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 | |||||||||
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 | |||||||||
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 |
% | 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 |
% | 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 |
% | 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 |
% | 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 | % | 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 | % | 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 | % | 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 | |
% | 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