Рыболовство во внутренних водоемах

The inland fisheries of Africa. CIFA Occasional Paper. No. 7.

Overview of inland fisheries

A brief review of the current status of the inland fisheries of Africa was presented as document CIFA/72/8 to the First Session of CIFA (N'Djamena, 1972). This was revised as document CIFA/75/Inf. 6 for presentation to the Second Session (Accra, 1975). Since then more information has been included to produce an expanded document on the inland fisheries of Africa. This document is intended for circulation and approval by the relevant authorities in the various African states after which it will be finalized to form part of the FAO series on World Appraisal of Inland Fisheries.

The inland waters of Africa are perhaps the best studies of tropical aquatic environments. Extensive, and in some cases intensive projects have examined the natural lakes, reservoirs and rivers, to provide information which has been used as a standard against which to judge other tropical inland fisheries. Nevertheless, the coverage on a continental basis remains thin and the statistical methodologies adopted for establishing many of the estimates quoted here are open to doubt. In fact, in many cases yield figures appear to have been arrived at intuitively, by rule of thumb or more recently by the use of indices which extrapolate from sets of data from other similar water bodies. Furthermore, only a percentage of the production is reported and is reflected in the offical figures. The catch from subsistence fisheries on small rivers and other water bodies, for instance, may enter into the diet directly. The quantity of fish from such fisheries is probably very important, as an analysis by Welcomme (1976) indicated that actual catches from rivers are about twice those appearing in the catch statistics. Estimates of catch are, therefore, likely to be conservative.

Catches in Africa have increased steadily since 1950 until, in 1970, many of the fisheries began to show signs of approaching full exploitation. Since then the traditional fisheries have tended to stabilize and in some cases decline as the stocks were overfished, or were subjected to adverse climatic conditions. Nevertheless some unusual or inaccessible fisheries remain and their systematic exploitation could lead to a further rise in fish production. Counter to the trend to increasing production through the opening-up of new fisheries, and through the spread of aquaculture, there is a tendency for fisheries to be lost as a consequence of environmental damage. For instance, the fisheries of the Kanji Reservoir only just compensate for the loss of yield from the floodplains below the dam. Many of the potentials quoted in this document are therefore likely to be unrealizable. In all probability losses and gains will just about counterbalance, stabilizing the yield of the continent at about 1.5 million tons.