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Item Impacts of south-western Indian Ocean tropical cyclones and storms on the rainfall pattern and vegetation productivity over Tanzania(University of Dar es Salaam, 2019) Kai, Kombo HamadThe present study investigate the impacts of warms Southwestern Indian Ocean (SWIO) tropical storms (TSs) and cyclones (TCs) on rainfall pattern and vegetation productivity indices in the cost area of Tanzania using field surveys, remote sensing and statistical modelling tools. The result revealed that over the last 34 December to March (DJFM) and November to May (NM) TCs seasons, 74 (during DJFM) and 90 (during NM) TCs and 154 (during DJFM) and 184 (during NM) TSs were observed. Higher sea surface temperature (SST) anomaly (0.4 to 0.9oc) and higher area averaged SST (27.5 to 28.75Oc) over SWIO occurred during September to November (SON) and December to May, while for the case study TCs the highest SST anomaly (-0.5 TO +2.5oCo was observed. Seasonal northward and southward oscillating environmental wind shear (Evws) varied between 0 to 15ms-1 (at 00 to 150s), while the zone mean wind (umst) ranging between -5 and -15ms-1 were observed during DJFM. The contribution of TCs /TSs to DJFM rainfall was very significant, with highest rainfall influence over the hinterlands and southern parts of Tanzania compare to northern coastal area of Tanzania. The seasonal (DJFM and NM) TCs/TSs statistical modelling showed strong correlations) p≤0.02) between the observed and the cross- validated TCs/ TSs (0.52< r < 0.84). The assessment of the model skills revealed skill (76%) for the NM TCs model. NDVI change OVER Rufiji during TCs ( besija and Fobane) was reduced and enhanced by < -0.19 and > 0.31, respectively. Moreover, EVI and NDVI results were consistent with the patterns shown by analysis of rainfall data.Item Investigating the potential of Tanzania’ honey quality and reputation for geographical indications labeling(University of Dar es Salaam, 2019) Nyunza, GodfreyInvestigating the potential of Tanzania’ honey quality and reputation for geographical indications labeling Godfrey Nyunza PhD (NARAM) University of Dar es Salaam, Institute of Resource Assessment, 2019 Honey produced in Uyui and Manyoni areas has potential for Geographical indication labeling. This study was conducted to investigate conditions that promote the quality and reputation of honey produced in Uyui and Manyoni districts and their influence on its potential for geographical indication labeling. Mixed research approaches were employed to collect both qualitative and quantitative data. Secondary data on honey, geographical indications, natural factors, human factors, institutions and electronic sources. Primary data were collected through interviews involving 129 beekeepers and 8 key informants from various institutions. In-depth interviews, focus group discussion, and documentary reviews were employed to collect qualitative dat. Through household questionnaire and laboratory analysis, 220 beekeepers and 14 honey samples were employed respectively to collect data. The five phased cycles including were used in analyzing qualitative data. Excel 2013 and IBM Statistical Package (SPSS version 21) were used in the descriptive analyzing of data collected through household questionnaires. In addition, the study used a linear regression analysis model to identify parameters that influence and differentiate the quality and reputation of honey from the data collected through household questionnaires. Pollen and physicochemical analysis were employed to determine the link between pollen types and quality of honey. The results of this study indicate that production methods (human skills) covering hive placement, honey harvesting seasons, ripeness of honey, honey harvesting procedures, honey filtering, and honey storage promote honey quality and reputation for potential GI labeling. This was also verified by linear regression analysis. In addition, the study results on natural factors’ influence on potential GI honey labeling have shown that Brachystegia spiciformis, Julbernardia globiflora, and Combretaceae species were most important honey- bee plant sources that led to the production of honey characterized by a golden colour, stickiness,and sweet taste in Uyui. On the other hand, Brachestegia spiciformis, pseudo prosopis fischeri (Taub), and Helianthus annuus have been found to be most important honey- bee plant sources in Manyoni. Pseudo prosopis fischeri (Taub.), in particular, has been found to produce honey characterized by whitish/ milk colour, thickets’ flower aroma, and sweet sour taste. The results have also shown that institutional environment in both the study areas support the production of honey with reputable quality but there various constrains associated. Besides, the results on physicochemical attributes indicate that 92.8 percent of the honey samples tested adhered to European Commission Council Directive 2001/110EC and Tanzania honey standards. It is therefore concluded that the traditional production methods, natural factors, institutional environment, and physic-chemical quality indicators in both study areas influence the quality and reputation of honey for potential GI labeling. It is recommended that various stakeholders should collaborate to employ various strategies to identify and label potential GIs honey from Tanzania to improve beekeepers livelihoods.Item Impacts of south-western indian ocean tropical cyclones and storms on the rainfall pattern and vegetation productivity over Tanzania(University of Dar es Salaam, 2019) Kai, Kombo HamadThe present study investigate the impacts of warms Southwestern Indian Ocean (SWIO) tropical storms (TSs) and cyclones (TCs) on rainfall pattern and vegetation productivity indices in the cost area of Tanzania using field surveys, remote sensing and statistical modelling tools. The result revealed that over the last 34 December to March (DJFM) and November to May (NM) TCs seasons, 74 (during DJFM) and 90 (during NM) TCs and 154 (during DJFM) and 184 (during NM) TSs were observed. Higher sea surface temperature (SST) anomaly (0.4 to 0.90C) and higher area averaged SST (27.5 to 28.750C) over SWIO occurred during September to November (SON) and December to May, while for the case study TCs the highest SST anomaly (-0.5 to +2.50C0 was observed. Seasonal northward and southward oscillating environmental wind shear (Evws) varied between 0 to 15ms-1 (at 00 to 150S), while the zone mean wind (Umst) ranging between -5 and -15ms-1 were observed during DJFM. The contribution of TCs/TSs to DJFM rainfall was very significant, with highest rainfall influence over the hinterlands and southern parts of Tanzania compare to northern coastal area of Tanzania. The seasonal (DJFM and NM) TCs/TSs statistical modelling showed strong correlations (p≤ 0.02) between the observed and the cross-validated TCs/TSs (0.52 < r < 0.84). The assessment of the model skills revealed skill (76%) for the NM TCs model. NDVI change over Rufiji during TCs (besija and Fobane) was reduced and enhanced by < -0.19 and > 0.31, respectively. Moreover, EVI and NDVI results were consistent with the patterns shown by analysis of rainfall data.Item Impacts of south western Indian ocean tropical cyclones and storms on the rainfall pattern and vegetation productivity over Tanzania(University of Dar es Salaam, 2018) Kai, Kombo HamadiThe present-day study investigated the impacts of warmed Southwestern Indian Ocean (SWIO) tropical storms (TSs) and cyclones (TCs) on rainfall pattern and vegetation productivity indices in the coast area of Tanzania using field surveys, remote sensing and statistical modeling tools. The results revealed that over the last 34 December to March (DJFM) and November to May (NM) TCs season, 74 (during DJFM) and90 (during NM) TCs and 154 (during DJFM) and 184 and90 (during NM) TCs was observed. Higher sea surface temperature (SST) anomaly (0.4 to 0.9oC) and higher area averaged SST (27.5 to 28.75oC) over SWIO occurred during September to November (SON) and December to May, while for the case study of TCs the highest SST anomaly (-0.5 to +2.5oC) was observed. Seasonal northward and southward oscillating environmental wind shear (Evws) varies between 0 to 15 ms-1 (at 0o to 15oS) while the zonal mean wind (Umst) ranging between -5 and -15 ms-1 were observed during DJFM. The contribution of TCs/TSs to DJFM rainfall was very significant, with highest rainfall influence over the hinterlands and southern parts of Tanzania compared to the northern coastal areas of Tanzania. The seasonal (DJFM) and NM) TCs/TSs statistical modeling showed strong correlation (p≤0.02) between the observed and the cross-validated TCs/TSs (0.52 0.31, respectively. Moreover, EVI and NDVI results were consistent with the patterns shown by analysis of rainfall data.Item Phytoplankton diversity and productivity wiht emphasis on the bloom dymamics of the potentially toxic cynobacterrium arthrospira fusiformis in Momela lake,Arusha, Tanzania(University of Dar es Salaam, 2007) Kaaya, Lulu TunuLimnological studies were conducted in Momela lakes ( Small Moinela, Big momela and Tulusia)for analysis of phyloplankton species composition, abudance, and biomass ( chlorophyll ‘’a’’) and environmental parameters (TSS, alkalinity, Ph salinity). transparency, water temperature and hardness and inorganic nutrients) as well estimamtions of primary production and nitrogen fixation rates, sampling was conducted once per month for a period of one year ( May 2005 to April 2006) .Calculated Shannon-weaver diversity indicates were higher in lake Small momela compared to lake big momela and Tulusia. Arthaspira fusiformis was the most dominant species in lake big (up to 1840 filaments/m1) while it existed at background concentrations in Lake Small Momela (maximum of 9 filaments/m1). Phytoplankton biomass was significantly and consistently low in Lake Small Momela compared to Lake Big Momela and Tulusia. However, there were no significant seasonal variations in phytoplankton biomass and abundance of a fusiformis. Environmental parameters were fairly stable showing insignificant temporal variations during the study period. However significant spatial variations in salinity and alkalinity among the hikes were noted. Lake Small Momela had significantly less, salinity and alkalinity levels compared to Lake Big Momela and Tulusia. Also, there were no significant differences in the rates of gross- and net-primary productivity as well as nitrogen fixation among the lakes and between seasons. In general, limnological parameters in Momela lakes did not vary much between seasons but much variation were observed among the lakes.Item Seasonal variability of phytoplankton diversity and biomass in the coastal waters of Unguja Island, Zanzibar(University of Dar es Salaam, 2017) Moto, Edward AngeloThe primary focus of this study was to describe patterns in phytoplankton distribution, composition, abundance, diversity and chlorophyll-a (Chl-a) concentration in Unguja Island coastal waters. The field study was conducted from May, 2012 to May, 2013 in Bawe and Chwaka Bay of Unguja Island. It involved species identification, abundance, diversity and chlorophyll-a determination in relation to physicochemical parameters with regard to spatial and temporal variations. A total of 260 species of phytoplankton were identified, belonging to 94 genera and six classes: Bacillariophyceae (171 species), Dinophyceae (71 species), Cyanophyceae (15 species), and one species each for Chlorophyceae, Crysophyceae and Dictyochophyceae. Species diversity at Bawe was not significantly different between seasons (p > 0.05), while at Chwaka Bay diversity was higher during the Southeast monsoon (SEM) than the Northeast monsoon (NEM) (p < 0.05). Species diversity index average was above 3.0, indicating that Unguja Island coastal waters have moderate diversity. Chl-a concentration was high near the shore of Stone Town and decreased further towards the open waters (p < 0.05). At Chwaka Bay, the spatial variability in Chl-a concentration was not significantly different among stations (p > 0.05). Temporal variation in Chl-a for insitu data revealed higher concentration of Chl-a during SEM than NEM (p < 0.05). The insitu measurements corresponded with satellite data which also showed high Chl-a concentration during the SEM that coincided with low sea surface temperature (SST). Time series satellite data for ten years further showed an inverse relationship between the interannual variation in Chl-a concentration and SSTItem Impact of climate change and variability on coastal penaeid shrimp abundance in Rufiji delta, Tanzania(University of Dar es Salaam, 2016) Bwire, Masinde KahitiraAn improved understanding of how key environmental factors drive the abundance and, thus, influence the catch of shrimps is important to prevent a decline or even collapse and to mitigate adverse effects of environmental change including climate change through fishery management. Primary and historical data of shrimp catches, rainfall, flows of the Rufiji River and temperatures were used to assess impact of climate variability on catches of coastal panaeid shrimps in the Rufiji delta. Fishing systems and socio -economic characteristics of shrimp fishers were also examined. Generally, both catches and environmental variables showed temporal variability and strong connectivity among them. Analyses of trend patterns, timing events and intensities for seasonal and interannual variability confirmed that climatic related factors influence the observed declining trends of shrimp catches in the Rufiji delta. Catches were observed to reach maximum peak during May, whereas rainfall and flows of the Rufiji River attain their maximum peaks during April of each year. Timing (phases) events and amplitude (intensities) in rainfall and river flows showed highest positive correlation with catches of coastal panaeid shrimps. Shrimp fishers had generated and adopted their own strategies to deal with a certain degree of variations in their local climate. Some of the adaptation strategies noted include shifting to new fishing areas, diversification of target species, switching and adjusting gear types, and acquiring non-fishing small scale works. This study provided the first scientific results showing drive-response relationship between climate factors and coastal panaeid shrimp catches and lays guiding foundation for formulations of climate resilience management policies of coastal penaeid shrimp fishery in Tanzania.Item Abundance, distribution and reproductive biology of two selected penaeid prawns in Tanzanian waters(University of Dar es Salaam, 2016) Mwakosya, Catherine AdamTanzania is one of the tropical countries, which practises both industrial and artisanal prawn fisheries targeting the shallow water penaeid prawns. Industrial prawn fishery takes place in three designated fishing grounds along the coast of Tanzania, namely zone 1, zone 2 and zone 3 of which in this study were considered the main sampling locations during the ship surveys conducted. On the other hand artisanal fishery is concentrated in the Ruvu estuary and along Rufiji Delta. The prawn fishery in Tanzania for the past decade has indicated serious unsustainable exploitation levels and a decline in production trends despite the reduction in fishing effort. The shallow water prawn species composition, abundance and distribution by site, zones, depth and season were assessed. Seasonal size frequency distribution, length-weight relationships, sex ratio, size at first sexual maturity, and gonad histology and growth parameters of the two prawn species (Fenneropenaeus indicus and Metapenaeus monoceros) were also studied. It was not known whether the prawn populations existing in the study area are genetically connected or distinct. To test the hypothesis that a single population exists, the mitochondrial DNA (mtDNA) sequence data were used to study the populations. From the findings of this study, it is concluded that the populations existing in the three prawn fishing grounds are not different. The study observed high exploitation levels at the two land-based sites (Bagamoyo and Nyamisati) with a slight improvement in the catch rates, which is an indicator of slow recovery of the stock. Consequently, a management strategy of extending the closed season to include the artisanal fishers’ grounds is recommended.Item Distribution and abundance of diseases on reef corals in Tanzania(University of Dar es Salaam, 2016) Mohammed, Mohammed SuleimanDiseases affecting reef corals are on the rise in the world oceans. Warming of the seas, deteriorating water quality and increased human activities in the nearshore waters are considered to play a major role in the prevalence of coral diseases. The goal of this study was therefore to characterize and investigate the abundance of coral diseases and its environmental drivers in reefs off Zanzibar and the main coast of Tanzania. To achieve these, 20 sites were selected along the whole coast of Tanzania and nearby islands. Rapid assessment surveys, line intercept transects and belt transects were used to monitor the selected study sites. In addition, the effect of temperature and nutrients on white syndrome (WS) disease on table Acropora and bleaching on Porites australiencis was assessed through sets of experiments done both in laboratory and in the field. The study has revealed seven coral diseases with significant difference between localities (p < 0.001). The mean prevalence was relatively low ranging from 2.24±1.6% in Pemba to 0.09± 0.3% in Zanzibar Stone town reefs. Prevalence of WS on table Acroporids was significantly higher during warm season 5.63±3.7 than cool season 3.55±2.2% (p<0.05). The progression rate was higher (p<0.05) during cool period where 80.42±15.42 cm2/day was recorded compared to 16.14±8.79 cm2/day recorded during warm period. These results show that there is no relationship between temperature and WS prevalence but the virulence of WS is more pronounced during cool season. When temperature and nutrients were manipulated over bleached Porites australiensis to check the progression rate of bleaching over time scale, the bleached corals did not show any significant difference between the treatments. Similarly, the treatments could not result in bleaching on healthy corals. These results show that temperature and nutrients at the levels used in this study may not have direct impact on corals but may delay coral recovery from any unforeseen impact. Disease prevalence in Tanzania water is low compared to other regions in the world. Low prevalence may be due to low levels of anthropogenic influence as compared to the areas with higher disease prevalence. Coral bleaching is the major threat to coral reefs as when it occur it cover large geographical area and involves many coral species.