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

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

KAINJI (NIGERIA) (continued)

Table 19
Percentage composition by number of the fish families according to trophic levels in Kainji Lake (From Ita and Otubusin 1981)

FAMILY	1969		1970		1971		1972		1973		1974		1975		1976		1977
FAMILY	No.	%	No.	%	No.	%	No.	%	No.	%	No.	%	No.	%	No.	%	No.	%
PRIMARY CONSUMERS
Characidae	196	7.12	759	52.82	1 331	72.53	616	46.42	328	42.32	561	54.73	165	29.00	258	27.95	257	21.61
Cyprinidae	617	22.41	220	15.31	89	4.85	68	5.12	32	4.13	27	2.63	49	8.61	175	18.96	109	9.17
Cichlidae	38	1.38	7	0.49	10	0.54	44	3.32	55	7.10	28	2.73	47	8.26	177	19.18	635	53.41
Citharinidae	1 228	44.61	129	8.98	65	3.54	154	11.61	108	13.94	26	2.54	103	18.10	61	6.61	49	4.12
Distichodontidae	22	0.80	24	1.67	64	3.49	36	2.71	54	6.97	27	2.63	59	10.37	91	9.86	19	1.60
Mochokidae	638	23.17	286	19.90	275	14.99	409	30.82	197	25.42	353	34.44	145	25.48	155	16.79	107	9.00
Bagridae	14	0.51	12	0.84	1	0.05	-	-	1	0.13	3	0.29	1	0.18	6	0.65	13	1.09
Sub-total	2 753	100.00	1 437	100.01	1 835	99.99	1 327	100.00	775	100.01	1 025	99.99	569	100.00	923	100.00	1 189	100.00
SECONDARY CONSUMERS
Mochokidae	302	40.59	312	42.80	195	30.81	118	33.05	86	57.72	70	60.34	49	51.58	121	39.93	77	24.84
Mormyridae	88	11.83	116	15.91	167	26.38	77	21.57	13	8.72	10	8.62	24	25.26	74	24.42	56	18.06
Cichlidae	-	-	-	-	-	-	2	0.56	-	-	-	-	-	-	-	-	-	-
Polypteridae	-	-	1	0.14	1	0.16	-	-	3	2.01	-	2.59	-	-	-	-	-	-
Tetradontidae	-	-	-	-	-	-	1	0.28	-	-	-	-	-	-	-	-	-	-
Bagridae	308	41.48	294	40.33	247	39.02	133	37.25	35	23.49	24	20.69	19	20.00	86	28.38	167	53.87
Schilbeidae	43	5.78	5	0.69	22	3.48	25	7.00	11	7.38	9	7.76	1	1.05	13	4.29	6	1.94
Centrapomidae	-	-	-	-	1	0.16	1	0.28	1	0.67	-	-	2	2.11	7	2.31	3	0.97
Cyprinidae	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1	0.33	1	0.32
Osteoglossidae	3	0.40	1	0.14	-	-	-	-	-	-	-	-	-	-	1	0.33	-	-
Sub-total	744	100.00	729	100.01	633	100.01	357	99.99	149	99.99	116	100.00	95	100.00	303	99.99	310	100.00
TERTIARY CONSUMERS
Characidae	492	17.23	437	36.39	665	40.47	274	41.96	298	51.65	344	46.30	195	36.86	90	32.03	163	37.73
Bagridae	20	0.70	6	0.50	14	0.85	9	1.38	26	4.51	23	3.10	20	3.78	43	15.30	114	26.39
Schilbeidae	1 212	42.45	623	51.87	858	52.22	288	44.10	230	29.86	339	45.63	256	48.39	99	35.23	78	18.06
Centropomidae	1 120	39.23	122	10.16	92	5.60	66	10.11	17	2.95	31	4.17	51	9.64	38	13.52	73	16.90
Gymnarchidae	-	-	-	-	1	0.06	4	0.61	-	-	-	-	1	00.19	4	1.42	1	0.23
Cichlidae	-	-	-	-	-	-	2	0.31	-	-	-	-	2	0.38	1	0.36	2	0.46
Polypteridae	10	0.35	5	0.42	11	0.67	7	1.07	2	0.35	3	0.40	-	-	-	-	-	-
Malapteruridae	-	-	-	-	-	-	1	0.15	-	-	1	0.13	-	-	-	-	-	-
Clariidae	1	0.04	5	0.42	2	0.12	2	0.31	4	0.69	2	0.27	4	0.76	1	0.36	-	-
Hepsetidae	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1	0.36	-	-
Ariidae	-	-	3	0.25	-	-	-	-	-	-	-	-	-	-	2	0.71	-	-
Channidae	-	-	-	-	-	-	-	-	-	-	-	-	-	-	2	0.71	1	0.23
Total	2 855	100.00	1 201	100.01	1 634	99.99	653	100.00	577	100.01	743	100.00	529	100.00	281	100.00	432	100.00
GRAND TOTAL	6 352		3 367		4 111		2 337		1 501		1 884		1 193		1 507		1 931

Table 20
Percentage composition by weight of the fish families according to trophic levels in Kainji Lake (From Ita and Otubusin, 1981)

FAMILY	1969		1970		1971		1972		1973		1974		1975		1976		1977
FAMILY	Wt.	Z	Wt.	Z	Wt.	Z	Wt.	Z	Wt.	Z	Wt.	Z	Wt.	Z	Wt.	Z	Wt.	Z
PRIMARY CONSUMERS
Characidae	40 312	3.49	114 126	28.15	208 991	50.36	101 415	42.57	67 407	40.52	104 301	59.50	36 593	39.70	52 300	29.53	52 529	19.57
Cyprinidae	202 591	17.54	105 650	26.06	37 474	9.03	22 111	9.28	9 942	5.98	5 190	2.96	10 852	11.77	28 572	16.13	26 141	9.74
Cichlidae	15 981	1.38	4 740	1.17	9 921	2.39	20 450	8.58	7 833	4.71	9 839	5.61	10 719	11.63	44 334	25.03	92 811	34.57
Citharinidae	701 741	60.76	95 297	23.51	56 074	13.51	32 638	13.70	32 855	19.75	13 885	7.92	15 999	17.36	17 178	9.70	35 495	13.22
Distichodontidae	4 915	0.43	5 972	1.47	13 704	3.30	5 808	2.44	9 943	5.98	7 005	4.00	6 620	7.18	10 343	5.84	5 174	1.93
Mochokidae	181 208	15.69	70 174	17.31	87 421	21.07	55 837	23.44	38 056	22.88	34 426	19.64	11 040	11.98	23 591	13.32	51 620	19.23
Bagridae	8 160	0.71	9 445	2.33	1 372	0.33	-	-	320	0.19	660	0.38	350	0.38	795	0.45	4 665	1.74
Sub-total	1 154 908	100.00	405 404	100.00	414 957	99.99	238 259	100.01	166 356	100.01	175 306	100.01	92 173	100.00	177 113	100.00	268 435	100.00
SECONDARY CONSUMERS
Mochokidae	49 276	37.83	33 037	37.17	17 909	24.72	10 650	24.54	11 843	45.30	11 622	58.74	6 839	53.78	10 833	28.27	12 205	20.44
Mormyridae	19 170	14.72	14 236	16.02	18 399	25.39	12 571	28.96	4 494	17.19	908	4.59	3 205	25.20	13 064	34.10	12 361	20.70
Cichlidae	-	-	-	-	-	-	153	0.35	-	-	-	-	-	-	-	-	-	-
Polypteridae	-	-	158	0.18	610	0.84	-	-	1 600	6.12	1 680	8.49	-	-	-	-	-	-
Tetradontidae	-	-	-	-	-	-	1 365	3.15	-	-	-	-	-	-	-	-	-	-
Bagridae	35 965	42.97	39 208	44.11	35 192	48.57	18 337	42.25	8 008	30.63	5 531	27.96	2 534	19.93	13 316	34.75	34 741	58.19
Schilbeidae	457	0.35	51	0.06	289	0.40	271	0.62	144	0.55	44	0.22	8	0.06	139	0.36	71	0.12
Centrapomidae	-	-	-	-	55	0.08	55	0.13	55	0.21	-	-	130	1.02	497	1.30	285	0.48
Cyprinidae	-	-	-	-	-	-	-	-	-	-	-	-	-	-	1	0.00	40	0.07
Osteoglossidae	5 375	4.13	2 200	2.47	-	-	-	-	-	-	-	-	-	-	465	1.21	-	-
Sub-total	130 243	100.00	88 890	100.01	72 454	100.00	43 402	100.00	26 144	100.00	26 144	100.00	19 785	100.00	38 315	99.99	59 703	100.00
TERTIARY CONSUMERS
Characidae	194 535	26.58	157 836	52.84	205 276	63.04	90 967	58.66	128 835	67.53	157 830	72.11	88 553	65.29	41 522	49.59	74 964	54.65
Bagridae	16 575	2.26	7 060	2.36	7 214	2.22	7 037	4.54	21 094	11.06	18 722	8.55	9 720	7.17	16 745	20.00	39 380	28.71
Schilbeidae	198 908	27.17	68 980	23.09	68 386	21.00	21 003	13.54	20 242	10.61	24 678	11.27	20 141	14.85	6 355	7.59	6 286	4.58
Centropomidae	313 679	42.85	52 537	17.59	30 496	9.37	17 452	11.25	16 746	8.78	13 178	6.02	16 341	12.05	16 654	19.89	15 405	11.23
Gymnarchidae	-	-	-	-	3 540	1.09	6 418	4.14	-	-	-	-	200	0.15	1 125	1.34	600	0.44
Cichlidae	-	-	-	-	-	-	111	0.07	-	-	-	-	90	0.07	55	0.07	250	0.18
Polypteridae	7 805	1.07	2 743	0.92	10 055	3.09	6 776	4.37	2 295	1.20	1 705	0.78	-	-	-	-	-	-
Malapteruridae	-	-	-	-	-	-	4 540	2.93	-	-	1 660	0.76	-	-	-	-	-	-
Clariidae	490	0.07	9 300	3.11	650	0.20	780	0.50	1 569	0.82	1 101	0.50	591	0.44	110	0.13	-	-
Hepsetidae	-	-	-	-	-	-	-	-	-	-	-	-	-	-	160	0.19	-	-
Ariidae	-	-	240	0.08	-	-	-	-	-	-	-	-	-	-	180	0.21	-	-
Channidae	-	-	-	-	-	-	-	-	-	-	-	-	-	-	825	0.99	280	0.20
Total	731 992	100.00	298 696	99.99	325 617	100.01	155 084	100.00	190 781	100.00	218 874	99.99	135 636	100.02	83 731	100.00	137 165	99.99
GRAND TOTAL	2 017 143		792 990		813 028		436 745		383 281		413 965		240 525		299 159		465 303

Table 21
Percentage number of total fish catch in the different trophic levels from 1969–1977

Year		1969	1970	1971	1972	1973	1974	1975	1976	1977
PRIMARY	No	2 753	1 437	1 835	1 327	775	1 028	569	923	1 189
PRIMARY	%	43.34	42.68	44.64	56.78	51.63	54.31	47.69	61.25	61.57
SECONDARY	No	744	729	633	357	149	116	95	303	310
SECONDARY	%	11.71	21.65	15.40	15.28	9.93	6.13	7.96	20.11	16.05
TERTIARY	No	2 855	1 201	1 643	653	577	749	529	281	432
TERTIARY	%	44.95	35.67	39.97	27.94	38.44	39.57	44.34	18.65	22.37
TOTAL	No	6 352	3 367	4 111	2 337	1 501	1 893	1 193	1 507	1 931
TOTAL	%	100.00	100.00	100.01	100.00	100.00	100.00	99.99	100.01	99.99

Table 22
Percentage weight (gm) of total fish catch in the different trophic levels from 1969–1977

YEAR			1969	1970	1971	1972	1973	1974	1975	1976	1977
	1°	wt	1 154 908	405 404	414 957	238 259	166 356	175 306	92 173	177 113	268 435
F	1°	%	57.25	51.12	51.04	54.55	43.40	42.35	38.32	59.20	57.69
	2°	wt	130 243	88 890	72 454	43 402	26 144	19 785	12 716	38 315	59 703
F	2°	%	6.46	11.21	8.91	9.94	6.82	4.78	5.29	12.81	12.83
	3°	wt	731 992	298 696	325 617	155 084	190 781	218 874	135 636	83 731	137 165
C	3°	%	36.29	37.67	40.05	35.51	49.78	52.87	56.39	27.99	29.48
TOTAL		wt	2 017 143	792 990	813 028	436 745	383 281	413 965	240 525	299 159	465 303
TOTAL		%	100.00	100.00	100.00	100.00	100.00	100.00	100.00	100.00	100.00

F/C			1.8	1.7	1.5	1.8	1.0	0.9	0.8	2.6	2.4

F = Forage species
C = Carnivorous species
F/C = Forage : Carnivorous ratio