Inaug.-Diss.--Göttingen, 1913. / Vita. eContent provider-neutral record in process. Description based on print version record. "Literaturverzeichnis": p. [91]-96.

The Nile perch, Lates niloticus (Linnaeus, 1758), is a predacious freshwater fish widely distributed throughout the Afro-tropic eco-zone. The species was introduced to Lake Victoria in the early 1950s and by 1980 it had dominated the fisheries of Lake Victoria. This was followed by a dramatic decrease in the Nile perch fisheries production due to uncontrolled exploitation. The purpose of this thesis is to provide fundamental knowledge that can be applied in aquaculture and fisheries management through the study of the reproductive biology of L. niloticus. The research was aimed at the studying of the diverse aspects of the reproductive biology of L. niloticus in the Lake Victoria, Ugandan populations. This included reproductive patterns in relation to proximate environmental conditions, size at sexual maturity, gonad and gamete structure, gametogenesis and induced ovulation. The size at 50% sexual maturity for female Nile perch was 59.4 cm, which is lower than the earlier reported size of greater than 90 cm total length. Male L. niloticus matured at 57.8 cm total length in Lake Victoria. Microscopy revealed that L. niloticus from Lake Victoria had one spawning period that started in November and ended in March. Type I atresia occurred at high frequency from March to June, and type III atresia was present from July to September and between November and December. Spermatogenesis in L. niloticus is cystic and sperm development is the result of asynchronous activation of the germ cells. Type II spermatozoa are simple, uni-flagellate aquasperm with no acrosome. Oogenesis in L. niloticus differed from that of other fishes in that no cortical alveoli were present in any stage of oogenesis. Numerous oil globules were present in the primary yolk vesicle stage. This formed one centrally positioned, large oil globule in the tertiary yolk vesicle oocytes during final oocyte maturation. Clove oil was an effective sedative and an anaesthetic for the handling of L. niloticus. Induction time was more rapid at clove oil concentrations of 50 - 100 μl L⁻¹ than in fish exposed to clove oil concentrations less than 50 μl L⁻¹. Fish exposed to high concentrations exhibited significantly short induction times of less than 240 seconds. On average, fish recovered within 673 ± 58 seconds for all the concentrations used. Prolonged exposure of L. niloticus to low clove oil concentrations of 2.5 - 10 μl L⁻¹ did not change the blood plasma cortisol, glucose, and the lactate and chloride ion concentration, relative to the control treatment. Captive breeding was attempted by conducting induced spawning experiments. Only final oocyte maturation was achieved using a decapeptide Gonadotropin Releasing Hormone (Dargin, sGnRH-MET), combined with a water-soluble dopamine receptor antagonist metoclopramide. This thesis suggests a research approach that provides a basis for aquaculture of the new species by first studying reproductive biology patterns and then linking the information to gonad and gamete structure so that spawning times can be estimated. It further provides insights into aspects of the reproductive biology of the species and the effects of hormonal intervention on oocytes by showing at which stage of oocyte development hormones should be applied in L. niloticus. Clove oil can be used to sedate and anaesthetise L. niloticus broodfish to reduce the stress related to the handling of large specimens.

Lake Victoria, the largest tropical lake, has faced an unprecedented assault on its ecosystem through a variety of anthropomorphic causes that include the introduction of Nile perch Lates niloticus and over-fishing. As a result there have been species extinctions and declining fish population trends. This thesis explores options for reversing these declining population trends and the restoration of collapsed fisheries based on indigenous non-cichlid species. A candidate species was chosen - the cyprinid fish Labeo victorianus. This thesis studied various aspects of L. victorianus' reproductive biology in two geographically distant populations. These included general reproductive patterns in relation to proximate environmental conditions, gonadal development and recrudescence, sex development, characterisation of genetic and morphological diversity, and induced spawning. Fish from both populations were found to be potamodrometic, and highly fecund, iteroparous spawners. L. victorianus was also shown to be an undifferentiated gonochorist, where all individuals pass through an intersexual juvenile stage prior to differentiation, and maturation to either sex. Sexual maturity was attained at a significantly larger size within the Kagera River than that of Sio River fish – possibly as a response to genotypic and/or phenotypic differences. Spawning seemed to be synchronised with rainfall in Kagera River - a pattern that was not strictly adhered to with the Sio River. Thorough microscopic investigation of recrudescence patterns indicated there was uninterrupted spawning in fish from the Kagera River followed by Type I oocyte atresia. In contrast, there was a 90% spawning failure, as characterised by Type II oocyte atresia, within the Sio River population. Aspects of spermatogenesis and sperm ultrastructure using light- and ultramicrotomic methods are described. Although the populations had varying reproductive biology parameters and were morphologically distinct, they remained undifferentiated at the mitochondrial level. Both populations were characterised by low nucleotide diversity – a feature attributed to a bottleneck event. The option of captive breeding was explored by conducting induced spawning experiments. Success was only achieved with a decapeptide Gonadotropic Releasing Hormone ([D-Arg⁶, Pro⁹-NEt])-sGnRH) in combination with a water-soluble dopamine receptor antagonist metoclopramide. This thesis stresses the importance of a research-oriented approach in the conservation of Lake Victoria's indigenous fish resources. It was concluded that information needed for the development of management policies can be generated within a reasonably short time period, of approximately three years, with modest levels of funding support.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2006. / In many part of the world, but especially in Africa, land degradation leads to severe soil erosion and high sediment yields. Mathematical models and empirical methods can be used to simulate the sediment yields. In many cases spatial and temporal data are however limited in the large catchments often found in Africa. A model should be able to simulate the long-term hydrology and sediment yields for sub-catchments and should be physically based as far as possible. In this thesis several models were evaluated and the agrohydrological model of the University of Kwa- Zulu-Natal (ACRU) was applied on two large catchments with limited data in Kenya. The key aim of the thesis was to assess the applicability of the ACRU modelling system for sediment yield prediction in large catchments under conditions of limited data availability. Two catchments in Kenya which drain into Lake Victoria were selected for this research: Nyando (3562 km2) and Nzoia River (13692 km2). Lake Victoria, with a surface area of 68000 km2 and an adjoining catchment of around 184200 km2, is the second largest fresh water lake in the world and the largest in the tropics. The Lake Victoria Basin area is increasingly being used for domestic, agricultural and industrial purposes by the three riparian countries Kenya, Tanzania and Uganda. About 21 million people (year 2000) rely primarily on subsistence agricultural and pastoral production for their livelihoods. But pervasive poverty has hindered sustainable use of the land resources and there has already been considerable land degradation. There has also been expansion of the increasing on-site erosion (overland flow) and reducing buffering capacity of the natural vegetation in wetlands and in the riparian zones (Hansen, Walsh, 2000). A regional assessment identified the Nyando River Basin and Nzoia River Basin as major sources of sediment flow into Lake Victoria on the Kenyan side of the Lake. Accelerated run off sheet erosion over much of the Nyando catchment area has led to severe rill, gully and stream bank erosion in lower parts of the river basin (Swallow, 2000). The ACRU model is a hydrological model using daily time steps with the Modified Universal Soil Loss Equation (MUSLE, Williams, 1975) module to simulate soil erosion. The MUSLE sediment yield module uses factors that characterize physical conditions on the surface of a catchment as input information. Data required for the model include: sub-catchment daily rainfall, historical flow records, general catchment topographical information, meteorological information, land use and cover, soil characteristics, sediment yield data, etc. The model used daily time steps for a 55 years record for the period 1950 to 2004. During calibration it was found that the sediment yield is overestimated which was expected since the model is a soil erosion model (based on MUSLE). The model was calibrated in each catchment against observed sediment load data, but this data were limited. Verification of the model was carried out by using satellite images and independent sediment load data when available. Scenario analysis was carried out by changing land use in the model to investigate how soil erosion could be reduced. Grassland to replace subsistence farming was found most effective, but irrigated sugarcane was also investigated. The model was found to be very effective in indicating which sub-catchments contribute most of the sediment yield. Under limiting data conditions it was found that it is very important to calibrate the model against field data. The most sensitive parameters affecting the sediment yield were found to be: a) Hydrological: • Daily rainfall spatial distribution of rain gauge • Time of concentration • Mean annual precipitation • Minimum and maximum temperature • Monthly evaporation b) Soil and catchment characteristics: • Number of sub-catchments making up catchment in model • Catchment slope and slope length, steepness factor • Land cover • Crop coefficient • Soil texture class and depths • Soil erodibility factor

The study explored, described and explained the current models of voluntary counselling and testing services delivery and analysed the extent to which a given VCT model had influenced uptake of VCT services in the fishing communities along the shores of Lake Victoria, in Wakiso District, with an aim of designing optimal VCT service delivery strategies. The study was therefore exploratory, descriptive and explanatory, and collected both qualitative and quantitative data in a three-phased approach. Phase I involved the Kasenyi fishing community respondents, while phases II and III involved VCT managers and VCT counsellors at the Entebbe and Kisubi Hospitals. The findings indicated that VCT services are generally available onsite at health facilities, and in the field through mobile VCT outreach or home-based VCT services provided at clients’ homes. Both client-initiated and health provider-initiated VCT services are available and services are integrated with other health services. Despite the availability of VCT, only about half of the respondents in phase I had accessed VCT services although almost all indicated a willingness to undergo HIV testing in the near future. The main challenges to service delivery and utilisation included limited funding and staffing as well as limited awareness in target communities. The strategies drawn are based on the need to increase availability, accessibility, acceptability and utilisation of VCT services. / Health Studies / D. Litt. et Phil. (Health Studies)

The study explored, described and explained the current models of voluntary counselling and testing services delivery and analysed the extent to which a given VCT model had influenced uptake of VCT services in the fishing communities along the shores of Lake Victoria, in Wakiso District, with an aim of designing optimal VCT service delivery strategies. The study was therefore exploratory, descriptive and explanatory, and collected both qualitative and quantitative data in a three-phased approach. Phase I involved the Kasenyi fishing community respondents, while phases II and III involved VCT managers and VCT counsellors at the Entebbe and Kisubi Hospitals. The findings indicated that VCT services are generally available onsite at health facilities, and in the field through mobile VCT outreach or home-based VCT services provided at clients’ homes. Both client-initiated and health provider-initiated VCT services are available and services are integrated with other health services. Despite the availability of VCT, only about half of the respondents in phase I had accessed VCT services although almost all indicated a willingness to undergo HIV testing in the near future. The main challenges to service delivery and utilisation included limited funding and staffing as well as limited awareness in target communities. The strategies drawn are based on the need to increase availability, accessibility, acceptability and utilisation of VCT services. / Health Studies / D. Litt. et Phil. (Health Studies)

The developemnt of fisheries in Lake Victoria is faced with a myriad challenges including overfishing, environmental destruction, disappearance of certain indigenous species and pollution. All these problems can be located within the social, economic and political systems that exists today and in the past. This thesis, ‘Fishers and Fish Traders of Lake Victoria : Colonial Policy and the Development of Fish Production in Kenya, 1880-1978’, argues that the Luo fishers had their own indigenous techniques of fishing, modes of preservation and systems of management that ensured sustainable utilisation of fisheries. The thesis examines the role of the Luo fishers in the sustainable usage of the Lake Victoria fisheries. The British colonial settlers came up with new policies of plantation and commercial farming, taxation and forced labour, all of which encouraged the Luo fishers to partially break with their pre-colonial systems and create new ways of responding to the demands of the colonial state. The study argues that the coming of colonialism and its attendant capitalism introduced new fishing gear as well as new species, such as mbuta, that were inimical to the sustainable utilisation of the Lake Victoria fisheries. The colonial regime also introduced new practices of fisheries management such as scouts, licensing, closed seasons and the numbering of boats, practices geared towards ensuring the commercial production and development of the fisheries. This commercialisation led to cut-throat competition between Asian, European and African fish traders. The coming of independence in 1963 brought some changes, such as the provision of credit facilities, new technology, and attempts by the new African government to more effectively control and manage the fisheries. However, not much changed in terms of policy objectives, and most of the colonial policies remained unchanged. New industries were established around the fisheries, but most remained in the hands of Asians and a few African middlemen. The small-scale fishers continued to struggle against the commercialisation of fishery production, remaining voiceless and marginalised. The study recommends an all inclusive participatory approach to solve the problems currently affecting the Lake Victoria fisheries. / History / DLITT (History)

The developemnt of fisheries in Lake Victoria is faced with a myriad challenges including overfishing, environmental destruction, disappearance of certain indigenous species and pollution. All these problems can be located within the social, economic and political systems that exists today and in the past. This thesis, ‘Fishers and Fish Traders of Lake Victoria : Colonial Policy and the Development of Fish Production in Kenya, 1880-1978’, argues that the Luo fishers had their own indigenous techniques of fishing, modes of preservation and systems of management that ensured sustainable utilisation of fisheries. The thesis examines the role of the Luo fishers in the sustainable usage of the Lake Victoria fisheries. The British colonial settlers came up with new policies of plantation and commercial farming, taxation and forced labour, all of which encouraged the Luo fishers to partially break with their pre-colonial systems and create new ways of responding to the demands of the colonial state. The study argues that the coming of colonialism and its attendant capitalism introduced new fishing gear as well as new species, such as mbuta, that were inimical to the sustainable utilisation of the Lake Victoria fisheries. The colonial regime also introduced new practices of fisheries management such as scouts, licensing, closed seasons and the numbering of boats, practices geared towards ensuring the commercial production and development of the fisheries. This commercialisation led to cut-throat competition between Asian, European and African fish traders. The coming of independence in 1963 brought some changes, such as the provision of credit facilities, new technology, and attempts by the new African government to more effectively control and manage the fisheries. However, not much changed in terms of policy objectives, and most of the colonial policies remained unchanged. New industries were established around the fisheries, but most remained in the hands of Asians and a few African middlemen. The small-scale fishers continued to struggle against the commercialisation of fishery production, remaining voiceless and marginalised. The study recommends an all inclusive participatory approach to solve the problems currently affecting the Lake Victoria fisheries. / History / DLITT (History)

The Lake Victoria Basin (LVB) is endowed with natural resources which are drivers for sustainable development at local, national and regional levels. However, these resources are adversely affected by dynamic social, economic, environmental and political factors. Poor coordination and ineffective knowledge management programmes among various players within the LVB has led to duplication of efforts as substantial information and knowledge generated is unavailable to users. As a result, over-exploitation of natural resources has resulted in unsustainable development of the LVB. This study sought to establish the role of knowledge management in promoting sustainable development of the LVB. Specific objectives were to: determine the role of knowledge management in sustainable development of LVB; determine challenges and barriers hindering effective knowledge management; establish tools and technology that can be used to enhance knowledge management; and establish the strategies used by organisations in LVB to manage knowledge generated for sustainable development. A descriptive survey design was used in this study targeting 98 (with 76.5% response rate) officers of various ranks working in 26 organisations involved in development programmes/projects and located in the five partner states within the LVB. Data was collected using self administered questionnaires and a desk review. Findings showed most respondents agreeing that knowledge management is a systematic utilisation of policies, processes, activities and tools which empower organisations to apply knowledge to improve effectiveness, innovation and quality. Up to 93.9% of the organisations facilitated discovery, capture, storage and retrieval of knowledge. Most organisations encouraged documentation of lessons learnt, with some making it mandatory to deposit key documents in the library. Paper-based media was the most preferred knowledge storage format. Lack of an open-minded sharing environment, bureaucratic procedures and poor information systems were the common barriers to knowledge management, while lack of time (68.4%) was an obstacle to proper xvi documentation. The internet was the most popular knowledge management tool/technology; though technical issues were the most critical problems affecting ICT use (71.4%). Based on these findings, this study recommends a holistic and coordinated approach to knowledge management among all institutions working in the LVB to address the challenges of sustainable development in the basin. / Information Science / M. Inf. (Information Science)

The state of the environment is increasingly present as an urgent concern for contemporary political, social, cultural and physical life. Yet the roles of the mass media (radio, television and newspapers) in shaping and influencing crucial public awareness, debates and environmental decision-making remain inadequately understood. Positioned as a critical studies inquiry into media representations and audience reception, this study forms part of a wider project amongst media scholars and culture critics on the relationship between media textual production and consumption. It explores how one radio station in Uganda, Central Broadcasting Service (CBS) radio, represents and constructs the environmental crises faced by Lake Victoria, especially pollution and overfishing. The focus is on the Victoria Voice radio documentaries aired on CBS radio in the year 2005. The study further explores how three lakeside communities negotiate these issues as radio broadcasts. It recognises that while the mass media contribute significantly to creating public awareness about such social concerns, their likelihood of having a direct and predictable impact on social behaviour is slight. The context and the lived experiences at the reception stage where the decisions are made on whether to adopt an innovation are ultimately the factors which impact on how they are negotiated. The thesis is informed by the theoretical and analytical framework of Cultural Studies as well as the Participatory Approach to Communication for Development perspectives. The study is specifically informed by the theories of ‘discourse’ (Foucault, 1980a, 1981) and the ‘circuit of culture’ (du Gay et al., 1997 and Johnson, 1987) and these provided the conceptual framework for investigating the representations, the production and the consumption of media texts. Predominantly qualitative methods have been employed in data collection and analysis. In the first place, a Critical Discourse Analysis (CDA) (Fairclough, 1995a, 1995c) of the radio texts has interrogated the discourses and discursive practices of CBS’ Victoria Voice environmental radio programmes in order to consider its representations of particular issues and consequently the discourses it privileged. Qualitative methods of participant observation, in-depth interviews and focus group discussions were deployed to investigate the negotiation of the texts by the lakeside communities. This research establishes that the Victoria Voice radio texts foreground three contesting types of discourses: the discourse of basic economic survival and livelihoods is articulated largely by the ordinary people, the lakeside communities; the discourse of sustainable development, particularly the protection and sustainability of Lake Victoria, by scientists and environmental experts; and the discourse of modernisation and corporate investment by politicians and/or policy makers and industrialists. The texts, to a large degree, reaffirm the hegemonic relations of power in Ugandan society, and thus contribute to the maintenance of the status quo. The selection of an elite category of informers (scientists, experts, politicians, policy makers) serves to marginalise the less powerful ordinary people (the fisher folk, farmers and other eyewitnesses). The construction of the elite as active and speaking subjects within the various debates introduced in these programmes, for example, works both to obscure and endorse the unequal power relations. At the reception side, while the lakeside communities attest to the relevance of the programmes in providing information on the issues concerning Lake Victoria and other aspects of their livelihood, they also recognise the power relations that underpin the sets of representations. Amongst these sets is government’s complicity with industry, in line with their economic policies and the global capitalist economy, while espousing the rhetoric of nature conservation. The study argues that sustainable solutions for the crises on Lake Victoria should take into account the socio-historical and cultural contexts of the lakeside communities. For the Ugandan media, particularly radio, there is a need to rethink the nature of the coverage, which tends to neglect the contextual factors, such as local socio-economic and cultural factors within which environmental issues and problems occur and which, as this thesis establishes, greatly influences the way people make sense of environmental issues and problems. I posit that the Participatory Approach that seeks to address the communities’ most pressing concerns should be adopted – to include more of the communities’ voices and involve them in the production of radio programmes.