Distribution of Oreochromis niloticus (L.) in the Ugandan waters of Lake Victoria

The Lake Victoria fish fauna was dominated by cichlids before the establishment of the exotic species Oreochromis niloticus (L.) and Latus niloticus (L.). With the alterations in the ecology of Lake Victoria, changes may be expected to occur in the population dynamics of the fish species. In two zones of Lake Victoria, the size structure, distribution and abundance, condition factors, length-weight relationship and sex ratios of O. niloticus were determined. Larger fish were found in zone II than in zone III, where very few larger fish were recorded. More O. niloticus were caught in zone III, especially in Itome Bay, than in zone II but catch by weight was greater in zone II. More males than females were encountered in both zones. Oreochromis niloticus had similar condition factors in both zones

The increased fishing pressure and the future of the fish stocks of Lake Victoria, Uganda

The Uganda sector of Lake Victoria occupies 29,580 km2 (43%). The lake used to boast of a multi-species fishery but presently relies on three major species Lates niloticus, Oreochromis niloticus and Rastrineobola argentea. During the past decade the total fish production on the Ugandan sector increased drastically from 17,000 tonnes in 1981 to about 13,000 tonnes 1991, indicating a healthy state of the fishery. This was contributed by a combination of factors including the explosive establishment of the introduced L. niloticus which contributed 60.8% in 1991 and the increase in the number of fishing canoes from 3470 in 1988 to 8000 in 1990. Isolated fishery resources studies carried out in different areas of the lake since 1971 seem, however, to indicate contrary trends in the available stocks and, therefore, the status of the fishery. In the experimental fishery, continued decline in catch rates have been recorded. Similarly, in the commercial fishery catch per unit of effort has been considerably poor (33 kg per canoe during January - March 1992) and the average size of individual fish laRded continued to decline, obviously pointing at possible over-fishing. This, therefore, calls for further urgent research on the available stocks for proper management strategies to be formulated

On the present fishery of Lake Wamala

A relatively small (180 km) and shallow (4.3 metres maximum depth in 1974) Lake Wamala, in central Uganda, was in 1956 stocked with the tilapiine species mainly Oreochromis niloticus (Tilapia nilotica), O. leucostictus (T. leucosticta) and Tilapia zillii (Okaronon 1987). The Lake provided a successful and profitable commercial fishing after it was opened to commercial fishing in 1960. During the 1960s and early 1970s the annual landed catches were estimated at 5000 metric tons on average; over 50% of the landed catch was composed of O. niloticus. A maximum of 250 canoes were licensed to operate on thi lake annually and each canoe was permitted to use a maximum of 10 gillnets of not less than 127mm mesh. Most of the fish was sold fresh to local communities and also to distant markets including Kampala. Following increasing number of canoes during the late 1960s and increased use of small mesh-sized (illegal) gillnets - and other illegal fishing practices - the annual fish production from the lake declined by about 93% from 7100 tons in 1967 to 500 tons in 1982 (Okaronon, op. cit). The average weight of the landed individual fish of O. niloticus - the predominant commercial fish species - also declined by about 57% from 716g in 1969 to 305g by 1976. During the period 1981/86 the area surrounding the lake was subjected to a guerrilla war and period of drought, resulting in a virtual halt of fishing activity and reduction in the size of the lake, respectively. These, too, inevitably led to stunting in the fishery and, consequently, to almost no commercial fish production. In 1988, following the end of the guerrilla war, scientific surveys of the lake's fisheries resources were resumed. The surveys aimed at assessing the status of the lake's fishery following the 1981/86 period of no fishing activity and prolonged dry season. The specific objectives included the determination of (a) catch composition, (b) the size structure of the harvestable fish stocks based on length frequency distribution, and (c) an estimate of abundance of exploited fish stocks based on catch per unit of effort. This paper, therefore, presents some of the results of the surveys during the period 1988-1991

Effect of the Red-Edge Band from Drone Altum Multispectral Camera in Mapping the Canopy Cover of Winter Wheat, Chickweed, and Hairy Buttercup

The detection and mapping of winter wheat and the canopy cover of associated weeds, such as chickweed and hairy buttercup, are essential for crop and weed management. With emerging drone technologies, the use of a multispectral camera with the red-edge band, such as Altum, is commonly used for crop and weed mapping. However, little is understood about the contribution of the red-edge band in mapping. The aim of this study was to examine the addition of the red-edge band from a drone with an Altum multispectral camera in improving the detection and mapping of the canopy cover of winter wheat, chickweed, and hairy buttercup. The canopy cover of winter wheat, chickweed, and hairy buttercup were classified and mapped with the red-edge band inclusively and exclusively using a random forest classification algorithm. Results showed that the addition of the red-edge band increased the overall mapping accuracy of about 7%. Furthermore, the red-edge wavelength was found to better detect winter wheat relative to chickweed and hairy buttercup. This study demonstrated the usefulness of the red-edge band in improving the detection and mapping of winter wheat and associated weeds (chickweed and hairy buttercup) in agricultural fields

Psychological Violence and Socio-Economic Development of Women in Uasin-Gishu County, Kenya

The growing corpus of studies on domestic violence continues to demonstrate that the vice, despite calls and efforts, is yet to be eliminated. As such, understanding gender violence requires a situation analysis that recognizes the effects of the larger social context on gender performances. This paper adds to this voice and seeks to understand the effects of psychological violence on the socio-economic development of women. By premising their arguments on the results of a study carried out in Uasin Gishu County, Kenya, the authors posit that in light of the callous approach taken by patriarchal authorities towards domestic violence against women, it is paramount to educate the populace on the “invisible” effects of domestic violence. Using a case study research design, and by employing a random sampling procedure, the authors engaged 120 women (30 each from Moi Teaching and Referral Hospital, Ngeria Prison, Eldoret Prison and Eldoret Police Station) who formed the study sample. Data was collected using questionnaires, interviews and focus group discussions. The findings of the study demonstrated that psychological violence is rife in the study area. Moreover, the authors found out that psychological violence against women has an adverse effect on their socio-economic development. This paper therefore calls for a paradigm shift in the approach to domestic violence against women. It advocates for a more detailed look into the less visible effects of this vice. Unlike victims of physical violence who have signs which are, at times, easily visible, women who undergo psychological violence have a steeper ladder to climb since their suffering is not easy to discern. This scenario has been compounded by the misconception, perpetuated by patriarchal authorities, among the victims that such atrocities are part of family secrets and should remain so. The discussions in this paper are a great contribution to studies on domestic violence against women and contextualize new knowledge which will assist researchers and policy makers in understanding of various issues which are related to psychological domestic violence. Keywords: psychological violence, domestic violence, women, Uasin-Gishu County, socio-economic developmen

The present status of the fish stocks in the experimental and commercial/artisanal gillnet fisheries in selected waters of Lake Victoria, Uganda

Lake Victoria had a multi-species fishery dominated until the 1970s by the tilapiine and the haplochromine cichlids, but with important subsidiary fisheries of more than 20 genera of non-cichlid fishes such as Bagrus, Barbus, C/arias, Mormyrus, Protopterus, Synodontis, etc (Kudhongania & Cordone 1974). From about 1930 to 1960, the fisheries of Lake Victoria were managed by controlling the mesh size of gill nets (Graham 1929). Gill nets of mesh sizes less than 127 mm (5 inches) stretched mesh had been prohibited on Lake Victoria because they cropped immature Oreochromis esculentus (Ngege) which were at that time the most important commercial species on the lake (Graham 1929). The catch in the legal 127 mm mesh nets per night was over 30 fish of Oreochromis esculentus prior to 1921; this dropped to 6 and 1.6 fish in 1928 and 1954, respectively,(Beauchamp1955),indicating overfishing ofthe stocks

Examining the Integration of Landsat Operational Land Imager with Sentinel-1 and Vegetation Indices in Mapping Southern Yellow Pines (Loblolly, Shortleaf, and Virginia Pines)

The mapping of southern yellow pines (loblolly, shortleaf, and Virginia pines) is important to supporting forest inventory and the management of forest resources. The overall aim of this study was to examine the integration of Landsat Operational Land Imager (OLI ) optical data with Sentinel-1 microwave C-band satellite data and vegetation indices in mapping the canopy cover of southern yellow pines. Specifically, this study assessed the overall mapping accuracies of the canopy cover classification of southern yellow pines derived using four data-integration scenarios: Landsat OLI alone; Landsat OLI and Sentinel-1; Landsat OLI with vegetation indices derived from satellite data—normalized difference vegetation index, soil-adjusted vegetation index, modified soil-adjusted vegetation index, transformed soil-adjusted vegetation index, and infrared percentage vegetation index; and 4) Landsat OLI with Sentinel-1 and vegetation indices. The results showed that the integration of Landsat OLI reflectance bands with Sentinel-1 backscattering coefficients and vegetation indices yielded the best overall classification accuracy, about 77%, and standalone Landsat OLI the weakest accuracy, approximately 67%. The findings in this study demonstrate that the addition of backscattering coefficients from Sentinel-1 and vegetation indices positively contributed to the mapping of southern yellow pines

Land cover land use mapping and change detection analysis using geographic information system and remote sensing

Land cover/land use categories are relevant components in land management. Understanding how land cover/land use change over time is necessary to assess the consequences of humans and natural stressors on the earth’s environment and resources. The aim of the study was to map and monitor the spatial and temporal change in land cover/land use for the periods of 1977, 1991 and 2016 and to predict change detection areas in Davidson County, Tennessee. The land cover/land use categories were classified using maximum likelihood algorithm and post classification comparison change detection analysis was performed. Classified image differencing technique was also used to predict change detection areas in Geographic Information System. The land cover/land use categories were successfully classified with a kappa value of about 78%. The land cover/land use classes changed significantly from 1977 to 2016 in Davidson County, Tennessee. Wetlands and bare land had a net decrease on average of about 97% between 1977 and 2016 whereas; developed areas and forest had a net increase on average of around 40% between 1977 and 2016. Urbanization appeared to be one of the main drivers of the change in land cover/land use. This information could be used in land management and planning by environmental managers, policy makers and other stakeholders

Assessment of the performance of beach management units (BMUs) on Lakes Victoria, Albert, Kyoga and George

Until the late 1990s the fisheries of Ugandan lakes had been managed by government where stakeholders were excluded from the decision-making process. In order to involve other stakeholders, co-management was adopted. Operationalising Co-management on landing sites has led to the formation of BMUs at gazetted landing sites. A BMU is made up of a BMU assembly and the BMU committee that it elects. A BMU committee should be: 30% boat owners; 30% boat barias 30% including fish processors, boat makers, local gear makers and repairers, fishing input dealers and managers and 10% fish mongers/traders; and if possible, 30% women. To operate at a particular landing site, one must be registered with the BMU. The BMU assembly is the supreme organ of a BMU empowered to elect, approve and remove the BMU committe

The principles and practices of mentoring for educators in a technical college in Africa : a self-study enquiry

Educators in higher education are expected by their institutions to enhance their learning and development in order to acquire the requisite knowledge and skills to keep up with the changes being presented by the external environment. Within this environment of change, educators are faced with challenges of professional development. Under certain circumstances, there are educators who will take the initiative to intervene in the learning and development of other educators in the absence of sufficient organisational support. A developmental mentoring approach is presented as a powerful intervention to enhance the learning and development of educators. Action research, utilising a self study approach to enquiry, is used to explore how mentoring practice can, from a developmental perspective, assist in enhancing the individual learning and development of educators in one Vocational Education and Training (VET) educational institution in Botswana. In this study, one mentor and two mentees undertake an innovative mentoring journey to build personal and professional capacity. Action research cycles are used in the collection of data from face-to-face conversations, personal reflective journals and focus group interviews. The findings indicate that the mentoring process contributed effectively to learning and development and enhanced the participants’ capacity to cope with the challenges facing the organisation. The intervention assisted the mentor to improve her mentoring capacities. Overall, the behavioural change that the participants gained through the mentoring process resulted in improved practices that contributed to the learning of the organisation. The value of this study lies in the fact that it provides insight into the learning and development of educators in VET educational institutions through an innovative mentoring experience and highlights how both the mentees and the mentor grew and were empowered by this experience. The individual learning of educators can influence the organisational behaviour of the VET educational institutions using mentoring. The implication of these findings points to the fact that educators need to be proactive and pursue their own professional development by making use of mentoring as an avenue to individual learning and personal and professional development. Educators who engage with more experienced colleagues in mentoring relationships contribute to organizational learning. A recommendation to VET educational institutions in Africa is to embrace mentoring as an organisational development intervention for the continuous learning and development of educators in their institutions.Thesis (PhD)--University of Pretoria, 2009.Human Resource Managementunrestricte