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COUNTRY FILES (Contd.)

DJIBOUTI

1. GEOGRAPHY AND CLIMATE

Djibouti, with a surface area of 21 980 km2, consists largely of volcanic plateau and desert. The climate is hot and dry. Djibouti is an important shipping port. There is some agriculture (coffee, livestock) but the soil is generally arid and unproductive.

2. HYDROLOGY

2.1 Lakes

There are two medium-sized lakes: Asal and Abbe.

2.2 Rivers, Floodplains and Swamps

None. Discharge to Lake Abbe is from Ethiopia and to Lake Asal from small mountain streams and gullies.

2.3 Reservoirs

None.

2.4 Coastal Lagoons

There is one medium-sized lagoon: Ghoubet Kharab.

2.5 Aquaculture

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

3. FISHERY PRODUCTION/POTENTIAL

3.1 Fish production and per caput supply (see Table 1, p.30)

3.2 Inland catch range and potential yield

No data available for Lakes Abbe and Asal, and Ghoubet Kharab Lagoon.

4. STATE OF THE FISHERY

4.1 Yield

Although no information is available, it may be assumed that a fishery exists at least on Ghoubet Kharab Lagoon. That catch, if any, could have been included in the marine production data.

4.2 Factors influencing yield

No significant freshwater waterbody. Active marine fishery.

4.3 Future development possibilities

No inland fishery development can be expected in Djibouti except, possibly, from the Ghoubet Kharab Lagoon.

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

 Nominal Production
(excluding exports)
(t) 2
Nominal Consumer Supply
(exclud. imports & exports)
(kg/person)
YearPopulation
'000
1
No inland captureAquaculture
3
Marine captureTotalMarine captureTotal
1970160  3003001.91.9
1971170  3003001.81.8
1972180  1001000.60.6
1973190  2002001.11.1
1974201  3803801.91.9
1975214  8008003.73.7
1976232  1 200   1 200   5.25.2
1977252  1 600   1 600   6.36.3
1978273  2 000   2 000   7.37.3
1979293  2312310.80.8
1980310  2512510.80.8
1981324  3853851.21.2
1982335  4264261.31.3
1983345  4094091.21.2
1984354  4094091.21.2
1985364  3803801.01.0
1986376  4104101.11.1
1987389  4404401.11.1

1 Source: FAO
2 Source: FAO Fisheries Department FISHDAB
The 1983–86 catch data refer to estimates based on 70% of the production officially reported.

3 No aquaculture in Djibouti (Vincke, 1989, pers.comm.)

5. KEY BIBLIOGRAPHY

Gasse, 1987

6. WATER BODIES DIRECTORY

Lakes
Abbe (= Abhe Bid Hayk)
Asal
 
Lagoon
Ghoubet Kharab

Fig. 1

Fig. 1. MAP OF DJIBOUTI

LAKE ABBE (= ABHE BID HAYK)
(International water)

Geographical data (Gasse, 1987)
Location:Djibouti, Ethiopia - 11°10'N; 41°46'E
Altitude:235 m asl
Surface area:about 250 km2; surface area decreased from 400 km2 to about 250 km2 between 1954 and 1984 (water pumped for irrigation)
Catchment basin:76 000 km2 (= Awash river basin)
Max. length:45 km
Max. width:45 km
Depth:less than 12 m (mean); 36 m (max)
Volume:about 4 200 106m3
Major inflowing river:Awash River
Outflow:none - internal basin.
 
Physical and chemical data (cited in Gasse, 1987)
pH:9.8–11
Ionic composition: mg/l
 Na55 000
 K    840
 Ca        5
 Mg     1.4
 Cl40 835
 SO417 000
 HCO3+CO3  1 060 meq/l
  
Fisheries data:no fishing activity.

LAKE ASAL

Geographical data (Gasse, 1987)
Location:Djibouti - 11°27'N; 42°25'E
Altitude:155 m below sea level
Surface area:54 km2
Max. length:10 km 
Max. width:7 km 
Depth:7.4 m (mean) 
Volume:400 106m3 
Catchment area:900 km2 
Water inflow:underground water and sea water through tectonic fissures.
Special features:hyper-saline lake franged by 60 km2 salt plain. Hot water springs.
 
Physical and chemical data (cited in Gasse, 1987)
pH:8.0–8.5 
Ionic composition: mg/l
 Na104 340
 K    5 104
 Ca    2 640
 Mg  12 366
 Cl196 756
 SO4    2 554
 SiO2      12.5
 HCO3+CO3        3.6 meq/l
  
Fisheries data:no fishing activity.

GHOUBET KHARAB LAGOON

Geographical data 
Location:Djibouti - 11° 32'N; 42° 37'E
Area:136 km2
Max. length:22 km
Max. width:10 km

7. BIBLIOGRAPHY

Gasse, 1987

EGYPT

1. GEOGRAPHY AND CLIMATE (Welcomme, 1979)

Egypt (with an area of 995 450 km2) is an almost rainless block of desert consisting of high plains and hills in the east and along the Nile Valley. The Nile River forms the main axis of the country and stretches some 1 300 km from the Sudan border to the Mediterranean. It can be divided into two main areas: the delta which extends as far as Cairo; and the rest of the Nile Valley. See Fig. 1.

Egypt is almost totally arid and all water enters the country through the Nile. Summer temperatures are high, but winter temperatures may fall as low as 10°C.

The inhabited strip of Egypt follows the banks of the Nile and expands into the delta. There is very intensive cultivation of crops as well as date palms, involving extensive irrigation networks. These, together with the flood control effects of the Aswan Dam, have stopped flooding over the previous floodplain.

2. HYDROGRAPHY (after Welcomme, 1979, and Balarin, 1986) See Fig. 2 and Table 1.

The water resources of Egypt fall into a limited number of categories. The desert condition and limited rainfall implies that runoff is minimal and that there are few surface water sources. The most important water resource is the Nile River which rises from central East Africa and is independent of the Egyptian climate. In addition, there are a number of natural brackish water lakes/lagoons, several oases, and the large Nasser Lake. Due to excessive irrigation Egypt also has an extensive recycled drainage water system.

According to SIS (1983a), available water resources in 1983 amounted to 60.7 billion m3, of which 59.5 billion m3 were used annually. It was planned to increase resources to 72.4 billion m3 by 1990. Inland waters represent about 405 000 ha. Lakes account for half this area; 162 000 ha are the Nile; and 40 000 ha are in the form of navigation and irrigation canals (Wunder, 1960).

2.1 Lakes

The largest natural lake is Lake Quarun, situated near El Fayum. It covers 220 km2 and, although originally freshwater, its salinity has increased steadily since 1920 to nearly 35. The lake is shallow and very productive. Lake Wadi Rayan (142 km2) is somewhat smaller. Some small, highly saline lakes are associated with the Siwa Oasis in the northwest and Wadi El Natrun in the northeast.

2.2 Rivers, Floodplains and Swamps

The Nile is the only river in Egypt and receives no tributaries in its 1 300 km course through the country. Its basin covers an area of 2 million km2. Before reaching Egypt, its waters travel 5 200 km through Tanzania, Zaire, Kenya, Uganda, Sudan and Ethiopia. In Egypt the Nile River discharges into the Mediterranean Sea through seven branches (the two main branches being the Rossetta and Damieta), creating the fan-shaped delta region. The Nile lies within the rift valley and the unstable shelf zone of Egypt. It is bound on its fringes by extensive plains of gravel creating tablelands. The eastern side is more developed and is dissected by “Wadis” that discharge into the Nile.

The water level in the Nile is lowest in April-July and highest in September, with no relation to rainfall in Egypt. Since the construction of the Aswan High Dam, the natural regime of the river flow in Egypt is being controlled and discharges are regulated.

The annual flow of the river varies considerably from year to year, ranging from 45 to 150 billion m3 (Hefny, 1982). Regulation of this flow has long been of primary concern in view of the importance of a regular supply for irrigation and to control floods from devastating crops and villages. Early attempts include the Old Aswan Dam and barrages at Assiut and below Cairo. The effect of the Aswan High Dam is clear from Fig. 5 (see entry “Nile River”, p.49).

Of concern, however, is the loss in silt. The Nile carried a total average load of 134 million t/yr of silt (Hefny, 1982) which was responsible for the Delta sediments, adding to the growth of the region, and playing an important role in the historical fertility of agricultural land. All the silt is now deposited in Lake Nasser; almost clear water, containing only 1.5–4% of the original mean silt load is now discharged downstream. The consequence of this is the loss in fertility to agricultural lands, the reduction in primary production in the Delta Estuarine region, increased coastal erosion, and an increased salinity in lakes, such as Lake Quarun.

The Nile Delta represents one of the largest floodplains in Africa which, prior to the Aswan High Dam, was almost entirely swamp, transformed into a lake at times of flooding. Following river control, only waterways and drainage channels are now under water.

There are a large number of oases in Egypt deriving water from artesian sources (Fig. 2, Table 1). SIS (1983b) mentions groundwater reserves in the Delta and Upper Egypt estimated at 2 billion m3. In addition, the New Valley underground reservoir of 150 000 km2 contains 6 billion m3. Further explorations are currently underway in the Delta, Upper Egypt, the Eastern Desert and the Sinai Peninsula.

Hefny (1982) mentions that topographical water-collecting basins occur on the western side of the Nile Delta (e.g. Wadi El Natrun and Qattara Depressions), while on the eastern side there are water-discharging basins (e.g. Wadi El Tumilat).

FAO (1974) attributed groundwater supplies to: (a) infiltration of Nile water; (b) storage in Nubian sandstones of the Western Desert; and (c) shallow infiltration of rain water, a total annual potential of 4 500 million m3.

2.3 Reservoirs

The Aswan Dam retains a large body of water, the Nasser/Nubia Reservoir, which covers 6 850 km2 at a level of 183 m (5 811 km2 in Egypt). Closed in 1965, it began to reach capacity in 1976 and is now the largest single source of fresh water for the whole of Egypt. (See Fig. 5, p. 49.)

Fig. 1
  1. Eastern Desert

  2. Western Desert

  3. Nile Valley and Delta
    3A Northern Littoral Region
    3B The Delta
    3C Middle Egypt (High population density zone)
    3D Upper Egypt

Fig. 1. MAJOR NATURAL REGIONS OF EGYPT
(Balarin, 1986)

Fig. 2

(Numbers refer to Table 1)

Fig. 2. MAJOR WATER BODIES AND OASES IN EGYPT
(Balarin, 1986)

Table 1. MORPHOLOGICAL DATA FOR MAJOR LAKES AND DEPRESSIONS
(modified, after Balarin, 1986)

Nos. refer to Fig.2Name
(date constructed)
Basin/District
DescriptionFishery Potential
(t/yr)
Use
e
Salinity
(ppt)
()
Water temp.
(°C)
Area
(km2)
Altitude
(m)
Mean depth
(m)
Natural Brackish Water Lakes
1.L.ManzalahDelta9000–0.61.131 000–75 000f  2–1519.4–26.8
2.L.BurullusDelta472–5600–0.61.07 000–43 000f16–1915.8–27.2
3.L.EdkuDelta1300–0.6  0.754 000f  5–1514.5–28.5
4.L.MariutAlexandria27.3-30.911 000–15 000f5–812.7–29.0
Natural Saline Lakes
5.Port Fouad depr.E.Suez96–20000.7–12600f  
6.Bardawil depr.N.Sinai600–7260     63 000f40–5512.7–30.5
Artificial Brackish Water Lake
7.L.QuarunW.Desert220-453.5–82 000f     3415–30
Artificial Freshwater Lakes
8L.Nasser (1964) 2 500–5 2501832530 000–35 000i,w,p,f        016–32
9.Wadi Natrum        
10.El Faiyum Oasis        
11.Qattara depression        
12.Siwa Oasis        
13.Bahariya Oasis        
14.Farafra Oasis        
15.Dakhla Oasis        
16.Kharga Oasis        
17.Amer        
18.Ruwayan        
19.Nozha HydrodromeAlexandria4.8-3.63 f 15.5–27.5

Key: c=commercial/industrial;
f=fishery
i=irrigation
p=power generation;
w=water supply.
Data sources: see text (directory)

2.4 Coastal Lagoons (see Fig. 3)

Egypt has an extensive surface area of coastal lagoons (circa 2 500 km2); the largest are Manzalah (900 km2), Bardawil (726 km2), and Burullus (560 km2).

The most characteristic of Egyptian lagoons are found in the Delta Region. Lagoons Manzalah, Burullus and Edku are similar in that they are permanently, or for at least a number of months in the year, connected to the open sea by a natural narrow channel. Mariut Lagoon, on the contrary, is permanently cut off from the sea by the Mex pumping station, its surface level being maintained at up to 3 m below sea level. All these lagoons are shallow (less than 1 m deep), fluctuating seasonally and varying in salinity from 9.5 to 28.5 .

Bardawil Lagoon and Port Fouad are depressions which are supplied by sea water through an artificial sea link. They are therefore artificial lagoons and are deeper than 5 m, their salinity varying from brackish to sea water strength. Most of these Delta lagoons receive a discharge of irrigation drainage water.

Fig. 3

Fig. 3. NILE DELTA LAGOONS
(Lemoalle, 1987)

2.5 Aquaculture

Aquaculture development in Egypt has taken many forms, ranging from lake stocking to fish production in hatcheries, howashs, ponds, enclosures, cages and tank systems. In view of the diverse nature of the industry and the problem of classification of certain forms of production, either as fishery or as fish farming, accurate statistics are difficult to obtain. The status of aquaculture was recently reviewed by Sadek (1984) and by Balarin (1986). The total area specially devoted to aquaculture in 1982 was estimated as follows:

private fish farms25 118 ha
government fish farms (intensive)5 330 ha
howash48 845 ha

The “howash”, or drain-in ponds, are low-lying areas enclosed by small earthen dykes. They fill when the water level rises, and the entrapped fish are harvested as the water level drops.

(For more detailed information on aquaculture, see Balarin, 1986.)

3. FISHERY PRODUCTION/POTENTIAL

3.1 Fish production and per caput supply

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

 Nominal Domestic Production
(including exports)
(t) 2
Nominal Consumer Supply
(excluding imports & exports)
(kg/person)
YearPopulation
'000
1
Inland captureAquaculture
3
Marine capture
6
TotalInland captureAquaculture
3
Marine captureTotal
197033 05353 700- 427 200  80 9001.6- 40.82.4
197133 67653 200-34 400  87 6001.6-1.02.6
197234 31155 000-38 800  93 8001.6-1.12.7
197334 95865 700-27 800  93 5001.9-0.82.7
197435 61768 700-27 465  96 1651.9-0.82.7
197536 28980 664-25 910106 5742.2-0.72.9
197637 28072 276-30 488102 7641.9-0.82.7
197738 29774 959-29 582104 5411.9-0.82.7
197839 34379 005-20 91099 9152.0-0.52.5
197940 417100 000  -37 480137 4802.5-0.93.4
198041 520108 148  -32 249140 3972.6-0.83.4
198142 546108 146  -33 564141 7102.5-0.83.3
198243 597112 614  18 520 524 594155 7282.60.40.63.6
198344 674106 856  24 000 526 446157 3022.40.50.63.5
198445 778116 130  25 000 522 708163 8382.50.50.53.5
198546 909130 757  47 346 537 817215 9202.81.00.84.6
198647 984140 036  50 000 539 042229 0782.91.00.84.7
198749 084141 700  60 000 548 300250 0002.91.21.05.1

1 Source: FAO
2 Source: FAO Fisheries Department FISHDAB
3 included in “Inland capture” if not specified.
4 - = data not available.
5 Fresh and brackishwater (Vincke, 1989, pers.comm.).
6 Marine exports from 1980 to 1983 were as follows: 1980: 278 t; 1981: 275 t; 1982: 384 t; 1983: 300 t.

Alternative data, presenting a compilation of several authors, done by Balarin (1986) are given in Table 3.

Table 3. NATIONAL FISH PRODUCTION AND CONSUMPTION (excluding aquaculture)
(Balarin, 1986)

 Production (t × 103/yr)Import
(t × 103/yr)
d
Export
(t×103/yr)
d
Consumption
YearInland
h
Marine
h
Total
d
(t × 103/yr)Pop (× 103)kg/ind/yr
cd
196344.6j– 62.8 65.0109.4j–127.86.52.4131.9–137.027.55.04.80
196446.3j– 76.144.4–51.4  98.2j–127.52.32.0127.8–144.028.35.14.52
196545.5j– 64.642.0  87.3j–106.6 9.9g–13.31.1g–2.4117.6–155.029.05.34.05
196641.5j– 61.337.679.2j–98.9 6.7–23.9g1.4101.0–104.229.73.43.51
196749.4j– 69.625.875.5j–95.418.5g–26.71.1g–1.6106.0–120.530.53.53.95
196838.9j– 58.5    3.4–16.5g55.5j–75.1 5.9g–12.90.7 87.5– 97.031.33.12.76
1969  40.5j– 60.5g    7.2–27.6g65.8j–89.32.2–4.6g 0.577.0–91.032.12.42.83
1970  39.4j– 60.0a   9.0–21.256-2j–81.22.0–2.7g 0.373.0–82.933.02.22.51
197140.1j– 61.6  11.0–30.1g70.2j–88.6  1.80.189.0–90.334.22.62.64
1972  42.7j– 64.0g  11.5–37.0g  81.5j–101.2  2.50.2  98.3–103.034.83.02.82
197351.5j– 71.8    7.9–27.9g78.6j–97.213.20.2  98.0–110.235.62.73.10
197463.7j– 84.3  15.1–27.7g 91.5j–110.019.10.1115.0–129.036.43.23.54
197571.1j– 89.615.0–28.0 94.5j–122.028.0–32.50.2117.0–149.937.23.1–3.34.03
1976  76.7j– 81.4d  16.0–30.2g106.6–109.0  27.0–55.50.2164.3–185.036.6–38.2  4.754.30
1977  83.5j– 87.5d  15.8–38.1g 104.5b–121.637.0–49.40.3–0.4b145.7–153.539.34.03.70
1978  79.0 – 91.4d  20.6–34.1g 99.9–125.466.50.1178.739.94.45
1979    96.5d – 100.5  39.5–43.6g104.1–165.033.9–60.0j0.4173.6–225.0j41.04.23–5.5
1980  94.7d35.6g130.326.40.3156.442.13.73
1981100.2d   28.0g–37.0g137.372.5       0.2(54)f209.643.04.88
1982101.0d49.0d150.1–160.089.40.1239.444.05.44
 (217)d    (355.3)d  (8.08)

Sources:
a Welcomme, 1979
b FAO, 1980
c Feidi, 1976
d Sadek, 1984
e CAPMS, 1982
f SIS, 1983b
g FAO, 1974
h Saad, 1982
i Ishak/Hamza, 1983
j Atkins Land & Water Mgmt., 1979.

3.2 Inland catch range and potential yield

Table 4. INLAND CATCH RANGE AND POTENTIAL YIELD

Water bodyPeriodAnnual catch range (t)Potential annual yield (t)
Lake Quarun1975–761 513; 2 000–3 000 b2 000–3 000 b
decreasing a
Lake Wadi Rayan1982200-
Nile River and irrigation canals1970–79
1976
7 500–9 000
15 000 b
8 000 e–20 000 c
15 000 b
Nasser Reservoir1980–81
1976
30 316–33 933
10 000–16 000 b
30 000 c–35 000 g
10 000–16 000 b
Lagoons   
 Bardawil1967; 1977; 1981–822 493–2 6583 500 c
 Burullus1962–70; 1975–76; 19828 128–43 01515 000–43 000 c
 Edku1972; 1975–76; 19824 008–7 7704 000 c
 Manzalah1907–35; 1957–80; 1982
1976
8 496–63 330
21 000 b
31 000 d–75 000 c
 Mariut1972; 1975–76; 1982
1976
22 000–58 200
38 000 b
11 000–15 000 d
 Port Fouad1976; 1982150–300600 c
 Um El Rish19792 267 
 No data available for:
 Alamain and Matrooh, Great Bitter, Little Bitter, Nozha Hydrodrome, and Timsah Lagoons
Other Lakes and Lagoons 2 000–3 000 b2 000–3 000 b
Aquaculture1982–198718 520–60 000 f24 000 c
   over 60 000 f

Sources:
a Ferlin, 1980
b Welcomme, 1979
c Sadek, 1984
d Balarin, 1986
e Latif, 1984
f Vincke, 1989 (pers.comm.)
g Entz, 1984

Total annual yield
in 1976: 72 800–80 000 t b
in 1987, including aquaculture: 200 000 t (Table 2)

Potential annual yield
126 000–277 000 t (Table 4).

4. STATE OF THE FISHERY

(Adapted and updated from Welcomme, 1979;
Balarin, 1986; Latif, 1984; and Entz, 1984)

4.1 Yield

Although there is a long recorded statistical history of fishery resources, Table 3 shows that there is some discrepancy in the records. Sadek (1984), in an analysis of the situation in 1982, presents official inland water statistics as amounting to 101 618 t, of which 81 618 t are from lakes and 20 000 t from the Nile and its canals. However, also presented are statistics of various studies conducted on the lakes which suggest that production in 1982 stood at 173 100 t, over twice that of the official records. Adding the marine catch (49 000 t) and aquaculture production (24 000 t), this gives a national estimate of 266 100 t — nearly 77% higher than that presented in Table 3. In addition, nearly 90 000 t of fish were imported in 1982 and it is possible, therefore, that fish consumption may lie between 5.4 and 8.1 kg/cap/yr.

In 1982 inland fisheries produced over 67.5% of the fish landed, over 54.2% coming from the lake fisheries. However, the diverse and dispersed nature of the inland fishery means that the activities of the numerous fishermen cannot be fully monitored.

Accurate estimates of catches in the Nile River fisheries are incomplete, due to the dispersed nature of the fishery represented by 93 000 ha of irrigation waterways and up to 12 000 km2 of river area. Recent catch estimates indicate a stable condition of 20 000 t/yr since 1976 (Sadek, 1984). This implies that accurate statistics are not available. Earlier estimates of potential varied between 8 000 and 15 000 t/yr (Table 4).

In the Nasser Reservoir there has been a near linear increase in fish production from 15 kg/ha/yr in 1968 to over 50 kg/ha/yr in 1978. This represents an increase in total production from 750 t in 1976 to 34 000 t/yr in 1981.

Earlier (1973) estimates of M.S.Y. based on MEF of 19 000 t/yr for the Nasser Reservoir have been surpassed with little indication of overfishing. The yield potential is now considered to lie between 30 000 and 35 000 t/yr.

Lake Quarun, although now a minor fishery, was once estimated by Welcomme (1972) to have a potential M.S.Y. of 10 000 t/yr. Originally a freshwater lake, it has now become saline (34 salinity in 1976). This change in salinity has resulted in the disparition of the freshwater species, except for some tilapia. Production dropped from 4 000 t in 1920 to 2 000 t/yr.

The lagoons form one of the main Egyptian fisheries with a potential of 143 000 t/yr (Sadek, 1984). Yields vary from 1 400 kg/ha/yr (for Mariut), to 250 kg/ha/yr (for Manzalah), to a low of 37–45 kg/ha/yr (for Edku, Port Fouad and Bardawil). Estimates are quite variable, however, and no accurate statistics have yet been advanced.

Recently the status of aquaculture in Egypt was reviewed by Sadek (1984) and a total estimate for 1982 was given as 24 000 t. Nearly 30 550 ha of ponds are included, with an average yield of 786 kg/ha/yr. Status of the howash, however, is uncertain. Certainly extensive aquaculture practices to increase yields of Lakes Quarun, Mariut, Edku and Nozha Hydrodome are possibly not included. This may well be represented by the estimate of Ishak (pers.comm.) of 6 000 t/yr.

Aquaculture production (t) from 1982 to 1987 has been estimated as follows by Vincke (1989, pers.comm.):

Species198219831984198519861987
Osteichthyes18 52024 00025 00047 34650 00060 000
(fresh and brackish water)

4.2 Factors influencing yield

It is likely that the present yield is approaching M.S.Y. although no allowance appears to have been made for loss in productivity due to the reduced silt load created by the Aswan High Dam.

The closure of the Aswan High Dam gave rise to a 7 000 km2 lake. It has had far-reaching implications on the decline of the Mediterranean fishery. Loss of nutrients due to the reduced silt load and, in particular, loss of planktomic food organisms which bloomed when the Nile flooded, have resulted in a drastic decline in sardine populations which used to gather in the delta at the time of floods.

Another effect of the Aswan High Dam is the increase in salinity in Lake Quarun. If the increase in salinity continues, Ferlin (1980) estimates that by the year 2000 the salinity will reach 50 ppt and it is feared that all fish life may disappear.

The coastal lagoons are extremely productive, but unfortunately have been filled in to some degree for agriculture. An extension of such land reclamation, together with the cessation of inflow of fresh waters after the closing of the Aswan Dam, may affect production. Pollution by domestic sewage and agro-chemicals is also a real problem in the delta area.

4.3 Future development possibilities

The reclamation of land around the lagoons, the extension of irrigation, the lower flow of the Nile and the increasing effects of the Aswan High Dam will probably all contribute to a diminution of fish catch from this more northerly part of the system. This may be offset to a certain degree by coastal aquaculture in the lagoons. The potential of Nasser/Nubia Reservoir is relatively high but it seems that the production from natural waters is already close to it. This is indicated by the smaller-sized fishes in current landings than in landings from earlier years. However, production of young fish in some Khors and the introduction of clupeids could increase the Nasser/Nubia Reservoir's potential.

5. KEY BIBLIOGRAPHY

General: Balarin, 1986
Delta Lagoons: Lemoalle, 1987
Nasser/Nubia Reservoir: Entz, 1984; Latif, 1984.

6. WATER BODIES DIRECTORY

Lakes
QuarunZeitun/Am Abd Et Gabbar Complex
Wadi Rayan 
 
Rivers/Reservoirs
Nile RiverNasser/Nubia Reservoir
 
Lagoons
Alamain and MatroohGreat BitterNozha Hydrodrome
BardawilLittle BitterPort Fouad (=El-Mallaha)
BurullusManzalahTimsah
EdkuMariutUm El Rish

LAKE QUARUN

Geographical data(Welcomme, 1972; Lemoalle, 1987)
Location:Egypt - 29° 29'N; 30° 35'E
Altitude:-45 m
Surface area:c. 235 km2
Length:40 km
Width:max. 9.25 km;
Depth:8 m (max); 3.5 m (mean)
Inflow:irrigation drainage water; average 390 × 103m3/yr
Outflow:none - internal basin
 
Physical and chemical data (Lemoalle, 1987)
Surface temperature:15–16°C in January
 28–30°C in August
pH:always c. 8
Salinity:13.4 in 1901
 30.6 in 1953–55
 30.9 in 1974
 34.5 in 1976
 Originally a freshwater lake, this process of salinization has been accelerated since the closure of the Aswan High Dam.
Ionic composition: 
 NO3: 40–50 μg/l
 PO4: 0–0.7 μg/l
Fisheries data 
 The freshwater fauna has virtually disappeared and the lake has since been stocked with a variety of brackishwater species.
Main fish species: 
 Tilapia zillii, Mugil cephalus, M. capito and Solea vulgaris - all introduced in 1928. Their fry are restocked into the lake  each year. (Lemoalle, 1987)
No. of fishermen:6 540 (Shaheen et al., 1980)
No. of boats:550 in 1976 (Ferlin, 1980)
Total annual catch: 
 2 000 t (1982); 1 660 t (1976); 1 513 t (1975); 4 000 (1920)
 2 000–3 000 t (Welcomme, 1979)
Potential annual yield:
 1 760 to 1 880 t/yr (80 kg/ha/yr) (Sadek, 1984).

LAKE WADI RAYAN

Geographical data 
Location:Egypt - 29° 15'N; 30° 29'E
Area:142 km2
  
Fisheries data 
Total annual catch:200 t (1982)

ZEITUN/AM ABD ET GABBAR LAKE COMPLEX

Geographical data 
Location:Egypt - 29° 12'N; 25° 28'E
Special features:a complex of 17 small saline lakes centered around the Siwa Oasis.

NILE RIVER
(International water)

Geographical data (Welcomme, 1979, if not otherwise specified)
Source:confluence of White Nile and Blue Nile at Khartoum
Total length:3 800 km from Khartoum to mouth. The longest continuous stream measures 6 669 km: Nile, White Nile, Lake Victoria, Kagera  River and Akanyaru River. 1 300 km in Egypt. (See Fig. 4)
Drainage area:2 944 000 km2 (Welcomme, 1985); 2 000 000 km2 (Balarin, 1986)
Area of water:1 160 km2 (in Egypt downstream from Aswan High Dam)
Countries traversed: 
 Egypt, Sudan; the Nile Basin also extends into Burundi, Ethiopia, Kenya, Rwanda, Tanzania and Uganda
Major tributaries:
 Atbara, Blue Nile, White Nile (= Bahr El Jebel + Sobat)
Contribution of tributaries to total Nile flow: 
  Average (%)During flood (%)
 Blue Nile5968
 White Nile  
 Sobat1422
  Bahr El Jebel14  5
 Atbara13  5
Discharges to:Mediterranean Sea through a delta consisting of the Damietta and Rosetta arms
Volume of discharge at mouth:
 2 832 m3/sec;
 45 to 150 109 m3/yr (Hefny, 1982) (See Fig. 5)
Suspended silt load: 
 124 × 106 t/yr (Welcomme, 1985);
 134 × 106 t/yr (Hefny, 1982), deposited in Nasser/Nubia Reserv.;
 only 1.5–4% discharged downstream (Balarin, 1986)
Special features:the cataracts, Nasser/Nubia Reservoir (Aswan High Dam).

Fig .4

Fig. 4. RIVERS AND LAKES OF THE NILE SYSTEM
(Welcomme, 1972)

Fisheries data

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

YearTotal catch
(t)
No.of boats
Egyptian waters below Aswan High Dam:
19631 2001 049
19641 1001 100
19651 6001 300
19662 0001 320
19672 9001 500
19684 4001 900
19694 8001 950
19708 9002 029
19718 9002 069
19728 7002 313
19738 0002 640
19747 5003 440
19758 6003 894
19768 6004 421
19777 6004 948
19788 3005 475
19799 0006 002
Nile, irrigation canals and aquaculture (Welcomme, 1979):
197615 000  -

Potential annual yield:
20 000 t/yr (Sadek, 1984)
225 kg/ha/yr (Sadek, 1984)

Fig 5

Fig. 5. ANNUAL FLOW REGIME OF THE NILE RIVER, 1956–1980
(Balarin, 1986)

NASSER/NUBIA RESERVOIR
(International water)

(See detailed ref. in Entz, 1984)

Geographical data (see Fig. 6)
Location:Egypt (Nasser); Sudan (Nubia) - 20° 27'–23° 58'N; 30° 35'–33° 15'E
Altitude:183 m at USL; 170–175 m mean
Dam height:111 m
Date closed:May 1964; working lake level reached Sept. 1979
Surface area:6 850 km2 at USL
 6 216 km2 at 180 m lake level (5 072 km2 in Egypt; 1 144 km2 in Sudan)
 3 057 km2 at 160 m lake level (2 497 km2 in Egypt; 560 km2 in Sudan)
Depth:meanat 180 m lake level:25.2 m
  at 160 m lake level:21.6 m
 max. at 180 m lake level: 130 m
  at 160 m lake level: 110 m
Volume:meanat 180 m lake level:65.9 km3
  (55.6 km3 in Egypt; 10.3 km3 in Sudan)
 max. at 180 m lake level:156.9 km3
  (132.4 km3 in Egypt; 24.5 km3 in Sudan)
Length:max. at 180 m lake level:   496 km
 mean at 160 m lake level:   430 km
Width:max. at 180 m lake level:  60.0 km
 mean at 180 m lake level:  12.5 km (total lake)
    18.5 km (only Nasser)
 meanat 160 m lake level:    7.5 km (total lake)
      8.9 km (only Nasser)
Shoreline:at 180 m lake level:9 250 km
 at 160 m lake level:6 027 km
Annual fluctuation in level: 7–10 m
Catchment area above High Dam: 2 400 000 km2
Mean inflow:84.0 km3/yr; 2 662 m3/sec
Suspended solids:1–10 mg/l (low water); 2–10 g/l (flood); inflow: 134 × 106 t/yr
Displacement time:2 years
Major inflowing river:Nile
Outflowing river:Nile
Specific references:Ali, 1984; Entz, 1984; Latif, 1984; Marshall, 1984.
   
Physical and chemical data
Surface temperature:
 16–32°C (23.9°C mean); 16–18°C during winter period
Conductivity:190–300 μS/cm; 260 μS/cm; (210–230 μS/cm mean)
Dissolved solids:175–200 mg/l (185 mean)
pH:6.8–9.0; 7.1–9.4
Oxygen:winter: 6.7–11 (surface); 5.4–8.7 (bottom)
 summer: 4.9–10 (surface); 0 (bottom)
Ionic composition:         mg/l 
 Na    8.2–27.8 
 K    1.9–8.0 
 Ca  14.3–27.5 
 Mg    4.5–12.5 
 HCO3     70–160 
 Cl  2.96–9.83 
 SO4       5–10.8 
 SiO212.45–17.18 
 NO3  
    surf.0.001–1.25 
    bottom  0.04–1.27 
 PO4-P  0.10–0.17 

Fig. 6

Fig. 6. NASSER/NUBIA RESERVOIR
(FAO/UNDP, 1975)

Table 5. LIST OF FISH SPECIES FOR NASSER/NUBIA RESERVOIR
(adapted from Latif, 1984 and Ali, 1984)

 FamilySpeciesNasser aNubia b
1.PROTOPTERIDAEProtopterus aethiopicus++
2.POLYPTERIDAEPolypterus bichir++
  P. spp. +
3.MORMYRIDAEMormyrops anguilloidos++
  Petrocephalus bane++
  Marcusenius isidori++
  M. spp. +
  Gnathonemus cyprinoides++
  Mormyrus kannume++
  M. caschive++
  Hyperopisus bebe++
4.GYMNARCHIDAEGymnarchus niloticus+ 
5.CHARACIDAEHydrocynus forskalii++
  H. lineatus+ 
  H. brevis+ 
  Alestes nurse++
  A. baremose++
  A. dentex++
6.DISTICHODONTIDAEDistichodus niloticus++
  D. rostratus +
  D. engycephalus +
7.CITHARINIDAECitharinus citharus++
  C. latus+ 
8.CYPRINIDAEChelaethiops bibie+ 
  Raiamas niloticus+ 
  R. loati+ 
  Labeo forskalii+ 
  L. niloticus++
  L. coubie++
  L. horie++
  Discognathus vinciguerrae+ 
  Barbus werneri+ 
  B. perince+ 
  B. neglectus+ 
  B. anema+ 
  B. bynni +
9.CLARIDAEClarias anguillaris++
  C. Lazera++
  Heterobranchus bidorsalie +
10.SCHILBEIDAEEutropius niloticus++
  Schilbe mystus++
  S. uranoscopus +
  Siluranodon auritus+ 
11.BAGRIDAEBagrus bayad++
  B. docmac++
  Chrysichthys auratus++
  C. rueppelli+ 
  Clarotes laticeps++
  Auchenoglanis biscutatus+ 
  A. occidentalis++
  A. spp. +
12.MOCHOKIDAESynodontis schall++
  S. serratus++
  S. clarias+ 
  S. batensoda +
  S. khartoumensis +
  Mochocus niloticus+ 
  Chiloglanis niloticus+ 
13.MALAPTERURIDAEMalapterurus electricus++
14.CICHLIDAEOreochromis niloticus++
  O. galilaea++
15.CENTROPOMIDAELates niloticus++
16.TETRODONTIDAETetraodon fahaka++
17.OSTEOGLOSSIDAEHeterotis niloticus +
   5343

a Latif, 1984
b Ali, 1984 (Note: Nubia data are for 1967–1979)

Fisheries data

No. of fish species:
In Nasser Reservoir:
53 in 16 families (Latif, 1984). See list, Table 4. Oreochromis niloticus and O. galilaea are the major fish landed, comprising 95% (1978) of the total fresh, and 75% (1978) of the total salted fish landed (Latif, 1984).
In Nubia Reservoir:
43 in 16 families (Ali, 1984). See list, Table 4.

Total annual catch and effort:

YearTotal catch
(t)
No.of fishermen
(Nasser only)
No.of boats
(Nasser only)
NasserNubia
1964    500   
1966    749    600200
1967  1 415 1 050350
1968  2 663 1 500500
1969  4 071 1 815599
1970  5 6181982 466816
1971  6 7161443 8221 039   
1972  8 5452284 5401 135   
197310 693424--
197412 257268--
197514 725295--
197615 971285-2 000   
197718 406249--
197822 5872045 9641 962   
197926 995355--
198030 316628--
198133 933625--
1982- 9 000-

Potential annual yield:

Nasser Reservoir:
earlier estimates based on MEI: 19 000 t/yr
30 000 t/yr (Sadek, 1984)
35 000 t/yr in 1982 (Entz, 1984)
30 kg/ha/yr (Sadek, 1984)
78 kg/ha/yr (Entz, 1984)

Nubia Reservoir:
5 000 t/yr (Ali, 1984)
5 100 t/yr (51 kg/ha/yr) (Henderson, 1975)

ALAMAIN AND MATROOH LAGOONS

Geographical data 
Location:Egypt
Area:14.6 km2
 
Fisheries data 
Total annual catch: no commercial exploitations

BARDAWIL LAGOON

Geographical data 
Location:Egypt- 31° 2'–31° 13'N; 32° 40'–33° 29' E
Altitude:0 m
Area:600–726 km2
Max. length:78 km
Max. width:20 km
Mean depth:6 m
 
Physical and chemical data (Pisanty, 1981)
Temperature:12.7–30.5 °C
Salinity:40–55
  
Fisheries data 
No. of fish species: 65

Total annual catch and effort:

YearTotal catch
(t)
No.of fishermenNo.of boats
19642 200--
19651 700--
19661 800--
19672 600--
1968–76---
19772 658--
1978–80---
19812 493--
19822 5282 280922
not specified-1 135                      399 (Balarin, 1986)

Potential annual yield:3 000 t/yr (Pisanty, 1981)
 3 500 t/yr (Sadek, 1984)
      41 kg/ha/yr (Sadek, 1984)

Fig. 7

Fig. 7. BURULLUS (BROLLUS) LAGOON
(Lemoalle, 1987)

BURULLUS (or Brollus) LAGOON

Geographical data (see Fig. 7)
(* data cited in Lemoalle, 1987)
Location:Egypt - 31°23'–35'N; 30° 33'–31° 8'E
Altitude:0–0.6 m as ½
Surface area:472–560 km2 (Balarin, 1986)
Depth:*0.7–2.4 m; mean: 1.0 m
Max. length:57 km
Max. width:14 km
Inflow:*drainage water via 7 drains, plus freshwater from Nile-Rosetta branch and underground water.
Outflow:*narrow channel to the sea. Exchange of water also occurs between the lagoon and the sea through that channel.
  
Physical and chemical data
Salinity:16–19
Surface temperature:*11°C (Feb.) – 29.5°C (Aug.)
pH:*8.08–8.72
O2:*2.7–11.8 mg/l
Ionic composition:Cl = 0.36–13.5 g/l
 
Fisheries data
No. of boats:2 980 in 1976; 3 000 (Ferlin, 1980)
No. of fishermen:8 500 (Shaheen, et al., 1980)
Total annual catch:   
 YearTotal catch (t) 
 1962  8 128 
 1963  8 756 
 196410 234 
 196510 525 
 196615 253 
 196713 515 
 196812 898 
 196910 429 
 197010 218 
 1971–74- 
 197512 178 
 197610 540 
 1977–81- 
 198243 015 
    
Potential annual yield:   
 7 000–15 000 t/yr (Balarin, 1986)
250 kg/ha/yr (Balarin, 1986)
43 000 t/yr (Sadek, 1984)
150 kg/ha/yr (Sadek, 1984) 

EDKU LAGOON

Geographical data (see Fig. 8)
(*data cited in Lemoalle, 1987)
Location:Egypt - 31° 15'N 30° 13'E
Altitude:0–0.6 m asl
Surface area:130 km2
Depth:*0.5–1.5 m; mean: 0.75 m
Inflow:*drainage water; sea water inflow during winter
Outflow:*El Maadiah channel to the sea.
 
Physical and chemical data
Salinity:5–15
For 1969–1970:
Surface temperature: 14.5C (Jan.) to 28.5C (Aug.) (Lemoalle, 1987)
pH:7.63–9.50
Ionic composition: (controlled by drainage and sea water influx)
 Cl0.44–23.24 g/l
 PO4-P     9–840   μ/l
 NO2  4.9–204   μ/l
 SiO2  0.6–7.5    μ/l
 Alkalinity: 183–235 mg/l

Fig. 8

Fig. 8. EDKU LAGOON
(Lemoalle, 1987)

Fisheries data  
Fish species:main catches in 1982:(Lemoalle, 1987)
 “tilapias”82%
 Anguilla anguilla10%
 Mugil sp.  6%
Total annual catch and effort:

YearTotal catch
(t)
No.of fishermenNo.of boats
19725 800--
1973–74---
19754 008--
19764 1603 0001 660
1977–81---
19827 770--
not specified-  4 030*    1 650**

* (Shaheen, et al., 1980)
** (Ferlin, 1980)

Potential annual yield: (Sadek, 1984)
4 000 t/yr
     45 kg/ha/yr

GREAT BITTER LAGOON

Geographical data 
Location:Egypt - 30° 26'N; 32° 23'E
Surface area:180 km2
Max. length:22 km
Max. width:11.5 km
Inflow/Outflow:Suez Canal in the north. Connected to Little Bitter Lagoon in the south.

LITTLE BITTER LAGOON

Geographical data 
Location:Egypt - 30° 14'N; 32° 32'E
Surface area:42 km2
Max. length:15 km
Max. width:4 km
Inflow/Outflow:Suez Canal in the south. Connected to Great Bitter Lagoon in the north.

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