COUNTRY FILES

SIFRA BOOK 3

ALGERIA

1. GEOGRAPHY AND CLIMATE

Algeria has a surface area of 2 381 740 km². Most of the country (86%) is situated within the Sahara desert. In the north the Atlas Mountains, rising to a maximum elevation of 2 328 m asl, provide surface runoff to a narrow fertile coastal strip which supports most of the population.

Summers are hot; winters are fairly mild. Rainfall is adequate along the coast, but the interior is dry with extremes of desert temperatures.

The limited rainfall and runoff has fostered construction of storage dams to ensure adequate water supplies for crop irrigation. High salinities and irregular inflow limit the potential use of most natural lacustrine bodies.

2. HYDROLOGY

2.1 Lakes

There are no important freshwater lakes. Several internal drainage basins possess salt lakes and marshes. The largest basin, containing Lakes Chott Melshir and Chott Merouane, has a total area of 61 000 km² with a mean annual inflow of 0.90 km³. Sebkha d'Oran is a large salt lake (296 km²) lying near the coast in the west. To the northeast is the Oubeira Lake, 21 km². For most salt lake basins only a small proportion of the area has standing water.

2.2 Rivers, Floodplains and Swamps

There are eleven river (“oued”) basins which discharge into the Mediterranean Sea from a combined catchment area of 132 910 km². The largest is the Oued Chelif (29 300 km² catchment; 0.55 km³ discharge). There are two important floodplains: Garaet el Mkhada (89 km²) and Chott Zahrez Chergui.

2.3 Reservoirs

To date some 21 large dams have been constructed. Most are for irrigation usage, and a smaller number produce hydroelectricity or supply municipalities. At present little fishery development has taken place in these reservoirs.

2.4 Coastal Lagoons

There is one small lagoon in the extreme east of the country: Mellah.

2.5 Aquaculture

No data available on ponds situation.

3. FISHERY PRODUCTION/POTENTIAL

3.1 Fish production and per caput supply

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

¹ Source: FAO
² Source: FAO Fisheries Department FISHDAB
Summary data received in 1982 and 1986, but no detailed returns submitted since 1979.
³ - = data not available.
⁴ including marine and inland aquaculture (Vincke, 1989, pers.comm.)

3.2 Inland catch range and potential yield

Table 2.

Total annual yield: 80–180 t
                                    241 t in 1987 (see Table 1).

Fig. 1. MAP OF ALGERIA

4. STATE OF THE FISHERY

4.1 Yield

Recorded yields are relatively small. Some fishing undoubtedly occurs in the reservoirs but no data are available. Production from aquaculture, from 1983 to 1987, is given in Table 3 (Vincke, 1989, pers.comm.).

Table 3. AQUACULTURE PRODUCTION IN ALGERIA, BY SPECIES (t)

4.2 Factors influencing yield

Fluctuations in catch in existing fisheries are largely due to problems in the maintenance of gear and boats and to climatic conditions.

4.3 Future development possibilities

Expansion of reservoir capture fisheries would appear to offer the most important possibility for inland fishery expansion. Increasing yields from the lagoons by introducing aquaculture practices would also appear feasible.

5. KEY BIBLIOGRAPHY

Lakes and lagoons: Lemoalle, 1987; Morgan, 1987
Sahara: Dumont, 1987

6. WATER BODIES DIRECTORY

OUBEIRA LAKE

Total annual catch and effort:

Fig. 2. LAKES AND SWAMPS COMPLEX OF THE KALA REGION
(after Lemoalle, 1987)

MEDJERDA RIVER
(International water)

GARAET EL MKHADA FLOODPLAIN

CHOTT ZAHREZ CHERGUI FLOODPLAIN

BAKHADDA RESERVOIR

BENI BAHDEL RESERVOIR

BOU HAMIDIA RESERVOIR

BOUZZOUL RESERVOIR

CHEFFIA RESERVOIR

CHEURFAS RESERVOIR

ERRAGUENE RESERVOIR

FERGOUG RESERVOIR

FODDA RESERVOIR

FOUM EL GHERZA RESERVOIR

FOUM EL GUEISS RESERVOIR

GHRIB RESERVOIR

GRANDE KABYLIE RESERVOIR

HAMIZ RESERVOIR

IRHIL-EMDA RESERVOIR

KSOB RESERVOIR

MEFFROUCH RESERVOIR

MERAD RESERVOIR

SARNO RESERVOIR

SIDI MAHOMED BEN AOUDA RESERVOIR

ZARDEZAS RESERVOIR

MELLAH LAGOON

Total annual catch and effort:

7. BIBLIOGRAPHY

Dumont, 1987
Lemoalle, 1987
Morgan, 1987

CHAD

1. GEOGRAPHY AND CLIMATE (Welcomme, 1979)

Chad (with a surface area of 1 284 000 km²) is shaped like a shallow basin cut in half. Lake Chad itself lies at the bottom with an altitude of 280 m. The land rises to the north (where the Tibesti Mountains reach altitudes as high as 3 400 m), to the east to the highlands of Sudan, and to the south to the Chari watershed. The southwest of the country is heavily wooded, but the country rapidly becomes desertic toward the north.

Most of the southern Chad has a prolonged rainy season; heavy rains last from April through October. Nearer the centre of the country the season becomes shorter (June-September), and north of Lake Chad there is little rainfall.

The south of Chad has an agrarian population, living mainly on subsistence agriculture. The north is desert and inhabited only by nomadic tribes. The Sahelian transitional savanna is used mainly by pastoral peoples for grazing cattle, sheep and goats.

2. HYDROGRAPHY (see Figs. 1, 2 and 3)

2.1 Lakes (Welcomme, 1979)

Lake Chad fluctuates in area in a pronounced cycle thought to be some 25 years long. This lake exists in two phases: the Greater Chad in pluvial periods, and the Lesser Chad in drought. During its Greater Chad phase, half of the lake's 22 000 km² lies within the country. In its more recent (1978) diminished state, about 1 200 km² of the remaining 2 000 km² of open water were left around the mouth of the Chari River. Apart from Lake Chad itself, there are several smaller lakes. In the Chad Basin there is Lake Iro (situated on the Salamat River floodplain, which extends over 200 km²), and Lake Fitri (a Lake Chad in miniature to the east of the main lake, which extends over 420 km² but can reach 1 200 km² in the rainy season). There are a further four small lakes lying along the Toubouri Depression of the Mayo Kebi River in the flood season, but during the dry period these are much smaller. Lake Tikem has an area of 14 km²; Lake Fianga, 28 km²; Lake Lere, 40.5 km²; and Lake Trene, 12 km².

2.2 Rivers, Floodplains and Swamps (Welcomme, 1979)

The whole of southern Chad is dominated by the Chari River system which, with its main tributaries, the Salamat and Azoum Rivers, extends over about 1 200 km. There are extensive swamps over most of the Chari Basin which are drained by such rivers as the Erguig and Aouk. These swamps have been estimated as covering about 80 000 km². The Chari combines with the Logone to discharge into Lake Chad. The Logone possesses the large Yaèrè floodplain. (See Fig. 3, p.21.)

2.3 Reservoirs

There are no important impoundments in Chad.

2.4 Coastal Lagoons

None; Chad is landlocked.

2.5 Aquaculture

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

3. FISHERY PRODUCTION/POTENTIAL

3.1 Fish production and per caput supply

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

¹ Source: FAO
² Source: FAO Fisheries Department FISHDAB
The 1970–87 catch data are estimates provided by the national reporting office.
³ No aquaculture in Chad (Vincke, 1989, pers.comm.)

Considerable statistical confusion arises from the situation around Lake Chad. The best estimate of production from the basin over the last few decades is given below (but these are at best speculative).

Table 2. ESTIMATES OF TOTAL PRODUCTION FROM LAKE CHAD BASIN
(all countries) (t)

Source: Stauch (1977)

Fig. 1. MAP OF CHAD

These estimates correspond roughly to the figures advanced by the Government of Chad as reflected in the nominal catches. It may be assumed, therefore, that Chad has laid claim to the total production from Lake Chad Basin, whereas in fact only a proportion of the catch originates within Chadian territory. In the case of the lake, Chad has between 50% and 60% of the waters and these are among the richest and most productive. Furthermore, Cameroon probably produces between 20 000 and 30 000 t from the Yaèrès floodplain and the river production should be diminished by this amount. Seen in this light, the Republic of Chad was probably producing about 50 000 t of fish in the 1950's, 70 000 t in the 1960's, up to 100 000 t during the earlier years of the drought, and about 50 000 t in the late 1970's (Welcomme, 1979).

3.2 Inland catch range and potential yield

Table 3.

* Sources: see text

Total annual yield: 50 000 (Welcomme, 1979)
                            110 000 (National reporting office, current).

4. STATE OF THE FISHERY (Welcomme, 1979)

4.1 Yield

The present state of the fishery of Lake Chad is very poor. The lake itself has never recovered from the 1972–74 drought and is still in its small phase. The fish population of the rivers were damaged by the changes in flood regime during the droughts and the fisheries there are also diminished.

4.2 Factors influencing yield

As with the other countries of the Sahelian belt, the main factor influencing the fishery is rainfall. This had an especially severe effect during the latest dry period when catches rose sharply as the lake decreased (1972–73) but fell sharply as the stocks of the small lake were unable to support the intensive effects of the same number of fishermen who were previously dispersed over ten times the area. In the rivers, too, the failure of two or more successive floods virtually exterminated several of the major migratory species, leading to a disequilibrium in population structure. Continuing adverse conditions have tended to change the population structure, with a progressive disappearance of the more migratory species.

4.3 Future development possibilities

No amelioration of the fisheries in the Lake Chad Basin can be anticipated so long as the present hydrological regime persists. However, historically, the lake has always recovered from these dry spells and it can be expected to regain its Large Chad phase of 22 000 km² during the next wet cycle. In that case the potential catch might be expected to exceed past yield (at 100 kg/ha, the lake should produce over 200 000 t), but only if the fishery relaxes its intensity sufficiently for the fish stock to build itself up. The floodplains, too, can be expected to return a better yield, although the potential needs clarification (at as little as 10 kg/ha the 90 000 km² of the Chari/Logone floodplains could produce 90 000 t).

5. KEY BIBLIOGRAPHY

Sahara-Northern Chad: Dumont, H.J., 1987
Chad Basin: Lèvêque, C., 1987

6. WATER BODIES DIRECTORY

LAKE CHAD
(International water)

Fig. 2. LAKE CHAD
(Welcomme, 1972)

Table 4. CHEMICAL COMPOSITION OF WATERS DURING “NORMAL” CHAD PERIOD IN MAIN LAKE ZONES
(cited in Lévêque, 1987)

Values are in meq/l when not otherwise specified.
Values between parentheses () are approximate and deducted from evaporation experiments.

Table 5. FISH PRODUCTION FROM LAKE CHAD *

* Production figures obtained from road traffic census of dried fish at entry to Maiduguri: Baga and N'Djamena from July 1969 to June 1977 (original data after Stauch, 1977) in fresh weight equivalent.

Fig. 3. RIVERS AND LAKES OF THE CHAD BASIN
(Welcomme, 1972)

Table 6. PRODUCTION FROM LAKE CHAD* (at Baga, 1978–85)

¹ Source: Federal Department of Fisheries, Lagos
² Baga figure multiplied by 100/70.
* Production figures obtained from road traffic census of processed fish at entry to Maiduguri: Baga, from 1978 to 1985, in fresh weight equivalent (conversion factor of 4.5). (Sagua, 1986)

Potential annual yield:

In entire lake:
     100–120 kg/ha (Durand, 1980)
     70 000 t/yr maximum sustainable yield (Moses, 1982)
in “normal” 20 000 km² Chad:
     80–100 kg/ha;      160 000 t to 200 000 t/yr (Van der Meeren, 1980).

In Nigerian waters:
     41 250–55 000 t/yr (Ajayi & Talabi, 1984).

By country, assuming a productivity of 80 to 120 kg/ha/yr:

LAKE FIANGA
(International water)

Fig. 4. LAKES OF THE TOUBOURI DEPRESSION
(Lèvêque, 1987)

LAKE FITRI

LAKE IRO

LAKE LERE

Fig. 5. BATHYMETRIC MAP OF LERE LAKE
(Lèvêque, 1987)

LAKE TIKEM

LAKE TRENE

BAHR AOUK RIVER
(International water)

CHARI RIVER AND YAERES FLOODPLAIN
(International water)

LOGONE RIVER AND YAERES FLOODPLAIN
(International water)

Fig. 6. SALAMAT RIVER AND FLOODPLAIN
(Lèvêque, 1987)

OUHAM RIVER
(International water)

SALAMAT RIVER AND FLOODPLAIN

7. Bibliography

Ajayi & Talabi, 1984
Blache, et al., 1964
Blache & Miton, 1962
Dumont, 1987
Durand, 1980
Dussart, 1969
Lèvêque, 1987
Moses, 1982
Sagua, 1986
Stauch, 1977
Van der Meeren, 1980
Welcomme, 1972; 1979