| FishBase | Complete | Literature | Reference | |||
|---|---|---|---|---|---|---|
| Species | Families | Species | Families | |||
| Marine | No | |||||
| Freshwater | 89 | 16 | No | Daget, J., J.-P. Gosse and D.F.E. Thys van den Audenaerde, 1984 | ||
| Total | 87 | 16 | No | |||
| Conservation | The following information is to be sought: - Status of knowledge of the freshwater fauna; - Existence of conservation plans; - Information on major aquatic habitats or sites within the country; - Current major threats to species; - Future potential threats to species; - Contact(s) for further information. |
| Geography and Climate |
Botswana is a vast tableland of 1,000 m mean altitude, but in the north and northwest several depressions are associated with the drainage patterns of the main river. The country is generally arid savanna, grading into the Kalahari Desert to the west. The Okavango Depression in the northwest is somewhat better wooded and is generally more moist.
Most of the country is dry with hot summers and cold winters; in the desert regions winter temperatures (May-August) can fall below zero at night. Late summer (February-April) is the wettest time of the year, but there is much variability from year to year. Flooding of the Okavango depends greatly on the rainfall in the upper catchment in Angola which may be very different from that in Botswana. Most of the water in the Okavango Delta is lost by evaporation. Ref. Vanden Bossche, J.-P. and G.M. Bernacsek, 1990 |
| Hydrography |
Lakes: The main natural lakes of importance are the Ngami, Xau and Liambezi. The Ngami and Xau Lakes form the terminal sumps of the Okavango Delta and are fed mainly by the Boteti River, while the Liambezi Lake is fed by the Chobe River. All three of these lakes used to be highly productive, supporting good fisheries, but in recent years, owing to continued drought, they have all dried up completely. Until it dried up in 1982, Lake Ngami was a very productive lake which supported a rapidly developing fishery yielding over 200 t/yr. According to estimates, this lake has a potential of producing more than 3,000 tons of fish a year. Lake Liambezi did not dry up completely until 1986. Before then, the lake used to support a sizeable fishery which was rapidly developing under a viable cooperative system. Yields as high as 1,000 t/yr have been obtained from this lake, most of which were exported.
Rivers, floodplains and swamps: The Okavango and its terminal swamps are the largest aquatic system in the country. The Okavango River enters Botswana and Angola after crossing the Caprivi strip, and almost immediately spreads out into fan-shaped delta swamp. The swamp is endorheic and only has outflow in exceptional years when part of the flow drains into the Zambesi system by way of the Selinda Spillway and the Linyati River, and into the Mababe Depression by way of the Khwai River. The Mababe Depression may also be flooded from the Zambesi River via the Savuti River. Some water also moves down the Boteti River toward the Makgadikgadi Depression, although this has not flooded in recent years. The Limpopo River forms part of the boundary with South Africa. Botswanian territory covers a minute part (4 km) of the Upper Zambesi River channel. Ref. Vanden Bossche, J.-P. and G.M. Bernacsek, 1990 |