COUNTRY FILES

SIFRA BOOK 2

BENIN

1. GEOGRAPHY AND CLIMATE (Welcomme, 1979)

Benin (with a surface area of 110 620 km²) is divided into four natural regions:

1. a flat sandy coastal plain which is transected by brackishwater lagoons;
2. a granitic plateau which occupies most of the centre of the country and rises toward the Atacora mountains in the northwest;
3. the valley of the Pendjari River; and
4. the valley of the Niger River.

The coastal region of the country is hot and humid with a moderately even temperature throughout the year. There are two rainy seasons, a major rain from March to June, and a minor one peaking in October. In the north the country becomes more arid, with a cool period in December and January and a hot period between March and June. Rainfall is concentrated into one season between July and October.

Benin is an agricultural country. The south concentrates on plantations of oil palm; to the north the main crops are maize and cotton. Cattle are abundant, particularly on the floodplains of the Niger in the north and the Ouèmè in the south. There is a considerable amount of drawdown agriculture on the floodplains in the south and rice cultivation has been introduced recently in the Ouèmè.

2. HYDROGRAPHY (after Welcomme, 1979; and Balarin, 1984a)

2.1 Lakes

Benin has over 330 km² surface area of lakes and lagoons. There are several groups of lakes associated with the floodplains of the south-flowing rivers. On the Ouèmè there are Lakes Azilli and Cele and on the Mono there are about six lakes, but siltation and other changes due to management of this basin are altering their characteristics very rapidly.

2.2 Rivers, Floodplains and Swamps (see Fig. 1 and Table 1)

Hydrologically the country can be divided into five main drainage areas:

1. to the north Benin borders on the Niger River for about 120 km and the three main mid-course tributaries of that river (the Alibori, Sota and Mekrou Rivers) arise on the central plateau of Benin to flow torrentially northward into the Niger. The Benin bank of the Niger has a broad floodplain covering about 275 km² at peak floods;
2. the Pendjari River, a tributary of the Volta, drains the western slopes of the Atakora mountains and runs for some 400 km through Benin before entering Togo.
   
   The south-flowing rivers:
3. the Mono (360 km),
4. the Couffo (240 km), and
5. the Ouèmè (700 km), arise on the central plateau and, below torrential upper courses, form broad fertile floodplains in the coastal zone. The floodplains terminate in a series of extensive lagoons. The greatest of the floodplains, that of the Ouèmè, extends over 2 000 km² at peak floods.

Fig. 1. WATER RESOURCES AND FLOW OF RIVERS IN BENIN
(Adam & Boko, 1983)

Table 1. MAIN CHARACTERISTICS OF WATER BODIES

^a FAO, 1977
^b Adam & Boko, 1983
^c Other lakes: Tobadjii (400 ha)
                        Dahounta (40 ha)
                        Djetoue (20 ha)
                        Dati (70 ha)
                        Azilli (200 ha)
                        Cele (200 ha)

2.3 Reservoirs

Given the seasonal drought, several dams had to be built for water storage. Figure 1 shows the location of the existing and projected reservoirs. At present, however, there are no major reservoirs in the country, although there are several small cattle dams in the north.

2.4 Coastal Lagoons

By far the most important bodies of water in the country are the brackish-water coastal lagoons which are contiguous with the whole lagoon system of the West African coast. There are two major lagoons: Nokoue and Porto Novo which together cover about 147 km² and are separated only by the numerous channels of the deltaic fan of the Oueme River; and Aheme Lagoon, which covers 85 km². Smaller lagoon systems covering about 28 km² connect the major bodies of water with the sea, and run parallel to the coast behind the dune systems. (See Fig. 2)

2.5 Aquaculture

Most of the existing ponds, built during the colonial period, have been abandoned. In 1984 there were 113–133 ponds in activity in the country, among them 55 in Godoumey, with a total surface area of 5.4 ha.

3. FISHERY PRODUCTION/POTENTIAL

3.1 Fish production and per caput supply

Table 2. FISH PRODUCTION AND PER CAPUT SUPPLY - Benin, 1970–1987

¹ Source: FAO
² Source: FAO Fisheries Department FISHDAB
Data for inland fisheries to be used with caution as no regular catch assessment surveys undertaken. Marine catches by Beninese canoes considerably greater than catches landed in Benin as many Beninese canoes operate from beaches in Cameroon, Congo and Gabon. Catches by these canoes included in totals for respective countries.
³ included in “Inland capture” if not specified
⁴ - = data not available
⁵ Vincke, 1989, pers. comm.
⁶ From 1980 to 1983, marine exports were as follows: 1980: 23 t; 1981: 104 t; 1982: 57 t; 1983: 163 t.

Fig. 2. LAGOONS OF BENIN
(Weigel, 1985)

3.2 Inland catch range and potential yield

Table 3

Sources:
¹ FAO (1977)
² MPSAE (1983)
³ MFEEP (1982)
⁴ See text

4. STATE OF THE FISHERY

(adapted and updated from Welcomme, 1979; and Balarin, 1984a)

4.1 Yield

The figures given in Table 2 indicate an almost steady production from the inland waters of Benin of 30 000–34 000 t/yr for the period 1980–1987, although Balarin's (1984a) estimate of the current inland catches is lower (20 000–30 000 t/yr). However, the catches were higher in the late 1950's and in the 1960's (38 288 t in 1959), before the decline of the 1970's (average: 20 000 t from 1970 to 1978).

Aquaculture production remains low (14 t in 1987) (Vincke, 1989 pers. comm.):

4.2 Factors influencing yield

Losses have occurred in the four main fisheries of the country for a variety of reasons. In the Niger River the decline was provoked, at least intially, by the failure of the main markets for fish from this region. However, the Sahelian drought also exercised a serious effect. Unfavourable conditions have continued with erratic and poor flooding in most years and the decline of the Niger River Fishery has continued.

In the Ouèmè basin, long and intensive exploitation affected the fishery; the catch dropped from about 10 000 t/yr prior to 1960 to about 6 000 t/yr in 1976. The fact that over-exploitation was responsible is indicated by the disappearance of the larger species of fish and decline in the mean size of the fish caught. Changes in salinity of the lower reaches of the river, caused by the permanent opening of Nokoue Lagoon to the sea, have also been implicated, but do not satisfactorily explain the changes in catch that have occurred.

There is, however, no doubt that changes in salinity were responsible for the collapse of the most important fishery on the lagoon. Thus, the acadja fishery used extensive areas of brush parks to rear and capture fish, giving yields as high as 10 t/ha of park in the late 1950's. Subsequently, invasion of the lagoon by teredo worms destroyed or rendered uneconomic large areas of parks, and placed greater fishing pressure on the other fish stocks which, in their turn, collapsed. Investigations in 1981 showed that the fishery recovered to a certain extent following the installation of a weir across the mouth of the channel. The fall in catch in Aheme Lagoon from 9 000 t in 1959 to about 5 000 t in 1976 coincides with the removal of acadjas from that lagoon for political reasons.

4.3 Future development possibilities

The history of the fisheries of Benin represents a classical example of past mismanagement of various types. Nevertheless, future possibilities could be moderately good. A return to a pluvial phase in the Sahel could increase production from the Niger river to its previous high level, if suitable markets for the products can be found.

Previous production levels could possibly be restored in the lagoons. In Aheme Lagoon, the simple reintroduction of acadjas in a planned fashion would probably bring immediate results. In Nokoue Lagoon the need to control the penetration of sea waters is paramount, and the recent construction of a barrage across the channel at Cotonou blocking the ingress of sea water may permit the lagoon to be used as a vast fish culture pond.

In the Ouèmè, however, the prospects are somewhat bleak. The fishery is already over-exploited and the valley is densely populated so it is difficult to see that the pressure will be relieved. Furthermore, the floodplain of the Ouèmè is now being increasingly used for rice culture and the drain-in fish ponds, which contributed much to the fishery, are being abandoned. There will almost certainly be an attempt to control the Ouèmè floods with an upstream dam in the future, and the floodplain fishery will be lost as a consequence (although of course a reservoir fishery resource will be created). Apart from the natural water bodies, considerable increases in production of fish from Benin can be foreseen with the successful introduction of brackishwater aquaculture into the coastal belt.

Present inland fisheries potential annual yield has been estimated at 28 000–33 000 t/yr (MFEEP, 1982; MPSAE, 1983).

5. KEY BIBLIOGRAPHY

Balarin, 1984a
Weigel, 1985 (Lagoons)

6. WATER BODIES DIRECTORY

LAKE AZILLI

LAKE CELE

LAKE DAHOUNTA

LAKE DATI

LAKE DJETOUE

LAKE TOGBADJI

MONO RIVER
(International water)

NIGER RIVER AND FLOODPLAIN
(International water)

Ionic composition:

Fig. 3. RIVERS AND LAKES OF THE NIGER-BENUE SYSTEM
(Welcomme, 1972)

Fisheries data

No. of fish species: 135 (Daget, 1954)
No. of fishermen: 3 000 in Benin
Total annual catch:

Potential annual yield: 1 200–3 000 t in Benin (FAO, 1977)

OTI/PENDJARI RIVER
(International water)

Fisheries data
Total annual catch in Benin:

Potential annual yield: 100–600 t in Benin (FAO, 1977)

OUEME RIVER AND FLOODPLAIN
(International water)

Fisheries data
No. of fish species: 60 (Welcomme, 1972)
Total annual catch and effort: in Benin

AHEME LAGOON

Fisheries data
Total annual catch and effort:

Potential annual yield: 5 000–9 000 t (FAO, 1977)

COTONOU LAGOON

DJONOU LAGOON

GRAND POPO/OUIDAH LAGOON COMPLEX

Fig. 4. NOKOUE AND THE PORTO NOVO LAGOONS
(Weigel, 1985)

NOKOUE LAGOON

Fisheries data
Total annual catch and effort:

* (includes Porto Novo Lagoon)

Potential annual yield: 6 000–16 000 t - including Porto Novo Lagoon (FAO, 1977)

PORTO NOVO LAGOON

TOHO LAGOON/FLOODPLAIN

Fisheries data
Total annual catch and effort:

7. BIBLIOGRAPHY

Adam & Boko, 1983
Balarin, 1984a
Daget, 1954; 1957
FAO, 1977
FAO/UN, 1962; 1970; 1971
MFEEP, 1982a,b
MPSAE, 1983
Raimondo, 1975
Weigel, 1985
Welcome, 1972; 1979; 1985
White, 1965