PART II - SYNTHESES OF INFORMATION ON SELECTED AFRICAN RESERVOIRS (continued)

PARTIE II - SYNTHESES DE L'INFORMATION SUR CERTAINS RESERVOIRS AFRICAINS (continuer)

KARIBA (ZIMBABWE/ZAMBIA) (continued)

Table 1. List of fish recorded from the Middle Zambezi area (from Jackson, 1961). Some names have been changed in accordance with recent systematic approaches (e.g., Jackson, 1975; Trewavas, 1980; Skelton et al., 1980)

Adults > 18 cm length	Adults < 18 cm length
Anguilla nebulosa labiata	Alestes imberi
Protopterus annectens	Micralestes acutidens
Mormyrus longirostris	Barbus barotseensis¹
M. deliciosus	B. fasciatus
Hippopotamyrus discorhynchus	Opsaridium zambezense
Hydrocynus vittatus	Chiloglanis neumanni
Distichodus mossambicus	Aplocheilichthys jonhstonii
D. schenga	Pharyngochromis darlingi
Labeo altivelis
L. congoro
Barbus marequensis
Eutropius depressirostris
Synodontis zambezensis
S. nebulosus (?)
Clarias gariepinus
Heterobranchus longifilis
Malapterurus electricus
Oreochromis mortimeri
Tilapia rendalli
Serranochromis codringtoni

¹ This is an Upper Zambezi species which has never since been found in Kariba. Original specimens were probably misidentified.

Table 2. Main morphometric features of major African lakes. Data from Welcomme (1982), Balon and Coche (1974), Bernacsek and Lopes (in press), Bowmaker et al. (1978) and Marshall et al. (1982)

	Kariba	Cahora Bassa	Nasser/Nubia	Volta	Kainji	Kossou
Length (km)	320	246	482	400	137	180
Width, mean (km)	19.4	10.8	13.0	6.8	9.3	8.9
Width, maximum (km)	40	40	20	24	24
Depth, mean (m)	29.2	20.9	25	18.6	12.3	18.4
Depth, maximum (m)	120	156	130	75	50	54
Shoreline length (km)	2 164	1 775	8 804	4 828	720	3 500
Shoreline development	8.3	9.7	31.2	14.5	5.7	24.7
Area (km²)	5 364	2 665	6 276	8 845	1 280	1 600
Volume (km³)	156.5	55.8	158	165	15.8	29.5
Approx. outflow: Volume ratio	1:3	2:1	1:2	1:4	4:1	1:5

Table 3. Average annual water budget for Kariba (1975/76–1979/80). Data from Central African Power Corporation (From Marshall et al., 1982)

			km³	%
Gains:	Rainfall on lake surface		5.0	7.6
	Inflows	- Zambezi R. (Livingstone)	51.7	78.4
		-Secondary rivers	9.2	14.0
	Total		65.9
Losses:	Gross evaporation		8.6	13.2
	Outflows	- Turbines	27.6	42.3
		- Spillage	29.0	44.5
	Total		65.2

Theoretical Replacement Time (Volume: Inflow) 2.4 yrs

Table 4. The potential fish yield from some African man-made lakes using the MEI relationship (from Marshall, 1982)

	MEI	Yield (kg/ha^-1yr^-1)
Volta (Ghana)¹	6.1	32.77
Nasser-Nubia (Egypt & Sudan)¹	9.2	40.4
Kainji (Nigeria)¹	6.6	34.6
Kariba (Zimbabwe & Zambia)²	2.8	23.2
Mwenje (Zimbabwe)³	10.0	42.1
Darwendale (Zimbabwe)⁴	16.8	53.6
McIlwaine (Zimbabwe)³	17.1	54.1
Claw (Zimbabwe)⁴	17.2	54.2
Mazoe (Zimbabwe)³	34.6	75.2

Sources: 1 Henderson and Welcomme (1974)
2 Marshall et al. (1982)
3 Mitchell and Marshall (1975)
4 Thornton (1980)

Table 5. Average ionic composition of Lake Kariba surface water compared to average African and World fresh waters (from Coche, 1974)

Ion	Lake Kariba 1965 average		World fresh waters average		African fresh water average		East and West African lakes and rivers
Ion	meq.L^-1	%	meq.L^-1	%	meq.L^-1	mg.L^-1	meq.L^-1	%	mg.L^-1
Calcium	0.465	57	1.49	64	0.624	12.5	0.324	29	6.5
Magnesium	0.160	20	0.42	17	0.313	3.8	0.239	21	2.9
Sodium	0.153	18	0.36	16	0.479	11.0	0.392	34	9.0
Potassium	0.042	5	0.08	3	?	?	0.182	16	7.1
Total cations	0.820	100	2.35	100	-	-	1.137	100	25.5
Fixed CO₂	0.756	89	1.71	74	?	?	(0.725)	(64)	(21.8)
SO₄	(0.062)	(7)	0.37	16	0.281	13.5	0.229	(20)	11.0
Cl	(0.028)	(3)	0.23	10	0.341	12.1	0.183	(16)	6.5
Salinity	1.67	-	4.66	-	(4.5)	-	(2.27)	(100)	(39.3)
SiO₂	12.3 mg/L		17.1 mg/L		-	23.2	-	-	15.5
Reference	Pers.data		Gorham, 1957		Livingstone, 1963		Visser cited in Imevbore, 1970

Table 7. Provisional chemical budget for Lake Kariba.
(From Coche, 1974)

			t × 1 000
Imports	- Zambezi River		1 695
	- Secondary Rivers		419
	- Rainfall		42
		TOTAL	2 156
Exports	- outflow		2 346

Table 6. Water quality of some African rivers, major inflows for lakes and rservoirs (from Coche, 1974)

River	Range temp. °C	Spec. cond. at 20°C micromhos	Salinity mg L^-1	Cations, mg L^-1				Anions, mg L^-1
River	Range temp. °C	Spec. cond. at 20°C micromhos	Salinity mg L^-1	Ca	Mg	Na	K	HCO₂+CO₃	Cl	SO₄
Zambezi (L. Kariba)	17–30	36–121	20–70	4.7–16.9	0.9– 7.3	1–8	0–2	12–36	(3)	(3)	Original data
Blue Nile (Khartoum)	-	140–390	-	19.6–28.1	5.0– 6.5	4.5–9.0	1.7–2.9	49–80	2.0–7.3	-	Hammerton, 1972
White Nile (Khartoum)	-	220–500	-	14.2–19.0	7.5–11.7	25–41	6.9–9.2	69–99	6.0–9.5	-
Nile (L. Nubia)	17–28	(190)	-	25	7	17	4	134	4.5	9	Entz (pers.comm.)
Niger (L. Kainji)	(25–30)	34–80	-	4.11	2.60	3.49	2.41	12–19	1.36	T	Imevbore, 1970
Volta (Ajena, L. Volta)	(25–30)	(60)	-	6.67	2.9	(2.4–3.5)	(1.4–2.6)	40.3	4.6	12.7	Entz, 1969 (Biswas, 1968)
Bandama (L. Kossou)	(25–29)	90–200	-	4.4–5.0	-	5.8–6.4	1.6–2.5	24–36	1–3.5	0.2–1.0	CTFT, 1972 Welcomme, 1972
Kafue (Flood Plain)	15–32	135–350	Avg. 202	18–102	7–57	1.7–15	0.8–4	25–114	1.6–10	(T)	Tait, 1967
Luapula (L. Mweru)	21–27	44–108	32–72	4.3–12.8	1.8–8.6	3.7–6.2	0.6–1.7	15–38	1.8–5.8	1–3	De Kimpe, 1964 Symoens, 1968
Congo (Matadi, April 1966)	-	40	30.7	2.71	1.81	3.15	1.72	9.46	6.48	5.32	Symoens, 1968

Table 8. Fish species of Lake Kariba, Middle Zambezi and possible invaders from Upper Zambezi. (Data from Jackson, 1961; Jubb, 1961 and 1967; Bell-Cross, 1972; Balon, 1974)

	Present before Kariba	Present in Lake Kariba	Widespread in Middle Zambezi	Introduced	Possible Upper Zambezi invader
Protopterus annectens (1)	X
Anguilla nebulosa labiata	X	X	X
Limnothrissa miodon		X		X
Mormyrops deliciosus	X	X	X
Hyppopotamyrus discorhynchus		X	X
Marcusenius macrolepidotus		X	X
Mormyrus longirostris	X	X	X
Hydrocynus vittatus	X	X	X
Alestes lateralis (2)		X			X
A. imberi	X	X	X
Micralestes acutidens	X	X	X
Distichodus mossambicus	X	X
D. schenga	X	X
Barbus poechii (3)		X
B. paludinosus		X	X
B. unitaeniatus		X	X
B. lineomaculatus		X	X
B. barotseensis (4)	X				X
B. fasciolatus	X	X
B. marequensis	X	X	X
B. radiatus		X	X
Labeo cylindricus		X	X
L. congoro	X	X
L. altivelis	X	X	X
Opsaridium zambezense	X	?	X		X
Chiloglanis neumani (5)	X
Schilbe mystus (6)		X			X
Eutropius depressirostris	X	X
Clarias gariepinus	X	X	X
Heterobranchus longifilis	X	X
Malapterurus electricus	X	X
Synodontis zambezensis	X	X
S. nebulosus	X	X
Aplocheilichthys johnstoni	X	X
Serranochromis codringtoni	X	X
S. giardi		X		?	X
S. carlottae		X		?	X
S. macrocephalus (7)		X		?	X
S. robustus (8)		X		X	X
Pharyngochromis darlingi	X	X	X
Pseudocrenilabrus philander		X	X
Oreochromis andersoni		X		?	X
O. macrochir		X		X	X
O. mortimeri	X	X
Tilapia rendalli	X	X	X	X

(1) Inhabits temporary pools, habitat destroyed
(2) Jubb (1976) claims that it was recorded from Middle Zambezi also that it may not be A. lateralis
(3) Found in N. Bank tributaries above and below Kariba (Balon, 1974, 1974a)
(4) Possibly misidentified. Occurs, however, in Kalomo River above Kariba (Balon, 1974)
(5) Inhabits running water, habitat destroyed
(6) Recorded from Middle Zambezi before Kariba (Jubb, 1967)
(7) Found in Chezia R., N. Bank tributary (J.F.R.O, 1967)
(8) Found in N. Bank tributaries (J.F.R.O, 1961; Balon, 1974) Also introduced (Toots and Bowmaker, 1976)

Table 9. Fish abundance in relation to vegetation

Habitat type	Species	No. ha^-1	kg ha^-1	Source
Gentle slope, rich vegetation	14	20 200	500	(1)
Intermediate slope, poor vegetation	12	7 700	132
Steep and rocky, very poor vegetation	11	1 100	48
Intermediate slope, no vegetation, (9–12 m deep)	6	1 800	27
Open water, 20 m deep	3	300	9
Permanent Salvinia mat	25		816	(2)
Rooted hydrophytes present	24		263
Poor vegetation	20		98
Good vegetation in coves (5 stations)	23	43 283		(3)
Poor vegetation in coves (3 stations)	17	1 988

Sources: (1) J.D. Langerman, Unpubl. (1981–82 data)
(2) Mitchell (1976)
(3) Balon (1973)

Table 10. Changes in the abundance of major fish species, lakeside station 1960–1982. Expressed as numbers per 50 standard gillnet fleet settings

	1960	1961	1962	1963	1964	1965	1966	1967	1968	1969	1970
Hyppopotamyrus discorhynchus	-	-	-	-	13	N.D.	N.D.	20	N.D.	225	318
Mormyrus longirostris	-	-	5	-	4			-		-	24
Mormyrops deliciosus	-	-	-	-	32			-		-	6
Marcusenius macrolepidotus	-	-	-	-	-			90		602	294
Hydrocynus vittatus	2 900	2 000	2 773	3 258	2 058			1 370		2 876	2 718
Alestes imberi	3 150	2 200	968	1 233	180			110		-	6
Labeo congoro	850	900	614	563	179			-		4	-
L. altivelis	10 800	3 700	1 482	821	477			-		-	-
Eutropius depressirostris	-	-	46	146	18			80		664	900
Synodontis zambezensis	-	-	-	-	26			-		63	18
Clarias gariepinus	600	1 450	828	667	45			90		209	42
Heterobranchus longifilis	-	-	-	-	-			-		-	6
Distichodus schenga	150	200	109	46	75			50		5	6
D. mossambicus	250	450	1 775	63	39			-		-	-
Tilapia rendalli	-	150	23	46	9			40		83	18
Serranochromis codringtoni	-	1	50	21	6			140		401	162
Oreochromis mortimeri	1 900	50	1 050	408	139			480		915	192
O. macrochir	-	-	-	-	-			-		-	-

	1971	1972	1973	1974	1975	1976	1977	1978¹	1979¹	1980	1981	1982²
Hyppopotamyrus discorhyncus	556	1 090	1 028	532	159	378	389	500	286	565	N.D.	270
Mormyrus longirostris	16	68	141	277	413	460	443	159	91	122		284
Mormyrops deliciosus	-	-	-	20	6	11	7	9	8	18		26
Marcusenius macrolepidotus	800	371	324	266	68	96	165	275	112	184		33
Hydrocynus vittatus	5 936	6 042	4 466	7 020	4 219	2 906	1 979	1 808	1 332	1 646		2 095
Alestes imberi	36	50	30	206	994	1 093	1 379	827	1 649	1 364		878
Labeo congoro	-	-	2	2	-	1	1	1	-	-		-
L. altivelis	-	6	4	2	22	8	44	28	90	87		18
Eutropius depressirostris	1 260	694	295	604	212	160	601	299	324	735		162
Synodontis zambezensis	36	50	99	167	88	103	125	80	57	103		84
Clarias gariepinus	48	172	104	458	345	231	168	294	73	78		204
Heterobranchus longifilis	-	3	4	6	12	13	16	2	1	2		4
Distichodus schenga	-	6	6	12	2	4	1	4	1	-		1
D. mossambicus	-	-	-	-	-	-	-	-	-	-		1
Tilapia rendalli	80	141	64	193	304	314	144	132	248	80		117
Serranochromis codringtoni	312	1 635	1 145	1 967	2 439	1 860	1 118	723	571	534		1 567
Oreochromis mortimeri	356	1 039	757	2 682	2 032	1 613	1 481	1 173	135	170		328
O. macrochir	-	-	-	2	16	19	12	5	15	1		4

¹ Some commercial fishing took place from 1978 to mid-1980

² Incomplete - 10 months data

Table 11. Standing stock of major fish species (i.e., > 1% of total standing stock) in Lake Kariba

	Balon (1973)		Mitchell (1976)		Langerman (unpubl.)
	kg ha^-1	%	kg ha^-1	%	kg ha^-1	%
Mormyrops deliciosus	92	15.1	126	30.0
Hippopotamyrus discorhyncus	96	15.9	70	16.7
Marcusenius macrolepidotus			8	1.8
Mormyrus longirostris	18	3.0	45	10.6
Hydrocynus vittatus	31	5.1	10	2.5	64	15.3
Alestes lateralis	29	4.8	6	1.4	13	3.1
A. imberi					13	3.0
Labeo altivelis	6	1.0			53	12.6
Eutropius depressirostris	9	1.5
Clarias gariepinus	52	8.6	13	3.2
Heterobranchus longifilis	14	2.3	7	1.7
Malapterurus electricus	48	8.0	10	2.3	5	1.3
Serranochromis codringtoni	13	2.2	12	2.9	33	8.0
S. macrocephalus					12	2.9
Pharyngochromis darlingi				1.1
Oreochromis mortimeri	97	16.0	22	5.2	25	6.1
Tilapia rendalli	56	9.3	54	12.7	190	45,3
TOTAL	580	96.0	409	97.2	408	97.6
Sampling period	1968–1971		1972–1974		1981–1982