Lake Sebakwe was originally completed in 1957 on the Sebakwe River, but it was raised by 7 m between 1982 and 1986. The dam was built as a buttress section, with downstream face slabbed over the spillway zone. It has a mean height of 47 m, a maximum water depth of 40.2 m and an area of 2 320 Ha and a maximum volume of 105 000 m³. It was mainly built for supplying water to the downstream city of Kwekwe and irrigating surrounding commercial farms. The lake has a huge potential for fisheries, but a few subsistence small scale fisheries exist. There have been no studies on the fish community assemblages of the Lake. Hence this brief snapshot survey of the fish species resident in the lake. We sampled continuously in the lake for four days using a combination of gill and seine nets. Gillnets of both cotton and monofilament were set up overnight. At each site nylon survey nets (10 metres with a mesh size 1.5 inches, 2 inches, 2.5 inches, 3 inches, 3.5 inches, 4 inches, 4.5 inches, 5 inches, 5.5 inches and 6 inches) were set. Gillnets were set at a distance of 30 metres apart to cover as much of the lake as possible (King, 1995). Gillnets were also described as the most effective in still water by Bell-Cross and Minshull (1988).

Gill nets were set from 1 600 hrs – 0600 hrs and sampled fish were identified to species level according to Skelton (2001), counted, measured to the nearest millimeter and weighed to the nearest gram. The catch per unit effort was standardized according to the sampling method (numbers per net day for gill nets). Fish data that is species present, their abundance and sex were collected for each net and the total figures for each sampling station collected.

A total of 8 species belonging to 6 families were recorded in Lake Sebakwe for the sampling period. The families were: Cichlidae; Tilapia rendalii(Boulenger, 1896), Serranochromisrobustus: Cyprinidae; Labeo cylindricus (Peters 1868): Clariidae; Clarias gariepinus (Burchell, 1822): Momyridae; Mormyrus longirostris (Peters, 1852), Marcusenius pongolensis (Fowler, 1934): Centrarchidae; Micropterus salmoides Lacepede, 1802: Alestiidae; Brycinus imberi (Peters, 1852). One exotic species was recorded in the lake (Micropterus salmoides), one introduced species was observed (S.robustus).The most frequent species has been the Micropterus salmoides accounting for 60% of the catch in the period sampled (Table 1).

Table 1 Frequency (%) of species in total catches in Lake Chivero for the sampling period (2013)

A snapshot collection of fish species in Lake Sebakwe reveal a dominance of the exotic Northern large mouth bass (Micropterus salmoides, Lacepede, 1802). This fish is a predator that feeds primarily on fish, although some invertebrates are taken and shows ontogenetic diet shift (Marshall, 2010). This fish thrives in waters where there is an absence of more voracious predators. This may be the case in this lake as we found no other competing predators like the tigerfish (Hydrocynus vittatus, Castelnau 1861). The second most abundant fish species were the Labeo cylindricus (Peters 1868):This species is widely distributed throughout Africa and consist of at least 80 species which comprise 16. 4% of the African cyprinid ichthyofauna.It is a benthopelagic species and occurs in both sediment-free and sediment rich rocky biotopes, where it can be abundant. L.cylindricusfavors clear, running waters in rocky habitats of small and large rivers, also found in lakes and dams over rocky areas. This species is also commercially important throughout the African continent, having contributed significantly to various fisheries (Skelton, 2001). It feeds on diatoms and other small algae from rocks. It is a cryptic species that hides under rocks and is most active at night (Gratwicke et al., 2003). It is a very small species attaining a maximum length and mass of 25 cm standard length and 0. 9 kg respectively (Skelton, 2001).

The third next frequent species was the Marcusenius pongolensis (Fowler, 1934): This fishis usually found in main channels but lower catchments. It does not enter still lagoons and backwaters in the lower floodplains. It feeds primarily on benthic insects and prefers white still waters. In Zimbabwe this is the first record of the fish that we have found. It also prefers clean white waters. The fourth most frequent species was the Eastern bottlenose, Mormyrus longirostris (Peters, 1852). This species is widespread but not always numerous. It is a demersal and potamodromous lives in caves and muddy areas, and it also hides among weeds (Marshall, 2010). It prefers quite deep waters with soft muddy bottoms and is rarely caught in marshy areas. It is active mainly at night and it breeds during the rainy season. It feeds on weeds and insects but may also feed on small fishes, bloodworms, crustaceans, mollusks and aquatic plants.

Skelton P. H., 2001, A complete guide to the freshwater fishes of Southern Africa, 2nd edition, Struik Publishers, Cape Town: pp.395