Introduction Considerable information exists on the limnology of the natural lakes of Ethiopia but little is known about the country’s reservoirs. There were almost no benthic invertebrates. The zooplankton was sparse and of very low diversity. A species of Microcystis was the most abundant phytoplankter. The water is somewhat turbid owing to the presence of organic debris, of low conductivity, slightly acidic, and apparently calcium-dominated. It covers the former Ch’omen Swamp and so contains many floating islands and large quantities of decomposing vegetation, causing undersaturation with oxygen even at the surface. Finchaa Reservoir in west central Ethiopia (altitude about 2200 m) is very different. There was a large population of benthic invertebrates. The zooplankton was of low diversity but abundant. The phytoplankton was dominated by Microcystis. At the time of measurement it was supersaturated with oxygen to a depth of about 8 m, and displayed a pronounced conductivity stratification, due probably to the incomplete mixing of two inflows. Its water is turbid because of suspended inorganic material. Box 5050, Burlington, Ontario, Canada L7R 4A6 ReceivedĪbstract Koka Reservoir in the Ethiopian Rift Valley (altitude about 1600 m) appears to be similar to natural lakes in the region. Box 1176, Addis Ababa, Ethiopia 2Department of Biology, University of Waterloo, Waterloo, Ontario, Canada 3National Water Research Institute, PO. ‘Department of Biology, Addis Ababa University, RO. Some limnological observations on two Ethiopian hydroelectric reservoirs: Koka (Shewa administrative district) and Finchaa (Welega administrative district) Melaku Mesfin,’ The lastįour have been recorded from Kainji Lake.157: 47 - 55 (1988) Publishers, Dordrecht Of these eight appear to be valid records, including T. Have been reported from the Niger river drainage by various authors (and one Noted by Thys van den Audenaerde (1968a) as being confused as T. zillii and the name isĪudenaerde, 1968b). ![]() Specimens of the latter have been identified by Dr. Presently recognized in Kainji Lake include T. Lewis (personal communication) tentatively identified a T. To date has not been positively recorded in Kainji Lake since its filling,Īlthough Dr. aurea “… was recognized in the Middle Niger by Daget nilotica, T.ĭescribes the differences between T. In Kainjii Lake since filling (FAO, 1970b FAO, 1972 Ita, 1972) have reported Thys van den Audenaerde (1968a) corrects the identification by Indicates that these are the species likely to occur in the proposed melanopleura as present in the Niger River. Preimpoundment surveys connected with the proposed Kainji Dam (Daget, 1961b īanks, Holden and McConnell, 1966 FAO, 1970a Motwani and Kanwai. mariae as occurring inĬlear water streams tributary to the Niger at least as far upstream as galilaea from the Niger River delta Thys vanĭen Audenaerde indicates the identity of T. In Thys van den Audenaerde (1968a) records T. ![]() Thys van den Audenaerde (1968a) corrects these to be T. collected from the Niger River delta mouth as T. lataįrom the Niger, probably Mistaken for T. LegerĪnd Leger (1914) as recorded in Thys van den Audenaerde (1968a) report T. zillii and an unidentified Tilapia from the Sokoto River, tributary to the Niger River in northern Nigeria. melanopleura is in several cases an unspecified Tilapia and melanopleura from the Cameroun section of the Benue River.Īmong these identifications, Thys van den Audenaerde (1968a) (1945, 1949) have reported extensively on Tilapia sampled from theĬentral Niger River delta near Timbuktu in Mali. ![]() A report prepared for the Kainji lake research (man-made lake) projectģ. Nigeria - Observations on Tilapia in Kainji lake, with emphasis on T.
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