The relationship between job satisfaction and absenteeism : a study of the shop floor workers in a motor manufacturing plant
- Authors: Mashonganyika, Oswald
- Date: 2004
- Subjects: Job satisfaction -- South Africa -- Eastern Cape Absenteeism (Labor) -- South Africa -- Eastern Cape Automobile industry and trade -- South Africa -- Eastern Cape -- Employees Industrial relations -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:809 , http://hdl.handle.net/10962/d1007518
- Description: This research hypothesises a statistical positive significant correlation between job satisfaction and absenteeism among the shop floor workers of a motor manufacturing plant in the impoverished province of the Eastern Cape in South Africa. According to the literature review, two schools of thought exist that argue on the nature of the relationship. One believes that absence from work is in some way a natural consequence of job dissatisfaction, i.e. arguing for a job satisfaction-absenteeism relationship. The second one argues for a no relationship, arguing that absence is a result of habitual behaviour and or behaviours influenced by socioeconomic factors such as poverty that affect the employees' ability and pressure to attend work. A sample of 150 workers was randomly selected from the 2500 shop floor workers. The Job Descriptive Index (lDI) questionnaires were used to measure the satisfaction index of the workers. The absence statistics for the sample workers were gathered from the organisation's Human Resources department and statistical tests for correlation and regression were conducted on the two variables - lDI and absence data. Contrary to the expectations of the study, the results showed that overall job satisfaction and absenteeism were not correlated. It concluded that the job dissatisfaction theory of absenteeism is empirically unsupportable and alternative conceptualisations of absence contributors and potentially fruitful research strategies are discussed.
- Full Text:
- Date Issued: 2004
- Authors: Mashonganyika, Oswald
- Date: 2004
- Subjects: Job satisfaction -- South Africa -- Eastern Cape Absenteeism (Labor) -- South Africa -- Eastern Cape Automobile industry and trade -- South Africa -- Eastern Cape -- Employees Industrial relations -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:809 , http://hdl.handle.net/10962/d1007518
- Description: This research hypothesises a statistical positive significant correlation between job satisfaction and absenteeism among the shop floor workers of a motor manufacturing plant in the impoverished province of the Eastern Cape in South Africa. According to the literature review, two schools of thought exist that argue on the nature of the relationship. One believes that absence from work is in some way a natural consequence of job dissatisfaction, i.e. arguing for a job satisfaction-absenteeism relationship. The second one argues for a no relationship, arguing that absence is a result of habitual behaviour and or behaviours influenced by socioeconomic factors such as poverty that affect the employees' ability and pressure to attend work. A sample of 150 workers was randomly selected from the 2500 shop floor workers. The Job Descriptive Index (lDI) questionnaires were used to measure the satisfaction index of the workers. The absence statistics for the sample workers were gathered from the organisation's Human Resources department and statistical tests for correlation and regression were conducted on the two variables - lDI and absence data. Contrary to the expectations of the study, the results showed that overall job satisfaction and absenteeism were not correlated. It concluded that the job dissatisfaction theory of absenteeism is empirically unsupportable and alternative conceptualisations of absence contributors and potentially fruitful research strategies are discussed.
- Full Text:
- Date Issued: 2004
The reproductive biology and artificial breeding of ningu Labeo victorianus (Pisces: Cyprinidae)
- Authors: Rutaisire, Justus
- Date: 2004
- Subjects: Fishes -- Victoria, Lake , Cyprinidae -- Reproduction , Labeo -- Reproduction , Labeo
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5317 , http://hdl.handle.net/10962/d1005162
- Description: 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.
- Full Text:
- Date Issued: 2004
- Authors: Rutaisire, Justus
- Date: 2004
- Subjects: Fishes -- Victoria, Lake , Cyprinidae -- Reproduction , Labeo -- Reproduction , Labeo
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5317 , http://hdl.handle.net/10962/d1005162
- Description: 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.
- Full Text:
- Date Issued: 2004
The role of management and leadership in the schooling of at-risk learners: a case study of a school in Namibia
- Authors: Ipinge, Emma
- Date: 2004
- Subjects: School management and organization -- Namibia -- Case studies Educational leadership -- Namibia -- Case studies Education and state -- Namibia School discipline -- Namibia Children with social disabilities -- Education -- Namibia Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1750 , http://hdl.handle.net/10962/d1003634
- Description: Most schools that serve learners who come from disadvantaged areas and backgrounds face unusually difficult challenges. These schools experience poor performance and disciplinary problems, and teachers lack motivation and commitment. This study explores the role of leadership and management in the schooling of at-risk learners at Pandu Primary School. This school accommodates learners mostly from Hafo, a township characterised by poverty with a high crime rate. However, in spite of these factors school inspectors and advisory teachers perceive the school to be successful. The school uses an abundance of energy and unusually high levels of human effort in a very focused way to improve the teaching and learning standard. The study found the co-existence of apparently conflicting management and leadership approaches in managing and leading the school. Strict control used in the school to make teachers work hard is an element of classical organisational theory, with its emphasis on span of control or number of workers supervised. Policies with strict rules are in place to create a calm atmosphere and serve as directives for teachers and learners. On the other hand, constructivist approaches – such as instructional leadership, transformational leadership, collegial model of management and open systems – are also clearly evident in the findings. Instructional leadership is evident in the emphasis on improvement of classroom practice. Elements of transformational leadership are seen in that the principal motivates the teachers and serves as a role model. The school also has some features of the collegial model of management, and can be described as an open system. Thus, by drawing on management and leadership approaches informed by different traditions and philosophies, the school succeeds against severe odds.
- Full Text:
- Date Issued: 2004
- Authors: Ipinge, Emma
- Date: 2004
- Subjects: School management and organization -- Namibia -- Case studies Educational leadership -- Namibia -- Case studies Education and state -- Namibia School discipline -- Namibia Children with social disabilities -- Education -- Namibia Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1750 , http://hdl.handle.net/10962/d1003634
- Description: Most schools that serve learners who come from disadvantaged areas and backgrounds face unusually difficult challenges. These schools experience poor performance and disciplinary problems, and teachers lack motivation and commitment. This study explores the role of leadership and management in the schooling of at-risk learners at Pandu Primary School. This school accommodates learners mostly from Hafo, a township characterised by poverty with a high crime rate. However, in spite of these factors school inspectors and advisory teachers perceive the school to be successful. The school uses an abundance of energy and unusually high levels of human effort in a very focused way to improve the teaching and learning standard. The study found the co-existence of apparently conflicting management and leadership approaches in managing and leading the school. Strict control used in the school to make teachers work hard is an element of classical organisational theory, with its emphasis on span of control or number of workers supervised. Policies with strict rules are in place to create a calm atmosphere and serve as directives for teachers and learners. On the other hand, constructivist approaches – such as instructional leadership, transformational leadership, collegial model of management and open systems – are also clearly evident in the findings. Instructional leadership is evident in the emphasis on improvement of classroom practice. Elements of transformational leadership are seen in that the principal motivates the teachers and serves as a role model. The school also has some features of the collegial model of management, and can be described as an open system. Thus, by drawing on management and leadership approaches informed by different traditions and philosophies, the school succeeds against severe odds.
- Full Text:
- Date Issued: 2004
The toxic effect of heavy metals on algal biomass (Spirulina sp.) and carbonic anhydrase activity, an enzyme which is central to algal application in metal precipitation
- Authors: Nightingale, Leigh
- Date: 2004
- Subjects: Heavy metals -- Toxicology , Spirulina , Carbonic anhydrase , Algae -- Metabolism , Photosynthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4093 , http://hdl.handle.net/10962/d1007858 , Heavy metals -- Toxicology , Spirulina , Carbonic anhydrase , Algae -- Metabolism , Photosynthesis
- Description: Acid rmne drainage (AMD) is a major pollution problem througbout the world, adversely affecting both surface and groundwaters. AMD is principally associated with the mining of sulphide ores. The most commonly associated minerals being sulphur, copper, zinc, silver, gold, lead and uranium. As conventional methods for removing heavy metals from wastewater are often prohibitively expensive, the implementation of biological processes for the removal of heavy metals has become a realistic practice. The objectives of this project was firstly to establish the effect of copper, lead and nickel, heavy metals commonly found in AMD waters, on the enzyme carbonic anhydrase, which is an integral part of the carbon concentrating mechanism (CCM) and secondly, to determine the feasibility of using the alkalinity generated by Spindina for the precipitation of heavy metals from solution. Initially, batch flask experiments were performed and it was found that the algae were able to utilise the bicarbonate supplied in the medium, under CO, limiting conditions, through the induction of their CCM, resulting in the generation of carbonate. The effect of the inhibitors, acetazolamide (AZ) and ethoxyzolamide (EZ), were also investigated in order to determine the importance of carbonic anhydrase (CA) in inorganic carbon accumulation and photosynthesis. Results obtained were consistent with those observed in literature and it was found that at IOOf.LM AZ and EZ, complete inhibition of photosynthesis and carbonic anhydrase occurred, with no oxygen being evolved. The results obtained from the inhibitor experiments substantiate the findings that carbonic anhydrase is an important part of the CCM, and that the dehydration of bicarbonate to carbon dioxide and hydroxide ions, is in fact an enzymatic process regulated by the enzyme carbonic anhydrase and is essential for efficient photosynthesis. The effect of heavy metals on Spirulina was also investigated. Lead, copper and nickel were all found to cause a reduction in the synthesis of chlorophyll a, which resulted in a decrease in photosynthetic efficiency and eventually death of the culture. The morphology of the algae was also severely affected by heavy metals, with degradation and aJmost complete disintegration of the algal filaments occurring. Using the Wilbur-Anderson assay method, carbonic anhydrase activity was found to be lower in the experimental flasks containing heavy metals, than the control flasks, reducing the algae's ability to utilise the bicarbonate in solution for effective photosynthesis. The Wilbur-Anderson assay method did not prove to be a reliable method for measuring changes in enzyme activity as results were found to be erratic. Therefore attempts were made to use an oxygen electrode as an alternative method for determining the effects of various parameters on enzyme activity and photosynthesis, this proved to be more successful. Because of the toxic effects of heavy metals on Spirulina it was decided that the use of the biogenic alkalinity generated by the algae for the precipitation of heavy metals may be successfully employed as an alternative method for bioremediation and metal recovery. Carbonate reacts readily with metals, therefore the carbonate produced by this algal system was used for the precipitation of metals. It was possible to categorise the precipitation reactions observed into three groups, namely those metals which, a) precipitate as hydroxides, b) precipitate as carbonates generated from the dissociation of bicarbonate and c) metals which can only precipitate if there is free carbonate present in solution.
- Full Text:
- Date Issued: 2004
- Authors: Nightingale, Leigh
- Date: 2004
- Subjects: Heavy metals -- Toxicology , Spirulina , Carbonic anhydrase , Algae -- Metabolism , Photosynthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4093 , http://hdl.handle.net/10962/d1007858 , Heavy metals -- Toxicology , Spirulina , Carbonic anhydrase , Algae -- Metabolism , Photosynthesis
- Description: Acid rmne drainage (AMD) is a major pollution problem througbout the world, adversely affecting both surface and groundwaters. AMD is principally associated with the mining of sulphide ores. The most commonly associated minerals being sulphur, copper, zinc, silver, gold, lead and uranium. As conventional methods for removing heavy metals from wastewater are often prohibitively expensive, the implementation of biological processes for the removal of heavy metals has become a realistic practice. The objectives of this project was firstly to establish the effect of copper, lead and nickel, heavy metals commonly found in AMD waters, on the enzyme carbonic anhydrase, which is an integral part of the carbon concentrating mechanism (CCM) and secondly, to determine the feasibility of using the alkalinity generated by Spindina for the precipitation of heavy metals from solution. Initially, batch flask experiments were performed and it was found that the algae were able to utilise the bicarbonate supplied in the medium, under CO, limiting conditions, through the induction of their CCM, resulting in the generation of carbonate. The effect of the inhibitors, acetazolamide (AZ) and ethoxyzolamide (EZ), were also investigated in order to determine the importance of carbonic anhydrase (CA) in inorganic carbon accumulation and photosynthesis. Results obtained were consistent with those observed in literature and it was found that at IOOf.LM AZ and EZ, complete inhibition of photosynthesis and carbonic anhydrase occurred, with no oxygen being evolved. The results obtained from the inhibitor experiments substantiate the findings that carbonic anhydrase is an important part of the CCM, and that the dehydration of bicarbonate to carbon dioxide and hydroxide ions, is in fact an enzymatic process regulated by the enzyme carbonic anhydrase and is essential for efficient photosynthesis. The effect of heavy metals on Spirulina was also investigated. Lead, copper and nickel were all found to cause a reduction in the synthesis of chlorophyll a, which resulted in a decrease in photosynthetic efficiency and eventually death of the culture. The morphology of the algae was also severely affected by heavy metals, with degradation and aJmost complete disintegration of the algal filaments occurring. Using the Wilbur-Anderson assay method, carbonic anhydrase activity was found to be lower in the experimental flasks containing heavy metals, than the control flasks, reducing the algae's ability to utilise the bicarbonate in solution for effective photosynthesis. The Wilbur-Anderson assay method did not prove to be a reliable method for measuring changes in enzyme activity as results were found to be erratic. Therefore attempts were made to use an oxygen electrode as an alternative method for determining the effects of various parameters on enzyme activity and photosynthesis, this proved to be more successful. Because of the toxic effects of heavy metals on Spirulina it was decided that the use of the biogenic alkalinity generated by the algae for the precipitation of heavy metals may be successfully employed as an alternative method for bioremediation and metal recovery. Carbonate reacts readily with metals, therefore the carbonate produced by this algal system was used for the precipitation of metals. It was possible to categorise the precipitation reactions observed into three groups, namely those metals which, a) precipitate as hydroxides, b) precipitate as carbonates generated from the dissociation of bicarbonate and c) metals which can only precipitate if there is free carbonate present in solution.
- Full Text:
- Date Issued: 2004
The use of environmental learning support materials to mediate learning in outcomes-based education: a case study in an Eastern Cape school
- Authors: Nduna, Nomalungelo Rosement
- Date: 2004
- Subjects: Environmental education -- South Africa -- Eastern Cape Environmental education -- Curricula -- South Africa Teaching -- Aids and devices -- South Africa Environmental education -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1812 , http://hdl.handle.net/10962/d1003698
- Description: Educational transformation and curriculum reform within the new South African Outcomes Based Education (OBE) system has introduced new roles for teachers, and a focus on environmental learning within each learning area. In an OBE system, teachers are required to mediate learning, develop learning programmes, and use a range of different learning support materials. This study aimed to explore how one teacher in an Eastern Cape school used environmental learning support materials to mediate learning within an OBE curriculum framework. Over the past ten years a number of environmental educators and researchers have been participating in curriculum policy development and curriculum implementation research. This has led to the incorporation of an environmental focus within different learning areas in Curriculum 2005. The focus on environment in the curriculum was strengthened by the introduction of the National Environmental Education Project in the General Education and Training (NEEP-GET) band in 2001. I am employed as a provincial co-coordinator within this project (for the Eastern Cape province), and one of my tasks is to work with service providers (who provide learning support materials) and teachers (who use these materials) to ensure improved environmental learning within the OBE curriculum. A qualitative and empirical case study was conducted in which I observed one teacher in a multi-grade class (with grade 6 and 7 learners) using learning support materials to achieve learning outcomes in three different lessons. The study employed a range of data collection methods such as questionnaires, interviews, field notes, video recording, and document analysis, photographs and journal entries. I compiled a contextual profile of the school and classroom and undertook two 'layers' of data analysis to report the findings of the study. This research indicates that theories of learning and associated teaching methods influence learning interactions, and the use of learning support material in the class. The study also highlighted emerging issues in the use of environmental learning support materials, which relate to planning; access to materials; over-use of materials; and the relationship between learning support materials and teaching methods.
- Full Text:
- Date Issued: 2004
- Authors: Nduna, Nomalungelo Rosement
- Date: 2004
- Subjects: Environmental education -- South Africa -- Eastern Cape Environmental education -- Curricula -- South Africa Teaching -- Aids and devices -- South Africa Environmental education -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1812 , http://hdl.handle.net/10962/d1003698
- Description: Educational transformation and curriculum reform within the new South African Outcomes Based Education (OBE) system has introduced new roles for teachers, and a focus on environmental learning within each learning area. In an OBE system, teachers are required to mediate learning, develop learning programmes, and use a range of different learning support materials. This study aimed to explore how one teacher in an Eastern Cape school used environmental learning support materials to mediate learning within an OBE curriculum framework. Over the past ten years a number of environmental educators and researchers have been participating in curriculum policy development and curriculum implementation research. This has led to the incorporation of an environmental focus within different learning areas in Curriculum 2005. The focus on environment in the curriculum was strengthened by the introduction of the National Environmental Education Project in the General Education and Training (NEEP-GET) band in 2001. I am employed as a provincial co-coordinator within this project (for the Eastern Cape province), and one of my tasks is to work with service providers (who provide learning support materials) and teachers (who use these materials) to ensure improved environmental learning within the OBE curriculum. A qualitative and empirical case study was conducted in which I observed one teacher in a multi-grade class (with grade 6 and 7 learners) using learning support materials to achieve learning outcomes in three different lessons. The study employed a range of data collection methods such as questionnaires, interviews, field notes, video recording, and document analysis, photographs and journal entries. I compiled a contextual profile of the school and classroom and undertook two 'layers' of data analysis to report the findings of the study. This research indicates that theories of learning and associated teaching methods influence learning interactions, and the use of learning support material in the class. The study also highlighted emerging issues in the use of environmental learning support materials, which relate to planning; access to materials; over-use of materials; and the relationship between learning support materials and teaching methods.
- Full Text:
- Date Issued: 2004
The viability of small-scale farming at the Tyhefu Irrigation Scheme, Eastern Cape
- Authors: Sishuta, Happy Babalwa
- Date: 2004
- Subjects: Farms, Small -- South Africa -- Eastern Cape , Irrigation -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3344 , http://hdl.handle.net/10962/d1004924 , Farms, Small -- South Africa -- Eastern Cape , Irrigation -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Description: This investigation is conducted against the background of current attempts to rehabilitate and revive the now defunct Tyhefu irrigation scheme. The poor track record of many irrigation schemes (despite huge investments) in the former homelands has prompted the government to reconsider its active and direct role in small-scale irrigation farming. This has resulted in the closure of many irrigation schemes including Tyhefu irrigation scheme. The new policy framework in South Africa, known as the irrigation management transfer, is premised on the transfer of ownership, authority and responsibility of small-scale irrigation schemes from government to the farmers. Tyhefu irrigation scheme was a state-driven, top-down initiative. This study argues that the justifications for the Tyhefu irrigation scheme were conflated, with the result that the need for political control of the Tyhefu area far outweighed the considerations regarding the financial viability and sustainability of the proposed project. Given the repressive political climate of the time in South Africa, the planners' proposals were a mechanism for the realization of the socio-political and economic agendas of the apartheid state and Ciskei government. Although technical factors critical for project success were examined, little or no attention was paid to the socio-economic aspects. For the planners, the main requirements for success entailed centralized managerial control, no participation of the beneficiaries, capital intensive and sophisticated agricultural techniques and the production of high value crops. Therefore, it can be argued that the nature of the planning and implementation of the Tyhefu irrigation scheme was ill-conceived, short-sighted and misguided. A review of the literature on irrigation development on the African continent provided useful insights for this study. The lessons from irrigation development experience in Sub-Saharan Africa indicate that the continent is littered with examples of derelict and costly failures. What stands out in many of these irrigation projects is their over-emphasis on technical issues to the complete neglect of human and other social aspects. Working partnerships between the farmers and irrigation scheme management could, thus, not be realized. Almost without exception the case studies used here indicate that the industrious type of farmer was never developed as was envisioned in the planning documents. Neither were rural livelihoods improved in a sustainable manner. The findings of this study suggest that irrigation management transfer is a complex and delicate process. In this new set of arrangements, beneficiaries face formidable challenges in terms of capacity (human and financial) if small-scale irrigation farming is to become a viable sector. No doubt, the viability and sustainability of the Tyhefu irrigation scheme demands a comprehensive package of interventions that address various issues of markets and marketing, capital investment and access to finance, technology, education and training, support and extension services. It is evident that institutional aspects and the related issue of functional literacy require much more attention than thus far. As a result, at the moment there is no possibility for independent agricultural production. , KMBT_363
- Full Text:
- Date Issued: 2004
- Authors: Sishuta, Happy Babalwa
- Date: 2004
- Subjects: Farms, Small -- South Africa -- Eastern Cape , Irrigation -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3344 , http://hdl.handle.net/10962/d1004924 , Farms, Small -- South Africa -- Eastern Cape , Irrigation -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Description: This investigation is conducted against the background of current attempts to rehabilitate and revive the now defunct Tyhefu irrigation scheme. The poor track record of many irrigation schemes (despite huge investments) in the former homelands has prompted the government to reconsider its active and direct role in small-scale irrigation farming. This has resulted in the closure of many irrigation schemes including Tyhefu irrigation scheme. The new policy framework in South Africa, known as the irrigation management transfer, is premised on the transfer of ownership, authority and responsibility of small-scale irrigation schemes from government to the farmers. Tyhefu irrigation scheme was a state-driven, top-down initiative. This study argues that the justifications for the Tyhefu irrigation scheme were conflated, with the result that the need for political control of the Tyhefu area far outweighed the considerations regarding the financial viability and sustainability of the proposed project. Given the repressive political climate of the time in South Africa, the planners' proposals were a mechanism for the realization of the socio-political and economic agendas of the apartheid state and Ciskei government. Although technical factors critical for project success were examined, little or no attention was paid to the socio-economic aspects. For the planners, the main requirements for success entailed centralized managerial control, no participation of the beneficiaries, capital intensive and sophisticated agricultural techniques and the production of high value crops. Therefore, it can be argued that the nature of the planning and implementation of the Tyhefu irrigation scheme was ill-conceived, short-sighted and misguided. A review of the literature on irrigation development on the African continent provided useful insights for this study. The lessons from irrigation development experience in Sub-Saharan Africa indicate that the continent is littered with examples of derelict and costly failures. What stands out in many of these irrigation projects is their over-emphasis on technical issues to the complete neglect of human and other social aspects. Working partnerships between the farmers and irrigation scheme management could, thus, not be realized. Almost without exception the case studies used here indicate that the industrious type of farmer was never developed as was envisioned in the planning documents. Neither were rural livelihoods improved in a sustainable manner. The findings of this study suggest that irrigation management transfer is a complex and delicate process. In this new set of arrangements, beneficiaries face formidable challenges in terms of capacity (human and financial) if small-scale irrigation farming is to become a viable sector. No doubt, the viability and sustainability of the Tyhefu irrigation scheme demands a comprehensive package of interventions that address various issues of markets and marketing, capital investment and access to finance, technology, education and training, support and extension services. It is evident that institutional aspects and the related issue of functional literacy require much more attention than thus far. As a result, at the moment there is no possibility for independent agricultural production. , KMBT_363
- Full Text:
- Date Issued: 2004
Thermal and photostability studies of triprolidine hydrochloride and its mixtures with cyclodextrin and glucose
- Authors: Ndlebe, Vuyelwa Jacqueline
- Date: 2004
- Subjects: Antihistamines , Glucose , Cyclodextrins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4387 , http://hdl.handle.net/10962/d1005052 , Antihistamines , Glucose , Cyclodextrins
- Description: Triprolidine hydrochloride (C₁₉H₂₂N₂.HCl.H₂O) (TPH) is a well-known antihistamine drug. It melts between 118°C and 122°C and the amount of water present is 4.5 mass percent. TPH is reported as being photosensitive and must be stored in sealed, light-tight containers. The thermal stabilities of TPH and of 1:1 molar and 1:1 mass ratio physical mixtures of TPH with beta-cyclodextrin (BCD) and with glucose have been examined using DSC, TG and TG-FTIR, complemented by X-ray powder diffraction (XRD) and infrared spectroscopic (IR) studies. Thermal studies of the solid TPH/BCD mixtures indicated that interaction between the components occurs and it is possible that the TPH molecule may be least partially accommodated in the cavity of the BCD host molecule. XRD results support this indication of inclusion. The results for mixtures of TPH/glucose also suggest that there is interaction between the two components. The results of molecular modelling suggest that TPH is most likely to be accommodated in the BCD cavity as a neutral triprolidine molecule with the toluene portion of the molecule entering first. There is also an indication that the Z-isomer should be accommodated slightly more readily than the E-isomer. Photostability studies were done by irradiating thin layers of solid samples of TPH and its mixtures for various times at 40°C using an Atlas Sun test CPS lamp operating at 550 W h m⁻². An analytical method using HPLC was developed and validated to determine the amounts of any photodegradants. DSC, TG, FTIR, XRD and IR were also used examine the irradiated samples. XRD results showed that changes in the TPH crystal structure occurred during irradiation and that these changes increased with the time of irradiation. Irradiation for 20 hours with UV or exposure to sunlight showed the presence of degradants. The results obtained illustrate the general stability of TPH, especially in the solid state. Although the potential for isomerization to the pharmaceutically inactive Z-isomer exists, this transformation would require extreme light conditions. The study has also shown TPH to be compatible with both glucose and BCD, which are potential excipients both in solid and liquid dosage forms. The presents of these excipients in dosage forms will thus not adversely affect the stability and the therapeutic efficacy of TPH. . An analytical method using HPLC was developed and validated to determine the amounts of any photodegradants. DSC, TG, FTIR, XRD and IR were also used examine the irradiated samples. XRD results showed that changes in the TPH crystal structure occurred during irradiation and that these changes increased with the time of irradiation. Irradiation for 20 hours with UV or exposure to sunlight showed the presence of degradants.
- Full Text:
- Date Issued: 2004
- Authors: Ndlebe, Vuyelwa Jacqueline
- Date: 2004
- Subjects: Antihistamines , Glucose , Cyclodextrins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4387 , http://hdl.handle.net/10962/d1005052 , Antihistamines , Glucose , Cyclodextrins
- Description: Triprolidine hydrochloride (C₁₉H₂₂N₂.HCl.H₂O) (TPH) is a well-known antihistamine drug. It melts between 118°C and 122°C and the amount of water present is 4.5 mass percent. TPH is reported as being photosensitive and must be stored in sealed, light-tight containers. The thermal stabilities of TPH and of 1:1 molar and 1:1 mass ratio physical mixtures of TPH with beta-cyclodextrin (BCD) and with glucose have been examined using DSC, TG and TG-FTIR, complemented by X-ray powder diffraction (XRD) and infrared spectroscopic (IR) studies. Thermal studies of the solid TPH/BCD mixtures indicated that interaction between the components occurs and it is possible that the TPH molecule may be least partially accommodated in the cavity of the BCD host molecule. XRD results support this indication of inclusion. The results for mixtures of TPH/glucose also suggest that there is interaction between the two components. The results of molecular modelling suggest that TPH is most likely to be accommodated in the BCD cavity as a neutral triprolidine molecule with the toluene portion of the molecule entering first. There is also an indication that the Z-isomer should be accommodated slightly more readily than the E-isomer. Photostability studies were done by irradiating thin layers of solid samples of TPH and its mixtures for various times at 40°C using an Atlas Sun test CPS lamp operating at 550 W h m⁻². An analytical method using HPLC was developed and validated to determine the amounts of any photodegradants. DSC, TG, FTIR, XRD and IR were also used examine the irradiated samples. XRD results showed that changes in the TPH crystal structure occurred during irradiation and that these changes increased with the time of irradiation. Irradiation for 20 hours with UV or exposure to sunlight showed the presence of degradants. The results obtained illustrate the general stability of TPH, especially in the solid state. Although the potential for isomerization to the pharmaceutically inactive Z-isomer exists, this transformation would require extreme light conditions. The study has also shown TPH to be compatible with both glucose and BCD, which are potential excipients both in solid and liquid dosage forms. The presents of these excipients in dosage forms will thus not adversely affect the stability and the therapeutic efficacy of TPH. . An analytical method using HPLC was developed and validated to determine the amounts of any photodegradants. DSC, TG, FTIR, XRD and IR were also used examine the irradiated samples. XRD results showed that changes in the TPH crystal structure occurred during irradiation and that these changes increased with the time of irradiation. Irradiation for 20 hours with UV or exposure to sunlight showed the presence of degradants.
- Full Text:
- Date Issued: 2004
Towards sustainable utilisation of the fishery resources of the Kowie Estuary, South Africa
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2004
- Subjects: Estuarine fisheries -- South Africa -- Eastern Cape -- Kowie Estuary , Estuarine ecology -- South Africa -- Eastern Cape -- Kowie Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4761 , http://hdl.handle.net/10962/d1007154 , Estuarine fisheries -- South Africa -- Eastern Cape -- Kowie Estuary , Estuarine ecology -- South Africa -- Eastern Cape -- Kowie Estuary
- Description: The annual biomass of fish caught from estuaries in South Africa is currently estimated at over 24,800 tons. These estuarine fishes are caught by over 73,000 fishers, most of them recreational. Annual income derived from South Africa’s total estuarine fishery was worth approximately R430,000,000 in 1997. There is increasing concern that unless our estuarine fisheries are effectively managed, we will not be able to sustain these benefits into the future. Two factors that contribute to inadequate management of the estuarine fisheries in South Africa are a lack of data on which to base management decisions, and the lack of indicators by which to assess trends towards sustainability. The main aims of this study were to provide a description of the Kowie estuary fishery, identify suitable indicators of sustainability for this fishery, and assess its sustainability. Boat-based and shore-based roving creel surveys were carried out on the Kowie estuary between July 2000 and June 2001; 1,091 interviews were conducted with linefishers, and 277 interviews with bait collectors. In the boat-based interviews, data were collected on fisher demographics, fishing site, fishing method, choice of bait, fishing duration and catch statistics. In the shore-based surveys, additional data were collected from shore-based linefishers and bait collectors on their perceptions, attitudes, and knowledge of fishery regulations. Total annual fishing effort on the Kowie estuary was estimated at 30,952 angler hours (SD=154); 84% of it recreational, and the rest subsistence. Most fishing occurred during December and January, and decreased during winter, especially June and July. The annual yield of fish from the estuary was estimated at 16,240 fish (SD=667) or 5.99 tons (SD=0.81). By number, recreational anglers caught 69% of the annual catch. Three species dominated the catch by number: Rhabdosargus holubi (62%), Pomadasys commersonnii (17%) and Argyrosomus japonicus (7%). By mass, the dominant species caught were Argyrosomus japonicus (60%) and Pomadasys commersonnii (19%). Overall catch rate on the estuary was 0.57 fish.ang.⁻¹h⁻¹ (SD=0.24), or 0.298 kg ang.⁻¹h⁻¹ (SD=0.31). Overall catch rate by number was highest in the subsistence sector at 1.13 fish.ang.⁻¹h⁻¹(SD=0.70), while the boat-based recreational sector recorded the highest overall catch rate by mass (0.427 kg.ang.⁻¹h⁻¹, SD=0.625). Argyrosomus japonicus had the highest overall catch rate by mass on the estuary (0.496 kg ang.⁻¹h⁻¹), and Rhabdosargus holubi the highest overall catch rate by number (1.233 fish.ang.⁻¹h⁻¹). Only 19% of the catch of R. holubi was above the minimum legal size, while the estimates for P. commersonnii and A. japonicus were 21% and 25%, respectively. The annual number of bait collecting outings on the estuary was estimated at 2,889, of which 75% were subsistence. The highest numbers of bait collecting outings were recorded in December and April. The Bay of Biscay was the most popular site for bait collecting. A total of five invertebrate species were collected from the estuary to be used as bait, of which the mud prawn Upogebia africana was the dominant species. Total annual number of mud prawns collected from the estuary was estimated at 260,648; of which 41% was collected by subsistence bait collectors. Thirteen indicators were selected to assess sustainability in three fishery sectors on the Kowie estuary: namely, the shore-based recreational linefishery, the subsistence linefishery and the subsistence bait fishery. Social sustainability was evaluated on the basis of the use fishery resources to fulfil Maslow's basic human needs of food and employment, safety and security, affiliation, self-esteem and selfactualisation. Indicators of ecosystem sustainability assessed the productivity, diversity, disturbance and degree of water quality in the estuary. Institutional sustainability was assessed on the basis that management systems in the fishery should be results-oriented, consent-based, truth-seeking and adaptable. Data on indicator performance was collected during the shore-based roving creel survey, and from published literature. Arbitrarily set reference points were used to assess indicator performance, which was graded on a scale from 1 (indicating minimum probability of sustainability) to 4 (indicating maximum probability of sustainability). Sustainability was illustrated with the aid of amoeba plots. Overall sustainability was low in all three fishery sectors investigated. Nine of the 13 indicators in the shore-based recreational fishery performed poorly, while 11 of 13 in the subsistence line fishery, and 10 of 13 in the subsistence bait fishery, performed poorly. In all three fishery sectors all four selected indicators of institutional sustainability performed poorly. The probability of social sustainability was higher in the shore-based recreational line fishery, where the performance of two of the five selected indicators was very good. The probability of ecological sustainability was lowest in the shore-based recreational linefishery, while in the subsistence linefishery only one selected indicator performed very well. Recommendations made towards assessing sustainability in small-scale estuarine fisheries include the formulation of national policy for assessing sustainability in fisheries, the involvement of fishers in the assessment process, use of fisher perceptions where data gaps exist, and the use of research results to guide future management decisions. Management changes recommended for the Kowie estuary fishery include the formulation of an effective and integrated management plan, identification of the key stakeholders in the fishery, inclusion of fishers in management, the protection of the estuary’s Zostera capensis beds, and the establishment of a programme to increase research and monitoring in the fishery.
- Full Text:
- Date Issued: 2004
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2004
- Subjects: Estuarine fisheries -- South Africa -- Eastern Cape -- Kowie Estuary , Estuarine ecology -- South Africa -- Eastern Cape -- Kowie Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4761 , http://hdl.handle.net/10962/d1007154 , Estuarine fisheries -- South Africa -- Eastern Cape -- Kowie Estuary , Estuarine ecology -- South Africa -- Eastern Cape -- Kowie Estuary
- Description: The annual biomass of fish caught from estuaries in South Africa is currently estimated at over 24,800 tons. These estuarine fishes are caught by over 73,000 fishers, most of them recreational. Annual income derived from South Africa’s total estuarine fishery was worth approximately R430,000,000 in 1997. There is increasing concern that unless our estuarine fisheries are effectively managed, we will not be able to sustain these benefits into the future. Two factors that contribute to inadequate management of the estuarine fisheries in South Africa are a lack of data on which to base management decisions, and the lack of indicators by which to assess trends towards sustainability. The main aims of this study were to provide a description of the Kowie estuary fishery, identify suitable indicators of sustainability for this fishery, and assess its sustainability. Boat-based and shore-based roving creel surveys were carried out on the Kowie estuary between July 2000 and June 2001; 1,091 interviews were conducted with linefishers, and 277 interviews with bait collectors. In the boat-based interviews, data were collected on fisher demographics, fishing site, fishing method, choice of bait, fishing duration and catch statistics. In the shore-based surveys, additional data were collected from shore-based linefishers and bait collectors on their perceptions, attitudes, and knowledge of fishery regulations. Total annual fishing effort on the Kowie estuary was estimated at 30,952 angler hours (SD=154); 84% of it recreational, and the rest subsistence. Most fishing occurred during December and January, and decreased during winter, especially June and July. The annual yield of fish from the estuary was estimated at 16,240 fish (SD=667) or 5.99 tons (SD=0.81). By number, recreational anglers caught 69% of the annual catch. Three species dominated the catch by number: Rhabdosargus holubi (62%), Pomadasys commersonnii (17%) and Argyrosomus japonicus (7%). By mass, the dominant species caught were Argyrosomus japonicus (60%) and Pomadasys commersonnii (19%). Overall catch rate on the estuary was 0.57 fish.ang.⁻¹h⁻¹ (SD=0.24), or 0.298 kg ang.⁻¹h⁻¹ (SD=0.31). Overall catch rate by number was highest in the subsistence sector at 1.13 fish.ang.⁻¹h⁻¹(SD=0.70), while the boat-based recreational sector recorded the highest overall catch rate by mass (0.427 kg.ang.⁻¹h⁻¹, SD=0.625). Argyrosomus japonicus had the highest overall catch rate by mass on the estuary (0.496 kg ang.⁻¹h⁻¹), and Rhabdosargus holubi the highest overall catch rate by number (1.233 fish.ang.⁻¹h⁻¹). Only 19% of the catch of R. holubi was above the minimum legal size, while the estimates for P. commersonnii and A. japonicus were 21% and 25%, respectively. The annual number of bait collecting outings on the estuary was estimated at 2,889, of which 75% were subsistence. The highest numbers of bait collecting outings were recorded in December and April. The Bay of Biscay was the most popular site for bait collecting. A total of five invertebrate species were collected from the estuary to be used as bait, of which the mud prawn Upogebia africana was the dominant species. Total annual number of mud prawns collected from the estuary was estimated at 260,648; of which 41% was collected by subsistence bait collectors. Thirteen indicators were selected to assess sustainability in three fishery sectors on the Kowie estuary: namely, the shore-based recreational linefishery, the subsistence linefishery and the subsistence bait fishery. Social sustainability was evaluated on the basis of the use fishery resources to fulfil Maslow's basic human needs of food and employment, safety and security, affiliation, self-esteem and selfactualisation. Indicators of ecosystem sustainability assessed the productivity, diversity, disturbance and degree of water quality in the estuary. Institutional sustainability was assessed on the basis that management systems in the fishery should be results-oriented, consent-based, truth-seeking and adaptable. Data on indicator performance was collected during the shore-based roving creel survey, and from published literature. Arbitrarily set reference points were used to assess indicator performance, which was graded on a scale from 1 (indicating minimum probability of sustainability) to 4 (indicating maximum probability of sustainability). Sustainability was illustrated with the aid of amoeba plots. Overall sustainability was low in all three fishery sectors investigated. Nine of the 13 indicators in the shore-based recreational fishery performed poorly, while 11 of 13 in the subsistence line fishery, and 10 of 13 in the subsistence bait fishery, performed poorly. In all three fishery sectors all four selected indicators of institutional sustainability performed poorly. The probability of social sustainability was higher in the shore-based recreational line fishery, where the performance of two of the five selected indicators was very good. The probability of ecological sustainability was lowest in the shore-based recreational linefishery, while in the subsistence linefishery only one selected indicator performed very well. Recommendations made towards assessing sustainability in small-scale estuarine fisheries include the formulation of national policy for assessing sustainability in fisheries, the involvement of fishers in the assessment process, use of fisher perceptions where data gaps exist, and the use of research results to guide future management decisions. Management changes recommended for the Kowie estuary fishery include the formulation of an effective and integrated management plan, identification of the key stakeholders in the fishery, inclusion of fishers in management, the protection of the estuary’s Zostera capensis beds, and the establishment of a programme to increase research and monitoring in the fishery.
- Full Text:
- Date Issued: 2004
Towards the development of species-specific fish production models for small reservoirs in Southern Africa
- Authors: Potts, Warren M
- Date: 2004
- Subjects: Freshwater fishes -- Africa, Southern Fish populations -- Africa, Southern Fisheries -- Africa, Southern Sustainable fisheries -- Africa, Southern Labeo -- Reproduction Cyprinidae -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5330 , http://hdl.handle.net/10962/d1005176
- Description: The fish populations in small southern African reservoirs are largely unexploited and there is potential for fisheries development. However, the development of sustainable fisheries requires reliable estimates of potential yield or production. Empirical models that have been developed to predict fish production only apply to large water bodies and only predict total fish production, not the production of individual species. Small reservoirs generally have few commercially important species and therefore species-specific fish production models are an alternative approach. The small reservoirs of the Eastern Cape are dominated by the moggel (Labeo umbratus). The principal objectives of this thesis were to gain an understanding of the ecology of small reservoirs and the function of moggel in these systems. This information was used to design a research approach to rapidly develop species-specific models for small reservoirs in southern Africa. The limnology of two small reservoirs was compared. During the study period the reservoirs were turbid and showed a warm, monomictic pattern of thermal stratification. Anthropogenic pressure in the reservoir catchments appeared to be the overriding factor increasing the nutrient input to the reservoirs and consequently, influencing the biomass of algae in the reservoirs. The feeding biology of moggel in Katriver and Laing reservoirs was examined. Moggel are detrivorous and successfully digested diatoms. The slower growth rate of moggel in Katriver reservoir was attributed to the poorer nutritional value of the diet as a consequence of the lower concentration of diatoms in the detrital aggregate. The reproductive characteristics of moggel were examined in four reservoirs. Moggel were able to reproduce successfully in the reservoirs. This could be attributed to their r-selected reproductive strategy, with a high fecundity and an extended spawning season and their ability to spawn in a floodplain environment. Differences in recruitment success between years were found to be a consequence of the timing and duration of seasonal rains. The number of mature females in a population and the availability of suitable spawning habitat influenced recruitment success. The life history of the moggel in five reservoirs was compared. Growth appeared to be related to food availability, while mortality was lower in the populations where food was abundant and there were less predatory species. Size and age at maturity were not affected by environmental factors, but were dependent on growth and mortality. Three contrasting methods were used to estimate moggel gillnet selectivity. The Sechin, direct fyke net method and length-structured model all yielded similar results and correction factors obtained from the selectivity study were applied to the gillnet data to estimate the fish population size and structure in each reservoir. Using information from the life history and selectivity studies, the biomass and production of five moggel populations was estimated and related to abiotic and biotic factors in the reservoirs and their catchments. Moggel biomass and production was dependent on the biomass of algae, which was dependent on morphoedaphic characteristics of the reservoirs. Small, shallow reservoirs with a reasonable amount of human habitation in their catchments would sustain the highest algal biomass and provided they had adequate spawning habitat would also have the highest moggel biomass and production. The future research requirements for small reservoir fisheries are outlined and include a three-year program to develop a species-specific production model for any of the dominant species.
- Full Text:
- Date Issued: 2004
- Authors: Potts, Warren M
- Date: 2004
- Subjects: Freshwater fishes -- Africa, Southern Fish populations -- Africa, Southern Fisheries -- Africa, Southern Sustainable fisheries -- Africa, Southern Labeo -- Reproduction Cyprinidae -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5330 , http://hdl.handle.net/10962/d1005176
- Description: The fish populations in small southern African reservoirs are largely unexploited and there is potential for fisheries development. However, the development of sustainable fisheries requires reliable estimates of potential yield or production. Empirical models that have been developed to predict fish production only apply to large water bodies and only predict total fish production, not the production of individual species. Small reservoirs generally have few commercially important species and therefore species-specific fish production models are an alternative approach. The small reservoirs of the Eastern Cape are dominated by the moggel (Labeo umbratus). The principal objectives of this thesis were to gain an understanding of the ecology of small reservoirs and the function of moggel in these systems. This information was used to design a research approach to rapidly develop species-specific models for small reservoirs in southern Africa. The limnology of two small reservoirs was compared. During the study period the reservoirs were turbid and showed a warm, monomictic pattern of thermal stratification. Anthropogenic pressure in the reservoir catchments appeared to be the overriding factor increasing the nutrient input to the reservoirs and consequently, influencing the biomass of algae in the reservoirs. The feeding biology of moggel in Katriver and Laing reservoirs was examined. Moggel are detrivorous and successfully digested diatoms. The slower growth rate of moggel in Katriver reservoir was attributed to the poorer nutritional value of the diet as a consequence of the lower concentration of diatoms in the detrital aggregate. The reproductive characteristics of moggel were examined in four reservoirs. Moggel were able to reproduce successfully in the reservoirs. This could be attributed to their r-selected reproductive strategy, with a high fecundity and an extended spawning season and their ability to spawn in a floodplain environment. Differences in recruitment success between years were found to be a consequence of the timing and duration of seasonal rains. The number of mature females in a population and the availability of suitable spawning habitat influenced recruitment success. The life history of the moggel in five reservoirs was compared. Growth appeared to be related to food availability, while mortality was lower in the populations where food was abundant and there were less predatory species. Size and age at maturity were not affected by environmental factors, but were dependent on growth and mortality. Three contrasting methods were used to estimate moggel gillnet selectivity. The Sechin, direct fyke net method and length-structured model all yielded similar results and correction factors obtained from the selectivity study were applied to the gillnet data to estimate the fish population size and structure in each reservoir. Using information from the life history and selectivity studies, the biomass and production of five moggel populations was estimated and related to abiotic and biotic factors in the reservoirs and their catchments. Moggel biomass and production was dependent on the biomass of algae, which was dependent on morphoedaphic characteristics of the reservoirs. Small, shallow reservoirs with a reasonable amount of human habitation in their catchments would sustain the highest algal biomass and provided they had adequate spawning habitat would also have the highest moggel biomass and production. The future research requirements for small reservoir fisheries are outlined and include a three-year program to develop a species-specific production model for any of the dominant species.
- Full Text:
- Date Issued: 2004
Trends and perceptions of sustainabilty reporting and corporate governance : a case study of Eskom
- Authors: Fabricius, Karin
- Date: 2004
- Subjects: Eskom (Firm) King Committee on Corporate Governance Corporate governance -- South Africa Corporation reports -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:826 , http://hdl.handle.net/10962/d1011782
- Description: The King II Report on Corporate Governance was released in March 2002. This report, although focusing on South African businesses, is acclaimed as a world first in setting superior governance standards. Corporate governance in South Africa is undergoing transformation due to the influence of the King II Report, and a range of other global trends such as Global Reporting Initiative guidelines and the infamous collapse of Enron due to governance failures. Non-financial reporting (also referred to as sustainability reporting) forms the main focus of this research project. The financial reporting aspects of corporate governance, and the role of governing boards and auditors fall outside the scope of this study. Through document analysis methods, Eskom's annual reports from 1998 - 2002, were analysed to establish whether patterns in sustainability reporting were identifiable. Employees and consumers of Eskom were. interviewed, using structured interviews to explore their awareness and knowledge regarding sustainability issues. A drastic increase in Eskom's non-financial reporting was identified in 2000. Apart from the corporate governance category, none of the chosen categories showed a major change after the 2002 release of the King II Report. Possible reasons for the lack of clear trends since 2002 are that the pattern is either not yet visible or it could be speculated that Eskom, who had won various reporting awards, is a leader in the field of corporate reporting and specifically on sustainability issues. Eskom had been involved in the reviewing of the first King Report and the drawing up of the recommendations for King II, and could therefore have modified their reporting procedures in 2000, prior'to the release of King II. As shown in the trend analysis, companies are coming under increased pressure to be socially accountable and transparent. This is fast becoming a 'core business issue', illustrated by the status of the King II Report requirements for corporate governance. Even though the terminology 'sustainability reporting' is unfamiliar to employees and consumers, both groups want disclosure and transparency of sustainability issues. Employees were, however, more aware than consumers of Eskom policies regarding sustainability issues. This report recommends that companies take a pro-active approach to corporate governance and sustainability reporting, noting the desire of consumers and employees to be informed about non-financial issues. These stakeholders also need to be made more aware of the meaning and significance of sustainability reporting.
- Full Text:
- Date Issued: 2004
- Authors: Fabricius, Karin
- Date: 2004
- Subjects: Eskom (Firm) King Committee on Corporate Governance Corporate governance -- South Africa Corporation reports -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:826 , http://hdl.handle.net/10962/d1011782
- Description: The King II Report on Corporate Governance was released in March 2002. This report, although focusing on South African businesses, is acclaimed as a world first in setting superior governance standards. Corporate governance in South Africa is undergoing transformation due to the influence of the King II Report, and a range of other global trends such as Global Reporting Initiative guidelines and the infamous collapse of Enron due to governance failures. Non-financial reporting (also referred to as sustainability reporting) forms the main focus of this research project. The financial reporting aspects of corporate governance, and the role of governing boards and auditors fall outside the scope of this study. Through document analysis methods, Eskom's annual reports from 1998 - 2002, were analysed to establish whether patterns in sustainability reporting were identifiable. Employees and consumers of Eskom were. interviewed, using structured interviews to explore their awareness and knowledge regarding sustainability issues. A drastic increase in Eskom's non-financial reporting was identified in 2000. Apart from the corporate governance category, none of the chosen categories showed a major change after the 2002 release of the King II Report. Possible reasons for the lack of clear trends since 2002 are that the pattern is either not yet visible or it could be speculated that Eskom, who had won various reporting awards, is a leader in the field of corporate reporting and specifically on sustainability issues. Eskom had been involved in the reviewing of the first King Report and the drawing up of the recommendations for King II, and could therefore have modified their reporting procedures in 2000, prior'to the release of King II. As shown in the trend analysis, companies are coming under increased pressure to be socially accountable and transparent. This is fast becoming a 'core business issue', illustrated by the status of the King II Report requirements for corporate governance. Even though the terminology 'sustainability reporting' is unfamiliar to employees and consumers, both groups want disclosure and transparency of sustainability issues. Employees were, however, more aware than consumers of Eskom policies regarding sustainability issues. This report recommends that companies take a pro-active approach to corporate governance and sustainability reporting, noting the desire of consumers and employees to be informed about non-financial issues. These stakeholders also need to be made more aware of the meaning and significance of sustainability reporting.
- Full Text:
- Date Issued: 2004
Variability in and coupling of larval availability and settlement of the mussel Perna perna : a spatio-temporal approach
- Authors: Porri, Francesca
- Date: 2004
- Subjects: Mussels -- South Africa Perna -- South Africa Perna -- Spawning Perna -- Larvae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5796 , http://hdl.handle.net/10962/d1005484
- Description: Population dynamics of many intertidal organisms are highly influenced by the abundance and distribution of planktonic larvae in the water column and their arrival on the shore. The brown mussel, Perna perna was used to investigate two of the primary processes that affect population size and dynamics, larval availability and settlement, on the south coast of South Africa. Perna perna is a dominant species on rocky shores of the southern and eastern coasts of South Africa. It creates three-dimensional beds that provide habitats for many other species and hence promotes biodiversity. Larval availability and settlement were examined at different spatial and temporal scales using a nested experimental design. To detect possible relationships between larval availability and settlement, the studies were simultaneous. Two sites, 4km apart, were chosen to investigate mussel settlement patterns. Within each site, three locations (300m from each other) were selected. At each location, five artificial settler collectors were placed at approximately 20cm intervals. Collectors were replaced at a range of time intervals, from daily to seasonal, for 16 months. Each intertidal location was paired with an offshore station, 500m from the shore, where larval availability was measured. At each offshore station, three vertical hauls were collected twice a month using a plankton net. Plankton sampling lasted for 14 months and was designed to examine variability on three temporal scales: seasonal, lunar and daily. The results showed no correlation between the distribution of larvae in the water and settlers on the shore. While larvae were abundant in the water at the start of sampling, they became very rare throughout the rest of the study at both sites and all locations. In contrast, distinct peaks of settler abundance were observed during the seasonal settlement study. In addition to the expected, strong temporal variation that emerged from both studies at all time scales, spatial patterns of variability were also observed. While no spatial effect was detected for the larvae in the water column, there was distinct spatial variation in settlement at the location level: some locations always showed higher settlement than others. These results suggest that, on scales of hundreds of meters to kilometers, larval availability and settlement are very unpredictable in time and that differential delivery of larvae occurs from nearshore waters to the shore. Although the effect of the state of the moon (new or full) was not significant in either study, more settlers seemed to arrive on the shore during new moon. Wind direction did not correlate significantly with settlement. However, the dropping of offshore winds and the prevalence of onshore winds, which are characteristic of summer, may be linked to the start of settlement. Nevertheless, further investigations on tidal or lunar cycles and on the influence of wind on surface currents are required to clarify the effects of moon and wind on settlement.
- Full Text:
- Date Issued: 2004
- Authors: Porri, Francesca
- Date: 2004
- Subjects: Mussels -- South Africa Perna -- South Africa Perna -- Spawning Perna -- Larvae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5796 , http://hdl.handle.net/10962/d1005484
- Description: Population dynamics of many intertidal organisms are highly influenced by the abundance and distribution of planktonic larvae in the water column and their arrival on the shore. The brown mussel, Perna perna was used to investigate two of the primary processes that affect population size and dynamics, larval availability and settlement, on the south coast of South Africa. Perna perna is a dominant species on rocky shores of the southern and eastern coasts of South Africa. It creates three-dimensional beds that provide habitats for many other species and hence promotes biodiversity. Larval availability and settlement were examined at different spatial and temporal scales using a nested experimental design. To detect possible relationships between larval availability and settlement, the studies were simultaneous. Two sites, 4km apart, were chosen to investigate mussel settlement patterns. Within each site, three locations (300m from each other) were selected. At each location, five artificial settler collectors were placed at approximately 20cm intervals. Collectors were replaced at a range of time intervals, from daily to seasonal, for 16 months. Each intertidal location was paired with an offshore station, 500m from the shore, where larval availability was measured. At each offshore station, three vertical hauls were collected twice a month using a plankton net. Plankton sampling lasted for 14 months and was designed to examine variability on three temporal scales: seasonal, lunar and daily. The results showed no correlation between the distribution of larvae in the water and settlers on the shore. While larvae were abundant in the water at the start of sampling, they became very rare throughout the rest of the study at both sites and all locations. In contrast, distinct peaks of settler abundance were observed during the seasonal settlement study. In addition to the expected, strong temporal variation that emerged from both studies at all time scales, spatial patterns of variability were also observed. While no spatial effect was detected for the larvae in the water column, there was distinct spatial variation in settlement at the location level: some locations always showed higher settlement than others. These results suggest that, on scales of hundreds of meters to kilometers, larval availability and settlement are very unpredictable in time and that differential delivery of larvae occurs from nearshore waters to the shore. Although the effect of the state of the moon (new or full) was not significant in either study, more settlers seemed to arrive on the shore during new moon. Wind direction did not correlate significantly with settlement. However, the dropping of offshore winds and the prevalence of onshore winds, which are characteristic of summer, may be linked to the start of settlement. Nevertheless, further investigations on tidal or lunar cycles and on the influence of wind on surface currents are required to clarify the effects of moon and wind on settlement.
- Full Text:
- Date Issued: 2004