Doctoral thesis (PhD in Social Sciences)
This study assessed anthropogenic activities, land uses and limnological characteristics, in relation to fisheries resources of Lake Babati (fresh water) and Burunge (soda water). Six villages were also involved, namely Majengo, Singe and Bagara adjacent to Lake Babati and Mwada, Sangaiwe and Vilima Vitatu adjacent to Lake Burunge. Data were collected by using questionnaire surveys, key informant interviews, observation, GIS and RS and Laboratory analysis. Findings have indicated encroachment, overfishing, soil erosion and siltation as major anthropogenic impacts. In Lake Babati, residence and cultivation increased by (44.8%, 12.6%), (28%, 18.1%) and (2%, 11.7%) while grazing decreased by 8%, 38.4% and 11% for Majengo, Singe and Bagara villages beween 2000 and 2017 respectively. As for Lake Burunge, residence and cultivation increased by (30%, 23.5%), (30%, 29.3.1%) and (10%, 53 %), while grazing decreased by 29.1%, and 24.2 % for Mwada, Sangaiwe and Vilima Vitatu villages beween 2000 and 2017, respectively. Physicochemical parameters were almost the same except salinity,
conductivity, pH and turbidity which differed (17.4, 28.8 ‰), (37.6, 55 μS/cm), (7.5, 9.54) and (46, 3.1 cm) in Lake Babati and Burunge, respectively. Pollution was evidently due to the existance of phytoplankton blooms. Phytoplanktons were represented by Bacillariophyceae, Dinophyceae, Cyanophyceae, Chlorophyceae and Dictyochophyceae whereas, zooplankton were represented by Cyclopoda, Rotifera, Ciliata and Holizoa. There was a significant difference in the number of plankton cells between Lakes being higher for the dry season than the wet. Fish species; Oreochromis amphimelas, Macrobrachiunus caradina were restricted to dry season; Oleochronmis esculentus Clarias gariepinus, Rhabdalestes leleupi and Petersius tangensis in wet season and Clarias gariepinus and Oleochronmis esculentus occurred in both wet and dry season. Variation in plankton composition, abundance and diversity in different seasons which implied that, the influence of season was important in the management of water quality, plankton and fish production.
Therefore, the study recommends local communities and stakeholders involvement in Lakes management, establishment of adequate buffer zones, promotion of income generating activities such as beekeeping, aquaculture and horticulture for sustainability of fishery resources. Finally, the study proposes Fisheries and Water Quality Management framework for implementation and operation.