| FishBase | Complete | Literature | Reference | |||
|---|---|---|---|---|---|---|
| Species | Families | Species | Families | |||
| Marine | 492 | 148 | No | Quéro, J.-C., J.-C. Hureau, C. Karrer, A. Post and L. Saldanha (eds.), 1990 | ||
| Freshwater | 210 | 34 | No | Daget, J., J.-P. Gosse and D.F.E. Thys van den Audenaerde, 1984 | ||
| Total | 695 | 175 | 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 |
Ghana is divided into three main regions. There is a narrow sandy coastal plain, behind which there is a range of low but abrupt hills; to the north there are low-lying plains. The southwestern part of the country is densely forested, and to the north are bush savanna and grasslands.
The coastal belt is warm, fairly dry to the east, but becoming more humid to the west. The forest zone is very humid but the rest of the country becomes progressively more arid northward. In the south there are two rainy seasons (March-June and September-November), separated by dry periods. In the north the two wet seasons tend to be closer together and merge into one (May-October).
Ghana is almost entry agricultural, except for some industries which are located mostly at Tema. The Akosombo Dam was built mostly to provide power for industrialization, especially the Volta Aluminium Company (Valco) based at Tema, which consumes 60% of this power. Ghana also supplies power to Togo and Benin. Forestry is also an important activity in the southwest of the country. Ref. Vanden Bossche, J.-P. and G.M. Bernacsek, 1990 |
| Hydrography |
Lakes: the only natural freshwater lake of any size in the country is Lake Bosumtwi, a crater lake situated in Ashanti Region. This supports some commercial fishing activity.
Rivers, floodplains and swamps: Ghana is extremely well watered and is drained principally by the Black, White and Red Volta Rivers and the Oti River, but several smaller water couses, including the Pra, Tano and Bia drain the forested southwestern areas. Flooding on the lower Volta River is now controlled by the Akosombo Dam.
The hydrography of the Volta River is well documented by Nerguaye-Tetteh et al. (1984) (Ref. 12109). The most important flow is from the Oti. Peak flows are between September and October, with an annual average of 1,230 cu. m./s. Examining past trends, it is noted that from 1936 to 1958 conditions altered fairly evenly between wet and dry years. However, from 1962 to 1971 the flow regime was relatively wet; then from 1972 to 1978 it became dry again, followed by two wet years. Thereafter 1981 to 1983 were the driest years of the series, emphasizing the effect of the Sahelian drought. In general, water quality is good for both irrigation and livestock uses.
Reservoirs: Ghana contains the largest man-made reservoir in Africa, the 8,482 sq. km. Volta Reservoir. The reservoir, which is backed up behind the Akosombo high dam, is over 400 km long and has drowned much of the lower courses of the various rivers of the Volta system. It is used as a water store to generate electricity, but the severe drought of 1981-83 drastically reduced the output.
Dowstream from Volta Reservoir is the newly created Kpong Reservoir. Other smaller reservoirs are Vea and Tono, both in the Upper East Region; Weija and Dawhenya, located near Accra; and Barakese, near Kumasi.
Coastal lagoons: there are about 50 brackishwater lagoons situated along the coast of Ghana with a total surface area of some 400 sq. km. (FAO/IFAD, 1981) (Ref. 12110). These are described in detail by Mensah (1979) (Ref. 12111). The largest of these is the Keta Lagoon, situated around the delta of the Volta River. The nature of this lagoon has changed considerably since the closure of the Akosombo Dam; the former periodic flushes of freshwater do not now occur, and the lagoon has become more saline as a consequence.
The salinity and temperature fo the lagoons vary with opening to the sea and flooding of inflowing rivers; open lagoons generally tend to be more productive. Ref. Vanden Bossche, J.-P. and G.M. Bernacsek, 1990 |