COUNTRY REVIEWS (continued)

MALAWI

About 20 percent of the area of the country is occupied by Lake Malawi which lies in the Great Rift Valley. The Great Rift continues from the south end of the lake past the southern borders of the country. East and west of the valley the land rises to form high plateaus generally between 1 000 and 1 300 m although the Nyika uplands rise as high as 2 800 m.

5. CLIMATE

In the Rift Valley the climate is hot and humid especially during the November to April wet season. Elsewhere the climate varies with altitude and can be seasonally very cool.

6. HYDROLOGY

6.1 Rivers

The Shire River (520 km) flows from Lake Malawi into the Zambezi. Most of its length is in Malawi where it floods over large areas to form the Elephant and Ndinde Marshes. The total system covers about 1 030 km² at peak floods but reduces in area to 480 km² at low water.

6.2 Lakes

There are four main lakes in Malawi: (a) Lake Malawi itself covers an area of 30 800 km², over half of which is effectively controlled by Malawi. Lake Malawi is a deep Rift Valley lake with a maximum depth of 758 m - the richer shallow southern areas of the lake both lie within Malawi; (b) Lake Malombe is a 390 km² lake to the south of Lake Malawi. It is a shallow lateral expansion of the Shire River whose regime has been stabilized by a flood control dam downstream; (c) Lake Chilwa is an endorheic lake showing extreme variations in level. It dries out almost completely in some years but may extend over 2 590 km² at highest water when it is surrounded by 1 000 km² of marshland. Its mean area is about 750 km²; (d) Lake Chiuta is a smaller lake of the same type as Lake Chilwa and covers about 113 km² when full.

7. LAND AND WATER USE

Malawi is a predominantly rural country. The only major modifications to the natural conditions is the barrage across the Shire River below Lake Malombe. This has changed the water regime of the river to a certain degree.

8. FISHERY YIELD/PRODUCTION

Table 34

Nominal catches in the inland waters of Malawi (1970–76)
(in tons)

Catches from the individual areas are as follows:

a) Shire River

The catches from the Shire River were summarized by Willoughby and Walker (1977) (Table 35).

Table 35

Production of fish from the Shire River

b) Lake Malawi

FAO/UNDP (1976) analysed the lake catches and gave the corrected values shown in Table 36.

Table 36

Catch of fish from Lake Malawi

(c) Lake Malombe

Captures are estimated at 5 000 t/y.

(d) Lake Chilwa

The catch from this lake varies with water level from about 100 t (1968) to a maximum recorded 9 800 t (1965). The total catch from the country as estimated by FAO/UNDP is shown in Table 37.

Table 37

Total catch from the inland waters of Malawi (1967–75)

These corrected figures are considerably greater than the nominal catch (Table 34).

9. STATE OF THE FISHERY

9.1 Yield

The yield from the two major fisheries, that of the Shire and that of Lake Malawi appear to have reached a plateau. Willoughby and Walker (1977) place the maximum yield of the Shire Floodplain at around 15 000 t and some increase is envisaged from Lake Malawi; however, it is doubtful whether total catches from the country can exceed 80 000 t for any number of years.

9.2 Factors influencing yield

The catch from Malawi is naturally somewhat variable from year to year. Both the Lake Chilwa and the Shire Floodplain fisheries are sensitive to climatic variability and can give greatly reduced catches in bad years.

9.3 Forecast

It is doubtful whether natural production from Malawi will much exceed 80 000 t/y. There are however excellent opportunities for fish culture in the country and production may be expanded in this manner.

10. SPECIFIC REFERENCES

FAO/UNDP, 1976 Promotion of Integrated Fishery Development: Malawi. FI:DP/MLW/71/516. 36 p.

Willoughby, N.G. and R.S. Walker, 1977 The traditional fishery of the Lower Shire Valley, Malawi. Paper presented to the CIFA Symposium on River and Floodplain Fisheries, Malawi. (in press)

MALI

The northern part of the country lies within the Sahara Desert and is essentially flat with occasional rocky outcrops. The southern part of the country is in the Sahel and is mostly low-lying rolling savanna.

5. CLIMATE

The desertic climate of the north, hot, dry with virtually no rainfall, gives way to a Sahelian climate south of Timbuktu. There is slightly greater seasonal variation in temperature and a single rainy season which lasts from April to October in Bamako.

6. HYDROLOGY

6.1 Rivers

The Niger River, and its tributaries the Baoulé and Bagoye which unite to form the Bani, are the major arteries of Mali. Apart from this river system there are a few headwaters of the Senegal River of which the Bafing and Bakoye are the most important. The Niger River consists of 3 000 km of major channels, whereas the rivers of the Senegal system total about 1 000 km. The Niger River forms a large floodplain between the Markalla Barrage at Sansanding and the Rocky Narrows at Timbuktu. This plain, the Central Delta of the Niger, effectively comprises two portions. The southern portion consists of a vast area of floating meadows during the flood, whereas north of Lake Debo the river breaks down into a number of anastomosing channels meandering through sandy beds interspersed with rocky ridges. In this region there are several floodplain lakes. The total area flooded at high water is about 20 000 km², and some 387 km² remain as permanent water at low water.

6.2 Lakes

The magnitude of the lacustrine resource associated with the Niger River floodplain is indicated by the following list of the main lakes:

Akhariben, 41 km²; Debo and Walado Debo, 190–220 km²; Do, 120 km²; Faguibine, 535–888 km²; Fati, 80–165 km²; Gakora, 29 km²; Garou, 60–120 km²; Gouber, 20–66 km²; Haribonga, 55 km²; Horo, 25–225 km²; Kobongo, 3–15 km²; Komago, 33–91 km²; Korarou, 80–170 km²; Korientze, 55 km²; Niangaye, 400 km²; Tanda and Kabara, 325 km²; Tele, 190–250 km²; Tidaimouen, 63 km²; Titolaouin, 22 km².

6.3 Reservoirs

Two major reservoirs are planned for Mali. The first of these the Selingué when closed will create a reservoir of over 400 km² near the capital, Bamako. The second lake, Manantali, which will cover about 600 km² in area, is still in project.

7. LAND AND WATER USE

Most of the country is arid or desertic and is only sparsely inhabited. The major concentration of people is along the fertile Niger River Valley and in the well-watered south and eastern parts of the country. Small-scale agriculture is widely practised although the Niger Valley is used increasingly for intensive rice culture and to this end the flood control barrages of Markala and Selingué were built to regularize flows and provide for irrigation. Outside the main irrigation areas floating rice is cultivated at a subsistence level all over the Niger floodplain.

8. FISHERY YIELD/PRODUCTION

Table 38

Nominal catches in the inland waters of Mali (1970–76)
(in tons)

Alternative statistics (Table 39) based on the findings of the ‘FED’ Project at Mopti (CILSS, 1978) give what are perhaps more realistic estimates of production in view of the Sahelian drought between 1972 and 1974.

Table 39

Catches from the Central Delta of the Niger (Mopti) as estimated by CILSS (1978) (in tons)

9. STATE OF THE FISHERY

9.1 Yield

The present yield of about 100 000 t is equivalent to 50 kg/ha of flooded area, which is typical of the production from other floodplains in Africa. This together with the rapid fall in catch in response to the Sahelian drought indicates that the fish stocks of the Central Delta are probably not far from full exploitation. That they are not yet fully exploited is witnessed by the rapid recovery of the fishery when more normal regimes were re-established.

9.2 Factors influencing yield

Being a flood fishery the catch from the Central Delta is influenced largely by the state of flooding in the river. There are therefore rather large variations in catch and during the 1972–74 Sahelian drought yields fell rapidly and only rose again when the floods returned to normal.

9.3 Forecast

Slight increases in catch can be anticipated from Mali though it is to be doubted that production from the Central Delta will exceed 150 000 t. Other resources remain and it is thought that the Salingué Reservoir could and another 2 000–3 000 t per year and Manantali eventually about the same.

10. SPECIFIC REFERENCES

CILSS, 1978 Rapport National d'ensemble: Mali. Consultation pour la promotion du programme de développement des pêches au Sahel. CILSS:CAS/PECHE/78/Inf. 5.4:46 p.

MAURITANIA

There are three distinct zones in Mauritania: (a) a narrow southern belt along the Senegal River Valley which is relatively well vegetated; (b) an intermediate central belt of broad sandy plains and dunes fixed with scrub grasses, and (c) a northern desertic belt of rocky plateaus and sand seas.

5. CLIMATE

Extremely hot and dry with very little rainfall which is confined to the south between July and August.

6. HYDROLOGY

6.1 Rivers

The only permanent rivers in the country are the Senegal, which forms the border with the Republic of Senegal for over 600 km and the lower reaches of its tributary, and the Gorgol, which drains the Massif de l'Assaba.

6.2 Lakes

There are several lakes associated with the Senegal Floodplain system, the principal of which, the Lake Rkiz, covers an area of 1 200 ha at high water.

7. LAND AND WATER USE

Mauritania is mainly occupied by nomadic peoples. Settled agriculture is confined to the valley of the Senegal River.

8. FISHERY YIELD/PRODUCTION

Table 40

Nominal catches in the inland waters of Mauritania (1970–76)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

The nominal catch figures (Table 39) do not represent the true situation of the catch although as a mean figure they are probably reasonable. True estimates have been made that between 13 000 and 15 000 t of fish are captured each year from the Mauritanian waters of the Senegal River, but during the Sahelian Drought catches from that river fell considerably on the Senegal side of the river and there is every reason to believe that the same happened in Mauritanian waters.

9.2 Factors influencing yield

Losses have occurred through hydrological management of the area. Lake Rkiz for instance produced about 1 200 t/y of fish up to 1959, but more recently drainage of the lake for irrigation has resulted in it remaining dry for five months of the year. As a result, the fish catch has fallen to 350 t/yr.

9.3 Forecast

Further losses can be anticipated as irrigated agriculture spreads in the area. The projected dams on the upper tributaries of the Senegal River will bring the floods under almost complete control. As most of the fisheries depend on the annual flood cycle, the disappearance of a large part of the stock can be anticipated with a resulting drop in catch.

MOZAMBIQUE

The country is divided into three areas: (a) coastal lowlands comprising about 44 percent of the country; (b) central uplands, formed by plateaus of between 200 and 600 m, make up about 17 percent of the area, and (c) a higher plateau, from 600 to 1 000 m high makes up a further 26 percent. Finally, there are mountainous areas along the western frontier.

5. CLIMATE

The climate varies from tropical to subtropical but becomes more temperate in the high plateau and mountainous areas. There is a warm, rainy season from November to March. Rainfall is irregular particularly in the south.

6. HYDROLOGY

Direcção Provincial dos Serviços Hidráulicos (1969) gives a complete listing of the inland waters of the country.

6.1 Rivers

The main river of the country is the Zambezi which flows for its last 800 km through Mozambique before entering the Indian Ocean. Other important rivers are the Limpopo (400 km) and the Save (300 km). There are many smaller coastal rivers which by reason of the irregularities of the rainfall patterns have hydrological regimes which vary wildly from spate to flood.

6.2 Lakes

Mozambique has 7 000 km² (23 percent) of Lake Malawi. Lakes Chilwa and Chuita lie partly within Mozambique. Both these lakes have very variable areas due to the irregularities of rainfall. There are twelve other lakes of various sizes with a total area of 122 km².

6.3 Reservoirs

One major reservoir has been installed on the Zambezi River behind the dam at Cabora Bassa. This reservoir has an area of 2 700 km².

6.4 Brackish waters

There are about 370 km² of brackishwater lagoons situated in 14 water bodies.

7. LAND AND WATER USE

Mozambique is an entirely agricultural country.

8. FISHERY YIELD/PRODUCTION

Table 41

Nominal catches in the inland waters of Mozambique (1971–76)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

Although the nominal catch figures (Table 41) indicate no catch from the inland waters of Mozambique, it is clear that this is incorrect. There are extensive resources, in lagoons, lakes and rivers, and reports from the Portuguese administration indicate active fisheries as existing in that period. While no firm estimates exist for this production, a figure of about 3 000 t has been advanced as a working estimate. The potential catch of the country is no doubt considerable.

9.2 Factors influencing yield

Catches from inland fisheries are very low, mainly because of the primitive state of development of all stages of the industry. Furthermore, communications within the country are very poor and marketing networks are generally absent.

9.3 Forecast

Because of the lack of data any estimate of potential catch is highly speculative but this may be calculated very roughly: assigning a production of about 10 kg/ha for Cabora Bassa (the same as Lake Kariba) this lake should yield 2 700 t. At 100 kg/ha the smaller lakes should yield about 1 220 t and at 300 kg/ha the brackishwater catch should be about 11 000 t. Production from Lake Malawi is more difficult to establish although 3 000 t is commonly adopted as a working figure for the Mozambique territory of the lake. The rivers may be moderately productive although their seasonal fluctuations may prevent the maintenance of stable fisheries in any but the largest rivers. Minimum catch per year can therefore be estimated at 15 000 t although real catches will probably exceed this figure. Further increases would be by aquaculture.

10. SPECIFIC REFERENCES

Direcção Provincial dos Serviços Hidráulicos, 1969 Indice dos Rios, Lagos e Lagoas de Moçambique. Publicação 1:218 p.

NIGER

Four fifths of Niger is desert and the remaining fifth is dry savanna lying within the Sahelian Belt. The north of the country is often mountainous with major rocky massifs: the Aïr, the Massif de Termit and the Plateau du Djado.

5. CLIMATE

The climate is extrmely hot and arid with only a very short rainy season between June and September.

6. HYDROLOGY

6.1 Rivers

The main river in Niger is the Niger itself which flows for 600 km through the country. Of this length, 140 km form the frontier with Benin. At high water the total flooded area in Niger is 90 704 ha of which 63 667 ha are seasonal floodplain and 27 037 ha are permanent waters of various types including the main channels of the river.

Other rivers in Niger are seasonal and several dried completely during the Sahelian drought. Such water courses as the Dallol Bosso and the Goulbi have pond and swamp systems associated with them. The Kamdougo, flowing into Lake Chad, forms the frontier with Nigeria for part of its course.

6.2 Lakes

The only lake of any size in Niger is Lake Chad. During the ‘Large Chad’ phase some 2 774 km² of 17 percent of the total lake area lies within Niger. However, during the ‘Small Chad’ phase the Northern Basin dries out to form a seasonal marsh. Thus, at the time of writing, when the Northern Basin is dry, Niger has no part of the open waters of this lake.

7. LAND AND WATER USE

Most of the population is concentrated into a narrow band along the southern border of the country. The population is largely nomadic, although there is a settled element in the arable lands of the south.

8. FISHERY YIELD/PRODUCTION

Table 42

Nominal catches in the inland waters of Niger (1970–76)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

Various estimates of production have been made from the Niger River between Mali and Nigeria. Daget (1962) estimated 8 250 t of fish as being caught per year, whereas Bacalbasa (FAO/UN, 1971) estimated some 9 600 t/y. However, these figures include catches from Benin waters of the river and the total for Niger is more probably about 7 000 t/y. In fact, catches are liable to fluctuate according to the flood intensity in each year and may range between 4 000 and 7 000 t. The catches from Lake Chad are more difficult to define as the mobility of fishermen on the lake makes the separation of the catches in any one part difficult. Catches have been generally assumed to be of the order of 10 000 t/y during the ‘Large Chad’ phase.

9.2 Factors influencing yield

There is no doubt that the fish catch within Niger is very variable. Fluctuations are due mainly to climatic variations and the periodic droughts that characterize the Sahelian region produce notable drops in production. During the peak years of the drought (1972–74) it would seem highly probable that catches fell considerably in the Niger River, even though there are no records to show this. Furthermore, the desiccation of Lake Chad during the same period and the persistence of the ‘Small Chad’ phase has robbed the country of some 10 000–12 000 t/y.

9.3 Forecast

The future of fisheries in Niger depends much on the future history of Lake Chad. While it is likely that with the re-establishment of normal flow regimes in the river, fisheries will fluctuate between 5 000–8 000 t/y, it is by no means certain that the northern basin of the lake will refill. One other factor which may affect fisheries in the future is the proposed construction of the flow regulatory dam at Kandaji. This will alter the characteristics of the floodplains downstream, with a possible loss of fish, but will at the same time create a reservoir with a potential of about 2 000 t/y. 2 000 t/y.

10. SPECIFIC REFERENCES

FAO/UN, 1971 Rapport au gouvernement du Niger sur le développement et la rationalisation de la pêche sur le fleuve Niger, établi sur la base des travaux de N. Bacalbasa-Dobrovici, technologiste des pêches. Rep.FAO/UNDP(TA), (2913):33 p.

FAO/UN, 1962 Rapport au gouvernement de la République du Niger sur la situation et l'évolution de la pêche au Niger. Basé sur le travail de J.M.A. Daget. Rep.FAO/UNDP(TA), (1526):53 p.

NIGERIA

Nigeria has four main topographic areas. There is a hot, humid coastal belt which varies in width between 16 and 90 km and is covered with mangrove forests. Inland from this, there is a tropical rain forest zone which penetrates up to 160 km into the interior. The central plateau of the country is high, between 2 000 and 2 500 m, relatively dry and covered with open woodland and savanna. The extreme north of the country is semi-desertic and lies within the Sahelian zone.

5. CLIMATE

There are two well-marked seasons during the year. The wet season, and a dry season which lasts from October to April in the north and from November to April in the south. The climate becomes progressively more arid toward the north of the country.

6. HYDROLOGY

6.1 Rivers

The Niger River drainage covers most of the hinterland of Nigeria. Two main arms, the Niger itself, which flows for about 1 300 km through the country, and the Benue, 1 440 km long, are joined by several major tributaries such as the Sokoto, the Gongola, the Kaduna and the Anambra Rivers. The main channels of the Niger and Benue Rivers were flanked by extensive floodplains, 480 000 ha and 310 000 ha in extent at peak floods respectively. Some of this area has disappeared since the closure of the Kainji Reservoir. The main Nigerian tributaries to these rivers also have extensive floodplain systems. The southern coastal part of Nigeria is drained by a series of shorter rivers principal among which are the Ogun, the Oshun (267 km) and the Cross River.

6.2 Lakes

During the ‘Large Chad’ phase 5 500 km² (25 percent) of Lake Chad lie within Nigeria. However, during the ‘Small Chad’ phase the waters of the lake are concentrated entirely within Cameroon and Chad, and the Nigerian portion virtually disappears.

6.3 Reservoirs

One major reservoir has been formed on the Niger River behind Kainji Dam. Kainji Lake covers an area of 1 270 km². Other large reservoirs are in project.

6.4 Brackish waters

There is a very extensive lagoon system running parallel to the coast in western Nigeria. This consists of three main elements: (a) the Badagri Creek which carried excess flood water from the Ouémé and Oshum Rivers to (b) the Lagos Lagoon which connects through a series of creeks to (c) the Lekki Lagoon. The whole system covers over 800 km². The Niger Delta, which covers a total of 36 260 km² consists of a network of distributaries up which saline waters penetrate for a considerable distance. There are estimated to be over 15 000 km² of swamplands in the delta which are suitable for aquaculture.

7. LAND AND WATER USE

Although Nigeria is predominantly agricultural, there is an active petro-chemical industry in the Niger Delta area and industrial development is expanding particularly in the south. Heavy urbanization along coastal rivers and lagoons, and intensive agriculture for cash crops in some other parts of the country may give rise to local pollution problems.

8. FISHERY YIELD/PRODUCTION

Table 43

Nominal catches in the inland waters of Nigeria (1970–76)
(in tons)

Sagua (1976) quotes Anon. (1974) as giving the very different estimate of production from inland waters of 164 500 t/y.

9. STATE OF THE FISHERY

9.1 Yield

Because of the widely disparate estimates of production it is useful to examine the individual fisheries within Nigeria in some detail.

(a) Lake Chad

Although it has always been difficult to obtain reliable estimates of the catch of the Lake Chad fishery, it seems reasonable to assume that during the ‘Greater Chad’ stage about 25 000 t, or 25 percent of the 100 000 t total catch from the lake is caught in Nigerian waters, which represent 25 percent of the lake surface. During the ‘Small Chad’ phase this falls to zero as the Nigerian part of the lake dries up.

(b) Niger and Benue Rivers

FAO/UN (1969) estimates the catch of these rivers without the delta at 14 350 and 9 570 t respectively or a total of 23 800 t. There is no doubt that a part of this has been lost with the closing of the Kainji Dam which controlled the flood of the Niger River downstream of the dam.

(c) Lake Kainji

The catch from this lake rose to about 11 000 t in 1963 and has remained at about this level since.

(d) Niger Delta

There are about 1 500 000 ha of floodplains and swamps in the delta. This may yield about 40 hm^-2 (figure based on mean performance of a sample of African floodplains) equivalent to 60 000 t.

(e) other rivers

Production from these is uncertain, but is estimated by Nigerian authorities at 45 000 t, possibly a high estimate, and 10 000 t would appear more realistic.

(f) coastal lagoons

The coastal lagoons cover about 80 000 hm² and at a mean yield of 500 kg hm^-2 an annual catch of 40 000 t y^-1 is possible.

(g) total

The total catch from natural waters might therefore be analysed approximately as shown in Table 44.

Table 44

Catch from individual water bodies of Nigeria
(in tons)

To this may be added the estimated 75 000 t produced by aquaculture as quoted by FAO/UNDP (1975) although it is not clear to what extent this tonnage is reflected in the figures for capture fisheries from other areas. It seems safe, however, to estimate the total annual yield of Nigerian inland waters at between 200 000 and 250 000 t.

9.2 Factors influencing yield

As northern Nigeria lies within the Sahelian Belt, there are very strong climatic effects on the size of water bodies, and the flow of the rivers. At present (1978) for instance, Lake Chad is still in its small phase with a corresponding loss of fish to the country. Considerable year-to-year variations can therefore be expected due to fluctuations in rainfall. Human agencies are also becoming very critical. Nigeria is one of the most advanced countries in Africa and is pursuing an active policy for agricultural and industrial development. Far reaching environmental changes are therefore to be anticipated with consequent losses in natural production.

9.3 Forecast

There is little hope of any great increase in production from the natural waters of the country, and indeed as development for other purposes proceeds a slow decline in catch from the capture fisheries is to be anticipated. On the other hand there is a good prospect of expansion of aquaculture into the very large areas available, especially in the residual pools of the floodplain and in the delta.

10. SPECIFIC REFERENCES

FAO/UN, 1969 Report to the Government of Nigeria on fishery investigations on the Niger and Benue Rivers in the northern region and development of a programme of riverine fishing management and training. Based on the work of M.P. Motwani, Rep.FAO/UNDP(TA) 2771, 196 p.

Sagua, V.O., 1976 Aquaculture and fishery development in Nigeria - a review paper. A paper read at the 12th Annual Conference of the Agriculture Society of Nigeria at University of Ife, 6–11 July 1976. 31 p. (mimeo)

Anon., 1974 Agricultural development in Nigeria, 1973–85. Published by F.M.A.N.R. Lagos. 588 p.

RWANDA

The country consists mainly of grassy uplands which form part of the watershed between the Zaire and Nile River systems. It slopes from a range of high volcanoes in the northwest to savanna plains in the east. To the west the hills descend abruptly into Lake Kivu.

5. CLIMATE

The high elevation makes for a temperate climate and frost may even occur in the high mountains. There is a short dry season in January with the major rainy season occurring from February to May. The main dry season lasts from May to September and the short rains from September to December. The rainfall is far heavier on the mountainous areas to the north and northwest than on the eastern savannas.

6. HYDROGRAPHY

6.1 Rivers

The country is dominated by the Akanyuru-Kagera River which drains the majority of the country. The river is encased in narrow valleys for much of its upper course, but forms broad papyrus-filled swamps in its lower reaches. Below the Rusumo Falls it expands over large areas of savanna. One other short, but important river is the Ruzizi which flows out of Lake Kivu toward Lake Tanganyika.

6.2 Lakes

Rwandan lakes fall into four main groups:

(a) Lake Kivu

Principal of these Rwandan lakes is Lake Kivu, 1 000 km² of which lies within Rwanda. Lake Kivu is very deep (240 m mean depth) but rich in nutrients.

(b) high altitude lakes

Cool, deep and rather infertile lakes at high altitude (Table 45)

Table 45

Surface areas of Rwandan high altitude lakes

(c) plateau lakes

Warm, shallow and fertile lakes interspersed among the flooded papyrus of the Akanyanaru Valley (Table 46).

Table 46

Surface areas of Rwanda Plateau lakes

There are eight other smaller lakes including Lake Cyohoha which is on the frontier with Burundi and whose Rwanda area is 630 ha².

(d) lakes of the Kagera Floodplain (lowland lakes)

Shallow, warm and fertile lakes spread over the lateral plain of the Kagera below the Rusumo Falls. There are eight major lakes (Table 47), as well as ten smaller water bodies.

Table 47

Surface areas of the lakes of the Kagera Floodplain

7. LAND AND WATER USE

The population of Rwanda is entirely rural with small holdings dispersed throughout most of the country. Cattle herding is also very important although limited to the highlands because of heavy Tsetse infestations in the plains. There is one extensive national park along the lower portion of the Kagera River which contains many of the more important lowland lakes.

8. FISHERY YIELD/PRODUCTION

Table 48

Nominal catches in the inland waters of Rwanda (1970–76)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

Present yield patterns broken down by groups of water bodies are shown in Table 49, giving a total of about 600 t/y.

Table 49

Catch by groups of water bodies for Rwanda (taken from Mahy, 1977)
(in tons)

9.2 Factors influencing yield

A variety of factors influence to yield of Rwandan inland waters. Lake Kivu has traditionally been a poor lake for fishing and as a consequence only the narrow coastal fringe has been exploited in a desultory manner.

The highland lakes and plateau lakes are fairly intensely exploited, although with proper management could possibly sustain higher levels of catch. The lowland lakes are barely exploited because most of them lie within the game reserve.

9.3 Forecast

Fish catch from Rwanda could be considerably increased. It is now evident that Limnothrissa miodon has become established in Lake Kivu and could form the basis of an important fishery which could yield up to about 10 000 t/y for the Rwandan waters of the lake. No great increases could be anticipated for the highland lakes, but the plateau lakes could probably produce about 100 kg/ha which the total area of 13 630 ha would be 1 300 t.

The total catch from Rwanda, therefore, could well increase up to about 12 000 t/y.

10. SPECIFIC REFERENCES

Mahy, G., 1977 Bases scientifiques pour l'aménagement de l'exploitation rationnelle des ressources piscicoles du Rwanda: Etudes Rwandaises. II, (1):3–35

SENEGAL

Most of Senegal is low lying, rolling terrain covered with savanna. In the southeast the country rises to the foothills of the Fouta Djallon Mountains. Some rainforest and swamps are found in the south.

5. CLIMATE

There are two well defined seasons. The rains occur from June to October. December to February is cool and dry.

6. HYDROGRAPHY

6.1 Rivers

The Senegal River and its tributary, the Falémé, form the northern and western frontiers of the country with Mali and Mauritania. The Senegal River has extensive floodplains both fringing the main channel (5 000 km² at peak flood) and in the delta (7 970 km² at peak flood). Other rivers are the Saloum, Gambia and Casemance.

6.2 Lakes

One major lake, the Lac de Guiers, is connected to the Senegal River by a short channel, the Tawey. The lake area fluctuates with changes in water level ranging between 120 km² at low water and 240 km² at high water.

6.3 Reservoirs

There are no major reservoirs at present although there are proposals to install a flood-control dam in the Senegal River Delta.

6.4 Brackish Waters

The Casemance River has an estuarine zone which extends far inland. There are also estuarine lagoons around the mouth of the Saloum River and the Senegal River has an extensive Delta which is deeply penetrated by salt water.

7. LAND AND WATER USE

Senegal is a very arid country over much of which marginal agriculture is practised. There is some pastoralism especially in the eastern parts and in the Senegal River Valley. Much of the river valley is being converted to irrigated agriculture, a process which will be accelerated after the construction of the projected upstream dams.

8. FISHERY YIELD/PRODUCTION

Table 50

Nominal catches in the inland waters of Senegal (1970–76)
(in tons)

After 1973 the figures in Table 50 contrast with those provided by Fall (1976) (Table 51) who shows a rise in catch in 1974 and 1975.

Table 51

Catches from the Senegal River (1967–75)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

The catches from the Senegal River fell to 12 000 t/y during the Sahelian Drought, but since rose to their preflood levels once normal flood patterns were re-established. The estimates of inland catch are based almost entirely on the catches from the Senegal River, but national catches are presumably higher as a fair but unreported quantity must also be caught in the Casemance, Gambia and Saloum systems.

In general the Senegal fishery appears to be exploited at or near the maximum level (Reizer, 1974). The swiftness of the collapse of the fishery during the drought bears witness to the intensity of fishing, however the equally swift re-establishment of previous catch levels would indicate that the fishery is not severely over-exploited.

9.2 Factors influencing yield

As can be seen from the figures from 1969 to 1975 climatic factors have a very strong influence on the catches within the country. The Senegal is a Sahelian river and its fisheries suffer from the periodic drought which beset this region.

9.3 Forecast

Although the capture fisheries of the river are near full exploitation, increases in production could result from an extensive, or semi-intensive use of the floodplain lagoons for aquaculture. Any plans for developments of this type would depend much on the various types of hydro-agricultural management proposed. Three major upstream dams are being considered: Galoupo, Manantali and Gourbessi. There is also a proposal to install a dam in the delta which would change its salinity characteristics. None of the upstream dams would be in Senegal, so the country would not benefit from the fisheries of the reservoirs they impound, and there would be a considerable loss in the fishery of the Senegal River floodplains and the long-term prospects for the Senegal River fishery are poor.

10. SPECIFIC REFERENCES

Fall, A.O., 1976 L'évolution des pêches du bassin du fleuve Sénégal au cours des cinq dernières années. Sénégal, Direction des Eaux et Forêts. 2 p. (mimeo)

Reizer, C., 1974 Définition d'une politique d'aménagement des ressources halieutiques d'un écosystème complexe par l'étude de son environnement abiotique, biotique et anthropique. Le fleuve Sénégal Moyen et Inférieur: Dissertation. Arlon, Fondation Universitaire Luxembourgeoise.

SIERRA LEONE

Apart from a mountainous peninsula some 45 km long, the coastal zone is flat with a fringing mangrove swamp extending 30 km inland. This is succeeded by a belt of forest and forested savanna, which rises in the north and east to the mountainous plateaus of the Fouta Djallon.

5. CLIMATE

The climate is generally hot and humid throughout the year but the rains are concentrated into a single rainy season extending from May to October.

6. HYDROLOGY

6.1 Rivers

Sierra Leone is well supplied with small rivers which drain the northern highlands and discharge into the Atlantic. Principal among these are the Sewa River (340 km approx.), Jong River (230 km), Little Scarcies River (260 km), Rokel River (260 km) and Moa River (190 km). The rivers are all rocky and torrential in their upper courses but open into wide estuaries which penetrate far inland and are bordered by mangrove swamps and floodplains.

6.2 Lakes

There are no major natural lakes in the country.

6.3 Reservoirs

There are no major reservoirs in the country.

6.4 Brackish waters

The lower courses of the rivers are deeply invaded by saline waters as are the extensive marshes surrounding the Little Scarcies and Sewa Rivers. There are two large lagoons, Lake Mabesi and Lake Mabe (4 500 and 4 600 ha, respectively). There are many smaller lagoons.

7. LAND AND WATER USE

Sierra Leone is mainly an agricultural and forestry country but has also considerable mineral resources.

8. FISHERY YIELD/PRODUCTION

Table 52

Nominal catches in the inland waters of Sierra Leone (1971–76)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

There is very little information on the inland fisheries of Sierra Leone although there are some indications that a diffuse artisanal fishery exists on most inland waters. Given the number of rivers and lagoons in the country, the current estimates of 1 100 t in Table 52 seem rather low. Assuming yields of between 200 and 500 kg/ha from the lagoons, some 2 000–5 000 t should be landed from those waters alone. The rivers might reasonably be expected to contribute a further 1 000 t if they perform more or less as other rivers on the West Coast of Africa. Potential catches of between 3 000 and 5 000 t might, therefore, be achieved from the inland waters of Sierra Leone.

9.2 Factors influencing yield

Insufficient information

9.3 Forecast

As the present performance of the fishery is virtually unknown, it is not possible to forecast future trends. There may be opportunities for aquaculture, especially in the brackish waters, which would increase the potential in years to come.

SUDAN

Sudan is a flat country with elevated lands to the east, south and southwest. Vegetation patterns change from tropical forest in the south, through semi-tropical savanna to sandy arid hills in the north. Extreme desert conditions prevail in the northwest. The central zone of the country is transected by the Nile Valley with its large swamp depression in the Sudd.

5. CLIMATE

The north of the country has a desertic climate with little rainfall throughout the year. The centre of the country has an unstable climate with a pronounced rainy season of variable duration. In the south the climate is equatorial with more or less daily rainfall.

6. HYDROLOGY

6.1 Rivers

The country is dominated by the Nile system. The White Nile enters Sudan at Nimule in the extreme south and flows for 3 000 km before entering Egypt below Wadi Halfa. The Blue Nile follows a torrential course through the Ethiopian highlands and emerges into Sudan to flow for 600 km before its confluence with the White Nile at Khartoum. The major tributaries of the Nile in Sudan are the Sobat (280 km), and the Atbara (600 km).

The Nile system expands into the Sudd Swamps which have an area at peak floods of around 92 000 km², when the waters of the Nile are joined by those of the Bahr el Ghizal and the numerous temporary rivers draining the Congo, Chari watershed toward the east. At low water the Sudd retains about 10 000 km² of permanent swamp and marsh.

6.2 Lakes

The only natural lakes in the country are the numerous floodplain lakes, most important of which is Lake No, which concentrates the major part of the flow from the Nile as it emerges from the Sudd.

6.3 Reservoirs

There are a number of reservoirs in the rivers of Sudan, whose characteristics are shown in Table 53.

Table 53

Characteristics of reservoirs in Sudan (based on Hendersen, 1975)

^a southern part of Lake Nasser

7. LAND AND WATER USE

Sudan is a mainly desertic country; there is therefore a very high demand for water. The several reservoirs are for flow retention associated with irrigation areas and the soon to be constructed Jonglei Canal will allow about 10 percent of the present Nile flow to bypass the Sudd Swamps to increase the amount of water available for irrigation downstream.

8. FISHERY YIELD/PRODUCTION

Table 54

Nominal catches in the inland waters of Sudan (1971–76)
(in tons)

Present estimates of catches would seem to indicate that the nominal catches (Table 54) are about correct. Henderson (1975) estimated production in 1975 as in Table 55.

Table 55

Estimated catch from individual reservoirs in Sudan
(in tons)

To this could be added about 12 000 t from the south of the country, giving a total of some 22 000 t.

9. STATE OF THE FISHERY

9.1 Yield

The potential production of the major reservoirs in Sudan has been estimated by Henderson (1975) (Table 56).

Table 56

Potential production from the reservoirs of Sudan
(in tons)

The potential yield of the Sudd is more difficult to assess. If its yield is to be comparable with other floodplains in Africa, i.e., about 40 kg/ha of total flooded area, the potential is enormous. Much of the area is apparently impoverished consisting of poor and unproductive waters, but the large area should give it a potential at least comparable to the Central Delta of the Niger, i.e., about 100 000 t.

A tentative minimum estimate of total annual yield for Sudan of 125 000 t would therefore seem reasonable.

9.2 Factors influencing yield

The main block to development of the inland fisheries of Sudan is the geographic isolation of the water bodies from the main centres of population. Communications are very poor so fish cannot reach the markets in substantial quantities. Population densities, especially in the Sudd or on Lake Nubia are too low to support a large fishing community. The whole future productivity pattern of the Sudd is also in doubt as the Jonglei Canal might well alter the flood regimes of that area. Ironically, the catch may well increase because of the canal and the better communications resulting from it.

9.3 Forecast

In response to the strong demand for fish and concerted efforts to develop the various fisheries as well as aquaculture in irrigated areas, the catch should rise to near its potential over the next decade. However, the potential itself may be lowered through environmental changes arising from the demand for water for agriculture.

10. SPECIFIC REFERENCES

Henderson, H.F., 1975 Report to the Government of the Democratic Republic of the Sudan on the Fisheries of the Reservoirs of Central Sudan. FAO. Cairo, 1975, 20 p.

TANZANIA

The topography of continental Tanzania is highly varied but four main types of terrain predominate: (a) the coast below 300 m altitude; (b) the alluvial plains of the main eastward flowing rivers from 300 to 1 000 m in altitude; (c) in inland plateau which covers most of the country, 1 000–2 000 m, and (d) highlands to the south and northeast, which range between 2 000 m and 5 900 m. Parts of both eastern and western arms of the Rift Valley systems lie within Tanzania. The island of Zanzibar is of no interest for inland fisheries.

5. CLIMATE

The climate is linked to the topography, having also four main areas: (a) a hot humid coastal zone; (b) a hot arid central area; (c) high moist lake regions, and (d) temperate uplands. The overall climate is regulated by the monsoons which give two equinostial rains, one from March to June, the other from October to December. At other times of the year the weather is hot and dry.

6. HYDROLOGY

6.1 Rivers

There are comparatively few river systems within Tanzania as the main central plateau is arid. The Pangani River (360 km) drains the northern highlands and the 720-km Rufigi/Ruaha system drains the southern uplands. The Rovuma River forms the border with Mozambique for 640 km. The other major river system, that of the Malagarasi, flows from the central plateau into Lake Tanganyika. The main channel is some 560 km long and expands into the Malagarasi Swamps.

6.2 Lakes

Tanzania is extremely well endowed with lakes:

1. Lake Victoria: Tanzania has 33 700 km² or 49 percent of the total area of this lake
2. Lake Tanganyika: 13 500 km² (41 percent) lie within Tanzania
3. Lake Malawi: Tanzania has 300 km of shore line
4. Lake Kitangiri: 1 200 km²
5. Lake Rukwa: 2 300 km²
6. A group of Rift Valley soda lakes, Natron, Eyasi and Manyara, which do not support fisheries

6.3 Reservoirs

The 180 km² Nyumba ya Mungu Reservoir was constructed on the Pangani River in 1965. The reservoir has a mean depth of 6 m. A further reservoir, which will be larger than Nyumba ya Mungu, is being constructed at Stiglers Gorge on the Ruaha River.

6.4 Aquaculture

Some 10 000 ponds with a surface area of 1 000 ha had been constructed by 1963, but because of poor technology and management many of these have since fallen into disuse.

7. LAND AND WATER USE

Tanzania is a predominantly agricultural country although some areas are used mainly for cattle ranching and game parks.

8. FISHERY YIELD/PRODUCTION

Table 57

Nominal catches in the inland waters of Tanzania (1970–76)
(in tons)

The catch figures from inland waters are broken down in the Annual Reports of the Fisheries Division of Tanzania as follows:

Table 58

Summary of catches from inland waters of Tanzania (1969–73)
(in 000 tons)

Although these figures are reasonably close to the nominal catch statistics (Table 57) there are some discrepancies.

9. STATE OF THE FISHERY

9.1 Yield

Although the series of figures from 1969 to 1973 indicates a stabilized catch, there have been considerable advances since 1966, when total catches were 73 044 t or 1962 when only 63 000 t were caught. Nevertheless potential exists for greater expansion of certain fisheries. In Lake Victoria there is a considerable standing stock of Haplochromis in the deeper offshore portions of the lake. These could amount to 100 000 t/y if exploited by an appropriate deepwater trawl fishery. In Lake Tanganyika research has shown a very rich resource of pelagic Limnothrissa sp. and Stolothrissa sp. which could yield at least 120 000 t/y if a commercial purse-seine fishery is developed. Similar increases in catch might be achieved in Lake Nyasa (Malawi).

9.2 Factors influencing yield

Whereas the fisheries mentioned above depend much on the development of a suitable infrastructure for commercial-scale fisheries, several other fisheries, particularly Lakes Rukwa and Kitangiri, which are subject to large natural fluctuations in area. The case of the Nyumba ya Mungu Dam shows a rise in production and subsequent fall which conform to the normal pattern for newly established reservoirs. The peak production of 28 500 t seems excessive for a body of water of this size, but the present yield of 2 700 t is consistent with yield patterns for other reservoirs in Africa.

9.3 Forecast

There is considerable room for increases in catch from the inland waters of Tanzania. As well as the extra 130 000 t from Lakes Victoria and Tanganyika, some additional production may be anticipated from the new reservoir on the Ruaha. The potentials from the capture fishery may therefore be estimated at about 250 000 t. Further development of fish production is hoped for by the spread of aquaculture, where it is estimated that 2 000 t could be produced from existing ponds, 10 000 t from expanding aquaculture in about 40 000 ha of small dams and reservoirs. Increases in production through aquaculture could obviously surpass this.

TOGO

Togo consists essentially of two savanna plains separated by a chain of hills extending from the Atakora Massif in the northeast to the Ghana border in the southwest. The southern plain is cut by a system of coastal lagoons; the northern plain is traversed by the Oti River.

5. CLIMATE

In the south the climate is tropical, with temperatures ranging between 22° and 32°C. Humidity is relatively low for the West African coast and rainfall is moderate, being confined into two short sea-sons - one from March to June and the other in October. Rainfall drops as one proceeds northward and the north of the country is moderately dry.

6. HYDROLOGY

6.1 Rivers

There are two main river systems in Togo. In the north the Oti River flows diagonally across the country for about 100 km before turning southward for 110 km to form the frontier with Ghana. The Mono River flows southward for 360 km although part of its lower course is in Benin.

6.2 Lakes

There are no natural freshwater lakes of any size in Togo.

6.3 Reservoirs

Although a large dam has been projected for some years to block the Mono River, no reservoirs yet exist in the country.

6.4 Brackish waters

There are a series of lagoons in Togo centred around the 10 000-ha Lake Togo and extending to join the sea via the Mono. A smaller water body, the Lome Lagoon, is now isolated from the main system.

7. LAND AND WATER USE

Although Togo has a rural population, there are extensive deposits of phosphate and limestone in the south which are mined.

8. FISHERY YIELD/PRODUCTION

Table 59

Nominal catches in the inland waters of Togo (1971–76)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

Lack of reliable statistics and other information on the fishery makes an evaluation of its state difficult. In view of the extent of the coastal lagoon system and comparison with catches from the Benin Lagoons, the estimate of 3 000 t/y seems low.

9.2 Factors influencing yield

Not known.

9.3 Forecast

It is reasonable to assume that the inland waters of Togo are exploited at or near their minimum potential. There is a moderately active fish culture programme in the country, which may contribute to some increases in production. More intense utilization of the lagoons for extensive culture could also increase yields.

UGANDA

Uganda is a high plateau dipping to the southeast to the Lake Victoria Basin. The west of the country is traversed from north to south by the western area of the Great Rift Valley. There is a high mountainous chain, the Ruwezoris in the extreme west, and to the southwest the Bufumbiro volcanoes block the Rift Valley. In the east a chain of volcanic peaks stretches north to south with Mounts Moroto, Kadem and Elgan. The rest of the plateau consists of rolling hills with extensive papyrus swamps in their valleys.

5. CLIMATE

Although Uganda lies astride the equator, any climatic severity is eased by its altitude. There are two rainy seasons (February–June and April–December) in the wettest areas along the western shore of Lake Victoria. While the twin season pattern prevails over the rest of the country, the north and west are very much more arid.

6. HYDROLOGY

6.1 Rivers

The main river system of Uganda is that of the Nile which flows out of Lake Victoria and leaves the country at Nimule in the north. It is customarily divided into the Victoria Nile (456 km) and the Albert Nile (216 km). A variety of smaller rivers flow into the Nile system including the Aswa (356 km), but many of them are lost under papyrus mats in swampy valleys.

6.2 Lakes

The Major lakes of Uganda are summarized in Table 60.

Table 60

Characteristics of lakes of Uganda

^a Lakes Mburo, Nakivali, Kijanebalola, Bunyoni, Mutanda, Karengye, Wamala

7. LAND AND WATER USE

Uganda has a mainly scattered rural population growing staples such as plantains and corn and cash crops such as coffee, cotton and tea. There is one major barrage, that of the Owen Falls across the point where the Nile leaves Lake Victoria.

8. FISHERY YIELD/PRODUCTION

Table 61

Nominal catches in the inland waters of Uganda (1971–76)
(in tons)

Detailed breakdowns by lakes are available for the same period as in Table 61 and are distributed as in Table 62.

Table 62

Breakdown of catch by individual water bodies in Uganda
(in tons)

^a Provisional figures

These figures do not agree entirely with the nominal catches but differences are moderate.

9. STATE OF THE FISHERY

9.1 Yield

All lakes in Uganda showed a steady increase over the 10 years from 1960 to 1970 as follows: Lake Victoria - 1.5 times; Lake Mobutu - 1.8 times; Lake Kyoga - 4.7 times; Lake Amin - 1.1 times; Lake George - 0.8 times; other lakes 1.9 times. Certain trends are evident from this. Lakes which were developed early, such as Lake George, Lake Victoria, Lake Amin or Lake Mobutu, have shown little increase in catch over the past few years. The overall increase in the Ugandan freshwater catch, is in fact traceable to the explosive development of the Lake Kyoga fishery. The even more remarkable increase in other lakes is limited by the small sizes of the water bodies concerned.

9.2 Factors influencing yield

In several lakes, individual stocks of fish have been overfished and overall increases in catch have been at the expense of a fishing-up process which has resulted in a steady decline in the mean size of the fish caught. The only exception to this is the fishery of Lake Kyoga, which expanded as the Nile perch population exploded after the species was introduced into the lake.

9.3 Forecast

Most Ugandan lakes seem to be at or near their maximum level of exploitation and indeed indications in 1976 show that several lakes may now be overfished. The major exception to this is Lake Victoria where although the catch from the conventional stocks has declined, considerable stocks of benthic Haplochromis could be fished by industrial trawlers. The potential yield from these stocks has been estimated at about 90 000 t (Henderson, Ryder and Kudhengania, 1975), which if realizable would put the Ugandan yield as high as 240 000 t/y. Any further increases would have to be achieved by aquaculture for which there are rich opportunities, especially in the mountainous south of the country.

10. SPECIFIC REFERENCES

Henderson, H.F., R.A. Ryder and A.W. Kudhengania, 1975 Assessing Fishery Potentials of Lakes and Reservoirs. J.Fish.Res.Board Can., 30(12):2000–9

UPPER VOLTA

Upper Volta is a land-locked country consisting mainly of flat savanna which lies within the Sahelian zone. In the east, low hills demarcate the White Volta and Niger River watersheds.

5. CLIMATE

The climate is generally hot and arid with very limited rainfall in the north. The south is somewhat more moist and has one main rainy season extending from May to October.

6. HYDROLOGY

6.1 Rivers

Upper Volta is well watered with rivers, forming as it does the watershed between the Volta and the Niger systems. The Volta is the most important with four major tributaries: the Black Volta flows for 650 km within the country and has extensive marshes situated in a large depression known as the Mer aux Hippopotames; the White Volta flowing for some 255 km in Upper Volta and the Red Volta for some 350 km. The other river, the Penjari, forms the frontier with Benin for about 200 km. Within the Niger Basin the Sirba River drains the central hills toward the north.

6.2 Lakes

There are few natural lakes of any size within the country.

6.3 Reservoirs

There are numerous small barrages which have been created mainly for watering cattle scattered over the south of the country. More than 300 of such water bodies exist but the majority of the area is concentrated in 7 large artificial lakes. The total area estimated as being underwater in such water bodies is about 22 000–25 000 ha.

7. LAND AND WATER USE

Upper Volta is an agricultural country with considerable pastoralism in the north. Much of this area, especially near the water courses is rendered uninhabitable by Simulium, the sector of river blindness. Intensive efforts on controlling this insect may open up much of the country close to the rivers with a consequent effect on the development of the fisheries.

8. FISHERY YIELD/PRODUCTION

Table 63

Nominal catches in the inland waters of Upper Volta (1971–76)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

The statistics available for the estimation of catches from Upper Volta are very unreliable. As a consequence, the nominal catch figures (Table 63) are more in the nature of general estimations with very little factual data to support them. It would seem likely from the relatively small surface area available in the country that the lower estimate of 3 500 t is the more reasonable at the present time.

9.2 Factors influencing yield

The limited area of surface water means that the potential production for Upper Volta is low and the fishery has remained in a relatively undeveloped state mainly due to the presence of river blindness in most of the water courses. Ambitious development plans based on extensive aquaculture in the barrages and dams project a production of as high as 7 000–10 000 t per year. However, the production of fish from the inland water in the Upper Volta is severely limited by climatic conditions and while the Sahelian Drought conditions prevail, increases in production can not be anticipated.

9.3 Forecast

It is difficult to make any definite forecast for future production due to climatic instability in the area. However it seems likely that with a concentrated effort the production from various inland water bodies could reach 6 000 t/y.

ZAIRE

Zaire consists mainly of a low lying central basin covered by tropical rain forest. The basin is surrounded by mountainous terraces in the west, elevated plateaus covered with savanna in the south and southeast and dense grasslands in the north. The eastern region is crossed by high mountains.

5. CLIMATE

Zaire lies astride the Equator, about ⅓ to the north and ⅔ to the south. The climate, therefore, is equatorial and is especially hot and humid in the forested central areas. North of the Equator there is a single rainy season from April to November and south of it a rainy season which lasts from October to May. In the central region rainfall is distributed evenly throughout the year.

6. HYDROLOGY

6.1 Rivers

With the exception of parts of the Ubangi system and the upper reaches of some of the southern tributaries, almost the whole of the Zaire River Basin lies within the country. The main channel of the Zaire is joined by such major tributaries as the Ubangi, Lualava, Luapula, Lulonga, Tchuapa. There is a total of some 33 000 km of major river channel and their area is increased by intensive floodplains, particularly in the Kamulongo Depression and in the Mbandaka region of confluence between the Ubangi and the Zaire streams. In total, the floodplains are thought to cover about 25 000 km² during high water but such a figure can only be approximate due to the difficulties of measuring such areas.

6.2 Lakes

The major lakes within Zaire are those of the Rift Valley and are found in the extreme east of the country (Table 64).

Table 64

Characteristics of the Rift Valley lakes of Zaire

In addition to these lakes, there are two major water bodies attached to the lower reaches of the river system: Lake Tumba - 700 km² and Lake Maindombe (Majindombe) - 2 300 km². The Kamulondo Depression contains some 50 lakes with a total area of 1 200 km², of which Lake Upemba (530 km²) is by far the largest.

6.3 Reservoirs

Two major reservoirs have been installed in the southeast part of the country - Lake Mwadingusha on the Lulua, with a surface area of 390 km² and Lake Nzilo on the Lualaba with a surface area of 280 km².

7. LAND AND WATER USE

Zaire is densely forested and much of the central basin is occupied by tribes using primitive ‘slash and burn’ agriculture. In the western highlands cash crops such as coffee and cotton are common and in the south, in Shaba and Katanga provinces, the considerable mineral resources have given rise to intensive development for mining.

8. FISHERY YIELD/PRODUCTION

Table 65

Nominal catches in the inland waters of Zaire (1971–76)
(in tons)

Catches from inland water bodies are estimated as in Table 66.

Table 66

Catches from individual water bodies of Zaire
(in tons)

The fact that this figure does not agree with the nominal catches is not serious as the statistics available from the various water bodies of Zaire are neither complete nor reliable.

9. STATE OF THE FISHERY

9.1 Yield

The present catches from the inland waters of Zaire are considerable less than those which had been achieved just prior to 1960. During the early post-independence period many fisheries collapsed and are only now being re-established. Early catch figures are indicative of the potential that can be achieved from the inland waters of Zaire (Table 67).

Table 67

Estimated catches from inland waters of Zaire prior to 1960
(in tons)

That these productions often approach the potentials is indicated by a comparison between Table 67 and Table 68.

Table 68

Estimates of potential from inland waters of Zaire
(in tons)

The potential catch from the rivers is estimated at between 90 000–140 000 t in all, giving a total potential catch of between 280 000 and 330 000 t.

9.2 Factors influencing yield

A considerable demand for fish in Zaire shows that the present low level exploitation is due to constraints on the marketing and distribution of fish. Many of the water bodies are isolated or inaccessible and adequate fisheries will only be developed as infrastructures are built up.

9.3. Forecast

It seems highly probable that the total catch of inland fish in Zaire will rise steadily over the next decade to its pre-1960 levels and that the establishment of two specialized fisheries, in particular, will eventually exceed these levels. The two fisheries are those of Lake Tanganyika where there is a considerable unexploited stock of Stolothrissa and Limnothrissa, and Lake Kivu, where a new resource of as yet unknown magnitude has been established following the introduction of Limnothrissa into that lake. One further area remains unexploited, that of the Mbandaka floodplains which, by reason of their inaccessibility and extremely low population density, will probably not be exploited for several decades.

ZAMBIA

Zambia is situated on a plateau which varies between 1 000 and 1 500 m in altitude. Land of slightly higher elevation traverses the country from the centre to the northeast and forms the watershed between the Zambezi and Zaire Basins.

5. CLIMATE

The climate is subtropical with a pronounced winter season (May to August) and summer (September to March). The main rainfall is concentrated into a single season from October to April.

6. HYDROLOGY

6.1 Rivers

Part of two major river basins, the Zambezi and the Zaire lie within Zambia. In the Zambezi Basin, the Zambezi River itself flows for 600 km through the country and forms the frontier successively with Namibia, Botswana, Rhodesia and Mozambique for a further 825 km. The main tributaries are the Kafue (855 km) and the Luangwa (780 km).

In the Zaire Basin the Chambezi River (465 km) flows into the Bangweulu swamplake complex and the Luapula (555 km) flows out of it into Lake Mweru. The Luapula River forms the frontier with Zaire for much of its length.

Several major floodplains are associated with the rivers (Table 69).

Table 69

Characteristics of the major floodplains of Zambia

^a About 30 percent of this area lies in Zambia

Minor flood areas are found on the Basanga Floodplain and the Bwela Flats.

6.2 Lakes

The major lake areas of Zambia are summarized in Table 70.

Table 70

Characteristics of the major lakes of Zambia

There are many smaller lakes associated with the major floodplains as well as Lakes Lushiwashi and Beu.

6.3 Reservoirs

Forty-five percent of Lake Kariba (2 412 km²) lies within Zambia and two smaller reservoirs Mulungushi and Mita Hills are situated near Lusaka.

7. LAND AND WATER USE

Zambia is mainly an agricultural country, but with a developed mining industry in the north. There is some pastoralism on the floodplain flats, and one major barrage, the Kariba Dam, has been installed for power generation.

8. FISHERY YIELD/PRODUCTION

Table 71

Nominal catches in the inland waters of Zambia (1970–76)
(in tons)

Estimates of catch for the different bodies of water published in 1974 were adjusted by Bazigos (1975) (Table 70).

Table 72

Adjusted catch estimates by water body (1970–74)
(in tons)

9. STATE OF THE FISHERY

9.1 Yield

Individual fisheries vary considerably. The production of Lake Kariba has been predicted at about 10 000 t (5 000 t for Zambia) so the present catches of about 2 000 t appear disappointingly low. Efforts to improve on this level of catch have failed. In Lake Tanganyika there may be room for increased production with intensified exploitation of Stolothrissa but the Zambian waters are already among the most intensively fished on the lake, and it is doubtful whether any considerable increase can be made. The Lake Mweru/Luapulu fishery has been in the decline for many years with a progressive decline of favoured fish species such as Labeo altivelis and Tilapia macrochir. However, the tonnage has been maintained through the fishing-up process which now exploits the smaller and faster-growing Alestes. The level of Lake Mweru Wa Ntipu is very variable and catches fluctuate from year to year depending on the rainfall. Lake Bangweulu has undergone a similar fishing-up process to Lake Mweru with increased catches of less desirable species. It is doubtful if the process can continue indefinitely and active measures to protect the fishery were being instituted in 1974. The fishery of the Kafue Flats has been altered by the installation of dams upstream and downstream of the floodplain. The fish catch is very sensitive to fluctuations in water level and the status of the fishery is in doubt due to the recent hydrological management of the system.

Two fisheries which at present seemingly underexploited are the floodplain fisheries of the Zambezi, where considerable increases in catch can be anticipated, and the Lukanga Swamp.

9.2 Factors influencing yield

Several of the Zambian fisheries are on floodplains and are therefore sensitive to seasonal floods, Similarly, Lake Mweru Wa Ntipu fluctuates in level and yield. It is to be anticipated that the total fish catch from Zambia will vary widely depending on the rainfall patterns. Two fisheries particularly are underexploited mainly because of their inaccessibility and distance from main markets.

9.3 Forecast

Most fisheries in Zambia appear to be near to their maximum potential. However, increased yields can be anticipated from the Barotse Plain. If these produce at the same level as the Kafue (17 kg/ha) a mean production of about 18 000 t might be attained. Furthermore, a new fishery on the Itesh Teshi Dem will produce about 1 800 t and the minor increases in production could raise total yields by 20 000 t. Total yields of up to 70 000 t might therefore be expected.

10. SPECIFIC REFERENCES

Bazigos, G.P. et al., 1975 Revised fisheries time series of the natural waters of Zambia (1966–74)

FAO/UNDP, 1974 Central Fisheries Research Institute, Zambia, Interim Report. FI:DP/ZAM/68/511:53 p.