INTRODUCTION

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.

SUMMARY

The estimated actual and potential catches from the inland waters of Africa are presented in Table 1 where they are compared with the total catch by country.

Table 1

Summary of estimated actual and potential catches from the inland waters of Africa as compared with those from marine waters

Country	Freshwater fish		Movement	Nominal total catch	% Freshwater fish
Country	Catch (t)	Potential (t)	Movement	Nominal total catch	% Freshwater fish
Angola	10 000^a	10 000+^a	↑	153 580	6.1
Benin	20 550^c	25 000^c	=	25 504	80.6
Botswana	1 600^b	15 000^b	↑	1 600	100.0
Burundi	20 330^c	20 000^c	=	20 330	100.0
Cameroon	40 000^b	40 000^b	=	61 600	64.9
Central African Empire	10 400^b	15 000+^a	↑	10 400	100.0
Chad	115 000^b	depends on climate	-	115 000	100.0
Congo	1 000^a	60 000^a	↑	19 447	5.1
Egypt	80 000^b	80 000±^a	=↓	106 574	75.1
Ethiopia	1 000^a	59 100^b	↑	26 800	3.7
Gabon	1 800^b	2 000+^a	↑	7 456	24.1
Gambia	800^a	8 000^a	↑	10 795	7.4
Ghana	41 945^c	40 000+^a	=	237 697	17.6
Guinea	1 000^a	5 000^a	↑	6 000	16.7
Ivory Coast	17 000^b	17 000^b	=	76 995	22.1
Kenya	37 000^c	37 000+^b	=	40 883	90.0
Liberia	4 000^a	unknown		16 600	24.1
Madagascar	41 500^c	41 500^c	=	54 950	75.5
Malawi	78 500^c	78 500^c	=	78 500	100.0
Mali	100 000^b	depends on climate		100 000	100.0
Mauritania	13 000^a	depends on climate		34 170	38
Mozambique	3 000^a	depends on climate		8 000	100.0
Niger	8 000^b	15 000+^a	↑	10 500	30
Nigeria	200 000^b	200 000^b	=	365 687	82.8
Rwanda	600^b	12 000^a	↑	600	100.0
Senegal	25 000^b	depends on climate		375 861	7.1
Sierra Leone	1 100^a	5 000^a	↑	67 797	1.6
Sudan	22 000^c	125 000^a	↑	24 700	95.1
Tanzania	150 552^c	250 000^b	↑	180 746	83.3
Togo	3 000^a	3 000^a	=	14 420	20.8
Uganda	174 537^c	240 000^b	↑	174 537	100.0
Upper Volta	3 500^a	6 000^a		3 500	100.0
Zaire	114 200^b	280 000^c		117 858	93.3
Zambia	49 000^c	70 000^b		49 000	100.0
Total	1 390 914	1 905 900		2 595 387	53.6

^a unreliable estimate
^b moderately reliable estimate
^c very reliable estimate
↑ increase
↓ decrease
= no change

The present nominal total catch of freshwater fish is estimated at about 1 400 000 t, although for the reasons quoted in the Introduction actual catches probably exceed these figures. The potential nominal catch of 1 900 000 t, represents an increase of 26 percent, but, because of overexploitation of existing fisheries and loss of catch through environmental degradation, it is doubtful whether this can ever be achieved from natural fishing. Nevertheless eleven countries have potential for increase based on fisheries information alone, ten would seem to be stable, and five depend very much on climatic variables as to whether their fisheries increase, decrease, or remain stable. Potentials for increased fish production through aquaculture are at present completely hypothetical. True, the potential is there, but in the existing socio-economic climate these may never be realized.

The importance of inland fish in Africa is indicated by the 54 percent of the total production that comes from inland waters of the countries described, however this does not sufficiently emphasize the significance as in no fewer than eleven countries of the thirty-two, inland fish contributes over 90 percent of the total products.