COUNTRY FILES (Contd.)

SOMALIA

1. GEOGRAPHY AND CLIMATE

Somalia (surface area of 627 340 km²) has four main topographic areas. The northwest and northeast regions consist of steppes lying on a highland of crystalline rocks which show numerous fissures and become uneven along the coast. Mudug area lies between Nogal and the Indian Ocean and the Scebeli River. It is an arid high plateau which rises 600 metres above sea level. The central and southern regions, situated between the Scebeli and Juba Rivers, are a fertile agricultural area characterized by extensive, comparatively densely populated, plains. The Upper Juba region, which lies between the Juba River, Ethiopia and Kenya, is covered by a thick bush and in certain places with forests.

The climate of the area where there is the possibility of harvesting inland fisheries is tropical, semi-arid with a seasonal rainfall pattern influenced by monsoon winds; two types of rainfall occur: Mogadishu type on the Scebeli River; and Kismayo type along the Juba River, where there is a continental steppe climate with 388.5 mm mean annual rainfall. The economy is based on subsistence livestock herding, with some agriculture in the better watered south.

2. HYDROGRAPHY

2.1 Lakes

There are no natural lakes of significant size.

2.2 Rivers, Floodplains and Swamps

There are two main rivers in Somalia: the Juba and Scebeli. Both run from the Ethiopian Highlands southeasterly across Somalia to the Indian Ocean. The Juba River empties itself at an estuary near Kismayo. It is about 800 km long and 122.5 metres wide, the area being roughly 98 000 km². The Scebeli River does not reach the Indian Ocean but ends in a swampy area near Gelib. It is 1 100 km long, 82 metres wide, with an area of about 90 000 km².

The Scebeli River floods in rainy season and fills up natural ground depressions and an ancient bed, creating temporary sloughs, swamps, pools, creeks and small lakes. Flooding of the Juba River also fills natural depressions, especially oxbows in its lower part. Marshes near Gelib are flooded by collected water and Juba infiltration.

2.3 Reservoirs

There are several projects for dams and compensating reservoirs (Bardhere, Fanole) for controlled irrigation, stabilization of the flow to prevent floods, and production of electricity. There are some 240 small reservoirs used for livestock watering.

2.4 Coast Lagoons

None.

2.5 Aquaculture

There is no aquaculture in Somalia (Vincke, 1989, pers.comm.).

3. FISHERY PRODUCTION/POTENTIAL

3.1 Fish production and per caput supply

Table 1. FISH PRODUCTION AND PER CAPUT SUPPLY - Somalia, 1970–1987

¹ Source: FAO
² Source: FAO Fisheries Department FISHDAB
³ No aquaculture in Somalia (Vincke, 1989, pers.comm.)
⁴ Marine exports, from 1980 to 1983, were as follows: 1980: 682 t; 1981: 606 t; 1982: 1 161 t; 1983: 2 951 t
⁵ Most of the fish being exported, the “nominal consumer supply” data for marine capture do not reflect the reality and are highly overestimated.

3.2 Inland catch range and potential yield

No information is available for the Juba and Scebeli Rivers.

4. STATE OF THE FISHERY

4.1 Yield

No data is collected. Some fishing is known to occur in the Tummi Marshes.

4.2 Factors influencing yield

Adverse factors are an aversion to eating fish by nomadic communities and rainfall variability.

4.3 Future development possibilities

Some expansion is possible in the future, but marine fisheries are likely always to overshadow inland fisheries.

Fig. 1. MAP OF SOMALIA

5. KEY BIBLIOGRAPHY (none)

6. WATER BODIES DIRECTORY

GENALE DORYA/JUBA/GIUBA RIVER
(International water)

SHABALE/SCEBELI RIVER
(International water)

SUDAN

1. GEOGRAPHY AND CLIMATE (Welcomme, 1979)

Sudan (with an area of 2 476 800 km²) 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.

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.

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

2. HYDROGRAPHY (adapted mainly from Balarin, 1988)

The freshwater resources of the Sudan have been comprehensively reviewed by CSTR (1982). Dumon (1984) presents the most recent series of papers on limnology and marine biology. This text summarizes some of that data. According to OSRO (1986), nearly 12.90 million hectares are under water, 5% of the total area in the Sudan. Of the available water, less than 50% is used, and the potential water supply is enormous if underground reserves are included (Table 2). The Nile system is the main feature of the hydrology of Sudan, including the Nile and its tributaries (Table 3), a number of man-made lakes (Table 1) and the swamps of the Sudd. Non-Nilotic streams of minor importance supply water to 806 hafirs (natural depressions enlarged into small ponds) and 31 dams (Table 4). (See Figs. 1, 2 and 3.)

2.1 Lakes

The principal natural lakes in the country are the numerous small 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. A few smaller isolated lakes also occur (Welcomme, 1979). (See Figs. 4 and 5.)

2.2 Rivers, Floodplains and Swamps

The main river system (Figs. 1, 2, 4, 5) is that of the Nile. The Albert Nile enters Sudan from Uganda through a narrow gorge in a series of rapids at Nimule. Northward, it becomes known as the Bahr El Jebel which flows into the great swamps of southern Sudan, North of Mangola. The main tributary of the Bahr El Jebel is the Aswa, originating from the Marolo mountain on the Kenyan border. The river widens to several kilometers and divides into the Bahr El Jebel and Bahr El Zeraf in the Sudd Region. There the rivers have numerous channels and follow a serpentine course, to be joined by the Bahr El Ghazal, which drains the southwest part of Sudan, forming the White Nile. South of Malakal, the Sobat River of a catchment area of 224 000 km² consisting of the Baro and Pibar tributaries, joins the White Nile. From here northward the valley is steep sided until it joins the Blue Nile at Khartoum.

The Blue Nile, with a catchment of 325 000 km², originates in Ethiopia and extends 2 000 km until it joins the White Nile to become the River Nile. Within Sudan the Blue Nile is joined by the Dinder and Rabad tributaries. The main Nile passes the Sabaloka Gorge and is joined by the Atbara, a catchment of 100 000 km² and main tributary Sesit. Thereafter there are two further cataracts before the Nile leaves Sudan at Lake Nubia.

In total, the Nile traverses 3 000 km of Sudan. Its water balance is given in Table 3. The overall runoff coefficient is low, at an estimated 6% (Ibrahim, 1984); during its passage through the Sudd and Machar swamps nearly 50% of the annual flow is lost through evaporation, seepage and evapotranspiration. (Europa Publs., 1986).

The Nile is also known for its marked seasonal and annual variations, with more than 80% of its annual flow occuring from August to October. The percentage contributions of the main tributaries indicates that 85% of its flow comes from the Ethiopian Highlands. This can increase to 95% during floods, or decrease to 60% in the dry season, due to the evaporation loss from the White Nile at the Sudd; consequently these waters tend to be more saline. The Sudd also has a regulating effect on flow, so the White Nile is not characterized by marked seasonal flow, as is the Blue Nile.

The flat clay plains, covered with vast areas of papyrus marsh and seaonsal grasslands, which lie between the Bahr El Jebel, Bahr El Zerat and the confluence of the White Nile are known as the Sudd. The word means “blockage”, and refers to rafts of vegetation which periodically block the river. The area includes 8 300 km² of permanent swamps and over 80 000 km² of flood during the flood seasons (Krishnamurthy, 1981). The shallow floodplains (termed “Touch”) flood during July-September. From November the waters recede, isolating the floodplain, which then drains through river channels and by February is dry, leaving a number of lagoons and deep pools which make up a major fishery.

The 360 km Jonglei Canal from Malakal to Bar (Fig. 5) will shortcircuit the swamp and divert water to irrigate 1.6 million ha of crops. Drainage of 20 million m³/day is likely to drop the flood level by 29 cm and drastically reduce the swamp area (Krishnamurthy, 1981).

2.3 Reservoirs

A number of major reservoirs have been built or are proposed for the Nile system, mainly for irrigation water storage (Figs 2 and 3, Table 1). Conditions require some form of water storage for the dry period. Natural depressions were enlarged into small ponds of up to 500 000 m³, 2–8 m deep; these are known as “hafirs”. Table 4 summarizes the status as of 1976, and greater detail of perennial “hafirs” is given in Table 5. CSTR (1982) lists over 809 hafirs and 32 earthen dams in 1976 and mentions that a further 200 hafirs and dams were planned. Some units serve all through the dry season; others last only two to three months. CSTR (1982) describes a number of systems.

Conventional hafirs:

Situated in areas of suitable soil and hydrology, these units generally are the shape of an inverted frustrum of a pyramid. The long sides have steep slopes of 1:1.5-2 with 1:3–4 slope on the end rams to allow machines to work. Two types are typical:

On-stream - usually sited across the course of a stream with a spillway; and
Off-stream - sited away from the river course, filled by a canal from the stream or via a weir.

Other types: Traditionally, stream flow characterizes the filling of a hafir but, as such sites are limited, others are sited near a hill to catch the runoff with diversion canals.

Fig. 1. MAP OF SUDAN

Fig. 2. MAIN RIVERS, SWAMPS AND RESERVOIRS
(Balarin, 1988)

Table 1. MORPHOLOGICAL DATA OF THE SUDD AND MAJOR RESERVOIRS
(Balarin, 1988)

Key: c=commercial/industrial;
i=irrigation;
f=fishery;
p=power generation;
w=water supply.
Sources:
^a Henderson (1975)
^b George et al., (1985)
^c Welcomme (1972)
^d Ibrahim (1984)
^e CSTR (1982)
^f Coche (1983)

Table 2. POTENTIALITY OF WATER SUPPLY IN THE SUDAN
(Balarin, 1988, after CSTR, 1982)

Table 3. WATER BALANCE OF THE NILE
(Balarin, 1988)

(Dots are Hafirs drawn after George, 1976)

Fig. 3. MAIN DAMS IN SUDAN
(Balarin, 1988)

Table 4. AN INVENTORY OF DAMS AND HAFIRS IN THE SUDAN - 1976
(Balarin, 1988, after CSTR, 1982)

Table 5. PERENNIAL HAFIRS AND FISH PRODUCTION POTENTIAL
(Balarin, 1988, after George, 1975 + FAO/WB, 1976)

* An average 3m depth is assumed and potential yield estimated from 70 kg/ha/yr. Huet (1959), however, considers 200 kg/ha/yr more appropriate; values in parentheses () are based on this level.

2.4 Coastal Lagoons

There are no lagoons of significant size.

2.5 Aquaculture

Aquaculture in Sudan has developed both for the classical rearing of food fish in ponds and the selective stocking of water reservoirs and hafirs with fish to increase production (see Section 2.3 - Reservoirs). In addition, rearing of fish in irrigation canals is also practised to clear aquatic weeds as well as for fish production.

Conventional pond fish farming has not developed to any large degree; the most recent estimates by Yousif (1985) indicate 25 ha functional in 1984.

3. FISHERY PRODUCTION/POTENTIAL

3.1 Fish production and per caput supply

Table 6. FISH PRODUCTION AND PER CAPUT SUPPLY - Sudan, 1970–1987

¹ Source: FAO
² Source: FAO Fisheries Department FISHDAB
³ included in “Inland capture” if not specified.
⁴ - = data not available.
⁵ Vincke, 1989, pers.comm.
⁶ Exports of inland dried fish, from 1980 to 1983, were as follows: (in equivalent fresh weights, assuming fresh weight = 3.5 × dry weight) 1980: 1 855 t; 1981: 2 237 t; 1982: 2 100 t; 1983: 2 520 t.

3.2 Inland catch range and potential yield

Table 7. (Sources: see text)

No information available for:
Lakes Ambadi, Anyi, Buhayrat Abyad, Keilak, Kundi, No, Nyiropo and Yirol;
Rivers Bahr El Ghazal, Blue Nile, Nile.

Total annual yield:
in 1975–76: 21 095 t (Table 7)
in 1981–82: 13 841 t (Table 7)
(see also Table 6)

Potential annual yield:
88 300 – 123 900 t (Table 7)
105 000 – 117 000 t (Henderson, 1975)

4. STATE OF THE FISHERY

(rearranged and adapted mainly from Balarin, 1988)

4.1 Yield

The distances involved and the remoteness of a large sector of the fishery means that statistics available do not necessarily reflect the situation; there is a general paucity of data.

Potential estimates of the inland fishery range from 105 000 to 130 000 t/yr (Henderson, 1975), although FAO (1982) estimates range between 37 000 and 400 000 t/yr for the Sudd alone (for an apparently overestimated 80 000 km² surface area). A moderate value of 75 000 to 100 000 t/yr is adopted here. The catch data (Table 6) shows that little improvement has taken place over the years, remaining between 20 000 and 30 000 t/yr, far below the potential.

Recent estimates by Chakraborty (1984) indicate that about 96% of the fish captured are from freshwater fisheries, of which 55% is from the Blue Nile, White Nile, Atbara River and Lake Nubia. The production figures from the south, however, remain doubtful as data collection is hampered by remoteness. Carleton and Pena (1982) surveyed the situation in the Sudd and estimate yields ranging from 6 000 to 43 000 t/yr.

From the Blue Nile the majority of the fish are sundried, while 70% of White Nile catches are consumed fresh. “Tilapia” is the predominant catch, accounting for 46%, followed by Labeo, Synodontis and Lates.

The Nile and its tributaries within Sudan have a surface area of 20 000 km², 85% of which is represented by the vast swamps in the south. Reservoirs total 3 075 km², made up of five main units (Table 1); riverine waters make up the rest of the fishery. The latter supplies fish to the main consumption centres, accounting for 12 000–15 000 t/yr.

Aquaculture production from ponds, (reservoirs stocking not included), from 1982 to 1987, is given below (Vincke, 1989, pers.comm.).

4.2 Factors influencing yield

FAO (1983) considers that development will be hindered not only because of the distance between resources and market, but also by the lack of landing, transport and storage facilities. This is overshadowed by problems in modernizing and mechanisation of a largely subsistence fishery, as well as the necessity to improve quality control, processing and marketing methods. The situation is aggravated by the often localized demand for fish and the unwillingness of a large portion of the Sudanese to accept fishing as an occupation, despite highly promising economic rewards. Fishing is regarded as an occupation of rather low status.

Fig. 4. GENERAL MAP OF THE SOUTHERN SUDAN
(Burgis, 1987)

The Sudd, which has the largest potential of expansion, is the most disorganized (Carleton & Pena, 1982) and therefore will take some time to develop.

Variations in rainfall are also known to affect flooded areas and, as a result, fish production.

The whole future productivity pattern of the Sudd is also in doubt, as the Jonglei Canal may alter the flood regimes of that area, with an expected loss of 20% of the production potential (FAO, 1982). Ironically, the catch may increase because of the canal and the better communications resulting therefrom.

Severe problems of communication, transport, inadequate and often unhygienic means of handling/marketing and shortage of trained and experienced personnel, poor security and unrest in the south, are all serious constraints to a more rapid development.

The low level of development is evident from FAO (1983) estimates that 440 marine and 6 000 inland fishermen are required, many of which are seasonal or part time.

4.3 Future development possibilities

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 continue to rise. However, the potential itself may be lowered through environmental changes arising from the demand for water for agriculture (Welcomme, 1979).

FAO (1983) considers that the reservoir fisheries are almost fully exploited; an increased yield from Jebel Aulia and Lake Nubia could realize a further 14 000 t/yr. Theoretically there would appear to be enormous scope for fishery expansion, considering that the 1980's freshwater landings only totalled 20 000–30 000 tons. However, there are very serious transport and marketing constraints in that the main fisheries are considerable distances from urban outlets.

Carleton and Pena (1982) clearly emphasize the problem; surveys of the Sudd suggest that present catch may be between 6 000 and 45 000 t/yr. If this is true, the potential for development is minimal, but without definite catch statistics it is difficult to estimate prospects for development.

5. KEY BIBLIOGRAPHY

Balarin, 1988
Burgis, 1987 (Southern Sudan)

6. WATER BODIES DIRECTORY

LAKE AMBADI

(all data from Green, 1987)

LAKE ANYI

LAKE BUHAYRAT ABYAD

LAKE KEILAK

(data from Green, 1987)

LAKE KUNDI

(data from Green, 1987)

(Stippling indicates approximate areas of permanent swamp.)

Fig. 5. MAP OF THE SOUTHERN SUDAN PLAINS
(showing the Sudd, Jonglei Canal and Lake No, and Lake Ambadi in the Bahr El Ghazal system) (after Bailey, 1987)

LAKE NO

(data from Green, 1987)

LAKE NYIROPO

LAKE YIROL

BAHR EL GHAZAL RIVER

BLUE NILE RIVER
(International water)

CHARI RIVER
(International water)

Fig. 6. RIVERS AND LAKES OF THE NILE SYSTEM
(Welcomme, 1972)

NILE RIVER
(International water)

Fisheries data
No. of fish species: 81 (Boulenger, 1907)
Total annual catch and effort:

Potential annual yield:

in Egypt:
20 000 t/yr (Sadek, 1984)
225 kg/ha/yr (Sadek, 1984)

in Sudan:
no data available.

Fig. 7. ANNUAL FLOW REGIMES OF THE NILE RIVER, 1955–1980
(Balarin, 1986)

SOBAT RIVER
(International water)

WHITE NILE RIVER
(International water)

(data mainly from Welcomme, 1972)

The White Nile changes its name several times in its course. From Lake Victoria to Lake Albert it is known as the Victoria Nile. From Lake Albert to the Uganda border it is known as the Albert Nile; from the Sudan to its confluence with the Bahr El Ghazal it is called the Bahr El Jebel; and down to its confluence with the Blue Nile it is finally called the White Nile or Bahr al Abiad. (See Fig. 6.)

Physical and chemical data (Talling, 1957)

SUDD SWAMP

Physical and chemical data in main channels
(from several authors, cited in Bailey, 1987)
(high variations occur between dry and wet seasons)

JEBEL AULIA RESERVOIR

KHASHM EL GIRBA RESERVOIR