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Please use this identifier to cite or link to this item:
http://hdl.handle.net/1834/1176
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| Title: | Ecological changes in Lake Victoria after the invasion of Nile perch (Lates Niloticus): the catchment, waters quality and fisheries management |
| Authors: | Ochumba, P.B.O.
Goshen, M.
Pollinger, U. |
| ASFA Terms: | Environmental impact
Fishery management
Introduced species
Lake fisheries |
| Issue Date: | 1994 |
| Publisher: | ICIPE Science Press |
| Citation: | Okemwa, E.; Wakwabi, E.O.; Getabu, A. (Ed.) Proceedings of the Second EEC Regional Seminar on Recent Trends of Research on Lake Victoria Fisheries, Nairobi : ICIPE Science Press, p. 29-39 |
| Abstract: | Lake Victoria, the second largest lake in the world, has undergone
successive dramatic changes since 1920's. Intensive non-selective
fisheries, extreme changes in the drainage basin of vegetation,
industrialization, agricultural developments, dams, introduction and
invasion of exotic fish species that led to the destruction of the
native and endemic components followed by a progressive build-up of
physical and chemical changes in Lake Victoria have identified
substantial increases in chlorophyll concentration and primary
productivity as well as decreases in silica compared to values
measured 30 years ago. Present sulphate concentration (0.1 mg/L) are
lower than the lowest values reported from other large lakes in the
world. There has been a shift in the phytoplankton community towards
dominance of blue-greens. The zooplankton densities are relatively low
and the body sizes of the organisms are small. Anoxic waters have
recently been found at shallower depths than previously reported in
the lake suggesting significant increases of oxygen demand in the
seasonally formed hypolimnion. Algal blooms have also been enhanced in
the lake. Fisheries management has led to a shift in the fishery from
a multi-species (400-500 fishes including haplochromids) to only two
major exotic species Lates niloticus and Oreochromis niloticus and the
endemic species Rastrineobola argentea. The present practices of lake
management have not resulted in the improvement of water quality. |
| URI: | http://hdl.handle.net/1834/1176 |
| ISBN: | 9290640789 |
| Appears in Collections: | Conference Papers
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