Browsing by Author "Mwijage, Alistidia Paul"

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    Organic matter sources and trophic interactions among fish species in Pangani estuary – Tanzania
    (University of Dar es Salaam, 2009) Mwijage, Alistidia Paul
    Estuaries are primary habitat that serves as feeding and nursery grounds for most juvenile marine fish. However, estuaries in Tanzania have been affected by anthropogenic activities in the upstream of the river catchments including the use of these areas as fishing grounds by the artisanal fishers. These human activities contribute to determine the abundance and diversity of OM sources that support the nutrition of fish; and also to define the complexity of the estuarine food webs. The four complementary methods: stomach contents, stable isotopes (Ֆ13C and Ֆ15N) fatty acid (FA) biomarkers and trophic flow modeling approach were used to describe the OM Nutritional sources and trophic interactions among the dominant marine fish in the Pangani estuary. Among the Fish species investigated (Hilsa Kelee, Valamugil buchanani, Arius africanus, Carangoides chrysophrys and Epinephelus malabaricus), PERMANOVA, Pseudo – F = 125.27: P = 0.001), stable isotopes (PERMANOVA, pseudo –F 300.29: p = 0.001), and FA composition (PERMANOVA, pseudo-F = 74.75; p = 0.001). Moreover, the stable isotopes results revealed slight differences in the most important OM sources relied by individual species from depleted in Ֆ13C values to relatively enriched in Ֆ13C OM Sources among the estuarine zones. Yet, the combined methods – stable isotopes, FA biomarkers and Eco path modeling emphasized that terrestrially – derived OM Supplement the main benthic micro-algae basal food sources is an indication resources to sustain the overall estuarine food web. The reliance on benthic diatom – dominated estuarine and marine basal food sources in an indication of low estuarine food connectivity to the fresh water related food web. This situation is most likely threatening the resilience and stability of the estuarine food web structure. This was also highlighted by Ecopath trophic flow model which indicated that the Pangani estuarine food web structure is less resilient to any perpetuation when compared with the other tropical estuarine systems
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    The role of local ecological knowledge in the sustainable use of wetland resources and poverty reduction: the case study of Kagera river Wetland, Misenyi district - Kagera region, Tanzania
    (Unversity of Dar es Salaam, 2010) Mwijage, Alistidia Paul
    Wetlands of the Lake Victoria Basin are currently facing management challenges due to continuing pressure exerted by local communities through exploitation of wetland resources for their livelihoods. Thus studies are required to furnish empirical data necessary for the better management of the ecosystems in question. Therefore, this study aimed at ascertaining and documenting the local ecological knowledge (LEK) of the communities surrounding the Kagera riverine wetland in Misenyi district which is applied in the utilization of the riverine resources; and assess how locally derived solutions of socio-economic problems have been realized while using these resources. Four villages namely Nyabihanga, Gabulanga, Bulifaniand Mushasha were selected for the study. Both qualitative and quantitative data collection methods were used. The questionnaires, interviews and focus group discussions were adopted for gleaning qualitative information whereas the riverine vegetation survey was carried out for collection of quantitative data on plant species diversity. The results showed that LEK practices applied in utilization of riverine resources make ecological sense in Kagerariver wetland ecosystem management. But increasingly socio-economic and environmental changes have led to a change in LEK practices and, thus, increased the risk of exhausting Kagera riverine wetland resources. The study concludes that Kagerariverine wetland management authorities should promote LEK practices and empower local communities to cope with increased demands for the resources and environmental changes. The authorities should increase their level of understanding of LEK for developing site-specific plans of conserving the Kagera riverine wetland ecosystem.