomic and systematic confusion affecting Haplochromis and its allies, it
1020-461: Is home to more than 80 species of non-cichlid fish and about 60% of these are endemic. The open waters of the pelagic zone are dominated by four non-cichlid species: Two species of "Tanganyika sardine" ( Limnothrissa miodon and Stolothrissa tanganicae ) form the largest biomass of fish in this zone, and they are important prey for the forktail lates ( Lates microlepis ) and sleek lates ( L. stappersii ). Two additional lates are found in
1088-420: Is likely to set in and produce a new adaptive radiation of these fishes. Until then, however, the ecological balance of the lake is still on the brink, and many of the cichlids that survived the peak population of Lates are still critically endangered and close to extinction. Haplochromis is the type genus of the tribe Haplochromini . Most of the tribe's members were at one time or another included in
1156-471: Is older than Lake Tanganyika, and before the lake was formed, it probably was a headwater of the Lualaba River , the main Congo River headstream. The lake has a complex history of changing flow patterns, due to its high altitude, great depth, slow rate of refill, and mountainous location in a turbulently volcanic area that has undergone climate changes. Apparently, it has rarely in the past had an outflow to
1224-432: Is relatively rare and is found in about 6% of living teleost species; male care is far more common than female care. Male territoriality "preadapts" a species for evolving male parental care. There are a few examples of fish that self-fertilise. The mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation. This mode of reproduction may be related to
1292-497: Is typically at depths around 100 m (330 ft) in the northern part of the lake and 240–250 m (790–820 ft) in the south. The oxygen-devoid deepest sections contain high levels of toxic hydrogen sulphide and are essentially lifeless, except for bacteria . Lake Tanganyika and its associated wetlands are home to Nile crocodiles (including famous giant Gustave ), Zambian hinged terrapins , serrated hinged terrapins , and pan hinged terrapins (last species not in
1360-482: Is unclear if they have a similar behavior. The facultative brood parasites often lay their eggs synchronously with mouthbroding cichlids. The cichlid pick up the eggs in their mouth as if they were their own. Once the catfish eggs hatch the young eat the cichlid eggs. Six catfish genera are entirely restricted to the lake basin: Bathybagrus , Dinotopterus , Lophiobagrus , Phyllonemus , Pseudotanganikallabes and Tanganikallabes . Although not endemic on
1428-563: The Congo River system and ultimately into the Atlantic Ocean . Lake Tanganyika is situated within the Albertine Rift , the western branch of the East African Rift , and is confined by the mountainous walls of the valley. It is the largest rift lake in Africa and the second-largest lake by volume in the world. It is the deepest lake in Africa and holds the greatest volume of fresh water on
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#17328557445281496-500: The Cyprinidae (in goldfish and common carp as recently as 14 million years ago). Ray-finned fish vary in size and shape, in their feeding specializations, and in the number and arrangement of their ray-fins. In nearly all ray-finned fish, the sexes are separate, and in most species the females spawn eggs that are fertilized externally, typically with the male inseminating the eggs after they are laid. Development then proceeds with
1564-587: The deep sea to subterranean waters to the highest mountain streams . Extant species can range in size from Paedocypris , at 8 mm (0.3 in); to the massive ocean sunfish , at 2,300 kg (5,070 lb); and to the giant oarfish , at 11 m (36 ft). The largest ever known ray-finned fish, the extinct Leedsichthys from the Jurassic , has been estimated to have grown to 16.5 m (54 ft). Ray-finned fishes occur in many variant forms. The main features of typical ray-finned fish are shown in
1632-422: The mantle cavity of the unionid mussel Pleiodon spekei , making it one of only two known commensal species of freshwater shrimp (the other is the sponge-living Caridina spongicola from Lake Towuti , Indonesia). Among Rift Valley lakes , Lake Tanganyika far surpasses all others in terms of crustacean and freshwater snail richness (both in total number of species and number of endemics). For example,
1700-481: The oviparous teleosts, most (79%) do not provide parental care. Viviparity , ovoviviparity , or some form of parental care for eggs, whether by the male, the female, or both parents is seen in a significant fraction (21%) of the 422 teleost families; no care is likely the ancestral condition. The oldest case of viviparity in ray-finned fish is found in Middle Triassic species of † Saurichthys . Viviparity
1768-713: The piscivorous Bathybates . Two of these, B. fasciatus and B. leo , mainly feed on Tanganyika sardines . Tanganyika cichlids differ extensively in ecology , and include species that are herbivores , detritivores , planktivores , insectivores , molluscivores , scavengers , scale-eaters and piscivores. These dietary specializations, however, have been shown to be variable and subject to opportunistic changes. That is, many species of Tanganyikan cichlid with specialized diets showed opportunistic, episodic exploitation of Stolothrissa tanganicae and Limnothrissa miodon when prey concentrations were unusually high. The fishes' breeding behavior falls into two main groups:
1836-651: The sister lineage of all other actinopterygians, the Acipenseriformes (sturgeons and paddlefishes) are the sister lineage of Neopterygii, and Holostei (bowfin and gars) are the sister lineage of teleosts. The Elopomorpha ( eels and tarpons ) appear to be the most basal teleosts. The earliest known fossil actinopterygian is Andreolepis hedei , dating back 420 million years ( Late Silurian ), remains of which have been found in Russia , Sweden , and Estonia . Crown group actinopterygians most likely originated near
1904-1071: The Devonian-Carboniferous boundary. The earliest fossil relatives of modern teleosts are from the Triassic period ( Prohalecites , Pholidophorus ), although it is suspected that teleosts originated already during the Paleozoic Era . The listing below is a summary of all extinct (indicated by a dagger , †) and living groups of Actinopterygii with their respective taxonomic rank . The taxonomy follows Phylogenetic Classification of Bony Fishes with notes when this differs from Nelson, ITIS and FishBase and extinct groups from Van der Laan 2016 and Xu 2021. [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] Lake Tanganyika Lake Tanganyika ( / ˌ t æ ŋ ɡ ə n ˈ j iː k ə , - ɡ æ n -/ TANG -gən- YEE -kə, -gan- ; Kirundi : Ikiyaga ca Tanganyika )
1972-637: The Niemba River, to maintain a flow. The lake may also have at times had different inflows and outflows; inward flows from a higher Lake Rukwa , access to Lake Malawi and an exit route to the Nile have all been proposed to have existed at some point in the lake's history. Lake Tanganyika is an ancient lake , one of only twenty more than a million years old. Its three basins, which in periods with much lower water levels were separate lakes, are of different ages. The central began to form 9–12 million years ago (Mya),
2040-508: The Tanganyika thalassoids, which are part of Prosobranchia , are endemic to the lake. Initially they were believed to be related to similar marine snails, but they are now known to be unrelated. Their appearance is now believed to be the result of the highly diverse habitats in Lake Tanganyika and evolutionary pressure from snail-eating fish and, in particular, Platythelphusa crabs. A total of 17 freshwater snail genera are endemic to
2108-552: The accumulated sediment and organic matter creates sections of " blackwater ", with a high concentration of tannins from dissolving wood and leaves, creating an environment in which cichlids simply do not thrive. Likewise, many tropical riverine species would likely suffer if exposed to the crisp, alkaline lake water. Although Lake Tanganyika has fewer cichlid species than Lakes Malawi or Victoria —which both have experienced relatively recent explosive species radiations (resulting in many closely related species)—, its cichlids are
Haplochromis - Misplaced Pages Continue
2176-402: The adjacent diagram. The swim bladder is a more derived structure and used for buoyancy . Except from the bichirs , which just like the lungs of lobe-finned fish have retained the ancestral condition of ventral budding from the foregut , the swim bladder in ray-finned fishes derives from a dorsal bud above the foregut. In early forms the swim bladder could still be used for breathing,
2244-436: The area were fishing. Most of them included using a lantern as a lure for fish that are attracted to light. There were three basic forms. One called Lusenga which is a wide net used by one person from a canoe. The second one is using a lift net. This was done by dropping a net deep below the boat using two parallel canoes and then simultaneously pulling it up. The third is called Chiromila which consisted of three canoes. One canoe
2312-463: The bichirs and holosteans (bowfin and gars) in having gone through a whole-genome duplication ( paleopolyploidy ). The WGD is estimated to have happened about 320 million years ago in the teleosts, which on average has retained about 17% of the gene duplicates, and around 180 (124–225) million years ago in the chondrosteans. It has since happened again in some teleost lineages, like Salmonidae (80–100 million years ago) and several times independently within
2380-402: The continent, accounting for 16% of the world's available fresh water. It extends for 676 km (420 mi) in a general north–south direction and averages 50 km (31 mi) in width. The lake covers 32,900 km (12,700 sq mi), with a shoreline of 1,828 km (1,136 mi), a mean depth of 570 m (1,870 ft) and a maximum depth of 1,470 m (4,820 ft) (in
2448-706: The different actinopterygian clades (in millions of years , mya) are from Near et al., 2012. Jaw-less fishes ( hagfish , lampreys ) [REDACTED] Cartilaginous fishes ( sharks , rays , ratfish ) [REDACTED] Coelacanths [REDACTED] Lungfish [REDACTED] Amphibians [REDACTED] Mammals [REDACTED] Sauropsids ( reptiles , birds ) [REDACTED] Polypteriformes ( bichirs , reedfishes ) [REDACTED] Acipenseriformes ( sturgeons , paddlefishes ) [REDACTED] Teleostei [REDACTED] Amiiformes ( bowfins ) [REDACTED] Lepisosteiformes ( gars ) [REDACTED] The polypterids (bichirs and reedfish) are
2516-761: The entire tribe remains badly resolved, however, and further changes in taxonomy are likely in the future. In particular, between Haplochromis , Astatotilapia and Thoracochromis , species have been moved to and from over the years. The habit of Pseudocrenilabrinae to hybridize is hampering molecular phylogenetic studies based on mtDNA alone, while trophic morphs of a single species may appear to be distinct "species" if they are not phylogenetically studied. Several proposed genera are again included in Haplochromis at present, but it cannot be ruled out that some of these will eventually be recognized as valid again. There are currently 229 recognized species in this genus: These populations are typically referred to by
2584-509: The fish populations, causing significant declines. In 2016, it was estimated that the total catch was up to 200,000 tonnes. It is thought that early Homo sapiens were making an impact on the region during the Stone Age . The time period of the Middle Stone Age to Late Stone Age is described as an age of advanced hunter-gatherers. There are many methods in which the native people of
2652-432: The fish's habit of spending long periods out of water in the mangrove forests it inhabits. Males are occasionally produced at temperatures below 19 °C (66 °F) and can fertilise eggs that are then spawned by the female. This maintains genetic variability in a species that is otherwise highly inbred. Actinopterygii is divided into the subclasses Cladistia , Chondrostei and Neopterygii . The Neopterygii , in turn,
2720-482: The genera Altolamprologus , Cyprichromis , Eretmodus , Julidochromis , Lamprologus , Neolamprologus , Tropheus and Xenotilapia , are popular aquarium fish due to their bright colors and patterns, and interesting behaviors. Recreating a Lake Tanganyika biotope to host those cichlids in a habitat similar to their natural environment is also popular in the aquarium hobby, with many species today being bred in captivity successfully. Lake Tanganyika
2788-438: The inner part is crossed with fibrous connective tissue. Leptoid scales are thinner and more transparent than other types of scales, and lack the hardened enamel - or dentine -like layers found in the scales of many other fish. Unlike ganoid scales , which are found in non-teleost actinopterygians, new scales are added in concentric layers as the fish grows. Teleosts and chondrosteans (sturgeons and paddlefish) also differ from
Haplochromis - Misplaced Pages Continue
2856-608: The lake ( Haplochromini , Tilapiini and Tylochromini ). Others have proposed splitting the Tanganyika cichlids into as many as 12–16 tribes ( Bathybatini , Benthochromini , Boulengerochromini , Cyphotilapiini , Eretmodini , Greenwoodochromini , Perissodini and Trematocarini , in addition to the aforementioned tribes). Most Tanganyika cichlids live along the shoreline, down to a depth of 100 m (330 ft), but some deep-water species regularly descend to 200 m (660 ft). Trematocara species have, exceptionally, been found at more than 300 m (980 ft), which
2924-455: The lake itself, but in adjacent lagoons). Storm's water cobra , a threatened subspecies of banded water cobra that feeds mainly on fish, is only found in Lake Tanganyika, where it prefers rocky shores. Lake Tanganyika is home to at least 250 endemic species of cichlids , and undescribed species likely remain to be discovered. Almost all (roughly 98%) of the lake's cichlid species are found solely there, and nowhere else, thus making it
2992-567: The lake, and as a base from which to launch surprise attacks on Allied troops. It therefore became essential for the Allied forces to gain control of the lake themselves. Under the command of Lieutenant Commander Geoffrey Spicer-Simson the British Royal Navy achieved the monumental task of bringing two armed motor boats HMS Mimi and HMS Toutou from England to the lake by rail, road and river to Albertville (since renamed Kalemie in 1971) on
3060-936: The lake, such as Hirthia , Lavigeria , Paramelania , Reymondia , Spekia , Stanleya , Tanganyicia and Tiphobia . There are about 30 species of non-thalassoid snails in the lake, but only five of these are endemic, including Ferrissia tanganyicensis and Neothauma tanganyicense . The latter is the largest Tanganyika snail and its shell is often used by small shell-dwelling cichlids . Crustaceans are also highly diverse in Tanganyika with more than 200 species, of which more than half are endemic. They include 10 species of freshwater crabs (9 Platythelphusa and Potamonautes platynotus ; all endemic), at least 11 species of small atyid shrimp ( Atyella , Caridella and Limnocaridina ), an endemic palaemonid shrimp ( Macrobrachium moorei ), about 100 ostracods , including many endemics, and several copepods . Among these, Limnocaridina iridinae lives inside
3128-636: The lake, the Tanganyika lates ( L. angustifrons ) and bigeye lates ( L. mariae ), but both these are primarily benthic hunters, although they also may move into open waters. The four lates, all endemic to Tanganyika, have been overfished and larger individuals are rare today. Among the more unusual fish in the lake are the endemic, facultatively brood parasitic "cuckoo catfish", including at least Synodontis grandiops and S. multipunctatus . A number of others are very similar (e.g., S. lucipinnis and S. petricola ) and have often been confused; it
3196-412: The lake. Among the endemic bivalves are three monotypic genera: Grandidieria burtoni , Pseudospatha tanganyicensis and Brazzaea anceyi . Many of the snails are unusual for species living in freshwater in having noticeably thickened shells and/or distinct sculpture , features more commonly seen in marine snails. They are referred to as thalassoids, which can be translated to "marine-like". All
3264-607: The lake. He noted the name "Liemba" for its southern part, a word probably from the Fipa language . Tanganyika means "stars" in the Luvale language . The lake was the scene of Battle for Lake Tanganyika during World War I . With the aid of the Graf Goetzen , the Germans had complete control of the lake in the early stages of the war. The ship was used both to ferry cargo and personnel across
3332-461: The main clades of living actinopterygians and their evolutionary relationships to other extant groups of fishes and the four-limbed vertebrates ( tetrapods ). The latter include mostly terrestrial species but also groups that became secondarily aquatic (e.g. whales and dolphins ). Tetrapods evolved from a group of bony fish during the Devonian period . Approximate divergence dates for
3400-505: The most morphologically and genetically diverse. This is linked to the maturity of Tanganyika, as it is far older than the other lakes. Tanganyika has the largest number of endemic cichlid genera of all African lakes. All Tanganyika cichlids are in the subfamily Pseudocrenilabrinae . Of the 10 tribes in this subfamily, half are largely or entirely restricted to the lake ( Cyprichromini , Ectodini , Lamprologini , Limnochromini and Tropheini ), while another three have species in
3468-404: The names they have in the aquarium fish trade. A number of them are likely to represent undescribed distinct species; others might just be subspecies or color morphs . Whether they all belong in Haplochromis is, of course, doubtful. Some of these populations are: Among other genera of Haplochromini that were formerly included here, many are small or monotypic . The distinctness of these
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#17328557445283536-460: The northern 7–8 Mya and the southern 2–4 Mya. The lake's water is alkaline with a pH around 9 at depths of 0–100 m (0–330 ft). Below this, it is around 8.7, gradually decreasing to 8.3–8.5 in the deepest parts of Tanganyika. A similar pattern can be seen in the electric conductivity , ranging from about 670 μS/cm in the upper part to 690 μS/cm in the deepest. Surface temperatures generally range from about 24 °C (75 °F) in
3604-497: The northern basin). It holds an estimated 18,750 km (4,500 cu mi). The catchment area of the lake is 231,000 km (89,000 sq mi). Two main rivers flow into the lake, as well as numerous smaller rivers and streams (whose lengths are limited by the steep mountains around the lake). The one major outflow is the Lukuga River , which empties into the Congo River drainage. Precipitation and evaporation play
3672-418: The only other Rift Valley lake with endemic freshwater crabs are Lake Kivu and Lake Victoria with two species each. The diversity of other invertebrate groups in Lake Tanganyika is often not well-known, but there are at least 20 described species of leeches (12 endemics), 9 sponges (7 endemic), 6 bryozoa (2 endemic), 11 flatworms (7 endemic), 20 nematodes (7 endemic), 28 annelids (17 endemic) and
3740-413: The present genus, but in many cases this was only temporary. Around the year 1900, as well 100 years later, the trend was to split up the genus; especially in the mid-20th century, on the other hand, most authors lumped any and all Haplochromini that were not conspicuously distinct in the type genus. While a number of African Rift Valley cichlids are certainly very close relatives of H. obliquidens ,
3808-494: The proximal or basal skeletal elements, the radials, which represent the articulation between these fins and the internal skeleton (e.g., pelvic and pectoral girdles). The vast majority of actinopterygians are teleosts . By species count, they dominate the subphylum Vertebrata , and constitute nearly 99% of the over 30,000 extant species of fish . They are the most abundant nektonic aquatic animals and are ubiquitous throughout freshwater and marine environments from
3876-653: The relatively high diversity is unique to Tanganyika, which likely is related to its old age. Among the non-endemic fish, some are widespread African species but several are only shared with the Malagarasi and Congo River basins, such as the Congo bichir ( Polypterus congicus ), goliath tigerfish ( Hydrocynus goliath ), Citharinus citharus , six-banded distichodus ( Distichodus sexfasciatus ) and mbu puffer ( Tetraodon mbu ). A total of 83 freshwater snail species (65 endemic) and 11 bivalve species (8 endemic) are known from
3944-464: The sea. It has been described as "practically endorheic " for this reason. The lake's connection to the sea is dependent on a high water level allowing water to overflow out of the lake through the Lukuga River into the Congo. When not overflowing, the lake's exit into the Lukuga River typically is blocked by sand bars and masses of weed, and instead this river depends on its own tributaries, especially
4012-413: The small hydrozoan jellyfish Limnocnida tanganyicae . Lake Tanganyika supports a major fishery, which, depending on source, provides 25–40% or c. 60% of the animal protein in the diet of the people living in the region. Lake Tanganyika fish can be found exported throughout East Africa. Major commercial fishing began in the mid-1950s and has, together with global warming, had a heavy impact on
4080-534: The smaller cichlids were fair game for the huge carnivorous Lates . The Nile tilapia ( Oreochromis niloticus ), an adaptable generalist , was also introduced and competed with the often specialized endemic cichlids of the lake for food and other resources. When the Nile perch stocks finally declined again in the late 1980s, an estimated 200 Haplochromini species (mostly Haplochromis ) may have become extinct – many of these had only been scientifically described
4148-402: The south and is wind-driven, but to a lesser extent, up- and downwellings also occur elsewhere in the lake. As a consequence of the stratification, the deep sections contain " fossil water ". This also means it has no oxygen (it is anoxic ) in the deeper parts, essentially limiting fish and other aerobic organisms to the upper part. Some geographical variations are seen in this limit, but it
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#17328557445284216-579: The southern part of the lake in early August to 28–29 °C (82–84 °F) in the late rainy season in March—April. At depths greater than 400 m (1,300 ft), the temperature is very stable at 23.1–23.4 °C (73.6–74.1 °F). The water has gradually warmed since the 19th century and this has accelerated with global warming since the 1950s. The lake is stratified and seasonal mixing generally does not extend beyond depths of 150 m (490 ft). The mixing mainly occurs as upwellings in
4284-459: The substrate- or sand-spawners (often in caves or rock crevices) and the mouthbrooders . Among the endemic species are two of the world's smallest cichlids, Neolamprologus multifasciatus and N. similis (both shell dwellers ), measuring up to 4–5 cm (1.6–2.0 in), and one of the largest, the giant cichlid ( Boulengerochromis microlepis ) at up to 90 cm (3.0 ft). Many cichlids from Lake Tanganyika, such as species from
4352-459: The type species of the present genus, it is not very clear where to draw the boundary of Haplochromis with regard to its relatives. Still, several genera are now recognized as distinct by many authors and scientific databases, such as FishBase (see below ); in particular the Haplochromini from Lake Tanganyika and Lake Malawi are usually removed from Haplochromis . The genus delimitation in
4420-577: The western shore of Lake Tanganyika. The two boats waited until December 1915, and mounted a surprise attack on the Germans, with the capture of the gunboat Kingani . Another German vessel, the Hedwig , was sunk in February 1916, leaving the Götzen as the only German vessel remaining to control the lake. In order to avoid his prize ship falling into Allied hands, Zimmer scuttled the vessel on July 26, 1916. The vessel
4488-423: Was abolished. As the years went by, other genera of (mostly) Haplochromini were lumped with and split again from Haplochromis , and the final delimitation of the clade around H. obliquidens is not yet done. The introduction of Nile perch ( Lates niloticus ) to Lake Victoria after 1954 severely upset the lake's ecosystem . By the late 1970s, the perch's population was approaching carrying capacity , and
4556-403: Was established by F.M. Hilgendorf in 1888. It was originally conceived as a subgenus of A.C.L.G. Günther 's "Chromis" , at that time an even larger "wastebin genus" for Pseudocrenilabrinae cichlids. The type species of Hilgendorf was H. obliquidens . "Chromis" of Günther turned out to be a junior homonym of G. Cuvier 's ocean fish genus Chromis , already established in 1814, and
4624-526: Was stationary with a lantern while another canoe holds one end of the net and the other circles the stationary one to meet up with the net. The first known Westerners to find the lake were the British explorers Richard Burton and John Speke , in 1858. They located it while searching for the source of the Nile River . Speke continued and found the actual source, Lake Victoria . Later David Livingstone passed by
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