Browsing Okavango Research Institute (ORI) by Author "Mosepele, B."
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Mmopelwa, G.; Mosepele, K.; Mosepele, B.; Moleele, N.; Ngwenya, B. (Blackwell Publishing, http://www.blackwellpublishing.com, NaN, 2009)[more][less]
Abstract: The hydrological regime of the Okavango River Basin is the main driver of ecological change in the delta. The delta supports a small-scale fishery which is a source of livelihood for communities within its fringes. The fish resource is particularly important to subsistence fishers, who have limited access to socio-economic opportunities. However, fish availability is subject to ‘concentration and dilution’ effects because of the hydrological regime. As a copying strategy, fishers use a variety of fishing methods to effectively harvest the delta’s fish community across all its trophic levels. This exploitation regime helps to maintain the delta’s species diversity and only reduces fish biomass proportionally across the different trophical levels. Furthermore, fishers have developed different fish-processing techniques to preserve their harvest for low fishing season periods to cope with low food availability. The aim of this paper therefore, was to explore spatio-temporal variations in fish availability and to show how the delta’s subsistence fishers cope with this dynamicity. URI: http://hdl.handle.net/10311/862 Files in this item: 1
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Dallas, H.F.; Mosepele, B. (African Journal of Aquatic Science http://www.nisc.co.za/journals?id=2, NaN, 2006)[more][less]
Abstract: The spatial distribution of aquatic macroinvertebrates in the Okavango River Delta, Botswana, was investigated during the low-water period in February 2003. This complements an earlier study undertaken during high-water in June 2000. Seventy-five samples were taken in a range of aquatic habitats at 29 georeference points in four focal areas: Upper Panhandle (UPH), Lower Panhandle and Guma Lagoon (LPH), Moremi Game Reserve/Xakanaka (MGR), and Chief’s Island (CI). Over 180 morphospecies (approximately 63 families) were recorded during the survey. Multivariate analyses of macroinvertebrate assemblages indicated that assemblages in each of the four focal areas were at least 54% similar at morphospecies level, and 71% similar at family level, although some taxa were more or less common in different areas. Differences in macroinvertebrate assemblages were observed amongst different habitat types, with differences most pronounced between the deltaic habitats and isolated seasonally-flooded pools and temporary rain-filled pools in MGR and CI. The highest number of taxa was recorded in the MGR (125), followed by the UPH (96), CI (93) and the LPH (89) areas. The most families were recorded in the Hemiptera (11), followed by Mollusca (10), Diptera (nine), Coleoptera (nine), Crustacea (six), Ephemeroptera (six) and Odonata (four). Three families of Hirudinea and Trichoptera, and one family of Lepidoptera, were also recorded. Hydracarina were common but not identified beyond order, while Oligochaeta were less frequently recorded. With respect to the different aquatic habitats sampled, the highest number of taxa was recorded in marginal vegetation in the channels and lagoons, although inundated floodplains, floating vegetation and marginal vegetation in backwaters also supported many taxa. The fewest taxa were recorded in sediment. This survey, whilst representing a ‘snapshot’ of the system under low-water conditions, highlights the importance of maintaining a mosaic of aquatic habitats in the Delta. Further studies would enhance our knowledge of the aquatic macroinvertebrate biodiversity of the Okavango Delta, thereby contributing to its conservation. URI: http://hdl.handle.net/10311/869 Files in this item: 1
Dallas_AJAS_2007.pdf (1.160Mb) -
Mosepele, K.; Mosepele, B.; Williams, L. (Botswana Society, NaN, 2005)[more][less]
Abstract: This study investigates the feeding ecology of Schilbe intermedius across its entire life history. Data were collected using experimental fishing nets in two habitats in a seasonal floodplain. The results showed that S. intermedius has an ontogenetic shift in feeding behaviour where the young fish are primarily generalist predators, feeding on aquatic invertebrates while the older fish are more specialised predators feeding primarily on fish. This study showed that there is a higher potential for intra-specific competition among the older fish than in the younger size classes. However, it was recognized that this study is a snap-shot of the feeding ecology of S. intermedius and that a longer time series study is needed to study its feeding ecology. URI: http://hdl.handle.net/10311/940 Files in this item: 1
Mosepele 2005 Prelim.pdf (1.295Mb) -
Mosepele, K.; Onalethata, B.; Mosepele, B.; Thethela, B. (Botswana Society, NaN, 2005)[more][less]
Abstract: Populations of three cichlid species from the upper and lower Okavango Delta were compared in terms of biological population parameters, in order to investigate whether the fish species of the Delta consist of one continuous, or two or more separate, stocks. Data were collected from the lower Delta and upper Delta using experimental fishing nets to ensure that representative samples were obtained. While no statistical tests for significance were conducted, the results show that the same species between the upper and lower Delta have different biological parameters. Therefore, it is concluded that these observed differences suggest that, for the three investigated species, there are at least two different populations in the Okavango Delta. URI: http://hdl.handle.net/10311/941 Files in this item: 1
Mosepele 2005 Using popul.pdf (1.635Mb)
Now showing items 1-4 of 4