COUNTRY FILES (Contd.)

MADAGASCAR

1. GEOGRAPHY AND CLIMATE (after Welcomme, 1979a)

The country consists of the main Island of Madagascar and some smaller offshore islands. Total surface area is 581 540 km². The main island consists of a central high plateau between 1 000 and 2 000 m in altitude which falls away steeply on all sides to a narrow coastal belt.

The central islands have a temperate climate with a single rainy season from November to April. The coastal regions have a tropical climate. On the north and west coast rains are light, whereas on the south and east rains are heavy and continuous throughout the year.

The country is wholly agricultural and bad land-use practices and deforestation have resulted in severe erosion problems which have led to many of the rivers being heavily charged with silt.

2. HYDROGRAPHY (see Fig. 1)

2.1 Lakes

There are hundreds of small and medium-sized lakes. Many are associated with the floodplains of westward flowing rivers. There are also many small mountain and crater lakes. Totalling the lakes, reservoirs and coastal lagoons, there are some 530 lacustrine water bodies with surface areas over 0.20 km² in Madagascar.

The ten largest lakes are:

The total lake area in Madagascar is probably over 600 km².

2.2 Rivers, Floodplains and Swamps

Many rivers flow from the central highlands of Madagascar. The largest river basins drain to the west and floodplains are developed along the lower courses. Total floodplain area has been estimated at 918 km² but the actual area may be greater than 2 000 km². Swamps are associated with some lakes (i.e., Lake Alaotra).

2.3 Reservoirs

Two medium-sized reservoirs (Mantasoa and Tsiazompaniry) with surface areas of 18.0 and 31.0 km², respectively, are situated near the capital (Tananarivo).

There are also several small reservoirs:

2.4 Coastal Lagoons

Madagascar has significant brackishwater resources. These consist of lagoons on the east coast and mangrove swamps grouped around the mouths of the main rivers on the west coast.

3. FISHERY PRODUCTION/POTENTIAL

3.1 Aquaculture

The number of ponds in existence in Madagascar since 1938 are shown below:

In 1982 fishponds totalled about 1 000 ha in area. In addition, about 250 km² of rice fields were used for rice-cum-fish culture.

In 1985, the number of ponds had already decreased to about 6 000, with an estimated production of 284 t, mainly common carp and tilapias. Production of aquaculture by species is shown below:

Source: Vincke, 1989 (pers.comm.)

3.2 Fish Production and per caput supply

Table 1. FISH PRODUCTION AND PER CAPUT SUPPLY - Madagascar, 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 From 1980 to 1983, marine exports were as follows: 3 429 t (1980); 3 237 t (1981); 3 989 t (1982); 3 120 t (1983).

3.3 Inland catch range and potential yield

Table 2. INLAND CATCH RANGE AND POTENTIAL YIELD

Total annual yield: 5 300–9 300 t (partial total, Table 2)
                            40 000–45 000 t (current: 1983–1987) (see Table 1)

Potential annual yield:
                              77 000 t fresh and brackishwater fish catches (Rabelahatra, 1988)

4. STATE OF THE FISHERY

4.1 Yield (mainly after Rabelahatra, 1988)

Inland fisheries take place mainly in lakes and lagoons; the rivers are less exploited. Among the most important lakes and lagoons, seven are heavily exploited (22 500 t for 630 km² in 1984 = 357 kg/ha). Two lakes (Alaotra and Itasy) are already overfished.

In 1984 there were 17 740 fishermen specialized in inland fisheries. About 70% of the catches are thought to be self-consumed by the fishermen's relatives and by the local farmers.

The current production from aquaculture (200–300 t/yr) can be substantially increased through training and better manangement. Production from 1982 to 1987, by species, is given in section 3.1.

4.2 Factors influencing yield

The fishery has been developing at about 2% per year over the last 15 years. In some lakes (i.e., Lake Alaotra), accelerated fishery development occurred when better fishing materials were introduced. Lake Itasy was over-exploited between 1960 and 1965 and the stocks did not reconstitute themselves. Many of the other areas, such as the Pangalanes, are recorded to be unproductive and intensively exploited.

4.3 Future development possibilities

No great increases in natural fish production can be anticipated from the inland and brackish waters of Madagascar. They are at present intensively exploited and need rational management to maintain their present levels of productivity. Further growth of the inland fisheries sector could occur through fish culture and intensive management of inland water bodies by stocking and feeding.

5. KEY BIBLIOGRAPHY

Collart & Rabelahatra, 1977
Kiener, 1963
Rabelahatra, 1988

6. WATER BODIES DIRECTORY

Fig. 1. RIVERS AND LAKES OF MADAGASCAR
(Welcomme, 1972)

LAKE ALAOTRA

Total annual catch and effort:

* Rabelahatra, 1988
** = 168 kg/ha

LAKE ANOSY

LAKE ANTSOHALY-FENOARIVO

LAKE BEMAMBA

LAKE IHOTRY

LAKE ITASY

Total annual catch and effort:

* Welcomme, 1972
** Rabelahatra, 1988
*** = 179 kg/ha

LAKE KINKONY

Total annual catch and effort:

LAKE MAHAZOARIVO

LAKE MANDROSEZA

LAKE MANDROZO

MONTAGNE D'AMBRE LAKES COMPLEX

LAKE NAMONTY

NOSSI BE CRATER LAKES COMPLEX

LAKE TSIMANAMPETSOTSA

BETSIBOKA RIVER

Fisheries data

Total no. of fishermen: 1 250 (in 1970)
Total annual catch: (from floodplain lakes)

SOFIA RIVER

TSIRIBIHINA RIVER

AMBILIVILY RESERVOIR

ANTANIFOTSY RESERVOIR

IVAKOANA RESERVOIR

MANTASOA RESERVOIR

Total annual catch:

MAROALA RESERVOIR

MAROMANDIA RESERVOIR

SAHAMALOTO RESERVOIR

TSIAZOMPANIRY RESERVOIR

Total annual catch and effort:

* Source: Rabelahatra, 1988

AMPAHANA LAGOON

ANONY LAGOON

FORT DAUPHIN LAGOON COMPLEX

LOZA LAGOON

MASIANAKA LAGOON

PANGALANES-EAST LAGOON COMPLEX

Total annual catch and effort:

* Source: Rabelahatra (1988)

7. BIBLIOGRAPHY

Collart & Rabelahatra, 1977
Kiener, 1963
Moreau, 1970
Rabelahatra, 1988
Welcomme, 1972; 1979a

MALAWI

1. GEOGRAPHY AND CLIMATE

Malawi has an area of 94 080 km², about 20% of which is occupied by Lake Malawi, 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.

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

Malawi is a predominantly rural country. The only major modification 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.

2. HYDROGRAPHY (see Fig. 1)

2.1 Lakes (Welcomme, 1979a)

There are four main lakes in Malawi:

1. 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;

2. 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;

3. 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;

4. Lake Chiuta is a smaller lake of the same type as Lake Chilwa and covers about 200 km² when full.

2.2 Rivers, Floodplains and Swamps (Welcomme, 1979a)

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.

2.3 Reservoirs

No important reservoirs as yet, but several are planned for the Shire River. There is one small reservoir on the Zomba Plateau.

FAO/UNDP (1981b), in an appraisal of irrigation, also described numerous reservoirs in the Central Regions, constructed in the 1960's for irrigation. Their present use is mainly for stock watering but, due to poor maintenance, most are in disrepair. These structures represent valuable assets which could be revived. They include not only scope for irrigation but also for fish farming development. Landell Mills Associates (1983) quote inventory records of the Department of Lands, Valuation and Water, showing 700–800 such reservoirs totalling 420–960 ha of water. The average size is 1–2 ha but only 80% are active and the dry season drawdown represents 50% of the potential capacity (Balarin, 1987).

2.4 Coastal Lagoons

None; Malawi is landlocked.

3. FISHERY PRODUCTION/POTENTIAL

3.1 Aquaculture

The status of aquaculture in Malawi has recently been the subject of an EEC-financed study by Landell Mills Associates (1983). In the past it has also been studied by Pruginin (1971, et seql)* and Vincke (1981), as well as by local experts such as Msiska (1981, et seql)*. Balarin (1987) summarized these studies as follows:

"The most recent statistics reported by SADCC (1984) report 70 t/yr as the total aquaculture production. Landell Mills Associates (1983) however arrived at 93.6 t/yr from 319 rural small-holder ponds and 26 ha of estate ponds. From data presented in the text of this report as well as Vincke (1981) and Msiska (1982), it is possible to arrive at a better composite picture. From 370 to 500 ponds are implicated, an area approaching 72 ha, with production estimates of 96–104 t/yr. In addition, there are about 700–800 reservoirs totàlling nearly 1 000 ha and producing at least 105–192 t/yr. It is possible, therefore, that the total fish farming production may reach 300 t/yr. Landell Mills Associations (1983) recommend a project capable of producing additional 695 t/yr. Meecham (1976) has indicated that over 20 000 ha in the marsh land of the Lower Shire Valley might be suitable for fish farming.

"The main indigenous fish species present in fish ponds are the tilapias (Oreochromis shiranus chilwae, O. mossambicus, Tilapia rendalli) and Clarias gariepinus.

"Malawi has been very cautious about fish species introduction for fear of affecting Lake Malawi fishery.

"The first introductions of exotic fish species were of trout, both Salmo gairdneri and Salmo trutta imported from Wales in 1906. Micropterus salmoides were introduced from Zimbabwe as a sport fish in the 1920's. Apart from reservoir stocking and tilapia control trials, this fish has never been cultured in ponds.

"The common carp was introduced from Israel in 1975/76. Yields of C. carpio have been higher than tilapia and the species is highly favoured as a polyculture candidate at Domasi and Kasinthula, finding ready market acceptability (Msiska, 1982).

“One exotic species worthy of mention if Macrobrachium rosenbergii. This freshwater prawn was introduced in 1976 and cultured at Domasi. Results suggest yields of 300 kg/ha, but maintenance of the hatchery was problematic. In 1984 the Dwangwa Sugar Estate has imported post larvae from Mauritius for starting a commercial growout operation.”

* see detailed bibliography in Balarin, 1987.

For a total aquaculture production of 103 t in 1987, Vincke (1989, pers. comm.) estimates a production of 83 t of tilapias, 9 t of Clarias gariepinus, 3 t of Cyprinus carpio, and 8 t of Macrobrachium rosenbergii.

For further information on aquaculture, see Balarin, 1987.

3.2 Fish production and per caput supply

Table 1. FISH PRODUCTION AND PER CAPUT SUPPLY - Malawi, 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 cited in Balarin, 1987
* Inland exports were: 1980: 2 522 t; 1981: 1 500 t; 1982: 1 456 t; 1983: 1 500 t.

3.3 Inland catch range and potential yield

Table 2. INLAND CATCH RANGE AND POTENTIAL YIELD

¹ Sources: see text
² NSO, 1984
³ Welcomme, 1979a

4. STATE OF THE FISHERY
(adapted from Balarin, 1987; Welcomme, 1979a; and Marshall, 1984a)

4.1 Yield

Malawi fisheries can be classified into three categories: ornamental, commercial and traditional. The ornamental fishery concerns tropical aquarium fish for export and is not considered here.

The statistics of national fishery catches are summarized in Tables 1 and 2. Catch data show a rise in annual landings to a peak of 84 000 t in 1972. At this point, Lake Malawi provided 67.8% of the national catch; it subsequently declined to less than 41% in 1982. Production from other sources has also fluctuated: Lake Chilwa yielded 25 800 t in 1979 but was below 3 000 t in 1975; Lake Malombe yielded 12 100 t in 1982 but prior to this landings were never over 8 000 t/yr; the Lower Shire floodplains produced 17 000 t in 1972 but have in recent years remained at 4 000–5 000 t/yr.

4.2 Factors influencing yield

One of the critical factors about Malawi's inland waters is the extent to which they fluctuate, due to climatic changes and variations in lake levels. In 1980, Lake Malawi reached its highest water level in history.

The fishery on Lake Malawi is poorly developed, except in the south, but studies suggest that an annual yield of 30–40 kg/ha may be possible (FAO, 1982a). In inshore waters most of this would be Haplochromis spp. but Engraulicypris sardella would be most abundant in open waters.

Both Lake Chilwa and Shire Floodplain fisheries are sensitive to climatic variability and can give greatly reduced catches in bad years.

4.3 Future development possibilities

The estimates of potential fish yields for Malawi range from 80 000 t/yr (Welcomme, 1979a) to 150 000 t/yr (SADCC, 1984), whereas the range of maximum/minimum catches since 1970 (Table 1) suggests a potential MSY of 31 000–113 500 t/yr. Catch data indicate a relatively stabilized catch of 55 000–75 000 t/yr since 1970. Welcomme's (1979a) estimate of 80 000 t/yr has been adopted as the average national MSY, pending new data establishing the actual potential yield of Lake Malawi.

There are, however, excellent opportunities for fish culture in the country, which contributed about 103 t to the total yield in 1987; production may be expanded in this manner.

5. KEY BIBLIOGRAPHY

Fisheries situation, general: Balarin (1987); Dunn & Smith (1988)
Lake Malawi: FAO, 1982
Limnology of Malawi: Tweddle & Mkoko, 1986

6. WATER BODIES DIRECTORY

LAKE CHIA

Fig. 1. MAJOR RIVER CATCHMENTS OF MALAWI
(Smith-Carington & Chilton, 1983)

LAKE CHILWA
(International water)

Surface water characteristics in the open water of Lake Chilwa in a ‘normal’ year (1970) (Source: Mepham, 1987a)

Total annual catch and effort: in Malawi (varies with water level and area):

Potential annual yield: 20 000 t in Malawi (for max area) (Chaika, 1982)

Specific reference: detailed data and bibliography in Mepham, 1987a.

LAKE CHIKUKUTU

LAKE CHIUTA
(International water)

LAKE MALAWI/NYASA
(International water)

Total annual catch: in Malawi

Potential annual yield: 73 200 – 97 600 t in Malawi (productivity 30–40 kg/ha/yr: FAO, 1982a)

Specific reference: FAO, 1982a

Fig. 2. LAKES MALAWI AND MALOMBE
(Welcomme, 1972)

LAKE MALOMBE

Total annual catch:

Potential annual yield: 2 000 t (Chaika, 1982)

BUA RIVER

DWANGWA RIVER

LILONGWE RIVER

LUFIRA RIVER

NORTH RUKURU RIVER

SHIRE RIVER AND FLOODPLAIN
(International water)

Physical and chemical data (Welcomme, 1972)

Fisheries data
No. of fishermen: 4 000 (Welcomme, 1972)
Total annual catch: in Malawi (excluding Lake Malombe)

Potential annual yield: 4 000–17 000 t, including floodplain (FAO, 1983)

SONGWE RIVER
(International water)

SOUTH RUKURU RIVER

7. BIBLIOGRAPHY

Balarin, 1987
Chaika, 1982
Dibbs, 1964
Dunn & Smith, 1988
FAO, 1982a; 1983a
FAO/UNDP, 1981b
Greenwood, 1964
Jackson et al., 1963
Kalk, 1969
Landell Mills Associates, 1983
Marshall, 1984a
Meecham, 1976
Mepham, 1987a
Msiska, 1981a,b; 1982
NSO, 1984
Pruginin, 1971
SADCC, 1984
Smith-Carington & Chilton, 1983
Talling & Talling, 1965
Tweddle & Mkoko, 1986
Vincke, 1981
Welcomme, 1972; 1979a