An investigation of the internal challenges that hinder sustainability of the Furntech Nyanga incubates
- Authors: Sakuba, Siyasanga
- Date: 2020
- Subjects: Business incubators -- South Africa -- Cape Town , Business incubators -- Training of -- South Africa -- Cape Town , Entrepreneurship -- South Africa – Cape Town , Unemployment -- South Africa , Rate of return -- South Africa , Economic development -- South Africa , Training needs -- South Africa -- Cape Town , Furntech (Nyanga)
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/142830 , vital:38121
- Description: The South African unemployment rate is currently at 27.6 per cent (Statistics South Africa, 2019). In an effort to combat unemployment, the South African government has implemented various mechanisms to provide opportunities to the people and combat unemployment. One of these mechanisms is to invest in the establishment of entrepreneurship incubators while the Furntech incubator is one of the incubators established for this purpose. It is imperative that the government spending on these mechanisms is justified by a return on investment which, in this case, should be to reduce unemployment and increase the overall entrepreneurial activity. In view of Furntech, with specific reference to the Nyanga incubation centre, there is a high failure rate with very little output of sustainable enterprises from the two-year incubation period. This study seeks to investigate the internal challenges that hinder the sustainability of these entrepreneurs to either drop out before the end of the two-year incubation period or to furnish the two years without becoming sustainable entrepreneurs. This study seeks to investigate this matter by using a semi -structured interview schedule that was geared towards investigating the research problem from the view of the incubates. The findings of the study showed that Furntech can be commended in respect of the transfer of technical skills. Furntech, however, failed to support the entrepreneurs with the other business support services that are part of their services, namely the business advisory, financial support and business skills. These findings provide a guideline of where Furntech needs to improve its service offering to gain a higher output of sustainable entrepreneurs. It is important to note that even though Furntech has representation in three provinces with two incubators in the Western Cape (Cape Town and Nyanga), however, this study was limited to the Furntech Nyanga incubates.
- Full Text:
- Date Issued: 2020
- Authors: Sakuba, Siyasanga
- Date: 2020
- Subjects: Business incubators -- South Africa -- Cape Town , Business incubators -- Training of -- South Africa -- Cape Town , Entrepreneurship -- South Africa – Cape Town , Unemployment -- South Africa , Rate of return -- South Africa , Economic development -- South Africa , Training needs -- South Africa -- Cape Town , Furntech (Nyanga)
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/142830 , vital:38121
- Description: The South African unemployment rate is currently at 27.6 per cent (Statistics South Africa, 2019). In an effort to combat unemployment, the South African government has implemented various mechanisms to provide opportunities to the people and combat unemployment. One of these mechanisms is to invest in the establishment of entrepreneurship incubators while the Furntech incubator is one of the incubators established for this purpose. It is imperative that the government spending on these mechanisms is justified by a return on investment which, in this case, should be to reduce unemployment and increase the overall entrepreneurial activity. In view of Furntech, with specific reference to the Nyanga incubation centre, there is a high failure rate with very little output of sustainable enterprises from the two-year incubation period. This study seeks to investigate the internal challenges that hinder the sustainability of these entrepreneurs to either drop out before the end of the two-year incubation period or to furnish the two years without becoming sustainable entrepreneurs. This study seeks to investigate this matter by using a semi -structured interview schedule that was geared towards investigating the research problem from the view of the incubates. The findings of the study showed that Furntech can be commended in respect of the transfer of technical skills. Furntech, however, failed to support the entrepreneurs with the other business support services that are part of their services, namely the business advisory, financial support and business skills. These findings provide a guideline of where Furntech needs to improve its service offering to gain a higher output of sustainable entrepreneurs. It is important to note that even though Furntech has representation in three provinces with two incubators in the Western Cape (Cape Town and Nyanga), however, this study was limited to the Furntech Nyanga incubates.
- Full Text:
- Date Issued: 2020
Reporting on home: how journalists from rural Botswana experience covering rural development while working at the Botswana Daily News
- Authors: Lekoma, Bame Dirakano
- Date: 2020
- Subjects: Botswana -- In mass media , Journalists -- Botswana , Rural development -- Botswana
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/146566 , vital:38537
- Description: The study investigates how journalists working for state media in Botswana experience reporting on development in rural communities. It is observed that many of these journalists are members of the rural communities they report on and therefore have personal knowledge of them. Furthermore, it describes how even though Botswana is often praised for its developmental achievements, the country continues to be characterized by social inequality. The study then articulates a theoretical framework designed to engage with the normative guidelines that inform journalistic practice within the Botswana media landscape. It draws, for this purpose, on normative theories of the press. It is concluded that the Botswana media landscape is representative of an authoritarian, polarised pluralised media system in which journalists work under strict control of the state. The empirical component of the study draws on this framework by conducting life history interviews of journalists working at the Botswana Daily News. It examines what such journalists know from personal experience about development from rural Botswana and how such knowledge impacts on their engagement with the processes of reporting for the paper. It is concluded that journalists working for this paper have a deep commitment to representing the interests of rural communities. However, they remain constrained in their ability to act on this commitment, in context of the guidelines for reporting that frame their institutional context.
- Full Text:
- Date Issued: 2020
- Authors: Lekoma, Bame Dirakano
- Date: 2020
- Subjects: Botswana -- In mass media , Journalists -- Botswana , Rural development -- Botswana
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/146566 , vital:38537
- Description: The study investigates how journalists working for state media in Botswana experience reporting on development in rural communities. It is observed that many of these journalists are members of the rural communities they report on and therefore have personal knowledge of them. Furthermore, it describes how even though Botswana is often praised for its developmental achievements, the country continues to be characterized by social inequality. The study then articulates a theoretical framework designed to engage with the normative guidelines that inform journalistic practice within the Botswana media landscape. It draws, for this purpose, on normative theories of the press. It is concluded that the Botswana media landscape is representative of an authoritarian, polarised pluralised media system in which journalists work under strict control of the state. The empirical component of the study draws on this framework by conducting life history interviews of journalists working at the Botswana Daily News. It examines what such journalists know from personal experience about development from rural Botswana and how such knowledge impacts on their engagement with the processes of reporting for the paper. It is concluded that journalists working for this paper have a deep commitment to representing the interests of rural communities. However, they remain constrained in their ability to act on this commitment, in context of the guidelines for reporting that frame their institutional context.
- Full Text:
- Date Issued: 2020
An analysis of the possible success of a tax on sugarsweetened beverages in South Africa
- Authors: Mabaso, Bandla Sazi
- Date: 2019
- Subjects: Nutrition -- Government policy -- South Africa , Value-added tax -- South Africa , Obesity -- South Africa -- Prevention , Excise tax -- South Africa , Taxations of articles of consumption -- South Africa , Tobacco -- Taxation -- South Africa , Alcohol -- Taxation -- South Africa , Carbonated beverages -- Taxation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/68333 , vital:29240
- Description: The increase in obesity is a global crisis that is prevalent in both the developed and developing economies, including South Africa. It endangers the health and threatens the life of many people. Sugar-sweetened beverages have become the key target in the fight against obesity, in preference to other foodstuffs that contain added sugar, because of the poor nutritional value they contain and harm they cause if consumed excessively. The Minister of Finance announced in the 2016 Budget Speech, that a proposed tax on sugar-sweetened beverages would be introduced in South Africa and would be implemented in April 2017, but the anticipated date is now 1 April 2018. The thesis examined the possible success of this proposed tax in South Africa, using as a benchmark the process followed prior to implementing the tax and the experience of selected foreign countries that have implemented the tax, one country subsequently abolishing it, and another country considering implementing it. Additionally, the research analysed the success of the existing excise taxes levied on tobacco and alcohol in South Africa, in attempting to predict the possible success of the proposed tax. The success of the proposed tax is, however, threatened by the emergence of illegal markets that offer the targeted products inexpensively, particularly if similar restrictions and laws do not exist in bordering countries. The research was carried out by means of the analysis of journal articles, information from the selected countries’ revenue authorities’ websites, National Treasury publications, commentaries by experts and publications by professional organisations and firms. Overall, the proposed tax has been successful in curbing obesity and high sugar intake in other countries. Similarly, the excise taxes on tobacco and alcohol have been successful in reducing the consumption of targeted products in South Africa. These successes have been realized through a collaborated effort and employing a multi-faceted approach, including advertising restrictions. Nevertheless, the proposed tax is popularly criticised for its regressive nature and the potential job losses that are associated with it.
- Full Text:
- Date Issued: 2019
- Authors: Mabaso, Bandla Sazi
- Date: 2019
- Subjects: Nutrition -- Government policy -- South Africa , Value-added tax -- South Africa , Obesity -- South Africa -- Prevention , Excise tax -- South Africa , Taxations of articles of consumption -- South Africa , Tobacco -- Taxation -- South Africa , Alcohol -- Taxation -- South Africa , Carbonated beverages -- Taxation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/68333 , vital:29240
- Description: The increase in obesity is a global crisis that is prevalent in both the developed and developing economies, including South Africa. It endangers the health and threatens the life of many people. Sugar-sweetened beverages have become the key target in the fight against obesity, in preference to other foodstuffs that contain added sugar, because of the poor nutritional value they contain and harm they cause if consumed excessively. The Minister of Finance announced in the 2016 Budget Speech, that a proposed tax on sugar-sweetened beverages would be introduced in South Africa and would be implemented in April 2017, but the anticipated date is now 1 April 2018. The thesis examined the possible success of this proposed tax in South Africa, using as a benchmark the process followed prior to implementing the tax and the experience of selected foreign countries that have implemented the tax, one country subsequently abolishing it, and another country considering implementing it. Additionally, the research analysed the success of the existing excise taxes levied on tobacco and alcohol in South Africa, in attempting to predict the possible success of the proposed tax. The success of the proposed tax is, however, threatened by the emergence of illegal markets that offer the targeted products inexpensively, particularly if similar restrictions and laws do not exist in bordering countries. The research was carried out by means of the analysis of journal articles, information from the selected countries’ revenue authorities’ websites, National Treasury publications, commentaries by experts and publications by professional organisations and firms. Overall, the proposed tax has been successful in curbing obesity and high sugar intake in other countries. Similarly, the excise taxes on tobacco and alcohol have been successful in reducing the consumption of targeted products in South Africa. These successes have been realized through a collaborated effort and employing a multi-faceted approach, including advertising restrictions. Nevertheless, the proposed tax is popularly criticised for its regressive nature and the potential job losses that are associated with it.
- Full Text:
- Date Issued: 2019
Using four different methods to reach a taxonomic conclusion in dung beetles (Scarabaeinae)
- Authors: Deschodt, Christian Michel
- Date: 2019
- Subjects: Dung beetles -- Classification , Scarabaeidae -- Classification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67845 , vital:29156
- Description: Four different techniques to make taxonomic decisions concerning different species in Scarabaeinae are being investigated. Firstly, I made measurements of the body dimensions which are plotted on a two dimensional graph. This method is successfully used to erect one new species, Copris crassus Deschodt and Davis, 2015, and to establish the synonymy of Copris bihamatus Balthasar, 1965 with Copris fidius (Olivier, 1789). Thereafter the classical or traditional comparative method is used to propose seven new species Scarabaeolus soutpansbergensis (Deschodt and Davis 2015), Scarabaeolus megaparvulus (Davis and Deschodt 2015), Scarabaeolus niemandi (Deschodt and Davis 2015), Scarabaeolus carniphilus (Davis and Deschodt 2015), Scarabaeolus ermienae (Deschodt and Davis 2015), Scarabaeolus planipennis (Davis and Deschodt 2015) and Scarabaeolus afronitidus (Davis and Deschodt 2015) and formally synonymise Scarabaeolus vansoni (Ferreira, 1958) with Scarabaeolus lucidulus (Boheman, 1860) and Scarabaeolus xavieri (Ferreira, 1968) with Scarabaeolus andreaei (zur Strassen, 1963). Morphometric measurements of external structures of a group of flightless relict beetles in the tribe Canthonini are used to compile a nexus file which is analysed with computer software. The interpretation of these results is used here to support the erection of a new genus Drogo Deschodt, Davis & Scholtz 2016, Lastly I analysed the DNA sequences of specimens from different species belonging to a species complex in the genus Epirinus Reiche, 1841 occurring over a wide geographic range. These sequences are used together with external morphological characters to propose the synonymy of Epirinus hluhluwensis Medina & Scholtz 2005 and Epirinus ngomae Medina & Scholtz 2005 with Epirinus davisi Scholtz & Howden 1987.
- Full Text:
- Date Issued: 2019
- Authors: Deschodt, Christian Michel
- Date: 2019
- Subjects: Dung beetles -- Classification , Scarabaeidae -- Classification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67845 , vital:29156
- Description: Four different techniques to make taxonomic decisions concerning different species in Scarabaeinae are being investigated. Firstly, I made measurements of the body dimensions which are plotted on a two dimensional graph. This method is successfully used to erect one new species, Copris crassus Deschodt and Davis, 2015, and to establish the synonymy of Copris bihamatus Balthasar, 1965 with Copris fidius (Olivier, 1789). Thereafter the classical or traditional comparative method is used to propose seven new species Scarabaeolus soutpansbergensis (Deschodt and Davis 2015), Scarabaeolus megaparvulus (Davis and Deschodt 2015), Scarabaeolus niemandi (Deschodt and Davis 2015), Scarabaeolus carniphilus (Davis and Deschodt 2015), Scarabaeolus ermienae (Deschodt and Davis 2015), Scarabaeolus planipennis (Davis and Deschodt 2015) and Scarabaeolus afronitidus (Davis and Deschodt 2015) and formally synonymise Scarabaeolus vansoni (Ferreira, 1958) with Scarabaeolus lucidulus (Boheman, 1860) and Scarabaeolus xavieri (Ferreira, 1968) with Scarabaeolus andreaei (zur Strassen, 1963). Morphometric measurements of external structures of a group of flightless relict beetles in the tribe Canthonini are used to compile a nexus file which is analysed with computer software. The interpretation of these results is used here to support the erection of a new genus Drogo Deschodt, Davis & Scholtz 2016, Lastly I analysed the DNA sequences of specimens from different species belonging to a species complex in the genus Epirinus Reiche, 1841 occurring over a wide geographic range. These sequences are used together with external morphological characters to propose the synonymy of Epirinus hluhluwensis Medina & Scholtz 2005 and Epirinus ngomae Medina & Scholtz 2005 with Epirinus davisi Scholtz & Howden 1987.
- Full Text:
- Date Issued: 2019
A case study of the role of leadership behaviour in the formation of organizational culture
- Authors: Moore, Aminah
- Date: 2018
- Subjects: Leadership -- Botswana -- Maun , Corporate culture -- Botswana -- Maun , Strategic planning -- Botswana -- Maun , Critical incident technique , Organizational behavior -- Botswana -- Maun , Tourism -- Management , Belmond Safaris (Botswana)
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/62061 , vital:28103
- Description: This case study research on the effect of leadership on organizational culture, is based on a small luxury tourism organization – Belmond Safaris – based in Maun, Botswana. The study set out to determine critical incidents that occurred during the tenure of the current general manager with the intention of uncovering her leadership behaviour and how it has shaped the culture of the organization. The literature review identified quantitative and qualitative approaches to researching organizational culture, but settles on Schein’s theory of organizational culture (Schein, 1992; 2010) as the approach adopted in this study. Furthermore, it reviews the various roles of strategic leaders and how these affect the culture of the organization. The study follows a qualitative methodology and applies the Critical Incident Technique to explore how, as a leader, the behaviour of the general manager shaped the organization’s culture. Data triangulation is achieved through the use of multiple sources – interviews, analysis of company documents and the examination of minutes of management meetings. Following the fieldwork, the evidence within the findings of the study required a theoretical reorientation and a shift from strategic leadership to a new focus on relational leadership, highlighting the prominence of social exchanges between the general manager and employees, as opposed to economic exchanges. The study concludes by acknowledging the limitations and delimitations of the study, which include time constraints as well as the deliberate exclusion of certain participants (e.g. camp managers) from the study. In its conclusion the study also presents recommendations for future studies. The researcher recommends a broader study within the tourism industry, as well as a larger and more inclusive sample size, in order to obtain better insights into the study of culture and leadership within organizations.
- Full Text:
- Date Issued: 2018
- Authors: Moore, Aminah
- Date: 2018
- Subjects: Leadership -- Botswana -- Maun , Corporate culture -- Botswana -- Maun , Strategic planning -- Botswana -- Maun , Critical incident technique , Organizational behavior -- Botswana -- Maun , Tourism -- Management , Belmond Safaris (Botswana)
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/62061 , vital:28103
- Description: This case study research on the effect of leadership on organizational culture, is based on a small luxury tourism organization – Belmond Safaris – based in Maun, Botswana. The study set out to determine critical incidents that occurred during the tenure of the current general manager with the intention of uncovering her leadership behaviour and how it has shaped the culture of the organization. The literature review identified quantitative and qualitative approaches to researching organizational culture, but settles on Schein’s theory of organizational culture (Schein, 1992; 2010) as the approach adopted in this study. Furthermore, it reviews the various roles of strategic leaders and how these affect the culture of the organization. The study follows a qualitative methodology and applies the Critical Incident Technique to explore how, as a leader, the behaviour of the general manager shaped the organization’s culture. Data triangulation is achieved through the use of multiple sources – interviews, analysis of company documents and the examination of minutes of management meetings. Following the fieldwork, the evidence within the findings of the study required a theoretical reorientation and a shift from strategic leadership to a new focus on relational leadership, highlighting the prominence of social exchanges between the general manager and employees, as opposed to economic exchanges. The study concludes by acknowledging the limitations and delimitations of the study, which include time constraints as well as the deliberate exclusion of certain participants (e.g. camp managers) from the study. In its conclusion the study also presents recommendations for future studies. The researcher recommends a broader study within the tourism industry, as well as a larger and more inclusive sample size, in order to obtain better insights into the study of culture and leadership within organizations.
- Full Text:
- Date Issued: 2018
A survey of organizational culture and organizational performance in a manufacturing company
- Authors: Dom, Veliswa Virginia
- Date: 2018
- Subjects: Corporate culture -- South Africa -- Eastern Cape , Organizational behavior -- South Africa -- Eastern Cape , Factories -- South Africa -- Eastern Cape , Analysis of variance , Shift systems -- South Africa -- Eastern Cape , Employees -- Rating of -- South Africa -- Eastern Cape , Competing Values Framework (CVF)
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/61861 , vital:28069
- Description: The purpose of this research was to explore the relationship between organizational culture and organizational performance in a manufacturing company. This company supplies metal products to the motor vehicle manufacturing industry, where the quality and quantity of parts produced is of paramount importance, since the buyers of these products are quality conscious. The organization has three production shifts that rotate each week. Anecdotal observations are that irrespective of the time that a shift operates over the course of the month, the different shifts tend to perform at different levels in terms of quality and quantity of output. This study therefore sought to investigate if these differences between shifts are statistically significant, and if so, whether these shifts also have differences in organizational culture. Components of organizational culture include values, norms, beliefs, attitudes, principles and expectations that give the organization a unique personality and differentiate it from other organizations. While the literature indicates that qualitative or quantitative approaches can be used in organizational culture research, this research adopted the quantitative approach, making use of the Competing Values Framework (CVF). The CVF is a four-category organizational culture typology established by Cameron and Quinn (2006). The framework is based on two dimensions: stability or flexibility of the organization, and external or internal focus. In this research, the CVF was used as a measurement tool to evaluate organizational culture. In order to determine differences in organizational culture between shifts, a survey was undertaken (N=138) which measured employee perceptions pertaining to the existing organizational culture of each of the three production shifts at the company. Secondly, differences in performance between the shifts were examined by using the performance data for a three-month period for each shift in terms of quantity and quality. This data was obtained from the management of the production process at the company. Statistical analysis was done using ANOVA to analyse the differences between the shifts. The findings indicated that the dominant existing organizational culture at the company under investigation is a clan culture. Furthermore, there is a statistically significant difference between the cultures of all the three shifts at the manufacturing company. The results also indicated that there is a statistically significant difference in the quantity and quality of production between the three shifts. In conclusion, the research indicated there are differences in culture and in performance, but given the nature of the data, it was not possible to statistically analyse the relationship between shift culture and performance. However, it is conceivable that cultural differences between shifts may be contributing to performance differences. With regards to further research, it is recommended that this research be extended to other branches of the manufacturing company in other regions, in order to determine whether there are any significant differences in culture and performance between these branches and their shifts. Research could also be extended to other South African organizations to create a sufficiently large sample of shift and/or business units, so as to be able to do statistical analysis of the relationship between culture and performance.
- Full Text:
- Date Issued: 2018
- Authors: Dom, Veliswa Virginia
- Date: 2018
- Subjects: Corporate culture -- South Africa -- Eastern Cape , Organizational behavior -- South Africa -- Eastern Cape , Factories -- South Africa -- Eastern Cape , Analysis of variance , Shift systems -- South Africa -- Eastern Cape , Employees -- Rating of -- South Africa -- Eastern Cape , Competing Values Framework (CVF)
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/61861 , vital:28069
- Description: The purpose of this research was to explore the relationship between organizational culture and organizational performance in a manufacturing company. This company supplies metal products to the motor vehicle manufacturing industry, where the quality and quantity of parts produced is of paramount importance, since the buyers of these products are quality conscious. The organization has three production shifts that rotate each week. Anecdotal observations are that irrespective of the time that a shift operates over the course of the month, the different shifts tend to perform at different levels in terms of quality and quantity of output. This study therefore sought to investigate if these differences between shifts are statistically significant, and if so, whether these shifts also have differences in organizational culture. Components of organizational culture include values, norms, beliefs, attitudes, principles and expectations that give the organization a unique personality and differentiate it from other organizations. While the literature indicates that qualitative or quantitative approaches can be used in organizational culture research, this research adopted the quantitative approach, making use of the Competing Values Framework (CVF). The CVF is a four-category organizational culture typology established by Cameron and Quinn (2006). The framework is based on two dimensions: stability or flexibility of the organization, and external or internal focus. In this research, the CVF was used as a measurement tool to evaluate organizational culture. In order to determine differences in organizational culture between shifts, a survey was undertaken (N=138) which measured employee perceptions pertaining to the existing organizational culture of each of the three production shifts at the company. Secondly, differences in performance between the shifts were examined by using the performance data for a three-month period for each shift in terms of quantity and quality. This data was obtained from the management of the production process at the company. Statistical analysis was done using ANOVA to analyse the differences between the shifts. The findings indicated that the dominant existing organizational culture at the company under investigation is a clan culture. Furthermore, there is a statistically significant difference between the cultures of all the three shifts at the manufacturing company. The results also indicated that there is a statistically significant difference in the quantity and quality of production between the three shifts. In conclusion, the research indicated there are differences in culture and in performance, but given the nature of the data, it was not possible to statistically analyse the relationship between shift culture and performance. However, it is conceivable that cultural differences between shifts may be contributing to performance differences. With regards to further research, it is recommended that this research be extended to other branches of the manufacturing company in other regions, in order to determine whether there are any significant differences in culture and performance between these branches and their shifts. Research could also be extended to other South African organizations to create a sufficiently large sample of shift and/or business units, so as to be able to do statistical analysis of the relationship between culture and performance.
- Full Text:
- Date Issued: 2018
Effects of CO2-induced ocean acidification on the early development, growth, survival and skeletogenesis of the estuarine-dependant sciaenid Argyrosomus japonicus
- Authors: Erasmus, Bernard
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Ecology , Argyrosomus -- Physiology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60585 , vital:27799
- Description: Although it is increasingly accepted that ocean acidification poses a considerable threat to marine organisms, little is known about the likely response of fishes to this phenomenon. While initial research concluded that adult fishes may be tolerant to changes predicted in the next 300 years, the response of early life stages to end-of-century CO2 levels (~ 1100 µatm according to the IPCC RCP 8.5) remains unclear. To date, literature on the early growth and survival of fishes has yielded conflicting results, suggesting that vulnerability may be species dependant. The paucity of ocean acidification research on fishes is particularly evident when one considers larval skeletogenesis, with no robust studies on its impacts on bone and cartilage development. This study addresses the early life embryogenesis, hatching success, growth, skeletogenesis and survival of an estuarine-dependant species. Dusky kob (Argyrosomus japonicus) were reared in a control (pCO2 = 327.50 ± 80.07 qatm at pH 8.15), intermediate (pCO2 477.40 ± 59.46 qatm at pH 8.03) and high pCO2 treatment (pCO2 910.20 ± 136.45 qatm at pH 7.78) from egg to 29 days post-hatch (dph). Sixty individuals from each treatment were sacrificed at the egg stage and at 2, 6, 13, 18, 21 and 26 dph, measured and stained using an acid-free double- staining solution to prevent the deterioration of calcified matrices in fragile larval skeletons. The proportion of bone and cartilage was quantified at each stage using a novel pixel-counting method. Growth and skeletal development were identical between treatments until the onset of metamorphosis (21 dph). However, from the metamorphosis stage, the growth and skeletal development rate was significantly faster in the intermediate treatment and significantly slower in the high treatment when compared to the control treatment. By 26 dph, A. japonicus reared in high pCO2 were, on average, 47.2% smaller than the control treatment, and the relative proportion of bone in the body was 45.3% lower in the high pCO2 treatment when compared with the control. In addition, none of the fish in the high pCO2 treatment survived after 26 dph. It appears that the combination of the increased energy requirements during metamorphosis and the increased energy cost associated with acid-base regulation may account for reduced growth, skeletogenesis and poor survival in high pCO2. Regardless of the driver, the results of this study suggest that the pCO2 levels predicted for the end of the century may have negative effects on the growth, skeletal development, and survival during metamorphosis.
- Full Text:
- Date Issued: 2018
- Authors: Erasmus, Bernard
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Ecology , Argyrosomus -- Physiology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60585 , vital:27799
- Description: Although it is increasingly accepted that ocean acidification poses a considerable threat to marine organisms, little is known about the likely response of fishes to this phenomenon. While initial research concluded that adult fishes may be tolerant to changes predicted in the next 300 years, the response of early life stages to end-of-century CO2 levels (~ 1100 µatm according to the IPCC RCP 8.5) remains unclear. To date, literature on the early growth and survival of fishes has yielded conflicting results, suggesting that vulnerability may be species dependant. The paucity of ocean acidification research on fishes is particularly evident when one considers larval skeletogenesis, with no robust studies on its impacts on bone and cartilage development. This study addresses the early life embryogenesis, hatching success, growth, skeletogenesis and survival of an estuarine-dependant species. Dusky kob (Argyrosomus japonicus) were reared in a control (pCO2 = 327.50 ± 80.07 qatm at pH 8.15), intermediate (pCO2 477.40 ± 59.46 qatm at pH 8.03) and high pCO2 treatment (pCO2 910.20 ± 136.45 qatm at pH 7.78) from egg to 29 days post-hatch (dph). Sixty individuals from each treatment were sacrificed at the egg stage and at 2, 6, 13, 18, 21 and 26 dph, measured and stained using an acid-free double- staining solution to prevent the deterioration of calcified matrices in fragile larval skeletons. The proportion of bone and cartilage was quantified at each stage using a novel pixel-counting method. Growth and skeletal development were identical between treatments until the onset of metamorphosis (21 dph). However, from the metamorphosis stage, the growth and skeletal development rate was significantly faster in the intermediate treatment and significantly slower in the high treatment when compared to the control treatment. By 26 dph, A. japonicus reared in high pCO2 were, on average, 47.2% smaller than the control treatment, and the relative proportion of bone in the body was 45.3% lower in the high pCO2 treatment when compared with the control. In addition, none of the fish in the high pCO2 treatment survived after 26 dph. It appears that the combination of the increased energy requirements during metamorphosis and the increased energy cost associated with acid-base regulation may account for reduced growth, skeletogenesis and poor survival in high pCO2. Regardless of the driver, the results of this study suggest that the pCO2 levels predicted for the end of the century may have negative effects on the growth, skeletal development, and survival during metamorphosis.
- Full Text:
- Date Issued: 2018
The effect of water temperature on the distribution of the Eastern Cape redfin minnow, Pseudobarbus afer (Peters, 1864)
- Authors: Bloy, Lesley Elizabeth
- Date: 2018
- Subjects: Minnows -- South Africa -- Eastern Cape , Cyprinidae -- South Africa -- Eastern Cape , Minnows -- Effect of temperature on -- South Africa -- Eastern Cape , Minnows -- Effect of exotic animals on -- South Africa -- Eastern Cape , Introduced organisms -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62017 , vital:28096
- Description: The main objective of this MSc study was to disentangle whether temperature or the presence of non-native fish was limiting the distribution of Pseudobarbus afer (Peters, 1864) in the Blindekloof stream, Eastern Cape, South Africa. The aims were to: i) describe the thermal regime of the Blindekloof stream; ii) conduct experiments to determine the preferred and critical temperatures of P. afer and; iii) use snorkel surveys to contextualise the distribution of both native and non-native fishes in the Blindekloof stream to assess whether the downstream distribution of P. afer was likely to be influenced by temperature or by the presence of non-native, predatory fishes. To describe the thermal regime, year-long temperature data from four long term monitoring sites in the Blindekloof stream were collected using Hobo temperature loggers and analysed in order to better understand the thermal profile, the thermal variation and the rate of temperature change in the stream. The warmest temperatures were recorded in late December 2015 (absolute maximum of 29.4 °C). The coolest water temperatures were recorded in early August 2015 (absolute minimum of 9.5 °C). There is both seasonal and diel variation in temperature with mean, minimum, maximum, 7 day mean, 7 day maximum and temperature ranges differing significantly between sites. With knowledge of the thermal regime of a monitored reach of the Blindekloof stream, the thermal tolerance and preference of P. afer were investigated. The thermal tolerance of P. afer was investigated using the Critical Thermal Method (CTM) which uses non-lethal endpoints (the loss of equilibrium). At low acclimatization temperatures (11.9 ± 0.7 °C), the mean CTmax of P. afer was found to be 29.9 ± 0.7 °C, while at a higher acclimatization temperature (19.9 ± 0.1 °C), the mean CTmax was 35.1 ± 0.6°C. Custom-built thermal choice tanks were used to investigate the thermal preference of P. afer in both summer and winter. The preferred median temperatures for the summer experiments ranged from 22.4 - 29.3 °C while the winter preferred median temperatures ranged from 18.5 - 23.1 °C. The thermal tolerance of P. afer was compared to the thermal regime of the stream and the results suggest that temperature is not limiting the distribution of P. afer. Snorkel surveys were used to determine the distribution of fishes in the Blindekloof stream. Analysis of the distribution data suggests that, in the absence of non-native predatory species, native fishes have the potential to inhabit pools throughout the system right to the confluence, thus predatory fishes and not temperature was limiting P. afer distributions.
- Full Text:
- Date Issued: 2018
- Authors: Bloy, Lesley Elizabeth
- Date: 2018
- Subjects: Minnows -- South Africa -- Eastern Cape , Cyprinidae -- South Africa -- Eastern Cape , Minnows -- Effect of temperature on -- South Africa -- Eastern Cape , Minnows -- Effect of exotic animals on -- South Africa -- Eastern Cape , Introduced organisms -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62017 , vital:28096
- Description: The main objective of this MSc study was to disentangle whether temperature or the presence of non-native fish was limiting the distribution of Pseudobarbus afer (Peters, 1864) in the Blindekloof stream, Eastern Cape, South Africa. The aims were to: i) describe the thermal regime of the Blindekloof stream; ii) conduct experiments to determine the preferred and critical temperatures of P. afer and; iii) use snorkel surveys to contextualise the distribution of both native and non-native fishes in the Blindekloof stream to assess whether the downstream distribution of P. afer was likely to be influenced by temperature or by the presence of non-native, predatory fishes. To describe the thermal regime, year-long temperature data from four long term monitoring sites in the Blindekloof stream were collected using Hobo temperature loggers and analysed in order to better understand the thermal profile, the thermal variation and the rate of temperature change in the stream. The warmest temperatures were recorded in late December 2015 (absolute maximum of 29.4 °C). The coolest water temperatures were recorded in early August 2015 (absolute minimum of 9.5 °C). There is both seasonal and diel variation in temperature with mean, minimum, maximum, 7 day mean, 7 day maximum and temperature ranges differing significantly between sites. With knowledge of the thermal regime of a monitored reach of the Blindekloof stream, the thermal tolerance and preference of P. afer were investigated. The thermal tolerance of P. afer was investigated using the Critical Thermal Method (CTM) which uses non-lethal endpoints (the loss of equilibrium). At low acclimatization temperatures (11.9 ± 0.7 °C), the mean CTmax of P. afer was found to be 29.9 ± 0.7 °C, while at a higher acclimatization temperature (19.9 ± 0.1 °C), the mean CTmax was 35.1 ± 0.6°C. Custom-built thermal choice tanks were used to investigate the thermal preference of P. afer in both summer and winter. The preferred median temperatures for the summer experiments ranged from 22.4 - 29.3 °C while the winter preferred median temperatures ranged from 18.5 - 23.1 °C. The thermal tolerance of P. afer was compared to the thermal regime of the stream and the results suggest that temperature is not limiting the distribution of P. afer. Snorkel surveys were used to determine the distribution of fishes in the Blindekloof stream. Analysis of the distribution data suggests that, in the absence of non-native predatory species, native fishes have the potential to inhabit pools throughout the system right to the confluence, thus predatory fishes and not temperature was limiting P. afer distributions.
- Full Text:
- Date Issued: 2018
The evaluation of potential dietary media, measurement parameters and storage techniques for use in forensic entomotoxicology
- Mbatha, Erica Isabel Tavares Da Silva
- Authors: Mbatha, Erica Isabel Tavares Da Silva
- Date: 2018
- Subjects: Blowflies -- Feeding and feeds , Blowflies -- Larvae , Blowflies -- Physiology , Blowflies -- Collection and preservation , Poisons -- Analysis , Death -- Causes , Forensic pathology , Forensic entomology , Forensic entomotoxicology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63323 , vital:28393
- Description: The term forensic entomotoxicology was coined by Pounder and is used to describe the process of using insects to determine the presence or absence of toxicants in decomposing corpses. Forensic entomotoxicology is most applicable when the orthodox sources of evidence (i.e. blood and urine) are no longer available for testing due to the degree of putrefaction as a result of the decomposition process. As the field is relatively new, various authors have conducted studies to determine the effects of different toxicants on different insects. These studies have all been conducted in the absence of a standardised protocol and we hypothesise that this has led to conflicting results (i.e. two different authors will conduct a study using the same toxicant and model insect and the effects on the insects will differ significantly). The aim of this thesis was to identify the areas which might have led to the artefacts in the results and identify ways in which to standardise them. The three areas selected were the feeding substrates and the measures taken to quantify growth rate, as well as the preservation techniques that should be used for preserving larval flies. The recommendation from the literature review was that artificial diets would be the most appropriate dietary media to use for entomotoxicological studies. An artificial diet was selected and modified for potential used in entomotoxicological studies. Four different diets (no meat treatment, fish, beef and pork artificial diets) were used to rear Chrysomya chloropyga larvae and their growth rates were measured using length and width. The fly larvae reared on the fish and no meat treatment diets did not reach pupation stage. The beef and pork diets produced the largest larvae and the flies in these treatments reached adult stage. The recommendation was that the beef and pork treatments be tested with various toxicants to establish their stability in the matrix and the diet that provides the toxicants with the most stability should be used for future entomotoxicological studies. The two other factors selected for standardisation were the parameters used to quantify growth rate, as well as the preservation techniques used to store empty Chrysomya chloropyga pupal casings and Calliphora croceipalpis third instar larvae. Previous authors have suggested that width be used as an alternative to length to quantify growth rate. The results from this thesis show that length should continue to be used as the standard parameter because the incremental change in length is much larger than the change in width, and these larger increments allow for greater resolution when estimating the age of the larvae. Various authors have also suggested that pupal casings should be stored without any preservative, whereas fly larvae should be stored in concentrations of ethanol >70%. The results in this thesis have shown that the concentration of ethanol does not make any significant difference to the proportional change of length and width of the empty pupal casings and the third instar larvae. The recommendation is that when selecting the preservation technique, the integrity of the specimen for examination of other evidence (i.e. DNA or toxicological extraction) should take precedence. Although this thesis has not completely standardised the protocol for forensic entomotoxicology, it has indicated the areas that need to be focused on in order for standardisation to occur. Future studies should focus on standardisation, as this makes studies more comparable and ultimately makes entomotoxicological evidence admissible in the court of law.
- Full Text:
- Date Issued: 2018
- Authors: Mbatha, Erica Isabel Tavares Da Silva
- Date: 2018
- Subjects: Blowflies -- Feeding and feeds , Blowflies -- Larvae , Blowflies -- Physiology , Blowflies -- Collection and preservation , Poisons -- Analysis , Death -- Causes , Forensic pathology , Forensic entomology , Forensic entomotoxicology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63323 , vital:28393
- Description: The term forensic entomotoxicology was coined by Pounder and is used to describe the process of using insects to determine the presence or absence of toxicants in decomposing corpses. Forensic entomotoxicology is most applicable when the orthodox sources of evidence (i.e. blood and urine) are no longer available for testing due to the degree of putrefaction as a result of the decomposition process. As the field is relatively new, various authors have conducted studies to determine the effects of different toxicants on different insects. These studies have all been conducted in the absence of a standardised protocol and we hypothesise that this has led to conflicting results (i.e. two different authors will conduct a study using the same toxicant and model insect and the effects on the insects will differ significantly). The aim of this thesis was to identify the areas which might have led to the artefacts in the results and identify ways in which to standardise them. The three areas selected were the feeding substrates and the measures taken to quantify growth rate, as well as the preservation techniques that should be used for preserving larval flies. The recommendation from the literature review was that artificial diets would be the most appropriate dietary media to use for entomotoxicological studies. An artificial diet was selected and modified for potential used in entomotoxicological studies. Four different diets (no meat treatment, fish, beef and pork artificial diets) were used to rear Chrysomya chloropyga larvae and their growth rates were measured using length and width. The fly larvae reared on the fish and no meat treatment diets did not reach pupation stage. The beef and pork diets produced the largest larvae and the flies in these treatments reached adult stage. The recommendation was that the beef and pork treatments be tested with various toxicants to establish their stability in the matrix and the diet that provides the toxicants with the most stability should be used for future entomotoxicological studies. The two other factors selected for standardisation were the parameters used to quantify growth rate, as well as the preservation techniques used to store empty Chrysomya chloropyga pupal casings and Calliphora croceipalpis third instar larvae. Previous authors have suggested that width be used as an alternative to length to quantify growth rate. The results from this thesis show that length should continue to be used as the standard parameter because the incremental change in length is much larger than the change in width, and these larger increments allow for greater resolution when estimating the age of the larvae. Various authors have also suggested that pupal casings should be stored without any preservative, whereas fly larvae should be stored in concentrations of ethanol >70%. The results in this thesis have shown that the concentration of ethanol does not make any significant difference to the proportional change of length and width of the empty pupal casings and the third instar larvae. The recommendation is that when selecting the preservation technique, the integrity of the specimen for examination of other evidence (i.e. DNA or toxicological extraction) should take precedence. Although this thesis has not completely standardised the protocol for forensic entomotoxicology, it has indicated the areas that need to be focused on in order for standardisation to occur. Future studies should focus on standardisation, as this makes studies more comparable and ultimately makes entomotoxicological evidence admissible in the court of law.
- Full Text:
- Date Issued: 2018
Two-tissue stable isotope analysis to elucidate isotopic incorporation and trophic niche patterns for chubbyhead barb Enteromius anoplus
- Authors: Kambikambi, Manda Juliet
- Date: 2018
- Subjects: Food chains (Ecology) , Barbus -- South Africa -- Great Fish River Estuary , Stable isotopes , Freshwater fishes -- Feeding and feeds , Freshwater fishes -- Food , Fins (Anatomy) , Akaike Information Criterion , Freshwater fishes -- Conservation , Chubbyhead barb Enteromius anoplus
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61906 , vital:28082
- Description: Knowledge of trophic ecology underpins conservation and management of threatened species. Stable isotope analysis has been widely used as a more objective approach for elucidating the trophic positions of freshwater fishes. Until recently, stable isotope analysis for trophic ecology studies in freshwater fishes largely utilised white muscle tissue. This sampling approach, however, involves either euthanasia or muscle biopsy procedures that may be inappropriate for small-sized and endangered fishes. These concerns raised the need to explore and validate the utility of non-lethal alternatives such as fin clips, mucus and scales. The present study investigated the use of caudal fin tissue as a potential non-lethal alternative to muscle tissue for trophic studies on the chubbyhead barb Enteromius anoplus. The chubbyhead barb was selected as a model taxon for the present study because it is closely related or comparable in body size to a number of highly threatened small-bodied minnows in southern Africa. The chubbyhead barb was also considered an ideal species for this study because it is widespread, abundant and classified as Least Concern on the IUCN list of threatened species. The study used a two-pronged approach based on laboratory and field experiments. A laboratory experiment was conducted to quantify isotopic turnover rates and diet-tissue discrimination factors (DTDFs/A) for both muscle and fin tissues. This involved feeding chubbyhead barb two diets with distinct carbon (δ13C) and nitrogen (δ15N) values, and monitoring the temporal isotopic incorporation patterns into the two tissues. These patterns were assessed by applying least squares non-linear one- and two-compartment isotopic kinetics models. Model comparisons, based on Akaike information criterion (AIC), revealed that one- compartment models described isotopic incorporation patterns better than two-compartment models for both muscle and fin tissues. For δ13C, relatively short and comparable turnover rates were observed for muscle and fin tissues, which suggests that fin tissue could potentially provide similar inference as muscle tissue when assessing short term dietary patterns for chubbyhead barb. In contrast to δ13C, turnover rates for δ15N between muscle and fin tissue were different for both diets. Specifically, stable isotope incorporation turnover rate was faster in muscle tissue for animals that were fed on isotopically enriched diets compared to fin tissue. Conversely, stable isotope incorporation into fin tissue was faster in animals fed on isotopically depleted diets compared to muscle tissue. This suggests that knowledge of animal diet is critical when inferring fin tissue δ15N turnover rates, particularly when extrapolating both short and long term dietary patterns. Diet-tissue discrimination factors were influenced by diet type, with the fish fed on isotopically enriched diet having lower DTDFs than animals fed on isotopically depleted diets. This variation may be explained by the protein quality hypothesis, which suggests that the DTDFs of consumers will decrease as protein quality increases. When A13C and A15N values were averaged across diets in muscle and fin tissue, the values were 0.74‰ and 0.64‰, respectively, for A13C, and 5.53‰ and 5.83 ‰, respectively, for A15N. This appeared to be consistent with studies on other taxa for A13C (0-1 ‰), but for A15N (3-5 ‰) the results of this study were higher than those reported for other taxa. These results suggest that investigating appropriate DTDFs for both muscle and fin tissues is important in trophic ecology studies of these minnows. A field-based study was conducted to investigate temporal dynamics in food web patterns for chubbyhead barb in the wild within the headwaters of the Koonap River, a tributary of the Great Fish River, in the Eastern Cape, South Africa. This was achieved by collecting and comparing stable isotope data for chubbyhead barb and its potential food sources on a seasonal scale. There was a discernible difference in both the composition of carbon and nitrogen isotope values for basal food sources and macroinvertebrate communities, which suggests that this headwater stream was subject to temporal changes in food web dynamics. For chubbyhead barb, comparison of its isotopic niche sizes on a temporal scale based on both muscle and fin tissue showed differences across seasons. Furthermore, isotopic niche sizes inferred from fin tissue were larger than those inferred from muscle tissue during winter and spring, whereas during summer and autumn the isotopic niche sizes inferred from muscle and fin tissue were generally comparable. This suggests the likely influence of different metabolic and physiological processes that these two tissues undergo on a temporal scale. Therefore, difference in tissue type, and their associated metabolic pathways should be considered when using fin tissue as a substitute for muscle tissue on broad temporal scales. The results from this study indicated that caudal fin tissue has the potential to be a substitute for muscle in trophic studies of chubbyhead barb Enteromius anoplus, as well as other related small bodied endangered minnow species from South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Kambikambi, Manda Juliet
- Date: 2018
- Subjects: Food chains (Ecology) , Barbus -- South Africa -- Great Fish River Estuary , Stable isotopes , Freshwater fishes -- Feeding and feeds , Freshwater fishes -- Food , Fins (Anatomy) , Akaike Information Criterion , Freshwater fishes -- Conservation , Chubbyhead barb Enteromius anoplus
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61906 , vital:28082
- Description: Knowledge of trophic ecology underpins conservation and management of threatened species. Stable isotope analysis has been widely used as a more objective approach for elucidating the trophic positions of freshwater fishes. Until recently, stable isotope analysis for trophic ecology studies in freshwater fishes largely utilised white muscle tissue. This sampling approach, however, involves either euthanasia or muscle biopsy procedures that may be inappropriate for small-sized and endangered fishes. These concerns raised the need to explore and validate the utility of non-lethal alternatives such as fin clips, mucus and scales. The present study investigated the use of caudal fin tissue as a potential non-lethal alternative to muscle tissue for trophic studies on the chubbyhead barb Enteromius anoplus. The chubbyhead barb was selected as a model taxon for the present study because it is closely related or comparable in body size to a number of highly threatened small-bodied minnows in southern Africa. The chubbyhead barb was also considered an ideal species for this study because it is widespread, abundant and classified as Least Concern on the IUCN list of threatened species. The study used a two-pronged approach based on laboratory and field experiments. A laboratory experiment was conducted to quantify isotopic turnover rates and diet-tissue discrimination factors (DTDFs/A) for both muscle and fin tissues. This involved feeding chubbyhead barb two diets with distinct carbon (δ13C) and nitrogen (δ15N) values, and monitoring the temporal isotopic incorporation patterns into the two tissues. These patterns were assessed by applying least squares non-linear one- and two-compartment isotopic kinetics models. Model comparisons, based on Akaike information criterion (AIC), revealed that one- compartment models described isotopic incorporation patterns better than two-compartment models for both muscle and fin tissues. For δ13C, relatively short and comparable turnover rates were observed for muscle and fin tissues, which suggests that fin tissue could potentially provide similar inference as muscle tissue when assessing short term dietary patterns for chubbyhead barb. In contrast to δ13C, turnover rates for δ15N between muscle and fin tissue were different for both diets. Specifically, stable isotope incorporation turnover rate was faster in muscle tissue for animals that were fed on isotopically enriched diets compared to fin tissue. Conversely, stable isotope incorporation into fin tissue was faster in animals fed on isotopically depleted diets compared to muscle tissue. This suggests that knowledge of animal diet is critical when inferring fin tissue δ15N turnover rates, particularly when extrapolating both short and long term dietary patterns. Diet-tissue discrimination factors were influenced by diet type, with the fish fed on isotopically enriched diet having lower DTDFs than animals fed on isotopically depleted diets. This variation may be explained by the protein quality hypothesis, which suggests that the DTDFs of consumers will decrease as protein quality increases. When A13C and A15N values were averaged across diets in muscle and fin tissue, the values were 0.74‰ and 0.64‰, respectively, for A13C, and 5.53‰ and 5.83 ‰, respectively, for A15N. This appeared to be consistent with studies on other taxa for A13C (0-1 ‰), but for A15N (3-5 ‰) the results of this study were higher than those reported for other taxa. These results suggest that investigating appropriate DTDFs for both muscle and fin tissues is important in trophic ecology studies of these minnows. A field-based study was conducted to investigate temporal dynamics in food web patterns for chubbyhead barb in the wild within the headwaters of the Koonap River, a tributary of the Great Fish River, in the Eastern Cape, South Africa. This was achieved by collecting and comparing stable isotope data for chubbyhead barb and its potential food sources on a seasonal scale. There was a discernible difference in both the composition of carbon and nitrogen isotope values for basal food sources and macroinvertebrate communities, which suggests that this headwater stream was subject to temporal changes in food web dynamics. For chubbyhead barb, comparison of its isotopic niche sizes on a temporal scale based on both muscle and fin tissue showed differences across seasons. Furthermore, isotopic niche sizes inferred from fin tissue were larger than those inferred from muscle tissue during winter and spring, whereas during summer and autumn the isotopic niche sizes inferred from muscle and fin tissue were generally comparable. This suggests the likely influence of different metabolic and physiological processes that these two tissues undergo on a temporal scale. Therefore, difference in tissue type, and their associated metabolic pathways should be considered when using fin tissue as a substitute for muscle tissue on broad temporal scales. The results from this study indicated that caudal fin tissue has the potential to be a substitute for muscle in trophic studies of chubbyhead barb Enteromius anoplus, as well as other related small bodied endangered minnow species from South Africa.
- Full Text:
- Date Issued: 2018
An analysis on role of judges in interpreting tax legislation
- Authors: Chanhuwa, Mildred Kudzanai
- Date: 2017
- Subjects: Taxation -- Law and legislation -- South Africa , Law -- South Africa , Judicial discretion -- South Africa , Judicial opinion -- South Africa , Judges -- Attitudes -- South Africa , South Africa. Constitution of the Republic of South Africa, 1996
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/4289 , vital:20644
- Description: This thesis focusses on the role of judges as interpreters of tax legislation. It examines the role of judges by analysing how the perceptions of judges can impact on how they interpret legislation. It also analyses various other factors that play a role when judges interpret legislation, in an effort to answer the question to what extent do philosophical theories and interpretative approaches explain the role of judges as interpreters? Jurisprudential theories such as the natural law theory, positivist theories, and American realist theories are used to analyse how judges interpret and how theorists think judges should play their interpretational role. It is noted that in pre-constitutional South Africa the courts followed a positivist paradigm; as a result, the judges used a strict literal approach to interpretation. The new Constitution brought a change in the jurisprudential paradigm accepted in South Africa and has transformed how judges perceive and carry out their role as interpreters of legislation. Judges have now adopted the purposive value-laden approach as authoritative. As custodians of the Constitution, judges should interpret provisions against the values imposed by it. The purposive value-laden interpretational approach allows judges to take into account more considerations and to weigh a provision against the constitutional values. Other issues discussed pertain to how institutional guidelines such as the doctrine of precedent and separation of powers, to a lesser extent, play a role in how judges interpret the law. It is demonstrated that the doctrine of precedent does not limit the role of judges but rather contributes to maintaining certainty, predictability and coherence in the legal system. It is also noted that judicial discretion is the mechanism by which judges use extra-legal factors such as public policy and moral considerations to assist in interpreting legislation.
- Full Text:
- Date Issued: 2017
- Authors: Chanhuwa, Mildred Kudzanai
- Date: 2017
- Subjects: Taxation -- Law and legislation -- South Africa , Law -- South Africa , Judicial discretion -- South Africa , Judicial opinion -- South Africa , Judges -- Attitudes -- South Africa , South Africa. Constitution of the Republic of South Africa, 1996
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/4289 , vital:20644
- Description: This thesis focusses on the role of judges as interpreters of tax legislation. It examines the role of judges by analysing how the perceptions of judges can impact on how they interpret legislation. It also analyses various other factors that play a role when judges interpret legislation, in an effort to answer the question to what extent do philosophical theories and interpretative approaches explain the role of judges as interpreters? Jurisprudential theories such as the natural law theory, positivist theories, and American realist theories are used to analyse how judges interpret and how theorists think judges should play their interpretational role. It is noted that in pre-constitutional South Africa the courts followed a positivist paradigm; as a result, the judges used a strict literal approach to interpretation. The new Constitution brought a change in the jurisprudential paradigm accepted in South Africa and has transformed how judges perceive and carry out their role as interpreters of legislation. Judges have now adopted the purposive value-laden approach as authoritative. As custodians of the Constitution, judges should interpret provisions against the values imposed by it. The purposive value-laden interpretational approach allows judges to take into account more considerations and to weigh a provision against the constitutional values. Other issues discussed pertain to how institutional guidelines such as the doctrine of precedent and separation of powers, to a lesser extent, play a role in how judges interpret the law. It is demonstrated that the doctrine of precedent does not limit the role of judges but rather contributes to maintaining certainty, predictability and coherence in the legal system. It is also noted that judicial discretion is the mechanism by which judges use extra-legal factors such as public policy and moral considerations to assist in interpreting legislation.
- Full Text:
- Date Issued: 2017
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