In this review, southern Africa is defined, for convenience, as those countries belonging to the Southern African Development Community (SADC). They include nine anglophone countries (Botswana, Lesotho, Malawi, Namibia, Swaziland, South Africa1, Tanzania, Zambia, Zimbabwe) and two lusophone ones (Angola, Mozambique). Although differing widely in their political and economic development, these eleven countries are connected by transportation and other links, and the policy of SADC is to promote closer relationships between them. Much of the work being carried out on small water bodies is located in these countries, although it is hoped that the findings will be applicable to others, like Kenya or Uganda, which are not part of the political grouping.
The food situation in sub-Saharan Africa is one of the most serious international problems. The production of food, per caput, is lower than in any other continent and has failed to keep up with the growth of the population. The region has the highest incidence of malnutrition and is more dependant on food aid than anywhere else in the developing world (Anon., 1990a). This situation is partly because the soils of the continent are relatively infertile, and rainfall is often low and highly erratic. It is made worse by various other factors, which include inappropriate government policies that make it difficult for farmers to make a living, and a lack either of infrastructure such as credit facilities or transportation, or of means to process and preserve produce.
Consequently, food security is an important priority for the SADC countries. Rainfall has been below average in the region throughout the 1980s and 1990s, and in 1992 the SADC countries experienced the worst drought on record. This led to a 60% shortfall in crop production and they were forced to import nearly 12 million t of food between April 1992 and March 1993, of which some 4 million t were in food aid (Malin, 1992). The loss of livestock during that drought has led to a reduction in protein availability, and it will take many years for livestock numbers to recover to their former level. It is imperative, therefore, that new sources of animal protein are developed.
Fish are an important resource in the region, but in many areas they are either unavailable or very expensive. Fish are obviously most plentiful along the coasts or near large natural lakes, but they become relatively scarce further away from these sources. The yield of fish from major lakes, hydro-electric reservoirs and larger rivers is currently around 1 870 000 t/yr (FAO, 1990), but the extent to which this can be increased is uncertain. Many of these inland fisheries are thought to have reached the limits of sustainable production and a large proportion of them may be overexploited. This situation has come about because populations in the areas bordering them have increased whilst the enforcement of fishing laws (regulating the number of fishers, types of gear, mesh size and so on) has declined. In some cases, pollution has affected water quality and contributed to a decline in productivity (Nyman, 1987).
However, numerous small water bodies (primarily reservoirs) exist throughout the region and, given adequate management, have the potential to allow a significant increase in the availability of fish. This paper considers the potential productivity of small water bodies in southern Africa and discusses aspects of their management.
1. South Africa did not join SADC until late 1994. Thus the data considered in this review are limited, as it was not possible to obtain comprehensive data on small water bodies in that country.