''Oreochromis'' is a large

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of oreochromine cichlids, fishes

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

and the

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...

. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very small ranges; some are seriously

threatened Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensa ...

, and ''O. ismailiaensis'' and ''O. lidole'' possibly are extinct. Although ''Oreochromis'' primarily are freshwater fish of rivers, lakes and similar habitats, several species can also thrive in

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estu ...

waters and some even survive in

hypersaline A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride, brines, and other salts, with saline levels surpassing that of ocean water (3.5%, i.e. ). Specific microbial species can thrive in hi ...

conditions with a salinity that far surpasses that of seawater. In addition to overfishing and habitat loss, some of the more localized species are threatened by the introduction of other, more widespread ''Oreochromis'' species into their ranges. This is because they—in addition to competing for the local resources—often are able to

hybridize Hybridization (or hybridisation) may refer to: *Hybridization (biology), the process of combining different varieties of organisms to create a hybrid *Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals *Nu ...

. ''Oreochromis'' are fairly robust fish, and medium–small to very large ciclids that can reach up to in total length depending on the exact species.

Taxonomy

Species in this genus, as well as those in several other oreochromine and tilapiine genera, share the common name "

tilapia Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically most ...

" and historically most were included in the genus ''

Tilapia Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically most ...

''. ''Oreochromis'' contains more than 30

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

, and several undescribed forms exist. Judging from

mtDNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is calle ...

analysis, several clades seem to exist. Research is hampered because hybridization runs rampant in these fishes, which confounds mtDNA data ( Wami tilapia is an example), and the fast speed of

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

makes choice of appropriate

nuclear DNA Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. I ...

sequences difficult. A comprehensive genetic study that included almost all the species, as well as the closely related ''

Alcolapia ''Alcolapia'' is a genus of small fishes in the family Cichlidae. Their native range is restricted to margins of Lake Natron and Lake Magadi, as well as similar conditions in nearby hot springs, in Kenya and Tanzania. They live in waters that are ...

'', found that ''Oreochromis'' as currently defined is paraphyletic. For example, two ''Oreochromis'' species (''O. amphimelas'' and ''O. esculentus'') appear closer to ''Alcolapia'' than the remaining ''Oreochromis'', and five other ''Oreochromis'' species (''O. angolensis'', ''O. lepidurus'', ''O. niloticus'', ''O. schwebischi'' and ''O. upembae'') appear to be as distant from the "core" ''Oreochromis'' as they are from ''Alcolapia''. A potential solution is to merge ''Alcolapia'' into ''Oreochromis'', as done by

Catalog of Fishes Catalog of Fishes is a comprehensive on-line database and reference work on the scientific names of fish species and genera. It is global in its scope and is hosted by the California Academy of Sciences. It has been compiled and is continuously u ...

Species

The 33 recognized species in this genus are: * '' Oreochromis amphimelas'' ( Hilgendorf, 1905) * '' Oreochromis andersonii'' ( Castelnau, 1861) (three-spotted tilapia) * '' Oreochromis angolensis'' ( Trewavas, 1973) * ''

Oreochromis aureus The blue tilapia (''Oreochromis aureus'') is a species of tilapia, a fish in the family Cichlidae. Native to Northern and Western Africa, and the Middle East, through introductions it is now also established elsewhere, including parts of the U ...

'' ( Steindachner, 1864) (blue tilapia) * '' Oreochromis chungruruensis'' ( C. G. E. Ahl, 1924) * ''

Oreochromis esculentus ''Oreochromis esculentus'', the Singida tilapia or Graham's tilapia, is a species of cichlid endemic to the Lake Victoria basin, including some of its satellite lakes such as Kyoga, in Tanzania, Uganda, and Kenya. Its common name refers to ...

'' ( M. Graham, 1928) (Singida tilapia) * '' Oreochromis hunteri'' Günther, 1889 (Lake Chala tilapia) * ''

Oreochromis ismailiaensis ''Oreochromis'' is a large genus of Oreochromini, oreochromine cichlids, fishes Endemism, endemic to Africa and the Middle East. A few species from this genus have been Introduced species, introduced far outside their native range and are import ...

'' Mekkawy, 1995 * '' Oreochromis jipe'' ( R. H. Lowe, 1955) (Jipe tilapia) * ''

Oreochromis karomo The karomo (''Oreochromis karomo'') is a species of cichlid endemic to Tanzania, where it is found in the Malagarasi River basin. This species can reach a standard length of . It is also considered an excellent food fish and is sought-after by ...

'' (

Poll Poll, polled, or polling may refer to: Figurative head counts * Poll, a formal election ** Election verification exit poll, a survey taken to verify election counts ** Polling, voting to make decisions or determine opinions ** Polling places o ...

, 1948) (karomo) * ''

Oreochromis karongae ''Oreochromis karongae'' is a critically endangered species of cichlid that is endemic to Lake Malawi, Lake Malombe, and upper and middle Shire River in Malawi, Mozambique, and Tanzania. This species is important to local commercial fisheries ...

'' ( Trewavas, 1941) * '' Oreochromis korogwe'' ( R. H. Lowe, 1955) (Korogwe tilapia) * '' Oreochromis lepidurus'' ( Boulenger, 1899) * ''

Oreochromis leucostictus ''Oreochromis leucostictus'' (the blue-spotted tilapia) is a species of cichlid native to Albertine Rift Valley lakes and associated rivers in DR Congo and Uganda. It has now been introduced widely elsewhere East Africa, and is believed to ha ...

'' (Trewavas, 1933) * ''

Oreochromis lidole ''Oreochromis lidole'' is a species of freshwater fish in the family Cichlidae. This tilapia is native to Malawi, Mozambique and Tanzania, where it is found in Lake Malawi, Lake Malombe, the Shire River and perhaps some crater lakes further nort ...

'' (Trewavas, 1941) * '' Oreochromis macrochir'' ( Boulenger, 1912) (longfin tilapia) * ''

Oreochromis malagarasi ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very ...

'' Trewavas, 1983 (Malagarasi tilapia) * ''

Oreochromis mortimeri ''Oreochromis mortimeri'', the Kariba tilapia or kurper bream, is a species of cichlid, formerly classified as a Tilapiine cichlid but now placed in the genus ''Oreochromis'', the type genus of the tribe Oreochromini of the subfamily Pseudocre ...

'' ( Trewavas, 1966) (Kariba tilapia) * ''

Oreochromis mossambicus ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have ver ...

'' ( W. K. H. Peters, 1852) (Mozambique tilapia) * '' Oreochromis mweruensis'' Trewavas, 1983 * ''

Oreochromis niloticus The Nile tilapia (''Oreochromis niloticus'') is a species of tilapia, a cichlid fish native to the northern half of Africa and the Levante area, including Land of Israel, Israel, and Lebanon. Numerous Introduced species, introduced populations ex ...

'' (

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

, 1758) (Nile tilapia) * '' Oreochromis placidus'' (Trewavas, 1941) ** '' Oreochromis placidus placidus'' (Trewavas, 1941) (black tilapia) ** ''

Oreochromis placidus ruvumae ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very ...

'' (Trewavas, 1966) * '' Oreochromis rukwaensis'' ( Hilgendorf &

Pappenheim Pappenheim is a town in the Weißenburg-Gunzenhausen district, in Bavaria, Germany. It is situated on the river Altmühl, 11 km south of Weißenburg in Bayern. History Historically, Pappenheim was a statelet within Holy Roman Empire. It ...

, 1903) (Lake Rukwa tilapia) * ''

Oreochromis saka ''Oreochromis saka'' is a species of cichlid fish that is endemic to Lake Malawi and Lake Malombe in East Africa where it inhabits relatively shallow coastal areas. Konings, Ad (1990). Ad Konings' Book of Cichlids and all the other Fishes of Lak ...

'' ( R. H. Lowe, 1953) * '' Oreochromis salinicola'' (

, 1948) * ''

Oreochromis schwebischi ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very ...

'' ( Sauvage, 1884) * '' Oreochromis shiranus'' Boulenger, 1897 ** ''

Oreochromis shiranus chilwae ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very ...

'' (Trewavas, 1966) (Chilwa tilapia) ** ''

Oreochromis shiranus shiranus ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very ...

'' Boulenger, 1897 * ''

Oreochromis spilurus ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very ...

'' (Günther, 1894) ** '' Oreochromis spilurus niger'' (Günther, 1894) (Athi River tilapia) ** ''

Oreochromis spilurus percivali ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very ...

'' (Boulenger, 1912) (Buffalo Springs tilapia) ** '' Oreochromis spilurus spilurus'' (Günther, 1894) (Sabaki tilapia) * '' Oreochromis squamipinnis'' (Günther, 1864) * ''

Oreochromis tanganicae ''Oreochromis tanganicae'', the Tanganyika tilapia, is a species of cichlid endemic to Lake Tanganyika and the mouths of its larger affluent rivers. This species can reach a length of SL. References Tang Tang or TANG most often refer ...

'' (Günther, 1894) * ''

Oreochromis upembae ''Oreochromis'' is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very ...

'' ( Thys van den Audenaerde, 1964) * ''

Oreochromis urolepis The Wami tilapia (''Oreochromis urolepis'') or Rufiji tilapia is a species tilapiine cichlid that is native to Morogoro Region of Tanzania. It is an important food fish and has been introduced to several other countries, although most of these ...

'' (Norman, 1922) ** '' Oreochromis urolepis hornorum'' (Trewavas, 1966) (Wami tilapia) ** '' Oreochromis urolepis urolepis'' (Norman, 1922) (Rufigi tilapia) * '' Oreochromis variabilis'' (Boulenger, 1906) (Victoria tilapia)

References

{{Taxonbar, from=Q4621959 Oreochromini Fish of Africa Cichlid genera Taxa named by Albert Günther