LAKE VICTORIA
(International water)
Geographical data (Welcomme, 1972) (see Fig. 9) | ||
Location: | Kenya, Tanzania, Uganda | |
0° 20'N-3° 0'S; 31° 39'-34° 53'E | ||
Altitude: | 1 136 m | |
Surface area: | Kenya | 4 100 km2 (6%) |
Tanzania | 33 700 km2 (49%) | |
Uganda | 31 000 km2 (45%) | |
Total | 68 800 km2 | |
Depth: | 84 m (max); 40 m (mean) | |
Max. length: | 400 km | |
Max. width: | 240 km | |
Shoreline: | 3 440 km | |
Catchment area: | 263 000 km2 | |
Major inflowing rivers: Kagera, Nzoia, Yala | ||
Outflowing river: Victoria Nile |
Physical and chemical data | ||||
Conductivity: | K20 91* to 98** μ S/cm (*EAFRO, 1952b) (**EAFRO, 1954) | |||
Surface temperature: | 23–28° C | |||
Dissolved solids: | 97 mg/l | |||
pH: | ||||
Kavirondo Gulf: | 8.2 (Talling & Talling, 1965) | |||
9.0 (Graham, 1929) | ||||
Open lake: | 8.0 (Talling & Talling, 1965) | |||
8.5 (Graham, 1929) | ||||
Ionic composition: | (EAFRO, 1952b) | (Talling & Talling, 1965) | ||
mg/l | mg/l | |||
Na | 12.5–13.5 | 10.4 | ||
K | 3.7–4.2 | 3.8 | ||
Ca | 5.0–7.0 | 5.6 | ||
Mg | 2.3–3.5 | 2.6 | ||
HCO3+CO3 | 61.0–67.1 | 54.9 | ||
Cl | - | 3.9 | ||
SO4 | 0.8 | - | ||
SiO2 | 3.9 | 4.2 | ||
μ g/l | μ g/l | |||
NO3-N | - | 11 | ||
PO4-P | - | 13 | ||
Total P | - | 47 | ||
Fisheries data No. of fish species: 177, of which 127 are cichlids (mostly Haplochromis species) (Greenwood, 1964) | ||||
Introduced: | ||||
- in the 1950's: Oreochromis niloticus, O. leucostictus, Tilapia zillii, T. rendalli; | ||||
- in late 1950's, beginning 1960's: Lates niloticus | ||||
In the 1960's and 1970's, Haplochromis species constituted an estimated 80% of the lake's fish biomass (FAO, 1973). | ||||
In the late 1970's and in the 1980's, the Nile perch L. niloticus population increased extremely, to the detriment mainly of the Haplochromis population. (see Table 6, underlined) | ||||
From data provided by the Fisheries Department between 1971 and 1975, the relative importance of the Nile Perch increased as follows: (TDRI, 1983) |
Year | Nile Perch % of total catch | |
1971 | 0.3 | |
1972 | 1.0 | |
1973 | 3.0 | |
1974 | 5.0 | |
1975 | 16.0 | |
1982/83 | 30.0 | (TDRI 1983 estimate) |
It is anticipated that the Nile Perch population will decrease as the Haplochromis stocks become seriously depleted. (TDRI, 1983) |
No. of boats: | In Uganda: | 2 643 canoes in 1970 |
2 900 canoes in 1983 (TDRI, 1983) | ||
Main catches: | see Table 5 |
Total annual catch:
Miscellaneous sources: | |
Year | Tons |
1955 | 10 550 |
1957 | 22 800 |
1960 | 22 700 |
1961 | 23 000 |
1962 | 23 500 |
1963 | 24 000 |
1964 | 24 000 |
1965 | 24 000 |
1966 | 27 600 |
1967 | - |
1968 | - |
1969 | 46 177 |
1970 | 34 800 |
1971 | 38 070 |
Definite sources: | |
1983 | 22 000 (TDRI, 1983) |
1972 to 1986 | see Table 4 |
Potential annual yield: in Uganda: 45 000 t (14.5 kg/ha; TDRI, 1983)
Table 5. MAIN FISH CATCHES IN UGANDA, 1975, 1979
(after Reynolds & Greboval, 1988)
Species | 1975 (t) | 1979 (t) |
O.esculentus | 70 | 180 |
O.niloticus | 5 890 | 750 |
Other tilapia | 1 040 | 720 |
Bagrus | 2 930 | 6 530 |
Lates | 250 | 190 |
Protopterus | 195 | 1 370 |
Haplochromis | 1 690 | 1 550 |
Clarias | 2 584 | 3 029 |
Barbus | 260 | 360 |
Synodontis | 70 | 2 540 |
Mormyrus | 40 | 130 |
Labeo | 10 | 40 |
Schilbe | - | - |
Rastrineobola | 10 | 70 |
Other small mixed | - | - |
TOTAL | 15 500 | 16 760 |
Sources: CIFA, 1981; DFK Statistical Bulletins;
Bwathondi, 1988.
Note: No figures are available for Uganda for 1985.
Table 6. LAKE VICTORIA - TOTAL FISH PRODUCTION (t), 1975, 1979, 1985
(after Reynolds & Greboval, 1988)
Species | 1975 | % | 1979 | % | 1985* | % |
O.esculentus | 3 690 | 4.8 | 94 | 2.2 | ||
O.niloticus | 6 092 | 7.9 | 3 320 | 3.2 | 20 093 | 10.7 |
Other tilapia | 3 509 | 4.6 | 6 355 | 6.0 | ||
Bagrus | 10 146 | 13.2 | 13 482 | 12.8 | 9 276 | 4.9 |
Lates | 301 | 0.4 | 4 476 | 4.3 | 87 637 | 46.7 |
Protopterus | 7 844 | 10.2 | 6 445 | 6.1 | 4 200 | 2.2 |
Haplochromis | 22 458 | 29.2 | 29 909 | 28.4 | 11 578 | 6.2 |
Clarias | 6 382 | 8.3 | 7917 | 7.5 | 6 107 | 3.3 |
Barbus | 775 | 1.0 | 1 141 | 1.1 | 515 | 0.3 |
Synodontis | 2 491 | 3.2 | 7 356 | 7.0 | 9 278 | 4.9 |
Mormyrus | 178 | 0.2 | 897 | 0.9 | 402 | 0.2 |
Labeo | 1 719 | 2.2 | 7 332 | 7.0 | 544 | 0.3 |
Schilbe | 1 069 | 1.4 | 1 958 | 1.9 | 1 582 | 0.8 |
Rastrineobola** | 4 558 | 5.9 | 10 989 | 10.4 | 25 866 | 13.8 |
Other small mixed | 5 707 | 7.4 | 1 419 | 1.3 | 10 417 | 5.6 |
TOTAL | 76 919 | 105 267 | 187 495 |
Sources: CIFA, 1981; DFK Statistical Bulletins; Bwathondi, 1988.
* Figures for 1985 combine Kenya and Tanzania only.
** Tanzania combines Rastrineobola with “Other small mixed”.
Fig. 9. LAKE VICTORIA
(Welcomme, 1972)
LAKE WAMALA
Geographical data: | |
Location: | Uganda - 0° 20'N; 31° 53'E |
Surface area: | 244 km2 |
Depth: | <9 m (max) |
Max. length: | 28 km |
Max. width: | 17 km |
Fisheries data | |
Fish species: | |
Main catches: | Oreochromis niloticus (introduced), O. leucostictus, Tilapia zillii, Clarias sp., Protopterus sp. (Okaronen, 1975, cited by Burgis et al., 1987) |
No. of boats: | 250 in 1975 (Okaronen, 1975a) |
250 in 1983 (TDRI, 1983) | |
Total annual catch: | 1972–1981: see Table 4 |
1983: 2 000 t (TDRI, 1983) | |
Potential annual yield: | |
4 000 t (164 kg/ha - TDRI, 1983) |
VOLCANIC CRATER LAKES OF WESTERN UGANDA
In the Rift Valley and on the neighboring uplands in western Uganda there are four clusters of volcanic craters containing a total of 89 lakes.
Melack (1978) reported the results of a limnological survey of 16 of these volcanic crater lakes. The following data are taken from Melack, 1978.
"The lakes range in latitude from 0° 42'N to 0° 19'S and vary in altitude from 1 520 to 895 m above sea level.
"Based on the concentration of dissolved salts in the surface waters the lakes can be divided into a concentrated saline group (electrical conductivity >15 000 μ S/cm at 20° C) and a dilute group (electrical conductivity <1 000 μ S/cm at 20° C). All the lakes were alkaline, and the pH of their surface waters ranged from about 7.5 to about 10.2.
Table 7. MAIN FEATURES OF SOME CRATER LAKES, UGANDA
(after Melack, 1978)
Lake | Location
| Altitude (m) | Lake area (ha) | Depth | Water temp. near bottom (°C) | Conductivity surface K20 μ S/cm | pH surface | ||
max (m) | mean (m) | ||||||||
Kanyangeye 1 | |||||||||
(unnamed on map) | 0° 42'N | 30° 15'E | 1 520 | 0.5 | 57 | 34 | 20.9 | 456 | 8.5 |
Saka Crater 1 | 0° 42'N | 30° 14'E | 1 520 | 1.1 | 8.5 | 2.7 | 21.0 | 533 | 7.6 |
Katanda 2 | 0° 29'N | 30° 16'E | 1 340 | 35 | 146 | - | 21.9 | 375 | 8.8 |
Mwengenyi 2 | 0° 29'N | 30° 16'E | 1 390 | 30 | 101 | - | - | 330 | 9.0 |
Kifuruka 2 | 0° 29'N | 30° 17'E | 1 400 | 15 | c.4 | - | 22.0 | 288 | 7.5 |
Mwamba 2 | 0° 28'N | 30° 17'E | 1 220 | 48 | 39? | - | - | 387 | 8.7 |
Lugembe 2 | 0° 27'N | 30° 17'E | 1 300 | 7.5 | 20 | 12.2 | 22.2 | 306 | 8.7 |
Kikorongo 3 | 0° 00'N | 30° 01'E | 925 | 103 | 8.5 | - | 24.6 | 16 800 | 10.0 |
Mahega 4 | 0° 01'S | 28° 58'E | 925 | 16 | 4.1 | - | 37.2 | 112 200 | 10.1 |
Bunyampaka 3 | 0° 02'S | 30° 08'E | 895 | 43 | 0.25 | - | 31.5 | 80 000 | 10.2 |
Katwe 4 | 0° 08'S | 29° 52'E | 895 | 245 | 0.33 | - | 29.6 | 160 500 | 9.7 |
Chibwera 3 | 0° 09'S | 30° 08'E | 975 | 78 | 12.5 | - | 24.7 | 431 | 7.8 |
Nyamusingire 5 | 0° 17'S | 30° 02'E | 975 | 440 | 4.9 | - | 24.6 | 875 | 9.1 |
Nyungu 5 | 0° 15'S | 30° 06'E | 1 220 | 20 | 18 | 10.0 | 22.0 | 431 | 9.2 |
Kamweru 5 | 0° 15'S | 30° 07'E | 1 160 | 25 | 33.5 | 22.7 | 22.2 | 129 | 9.1 |
Nkugute 5 | 0° 19'S | 30° 06'E | 1 220 | 105 | 58 | 20 | 21.5 | 86 | 8.5 |
1 Bundibugyo, Uganda, 1:50 000. (Series Y732, sheet 56/3. Uganda Government 1964)
2 Kahunge, Uganda. 1:50 000. (Series Y732, sheet 66/2, edition 3-U.S.D. Uganda Government 1969)
3 Katanguru, Uganda. 1:50 000 (Series Y732, sheet 76/1, edition 4-U.S.D. Uganda Government 1965)
4 Katwe, Uganda. 1:50 000. (Series Y732, sheet 75/2, edition 3-U.S.D. Uganda Government 1965)
5 Rubirizi, Uganda. 1:50 000. (Series Y732, sheet 76/3, edition 3-U.S.D. Uganda Government 1965)
The midday temperatures of the surface waters ranged from 22.5 to 26.65° C in the dilute lakes and from 26 to 33° C in the saline lakes. In the lakes with persistent thermoclines the temperatures of the water near the bottom varied from 20.9° C (Lake Kanyangeye) to 24.75° C (Lake Chibwera) and tended to be higher in lakes at lower altitudes. In the lakes over 5 m deep both transient, superficial and persistent, deep-seated thermoclines existed.
“The hypolimnia were anoxic in all the lakes over 5 m deep, and the depth at which the deoxygenated water began coincided with the persistent thermoclines but varied more than was expected.”
Table 7 summarizes the main features of the 16 lakes. Fisheries data are not available.
See Lakes Nyamusingire, Saka and Katwe for more details on their characteristics.
KAGERA RIVER
(International Water)
Geographical Data | |
Source: | Burundi/Rwanda |
Total length: | 785 km |
Countries traversed: | Burundi, Rwanda, Tanzania, Uganda |
Main tributaries: | Akanyaru, Nyabarongo, Ruvubu |
Discharges to: | Lake Victoria |
Special features: |
(1) | Upper Kagera Lakes Complex. A group of lakes distributed as follows: | |
In Burundi: | Ingitamo, Kacamurinda, Kanzigiri, Lirwihinda, Rungazi; | |
In Rwanda: | Birira, Gaharwa, Gashanga, Kidogo, Kirimbi, Mirayi, Mugesera, Muhazi, Murago, Sake; | |
International waters (Burundi/Rwanda): Cyohoha South, Rugwero. | ||
(2) | Rusumo Falls in Rwanda. | |
(3) | Lower Kagera Lakes Complex and Floodplain/Swamp. A group of lakes and adjacent floodplain/swamp lakes distributed as follows: | |
In Rwanda: | Chuju, Hago, Ihema, Iwapibali, Kishanja, Kivumba, Mihindi, Muhari, Nasho, Ngerenke, Rukira, Rwakibare, Rwampanga, Rwanyakizinga, Rwehihama, Sekena; Floodplain/swamp area in Rwanda is circa 1 000 km2 | |
In Tanzania: | Bisongo, Kajumbura, Lwelo, Mujunju, Rushwa. | |
Note: | also called “Akagera”. |
Physical and chemical data (Kiss, 1977a) | ||
Conductivity: | K25 111 μ S/cm | |
pH: | 7.01 | |
Ionic composition: | mg/l | |
Na | 4.1 | |
K | 1.0 | |
Ca | 4.60 | |
Mg | 4.90 | |
Cl | 7.40 | |
HCO3-CO3 | 42.70 | |
Fe | 0.30 |
KAZINGA CHANNEL (RIVER)
Geographical Data | |
Source: | Lake George |
Altitude: | 914 m |
Total length: | 25 km |
Area of water: | 25 km2 |
Countries traversed: | Uganda |
Discharges to: | Lake Edward |
Volume of discharge at mouth: downstream flow very sluggish | |
Special features: | channel connecting Lake George to Lake Edward (see Fig. 5) |
Fisheries data
Total annual catch:
Miscellaneous sources | ||
Year | Tons | |
1955 | 2 500 | (includes Lake Edward) |
1957 | 7 000* | |
1968 | 12 808* | |
1969 | 11 826* | |
1970 | - | |
1971 | 900 | |
1972 | 900 | |
1973 | 400 | |
1974 | 400 | |
1975 | 500 | |
1976 | 500 | |
Definite sources | ||
1983 | 6 500* (TDRI, 1983) | |
1972–1986 | see Table 4 |
* includes Lakes George and Edward
Potential annual yield: | ||
11 000 t | (includes Lakes George and Edward) (116 kg/ha - TDRI, 1983) | |
290 t | (116 kg/ha - TDRI, 1983) |
SEMLIKI RIVER
(International water)
Geographical data | ||||
Source: | Zaire, Lake Edward | |||
Altitude: | 619 m | |||
Countries traversed: | Uganda, Zaire | |||
Discharges to: | Lake Albert | |||
Physical and chemical data | ||||
Conductivity: | K20 400–910 μ S/cm (Beauchamp, 1956) | |||
Ionic composition: | ||||
(EAFRO, 1952b) | (Van der Ben, 1959) | |||
Ca | 15 mg/l | - | ||
HCO3+CO3 | 7.16 meq/l | 7.3 meq/l | ||
Cl | - | 30.7 mg/l | ||
SO4 | - | 36.6 mg/l | ||
SiO2 | 24 mg/l | - |
TURKWEL RIVER
(International water)
Geographical Data | |
Source: | Mt. Elgon (Bukwa tributary) |
Altitude: | 4 322 m |
Total length: | 340 km (300 km in Kenya) |
Countries traversed: | Kenya, Uganda |
Major tributaries: | Suam (Bukwa), Morun |
Discharges to: | Lake Turkana (3° 3'N; 36° 8'E) |
WHITE NILE RIVER
(International water)
Geographical data (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; and from the Sudan to its confluence with the Blue Nile it is called the White Nile or Bahr el Abiad. (See Fig. 1) | |
Source: | Owen Falls dam, Uganda |
Altitude: | 1 136 m |
Total length: | 2 084 km (Albert Nile: 215 km) (Victoria Nile: 390 km) |
Countries traversed: | Sudan, Uganda |
Major tributaries: | Aswa, Bahr el Ghazal, Sobat, Semliki (via Lake Albert), Kagera (via Lake Victoria) |
Discharges to: | Nile at Khartoum |
Volume of discharge at mouth: 71 × 106 m3/day | |
The While Nile contributes 10% of the total flow during the summer floods and 83% at low water. | |
Special features: | Lake Kyoga, Kaba lega, Murchison Falls, Lake Albert (Uganda) Sudd swamps (70 000 km2), Jebel Aulia reservoir (Sudan) |
Physical and chemical data (after Talling, 1957)
Distance from source: Lake Victoria | ||||
800 km | 1 200 km | 2 000 km | ||
Conductivity: K20 | 180–230 μ S/cm | 190–240 μ S/cm | 150–180 μ S/cm | |
pH: | 7.9 | 7.1–7.3 | 7.2–7.8 | |
Temperature: °C | 28.0–29.0 | 27.0–28.0 | 24.0–28.5 | |
Ionic composition: | ||||
mg/l | mg/l | mg/l | ||
Ca | 7.0 | 7.0–9.0 | 8.0–10.0 | |
SiO2 | 2.5–5 | 4–5.5 | 7.5–11.5 | |
Fe | 0.1–0.3 | 0.4–1.4 | 0.2–0.7 | |
Cl | 7.0–10.0 | 6.0–11.0 | 2.0–6.0 | |
SO4 | 5.0 | 1.0 | 1.0 | |
NO3-N | 0.02–0.06 | 0.01–0.06 | 0.01–0.10 | |
NH3-N | 0.02–0.04 | 0.04–0.08 | 0.04–0.07 | |
PO4-P | 0.04–0.06 | 0.02–0.09 | 0.04–0.09 | |
Fisheries data | ||||
No. of boats: | Canoes on Albert Nile in Uganda: | |||
667 in 1969; | ||||
957 in 1970; | ||||
2 640 in 1983 (Fisheries Department, Uganda) |
Total annual catch: Albert Nile in Uganda
Year | Tons |
1969 | 4 500 |
1970 | 4 838 |
1971 | 4 170 |
1972 | 4 100 |
1973 | 4 200 |
1974 | 3 000 |
1975 | 7 200 |
1976 | 3 300 |
1977 | 1 800 |
1978 | 5 700 |
1979 | 4 500 |
1980 | 3 200 |
1981 | 3 000 |
1982 | 1 000 |
1983 | 4 000 |
1984 | 1 900 |
1985 | 1 600 |
1986 | 1 600 |
Sources: | |
1969–1981: | Fisheries Depart., Uganda |
1982–1986: | Stat.Bundesamt Länderbericht, Uganda, 1988. |
Potential annual yield: 6 000 t - Albert Nile (TDRI, 1983)
KANYANYA RESERVOIR
Geographical Data | |
Location: | Uganda |
Fisheries data | |
Total annual catch: | 29.23 t in 1969 |
KIGABAGABA RESERVOIR
Geographical Data | |
Location: | Uganda |
Fisheries data | |
Total annual catch: | 10.71 t in 1969 |
KIZIRAMERE RESERVOIR
Geographical Data | |
Location: | Uganda |
Fisheries data | |
Total annual catch: | 7.69 t in 1969 |
RUGONGI RESERVOIR
Geographical Data | |
Location: | Uganda |
Fisheries data | |
Total annual catch: | 12.9 t in 1969 |
RUSHOZI RESERVOIR
Geographical Data | |
Location: | Uganda |
Fisheries data | |
Total annual catch: | 15.44 t in 1969 |
7. BIBLIOGRAPHY
Balarin, 1985c
Beadle, 1932; 1981
Beauchamp, 1956
Burgis, 1987
Burgis, Mavuti, Moreau & Moreau, 1987
Bwathondi, 1988
CIFA, 1981
Dunn, 1989
Dunn, et al., 1969
EAFRO, 1952a, b; 1954
FAO, 1973; 1982b
Giudicelli et al., 1987
Graham, 1929
Greenwood, 1964; 1965
Hurst, 1925
HYDROMET, 1974
Jensen et al., 1983
Kerr, 1966
Kiss, 1977a
Marriott, et al., 1988
Melack, 1978
Okaronen, 1975a,b
Proude, 1984
Reynolds & Greboval, 1988
Statistisches Bundesamt, 1988
Talling, 1957
Talling & Talling, 1965
TDRI, 1983
Vakily, 1989
Van Der Ben, 1959
Viner, 1969
Visser, 1962
Welcomme, 1972; 1979a
Worthington, 1929; 1932
1. GEOGRAPHY AND CLIMATE (Welcomme, 1979a)
Zaire (surface area of 2 364 200 km2 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.
Zaire lies astride the Equator, about one-third to the north and two-thirds to the south. The climate, therefore, is equatorial and especially hot and humid in the forested central areas. North of the Equator there is a single rainy season from April to November; south of it a rainy season lasts from October to May. In the central region rainfall is distributed evenly throughout the year.
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; in the south, in Shaba province, the considerable mineral resources have given rise to intensive mining development.
2. HYDROGRAPHY (adapted from Welcomme, 1979a) (See Fig. 1)
2.1 Lakes
The major lakes within Zaire are those of the Rift Valley and are found in the extreme east of the country (Tanganyika, Mweru, Kivu, Edward and Albert). In addition to these lakes, there are two major water bodies attached to the lower reaches of the river system: Lake Tumba and Lake Maji Ndombe (2 300 km2). The Kamulondo Depression (Lualaba floodplain) contains some 50 lakes, of which Lake Upemba is by far the largest. Numerous small lakes are scattered throughout the country. The combined lake surface area is circa 28 000 km2.
2.2 Rivers, Floodplains and Swamps
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, Lualaba, Luapula, Lulonga, Tshuapa. There is a total of some 33 000 km of major river channel and their area (circa 34 000 km2) is increased by intensive floodplains, particularly in the Kamulondo Depression and in the Mbandaka region of confluence between the Ubangi and the Zaire streams. In total, the floodplains are thought to cover about 50 000 km2 during high water, but such a figure can only be approximate due to the difficulties in measuring such areas.
2.3 Reservoirs
Two major reservoirs have been installed in the southeast of the country: Mwadingusha on the Lufira, and Nzilo on the Lualaba.
2.4 Coastal Lagoons
None of significant size.
3. FISHERY PRODUCTION/POTENTIAL
3.1 Aquaculture
In 1956 there were 94 761 ponds with a combined surface area of 3 863 ha. By 1960 this had increased to 120 000 ponds with an area of 4 200 ha.
In 1987, aquaculture production was estimated at about 700 t/yr (mainly Oreochromis niloticus) with possibilities of further development (Giudicelli et al., 1987).
3.2 Fish production and per caput supply
Table 1. FISH PRODUCTION AND PER CAPUT SUPPLY - Zaire, 1970–1987
Nominal Domestic Production (excluding exports) (t) 2 | Nominal Consumer Supply (excluding imports and exports) (kg/person) | ||||||||
Year | Population '000 1 | Inland capture | Aquaculture 3 | Marine capture | Total | Inland capture | Aquaculture 3 | Marine capture | Total |
1970 | 19 481 | 121 900 | - 4 | 14 700 | 136 600 | 6.2 | - 4 | 0.75 | 7.0 |
1971 | 20 032 | 111 200 | - | 12 700 | 123 900 | 5.6 | - | 0.63 | 6.2 |
1972 | 20 600 | 111 200 | - | 13 000 | 124 200 | 5.4 | - | 0.63 | 6.0 |
1973 | 21 283 | 144 700 | - | 12 200 | 156 900 | 6.8 | - | 0.57 | 7.4 |
1974 | 21 782 | 115 430 | - | 13 380 | 128 810 | 5.3 | - | 0.61 | 5.9 |
1975 | 22 399 | 100 000 | - | 13 380 | 113 380 | 4.5 | - | 0.60 | 5.1 |
1976 | 23 050 | 110 000 | - | 7 858 | 117 858 | 4.8 | - | 0.34 | 5.1 |
1977 | 23 719 | 104 600 | - | 2 400 | 107 000 | 4.4 | - | 0.10 | 4.5 |
1978 | 24 408 | 107 600 | - | 1 106 | 108 706 | 4.4 | - | 0.05 | 4.5 |
1979 | 25 117 | 114 200 | - | 982 | 115 182 | 4.5 | - | 0.04 | 4.6 |
1980 | 25 847 | 101 800 | - | 615 | 102 415 | 3.9 | - | 0.02 | 3.9 |
1981 | 26 618 | 102 000 | - | 640 | 102 640 | 3.8 | - | 0.02 | 3.8 |
1982 | 27 412 | 100 000 | - | 700 | 100 700 | 3.6 | - | 0.02 | 3.6 |
1983 | 28 229 | 100 875 | 125 | 1 000 | 102 000 | 3.6 | 0.004 | 0.03 | 3.6 |
1984 | 29 071 | 146 275 | 125 | 1 900 | 148 300 | 5.0 | 0.004 | 0.06 | 5.1 |
1985 | 29 938 | 146 220 | 180 | 1 900 | 148 300 | 4.9 | 0.006 | 0.06 | 4.9 |
1986 | 30 862 | 163 311 | 689 | 2 000 | 166 000 | 5.3 | 0.022 | 0.06 | 5.3 |
1987 | 31 814 | 163 300 | 700 5 | 2 000 | 166 000 | 5.1 | 0.022 | 0.06 | 5.2 |
1 Source: FAO
2 Source: FAO Fisheries Department FISHDAB
3 included in “Inland capture” if not specified
4 - = data not available
5 Giudicelli, et al., 1987
Fig. 1. RIVERS AND LAKES OF THE CONGO/ZAIRE SYSTEM
(Welcomme, 1972)
3.3 Inland catch range and potential yield
Table 2. INLAND CATCH RANGE AND POTENTIAL YIELD
Water body | Period | Annual catch range (t) 2 | Potential annual yield (t) 2 |
Lakes | - | 42 525–60 625 | 185 205–274 790 |
Albert/Mobutu | 1982 | 5 000 | 11 500–15 640 |
Boya | - | - | - |
Edward/Idi Amin | 1982; 1979 | 3 500; 5 000 | 15 000 |
Kafakumba | - | - | - |
Kasuku | - | - | - |
Katania | - | - | |
Kivu | 1987 | 1 925 | 1 305–7 500 |
Libanda | - | - | - |
Mai Ndombe | 1982 | 1 000 | 5 750–10 000 |
Malebo (Pool) | 1984 | 3 000–3 500 | - |
Mukamba | - | - | - |
Mweru | 1983 | 6 600–8 700 | 12 000 |
Tanganyika | 1983–1988 | 16 000–30 000 | 135 000–210 000 |
Tumba | 1982 | 500 | 2 000 |
Upemba | 1981 | 5 000 | 2 650 |
Floodplains/Forests | - | 12 000–13 000 | 91 600–129 500 |
Kamolondo/Lualaba | 1981 | 10 000 | 30 000 |
Kifakula/Luapula | 1983 | 2 000–3 000 | 5 000 |
Mai Ndombe | - | - | 5 000–8 500 |
Mbandaka | - | - | 15 600–26 000 |
Lisala Makanza | - | - | 36 000–60 000 |
Reservoirs | - | 3 220–3 430 | 6 960 |
Mwadingusha | 1983 | 3 100 | 4 460 |
Nzilo | 1983; 1981 | 120; 330 | 2 500 |
Rivers | 1984 | 77 500–105 000 | 100 000 1 |
Zaire | 1961–1984 | 47 500–75 000 | 50 000 1 |
Others | 1961 | 30 000 | 50 000 1 |
TOTAL (rounded) | 130 000–180 000 | 380 000–510 000 |
1 rough estimate based on several authors
2 Sources: see text.
4. STATE OF THE FISHERY (adapted from Welcomme, 1979a)
4.1 Yield
Up to the early 1960's the catch from the inland waters of Zaire underwent a growth phase. During the early post-independence period many fisheries collapsed, recovered in the late 1960's and early 1970's, declined a second time, and increased again in the 1980's. The potential catch from all water bodies is between 380 000 and 510 000 t/yr.
4.2 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.
4.3 Future development possibilities
It seems highly probable that the total catch of inland fish in Zaire will rise steadily over the next decade and that 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 has been established following the introduction of Limnothrissa into that lake. One further area remains unexploited: that of Mbandaka Floodplains which, by reason of their inaccessibility and extremely low population density, will probably not be exploited for several decades.
5. KEY BIBLIOGRAPHY
General fisheries in Zaire: Aubray, 1976
Zaire Basin: Compere & Symoens, 1987
6. WATER BODIES DIRECTORY
Lakes | ||
Albert (= Mobutu) | Kivu | Mukamba |
Boya | Libanda | Mweru |
Edward (= Idi Amin) | Lualaba Floodplain/Lakes Complex (= Kamolondo Depression) | Tanganyika |
Kafakumba | Maji Ndombe | Tumba |
Kasuku | Pool Malebo (= Stanley Pool) | Upemba |
Katania | ||
Flooded forests | ||
in Central Zaire Basin | in Mbandaka area | |
Rivers | ||
Aruwimi/Ituri | Lualaba | Ruki |
Itimbiri | Luapula | Ruzizi |
Kasai/Kwa | Lulonga | Semliki |
Lomani | Mongala | Ubangi/Oubangui |
Zaire/Congo | ||
Reservoirs | ||
Mwadingusha (= Tshangalele; = Lufira) | Nzilo I (= Delcommune) | |
Nzilo II (= Marinel) |
LAKE ALBERT (= MOBUTU)
(International water)
Geographical data (see Fig. 2) | |
Location: | Uganda, Zaire - 1° 9'–2° 17'N; 30° 25'–31°25'E |
Altitude: | 618 m |
Surface area: | Uganda, 2 850 km2 (54%); Zaire, 2 420 km2 (46%) |
Total: 5 270 km2 | |
Depth: | 58 m (max); 25 m (mean) |
Volume: | 140 km3 total; 60 km3 in Zaire |
Max. length: | 160 km |
Max. width: | 35 km |
Major inflowing rivers: | Semliki, Victoria Nile |
Outflowing rivers: | Albert Nile (Uganda) |
Physical and chemical data (Welcomme, 1972) | ||||
Conductivity: | K20 675–730 μ S/cm | |||
Surface temperature: | 26–29° C | |||
Dissolved solids: | 565 mg/l (mean); 518–672 mg/l (main lake); 370–680 mg/l (Semliki Delta) | |||
pH: | 8.4–9.5 | |||
Oxygen: | water rich in oxygen at all depths | |||
Ionic composition: | (Van Der Ben, 1959) | (Talling and Talling, 1965) | ||
mg/l | mg/l | |||
Na | 97.0 | 91.0 | ||
K | 66.0 | 65.0 | ||
Ca | 9.8 | 9.8 | ||
Mg | 31.5 | 32.1 | ||
HCO3+CO3 | 475.8 | 445.3 | ||
Cl | 31.0 | 31.0 | ||
SO4 | 25.0 | 32.0 | ||
SiO4 | 3.4 | 0.09–0.9 | ||
μ g/l | μ g/l | |||
NO3-N | 9.0 | - | ||
PO4-P | 130.0 | - | ||
Total P | - | 200.0 |
Fisheries data
No. of fish species: 46 (Greenwood, 1964)
Main catches: 75–85% of catches are:
Characidae: Alestes baremose; Hydrocynus forskahli;
Centropomidae: Lates niloticus albertianus (Proude, 1984)
Annual production, entire lake: 15 000 t in 1982 (Giudicelli et al., 1987)
Total annual catch and effort: in Zaire
Year | Total catch (t)** | No. of fishermen | No. of boats |
1920 | 430 | - | - |
1921–37 | - | - | - |
1938 | 2 200 | - | - |
1939 | - | - | - |
1940 | 2 600 | - | - |
1941–49 | - | - | - |
1950 | 1 827* | - | - |
1951 | 2 545* | - | - |
1952 | 3 299* | - | - |
1953 | 4 166* | - | - |
1954 | 6 279* | - | - |
1955 | 7 911* | - | - |
1956 | 9 106* | - | - |
1957 | 11 886* | - | - |
1958 | 9 226* | - | - |
1959 | 10 691 | - | - |
1960 | 8 502 | - | - |
1961 | 2 749 | - | - |
1962 | 1 884 | - | - |
1963 | 3 055 | - | - |
1964 | 3 360 | - | - |
1965 | 3 564 | - | - |
1966 | 4 124 | - | - |
1967 | 4 276 | - | - |
1968 | 4 266 | - | - |
1969 | 4 785 | - | - |
1970 | 5 500 | - | - |
1971 | 7 000 | - | - |
1972 | 7 939 | - | - |
1973 | 9 000 | - | - |
1974 | 5 226 | - | - |
1975 | 7 700 | 18 000 | 1 860 |
1976 | 6 443 | - | - |
1977 | 4 412 | - | - |
1978 | 9 711 | - | - |
1979 | 7 913 | - | - |
1980 | 2 988 | - | - |
1981 | 5 705 | - | - |
1982 | 5 000 | 11 125 | - |
1983 | 3 873 | - | 2 108 |
* industrial catches only
** Total catch: industrial + small scale (cited by Proude, 1984)
Note: Due to the variety of sources and methods used, these
estimates do not necessarily reflect the actual catches.
Potential annual yield: | ||
Proude (1984), citing several authors, estimates the mean potential annual yield as follows: | ||
11 500 t - Zaire | ||
13 500 t - Uganda | ||
25 000 t - Total lake | ||
Giudicelli et al. (1987) gives the following estimates: | ||
15 640 t - Zaire | ||
34 000 t - Total lake | ||
Key reference for Lake Albert (Mobutu): Proude, 1984 |
Fig. 2. LAKE ALBERT (MOBUTU)
(after Welcomme, 1972)
Fig. 3. LAKE EDWARD/IDI AMIN
(after Welcomme, 1972)
LAKE BOYA
Geographical data | |
Location: | Zaire, 7° 22'S; 25° 39'E |
Surface area: | 7.9 km2 |
Max. length: | 4.5 km |
Max. width | 2.5 km |
LAKE EDWARD (= IDI AMIN)
(International water)
Geographical data (see Fig. 3) | |||
Location: | Uganda, Zaire - 0° 04'-0° 39'S; 29° 20' –30° E | ||
Altitude: | 914 m | ||
Surface area: | Uganda: 670 km2 (29%); Zaire: 1 630 km2 (71%) | ||
Total: 2 300 km2 | |||
Depth: | 117 m (max); 34 m (mean) | ||
Volume: | 78.2–90 km3 | ||
Max. length: | 90 km | ||
Max. width: | 40 km | ||
Major inflowing rivers: Rutshuru (also connected to Lake George by the Kazinga Channel), Rwindi, Luholu, Ishasha | |||
Outflowing river: | Semliki | ||
Physical and chemical data (Welcomme, 1972) | |||
Conductivity: | K20 900 μ s/cm (EAFRO, 1954); | ||
925 μ s/cm (Talling & Talling, 1965) | |||
Surface temperature: | circa 26° C | ||
Dissolved solids: | 521 mg/l | ||
pH: | 8.5–9.3 | ||
Ionic composition: (Talling & Talling, 1965) | |||
mg/l | |||
Na | 110.0 | ||
K | 9.0 | ||
Ca | 12.4 | ||
Mg | 47.3 | ||
HCO3+CO3 | 600.0 | ||
Cl | 36.0 | ||
SO4 | 31.0 | ||
SiO2 | 6.5 | ||
μ/l | |||
NO3-N | 24.0 | ||
PO4-P | 18.0 | ||
Total P | 127.0 |
Fisheries data | |||
No. of fish species: | 53, of which 28 are cichlids (Greenwood, 1964) | ||
Main catches: | (Jensen et al., 1983; and Vakily, 1989) | ||
Tilapia (Oreochromis niloticus eduardianus) | 60–70% | ||
Bagrus (Bagrus docmak) | 10% | ||
Barbus (Barbus altianalis eduardianus) | 5% | ||
Protoptere (Protopterus aethiopicus aethiopicus) | 10% | ||
Clarias (Clarias gariepinus) | 10% | ||
No. of boats: | about 700 canoes in Zaire in 1988 (Vakily, 1989) | ||
Total annual catch and effort: in Zaire |
Year | Total catch (t) | No. of fishermen | No. of boats |
Miscellaneous sources | |||
1952 | 2 000 | - | - |
1953 | 2 836 | - | - |
1954 | 3 241 | - | - |
1955 | 3 007 | - | - |
1956 | 3 108 | - | - |
1957 | 5 715 | - | - |
1958 | 4 218 | - | - |
1959 | 6 000 | - | - |
1960 | 6 500 | - | - |
1961 | 5 500 | - | - |
1962 | 4 000 | - | - |
1963 | 3 700 | - | - |
1964–66 | - | - | - |
1967 | 3 500 | - | - |
1968 | 2 440 | - | - |
1969 | 2 150 | - | - |
1970 | - | - | - |
1971 | - | 1 000 | - |
1972–74 | - | - | - |
1975 | 2 000 | - | - |
1976 | 2 000 | 8 000 | - |
1977–78 | - | - | - |
1979 | 5 000 | - | - |
1980 | - | - | - |
1981 | 1 731 | - | - |
1982 | 3 500 | - | - |
1983 | - | 2 298 | 383 |
Note: Due to the variety of sources and methods used, these estimates do not necessarily reflect the actual catches.
Total annual catch and effort: | |||||
Definite sources (t) | |||||
Author | Year | Zaire | Uganda | Total lake | |
Welcomme, 1972 | 1969–1970 | 10 351 | 5 731 | 16 082 | |
Welcomme, 1979b | - | 5 000 | - | - | |
Giudicelli et al., 1987 | 1985 | - | - | 10 400 | |
Vakily, 1989 | 1988 | 10 000–11 000 | 3 000 | 14 000 | |
Potential annual yield: (t) | |||||
Author | Zaire | Uganda | Total Lake | ||
Jensen et al., 1983 | 15 000–20 000 | - | - | ||
Giudicelli et al., 1987 | - | - | 13 000 | ||
Vakily, 1989 | - | 15 000–16 000 | |||
Key reference for Lake Edward/Idi Amin: Vakily, 1989 |
LAKE KAFAKUMBA
Geographical data | |
Location: | Zaire - 9°42'S; 23°51'E |
Surface area: | 7.5 km2 |
Max. length: | 5 km |
Max. width: | 1.5 km |
LAKE KASUKU
Geographical data | |
Location: | Zaire - 3°15'S; 25°43'E |
Surface area: | 21 km2 |
Max. length: | 15 km |
Max. width: | 2 km |
Major inflowing river: | Kasuku |
Outflowing river: | Kasuku |
LAKE KATANIA
Geographical data | |
Location: | Zaire - 6°29'S; 25°32'E |
Surface area: | 3.7 km2 |
Max. length: | 3.5 km |
Max. width: | 1.5 km |
LAKE KIVU
(International water)
Geographical data (see Fig. 4) | ||
Location: | Rwanda, Zaire - 1°30'–2°30'S; 28°50'–29°25'E | |
Altitude: | 1 463 m | |
Surface area: | Zaire: | 1 370 km2 (58%) |
Rwanda | 1 000 km2 (42%) | |
Total: | 2 370 km2 | |
Depth: | 489 m (max); 240 m (mean) | |
Max. length: | 102 km | |
Max. width: | 50 km | |
Outflowing river: | Ruzizi |
Physical and chemical data (adapted from Welcomme, 1972) | ||||
Surface temperature: 24–26°C, thermocline 20–30 m | ||||
Conductivity: | K20 1 240 μ S/cm (Van Der Ben, 1959); | |||
K20 1 276–1 294 μ S/cm (Reusens, 1987) | ||||
Dissolved solids: | 597–1 020 mg/l | |||
pH: | 9.1–9.5 (Van Der Ben, 1959) | |||
8.8 (Reusens, 1987) | ||||
Ionic composition: | (Verbeke, 1957) (Van Der Ben, 1959) | |||
mg/l | mg/l | |||
Na | 130.0 | 129.0 | ||
K | 100.0 | 85.0 | ||
Ca | 5–15.0 | 21.2 | ||
Mg | 100.0 | 84.0 | ||
HCO3+CO3 | 915.0 | 1 000.4 | ||
Cl | 35.0 | 31.0 | ||
SO4 | 30.0 | 15.0 | ||
SiO2 | 2–13.0 | 9.0 | ||
μ g/l | μ g/l | |||
NO3-N | - | 41.0 | ||
PO4-P | - | 39.0 |
Special feature: | 50 km3 methane gas below 200 m depth (Degens et al., 1971) | |
Oxygen: | Surface to thermocline: saturated; thermocline to -70 m: decreasing; below 70 m: no oxygen | |
Photosynthetic production: | ||
1.44 gC/m2/day (Degens et al., 1971, cited by Beadle, 1981) (240–540 gC/m2/year) | ||
Fisheries data | ||
No. of fish species: about 25 | ||
Endemic fish species: (Beadle, 1981) | ||
Cyprinidae: | Barbus spp., Raiamas (ex Barilius) sp. | |
Clariidae: | Clarias sp. | |
Cichlidae: | Oreochromis niloticus | |
Haplochromis spp. (6 spp.) | ||
Introduced species: | ||
in 1950: | Cichlidae: | Tilipia rendalli |
Oreochromis macrochir | ||
in 1959: | Clupeidae: | Stolothrissa tanganicae; Limnothrissa miodon |
Total annual catch and effort: |
Year | Total catch (t) | No.of fishermen | No.of boats |
in Zaire (miscellaneous sources) | |||
1952 | 20 | - | - |
1957 | 860 | - | - |
1958–59 | - | - | - |
1960 | 1 200 | - | - |
1962–73 | - | - | - |
1974–75 | 200 b* | - | - |
1976–81 | - | - | - |
1982 | 300 | - | - |
in Lake Kivu | |||
1950** | 303 a | - | shore fishing |
1957** | 841 a | - | shore fishing |
1958** | 965 a | - | shore fishing |
1986** | 723 a | - | shore fishing |
1987*** -Total | 3 500 b | 1 915 | 174 (pelagic fishing) |
-in Zaire | 1 925 b | 1 061 | |
-in Rwanda | 1 575 b | 854 |
a Fish: tilapia + Haplochromis
b Fish: Limnothrissa miodon
Sources :
* (Aubray, 1976)
** (cited by Hanek et al., 1988)
*** (Hanek et al., 1988)
in Rwanda
Catches obtained by Project “Dèvelop. de la pêche au Lac Kivu” (RWA/87/012):
Year | 1979 | 1980 | 1981 | 1982 | 1983 | 1984 | 1985 | 1986 |
Total catch: (t) | 1 | 40 | 70 | 95 | 91 | 200 | 330 | 249 |
In addition, 55 private fishing units are estimated to produce two times more Limnothrissa miodon than the Project (Hanek et al., 1988).
Estimated total annual catch in Rwanda (1987): 1 900 t; (1 575 t Limnothrissa + 325 t tilapia/Haplochromis)
LIMNOTHRISSA MIODON FISHERIES SITUATION
in 1987 (Reusens, 1987) and in 1989 (Johannesson & Lamboeuf, 1989)
Zaire | Rwanda | Total | ||
No. fishermen (1987) | 1 061 | 854 | 1 915 | |
No. boats (1987) | ||||
catamarans | 4 | 42 | 46 | |
trimarans | 63 | 55 | 118 | |
traditional | 10 | - | 10 | |
Biomass (1989) | ||||
prerecruits: (2–4cm) | 458 t | 32 t | 790 t (26%) | |
catchable stock (4–12cm) | 1 305 t | 945 t | 2 250 t (74%) | |
Total | 1 763 t | 1 276 t | 3 039 t (100%) | |
density: 12–82 kg/ha | ||||
No. of fishes (1989) | ||||
prerecruits (million) | 746 | 540 | 1 286 (66%) | |
catchable stock (million) | 385 | 278 | 663 (34%) | |
Total (million) | 1 131 | 818 | 1 949 (100%) |
Potential annual yield:
• Estimation based on Morpho-Edaphic Index (MEI): (Reyntjens, 1982) | |||
MEI, Lake Kivu: 18.29: | |||
Zaire | 7 620 t | ||
Rwanda | 5 580 t | ||
Total | 13 200 t | ||
• Estimation based on zooplankton biomass: (Reyntjens, 1982) | |||
Potential annual yield: 55 kg/ha: | |||
Zaire | 7 500 t | ||
Rwanda | 5 500 t | ||
Total | 13 000 t | ||
• Estimation based on primary productivity: | |||
(Melack, 1976) | (Oglesby, 1977) | ||
Zaire | 40 200 t | 1 800 t | |
Rwanda | 26 800 t | 1 200 t | |
Total | 67 000 t | 3 000 t | |
• Estimation based on acoustic stock assessment surveys: | |||
(Johannesson & Lamboeuf, 1989) | |||
Biomass catchable stock in 1989: | |||
Zaire | 1 305 t | ||
Rwanda | 945 t | ||
Total | 2 250 t | ||
This estimation must be considered as the most reliable. |
Key reference for Lake Kivu: Hanek et al., 1988
Fig. 4. LAKE KIVU
LAKE LIBANDA
Geographical data | |
Location: | Zaire - 1°31'S; 18°50'E |
Surface area: | 7.9 km2 |
Max. length: | 4.5 km |
Max. width | 2.5 km |
Fig. 5. LAKES OF THE KAMOLONDO DEPRESSION
(Welcomme, 1972)