In East Africa, the species was introduced in Kenya in 1980 from Botswana (Motiti Pan, Okavango drainage) by I. Parker for aquaculture purposes. It was introduced to a dam near Nairobi and it is possible that some specimens found their way into the Nairobi River system.
Zambezi River Benthopelagic Habitat
This taxon is one of a number of benthopelagic species in the Zambezi River system of southern Africa. Benthopelagic river fish are found near the bottom of the water column, feeding on benthos and zooplankton
Nutrient levels in the Zambezi River are relatively low, especially in the upper Zambezi; in that reach, above Victoria Falls, most of the catchment drains Kalahari sands, whose nutrient levels are inherently low due to their aeolian formation; moreover, agricultural fertilizer addition throughout the Zambezi watershed is low, due to the shortage of capital available to farmers of this region.
Nitrate levels (as nitrogen) in the upper Zambezi are typically in the range of .01 to .03 milligrams per liter. Correspondingly electrical conductivity of the upper Zambezi is on the order of 75 micro-S per centimeter, due to the paucity of ion content. From the Luangwa River downstream nitrate levels elevate to .10 to .18 milligrams per liter, and electrical conductivity rises to a range of two to four times the upper Zambezi levels. Not surprisingly, pH, calcium ion concentration, bicarbonate and electrical conductivity are all higher in portions of the catchment where limestone soils predominate compared to granite.
There are a total of 190 known fish species present in the Zambezi River, including eel and shark taxa. The largest native benthopelagic fish in the Zambezi are the 170 cm North African catfish (Clarias gariepinus), the 146 cm common carp (Cyprinus carpio carpio), the 150 cm Indo-Pacific tarpon (Megalops cyprinoides) and the introduced 120 cm rainbow trout (Oncorhynchus mykiss).
Kunene River Benthopelagic Habitat
This taxon is one of a number of benthopelagic species in the Kunene River system. Benthopelagic river fish are found near the bottom of the water column, feeding on benthos and zooplankton
The Kunene River rises in the central highlands of Angola, and thence flows southward to form a major element of the border between Namibia and Angola before the final discharge is to the Atlantic Ocean in the vicinity of the Angola-Benguela Front. The geometry of the Kunene riparian zone is distinctly narrow, with rugged arid landscapes persisting on both sides of the river over long distances, and a virtual lack of any extensive floodplains.
There is a relatively high rate of endemism of aquatic biota in the Kunene. Proposed expansion of dams on the Kunene poses a threat to biodiversity in the river, especially regarding proposals at Epupa Falls. However, a greater threat to the Kunene is a plan by Angola to greatly expand withdrawal of water from the river to expand irrigated agriculture by 600,000 hectares; not only will this action significantly diminish downriver flow rates, but also add considerable nitrate, herbicide and pesticide substances to the river.
The catchment area of the Kunene Basin is approximately 106,560 square kilometres (41,143 square miles) in area, of which 14 100 km² (13%) lies within Namibian territory. Its mean annual discharge is 174 cubic meters per second (6145 cubic feet per second) at its mouth on the Atlantic. Water quality of the Kunene River is relatively high, since the human population density and agricultural intensity is relatively low, including a conspicuous absence of overgrazing. However, bacteria and other microbial pathogens pose a material threat to Kunene water quality, due to the fact that only a small fraction of the domestic wastewater in Angola is treated;
Regarding freshwater bivalves, the central reaches of the Kunene manifest particularly high endemism, similar to parts of the Okavango, Chobe, Upper Zambezi and Etosha Pan basins. The bivalve Etheria elliptica, which also occurs in the Upper Zambezi, is a freshwater mussel in the family Etheriidae, known from a limited extent of the central Kunene River in Angola. It is threatened by proposed dam construction on the Kunene.
There are several endemic benthopelagic fishes in the Kunene River: the eight centimeter (cm) long Kunene dwarf happy (Orthochromis machadoi); the 14 cm benthopelagic Namib happy (Thoracochromis buysi); and the seven cm benthopelagic Kunene kneria (Kneria maydelli).
Habitat and Ecology
Depth range (m): 10 - 10
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
Diseases and Parasites
Life History and Behavior
Molecular Biology and Genetics
Statistics of barcoding coverage: Oreochromis andersonii
Public Records: 0
Specimens with Barcodes: 13
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
At present, the Okavango population is not immediately threatened, but this system is intermittently linked to the Zambezi and thus it is inevitable that O. niloticus will invade the system unless a barrier is constructed across the Selinda Spillway to prevent migration.
O. andersonii is also recorded from the Cunene River, where O. niloticus does not yet occur. The alien species Oreochromis mossambicus (Peters, 1852) is, however, being extensively cultivated in Namibia and may hybridise with O. andersonii if it escapes in to the Cunene.
Establishing refuges in lakes that are not directly connected to the main rivers or to aquaculture establishments may allow small populations to survive. For this reason, and the possibility that the Cunene population may be secure at present, the species is assessed as Vulnerable globally.
Increasing fishing effort and increasingly widespread use of small-meshed fishing nets has depleted stocks in many areas, such as the heavily-populated areas of the Barotse Floodplain on the Upper Zambezi River in Zambia. Floodplain lagoons no longer provide refugia as they are all intensively seine netted.
A commercial gillnet fishery in the Panhandle area of the Okavango Delta also targets this species.
Relevance to Humans and Ecosystems
Oreochromis andersonii, the three spotted tilapia, threespot tilapia or threespot bream, is a species of cichlid native to Africa, where it is found in rivers and swamps in the southern half of the continent. This species reaches a length of 61 cm (24 in). It is important to local commercial fisheries, as well as being commercially farmed. It is also popular as a gamefish.
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