Stock structure of Patagonian toothfish Dissostichus eleginoides (Smitt 1898, family Nototheniidae) in the Southwest Atlantic
- Authors: Lee, Brendon
- Date: 2022-10-14
- Subjects: Otoliths , Patagonian toothfish Geographical distribution , Fish tagging , Biogeography , Microstructure , Microchemistry
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365599 , vital:65763 , DOI https://doi.org/10.21504/10962/365599
- Description: The identification of discrete self-sustaining productive units in marine populations is essential for achieving sustainable fisheries objectives. Marine fish populations frequently exhibit dynamic characteristics across their life-histories, displaying variability in spatial structure and mixing patterns, both within and among populations. The incoherent application of management boundaries on biological populations can bias stock assessment results and have important implications on sustainable fisheries management. Patagonian toothfish (Dissostichus eleginoides) is a long-lived, slow-growing, late-maturing, deep-sea, benthopelagic species. It forms the basis of important and highly lucrative industrial and artisanal fisheries across its distribution. Patagonian toothfish have complex life-histories characterised by high dispersal potential during the egg and larval phase, a wide depth range because of their ontogenetic migratory behaviour, and large adult size that is capable of undertaking long-distance active movements (>200 km). These characteristics provide opportunities for high levels of connectivity, and as such, the stock structure is not well understood. We applied an integrated, multidisciplinary approach to provide an improved understanding of the complex stock structure dynamics for Patagonian toothfish on the Patagonian Shelf, specifically in relation to the shelf, slope, and deep-sea plains around the Falkland Islands. Research results were focused on aspects pertaining to (1) geographic variation in phenotypic characters (otolith shape); (2) a description of the spatial-temporal distribution patterns; (3) the active movements of deep-sea adults (tag-recapture study); and (4) the identification of early life-history dispersal through otolith microstructure and microchemical chronologies. Results from the study indicate high regional connectivity during the early life-history stages derived from at least two spawning contingents into spatially discrete nursery areas (cohort groups) on the Falklands Shelf. Fish followed distinct ontogenetic pathways into deeper waters adjacent to the areas wherein juvenile settlement into a demersal habitat occurred. There is little to no evidence of mixing among cohort groups during their ontogenetic migration into deep-sea adult habitats, reflecting a mixed population based on oceanographically defined egg and larval dispersal. The majority of the adult component of the population continue to display high site fidelity. However, between 9 and 25% of the population, consisting predominantly of larger reproductively capable adults undertake long-distance dispersal behaviour, identified as home-range relocations from the adult deep-sea habitats towards three of the known southern spawning grounds in the region. Results are suggestive of a requirement for improved collaborative efforts for regionally-based management approaches with careful consideration of local stock contingents. Future monitoring and research priorities should focus on the identification of reproductive potential, dispersal pathways and settlement patterns of stock contingents to inform the dynamics of mixed stock origins across the Patagonian region. While many aspects regarding the stock structure remain unresolved, results derived from the current studies can be used to inform the development of management measures to ensure the continued recovery and sustainable management of Patagonian toothfish within the region. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Lee, Brendon
- Date: 2022-10-14
- Subjects: Otoliths , Patagonian toothfish Geographical distribution , Fish tagging , Biogeography , Microstructure , Microchemistry
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365599 , vital:65763 , DOI https://doi.org/10.21504/10962/365599
- Description: The identification of discrete self-sustaining productive units in marine populations is essential for achieving sustainable fisheries objectives. Marine fish populations frequently exhibit dynamic characteristics across their life-histories, displaying variability in spatial structure and mixing patterns, both within and among populations. The incoherent application of management boundaries on biological populations can bias stock assessment results and have important implications on sustainable fisheries management. Patagonian toothfish (Dissostichus eleginoides) is a long-lived, slow-growing, late-maturing, deep-sea, benthopelagic species. It forms the basis of important and highly lucrative industrial and artisanal fisheries across its distribution. Patagonian toothfish have complex life-histories characterised by high dispersal potential during the egg and larval phase, a wide depth range because of their ontogenetic migratory behaviour, and large adult size that is capable of undertaking long-distance active movements (>200 km). These characteristics provide opportunities for high levels of connectivity, and as such, the stock structure is not well understood. We applied an integrated, multidisciplinary approach to provide an improved understanding of the complex stock structure dynamics for Patagonian toothfish on the Patagonian Shelf, specifically in relation to the shelf, slope, and deep-sea plains around the Falkland Islands. Research results were focused on aspects pertaining to (1) geographic variation in phenotypic characters (otolith shape); (2) a description of the spatial-temporal distribution patterns; (3) the active movements of deep-sea adults (tag-recapture study); and (4) the identification of early life-history dispersal through otolith microstructure and microchemical chronologies. Results from the study indicate high regional connectivity during the early life-history stages derived from at least two spawning contingents into spatially discrete nursery areas (cohort groups) on the Falklands Shelf. Fish followed distinct ontogenetic pathways into deeper waters adjacent to the areas wherein juvenile settlement into a demersal habitat occurred. There is little to no evidence of mixing among cohort groups during their ontogenetic migration into deep-sea adult habitats, reflecting a mixed population based on oceanographically defined egg and larval dispersal. The majority of the adult component of the population continue to display high site fidelity. However, between 9 and 25% of the population, consisting predominantly of larger reproductively capable adults undertake long-distance dispersal behaviour, identified as home-range relocations from the adult deep-sea habitats towards three of the known southern spawning grounds in the region. Results are suggestive of a requirement for improved collaborative efforts for regionally-based management approaches with careful consideration of local stock contingents. Future monitoring and research priorities should focus on the identification of reproductive potential, dispersal pathways and settlement patterns of stock contingents to inform the dynamics of mixed stock origins across the Patagonian region. While many aspects regarding the stock structure remain unresolved, results derived from the current studies can be used to inform the development of management measures to ensure the continued recovery and sustainable management of Patagonian toothfish within the region. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-10-14
The School Governing Bodies conceptualization of ulwaluko in school-based policies: Towards a deconstructed educational leadership and management framework
- Gqeba, Nokuzola Gloria https://orcid.org/ 0000-0002-9009-2150
- Authors: Gqeba, Nokuzola Gloria https://orcid.org/ 0000-0002-9009-2150
- Date: 2021-07
- Subjects: Initiation rites
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/20057 , vital:45104
- Description: Ulwaluko (male initiation), one of the African traditions, which serves as transitional rite of passage from boyhood, has evolved over time, through the colonial era, apartheid regime and the current dispensation (Ntsebeza, 2004). Evidence indicates that within the South African context, the majority of candidates of Ulwaluko are males of school-going age. Ulwaluko is said to be a school where initiates are taught, yet there is no link between ulwaluko and formal schooling. Therefore, the study examines the extent to which School Governing Bodies (SGBs) conceptualize ulwaluko in the school-based policies. The study used theoretical lenses of Hall’s ‘Third Space’ or hybridity, as well as Decoloniality, qualitative approach, and a Case Study Design. For this study, two high schools were purposely sampled, with a total of twelve participants that included Principals, SGB Chairpersons, and SGB Educator Representatives, Representatives of Learners and Ordinary SGB members. In-depth interviews and document reviews were employed as research instruments. The findings of the study suggest that even though ulwaluko seemed to affect the management of the two schools, it was not explicitly addressed in their policies. Ulwaluko is reluctantly and cautiously addressed informally. Lastly, the schools were reportedly reluctant to open debates on how ulwaluko could be accommodated for fear of “contaminating” school protocols with the African culture, which they thought did not belong in schools. The study makes various suggestions to build a strong relationship between ulwaluko and formal school practices. One of the main recommendations is the integration of ulwaluko into the mainstream education system through school governance and school-based policy. The study also proposes a deconstructed leadership and management framework that places African cultural practices such as Ulwaluko into the mainstream of management and curriculum. , Thesis (PhD) -- Faculty of Education, 2021
- Full Text:
- Date Issued: 2021-07
- Authors: Gqeba, Nokuzola Gloria https://orcid.org/ 0000-0002-9009-2150
- Date: 2021-07
- Subjects: Initiation rites
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/20057 , vital:45104
- Description: Ulwaluko (male initiation), one of the African traditions, which serves as transitional rite of passage from boyhood, has evolved over time, through the colonial era, apartheid regime and the current dispensation (Ntsebeza, 2004). Evidence indicates that within the South African context, the majority of candidates of Ulwaluko are males of school-going age. Ulwaluko is said to be a school where initiates are taught, yet there is no link between ulwaluko and formal schooling. Therefore, the study examines the extent to which School Governing Bodies (SGBs) conceptualize ulwaluko in the school-based policies. The study used theoretical lenses of Hall’s ‘Third Space’ or hybridity, as well as Decoloniality, qualitative approach, and a Case Study Design. For this study, two high schools were purposely sampled, with a total of twelve participants that included Principals, SGB Chairpersons, and SGB Educator Representatives, Representatives of Learners and Ordinary SGB members. In-depth interviews and document reviews were employed as research instruments. The findings of the study suggest that even though ulwaluko seemed to affect the management of the two schools, it was not explicitly addressed in their policies. Ulwaluko is reluctantly and cautiously addressed informally. Lastly, the schools were reportedly reluctant to open debates on how ulwaluko could be accommodated for fear of “contaminating” school protocols with the African culture, which they thought did not belong in schools. The study makes various suggestions to build a strong relationship between ulwaluko and formal school practices. One of the main recommendations is the integration of ulwaluko into the mainstream education system through school governance and school-based policy. The study also proposes a deconstructed leadership and management framework that places African cultural practices such as Ulwaluko into the mainstream of management and curriculum. , Thesis (PhD) -- Faculty of Education, 2021
- Full Text:
- Date Issued: 2021-07
The economic contribution of the tourism accommodation sector in the Karoo
- Authors: Chandler, Biddy Lee
- Date: 2013-04-06
- Subjects: Hospitality industry South Africa Karoo , Karoo (South Africa) Economic conditions , Small cities South Africa Karoo , Tourism South Africa Karoo
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/366169 , vital:65838
- Description: Tourism is not only the world’s largest traded commodity in which many countries have gained economic advantage and stability, it is also a phenomenon of great economic and social significance. Tourism’s contribution, especially within developing countries and within emerging markets like South Africa, has become increasingly significant as it has created major economic growth and has highlighted areas of potential new sustainable development. The ultimate goal of achieving an increase in GDP and the creation of new employment opportunities is enhanced through the development of tourism. Considering the importance of the above and because the impact of tourism development in small towns is of significant economic benefit, research into this field is of value. This is the core of this study. As a result of tourism demand continually changing in small towns, mostly due to globalisation, demographic changes and agricultural changes, the need to continually update tourism data to ensure that tourism products remain highly rated is vital. This requires identifying tourists’ needs and supplying exactly what tourists demand. More specifically, evaluating tourist satisfaction and dissatisfaction will give accurate indications of a destination’s ability to satisfy its tourists, which is what will encourage repeat visits. The first objective of this dissertation was to qualitatively evaluate, through determining 27 product owners’ and 206 tourists’, opinions/perceptions of the tourism product offering in the Karoo. This study examined the accommodation sector of the tourism industry within 13 small towns in the Karoo. This is a fast growing and maturing industry. The study revealed that product owners and tourists expressed a positive attitude towards the growth of tourism in the Karoo, which they said was due to its heritage and authenticity, climate, desert tourism, natural beauty, ecotourism, remoteness, peace and quiet and acting as a refuge in an unspoilt natural environment. Amongst other recommendations, this result highlighted the importance of keeping closed the ‘gap’ between the expected product/level of service and the customer’s perception of the actual product/service received, by paying special attention to each of the identified tourist benefits. Most importantly, product owners, local tourism organisations (LTOs), municipalities, the government and all tourism stakeholders need to ensure that they work efficiently and effectively through transparent and collaborative relationships to ensure that they generate the highest possible returns from tourism investment through strategies that take cognizance of the above. The second objective of this dissertation was to quantitatively evaluate the economic impact of tourism through gathering and calculating 107 tourists’ spending data and 15 product owners’ expenditure data over a six month period between December 2010 and May 2011 in Graaff-Reinet. It was found that there was an increase over time in tourist spending, which led to an increase in direct income (net injection of visitor spending) and thus there was an increase in indirect income(affecting the level of product owners’ income)in the Graaff-Reinet economy. The key calculations in this study reflected a high multiplier of 1.2and a small amount of leakage (21%);and the final tourism economic impact of the accommodation sector in Graaff-Reinet wasR8940 982.00. This implies a positive economic contribution to this town. A focus on growing the tourist market is therefore a goal worth pursuing. This study provides up-to-date, statistically valid numerical/quantitative data as well as current qualitative data. However, gathering data for a longitudinal study would be highly beneficial to determine trends of how the tourism market in small towns is developing. This field has been given minimal attention, specifically within small towns. This dissertation was thus an attempt to initiate and motivate further ongoing efforts with regards to gathering, specifically economic, tourism data. Showing the positive economic contribution, and the multiple ripple effects that attracting tourists to an area can have, and the ultimate measurable economic benefit created through having a strong multiplier effect, will hopefully encourage all stakeholders to be confident and take the tourism industry more seriously. This highlights the need to recognise the economic impact potential of the tourism sector and to use the positive results identified in this study as a tool to lobby for tourism investment, which is unfortunately not reflected currently in many governmental programmes. Developing greater co-operation and co-ordination between the private and public sectors is needed: the most appropriate development model for the tourism industry being government led, private sector driven, community based and labour conscious in order for it to reap the benefits reflected in this tourism study. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2013
- Full Text:
- Date Issued: 2013-04-06
- Authors: Chandler, Biddy Lee
- Date: 2013-04-06
- Subjects: Hospitality industry South Africa Karoo , Karoo (South Africa) Economic conditions , Small cities South Africa Karoo , Tourism South Africa Karoo
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/366169 , vital:65838
- Description: Tourism is not only the world’s largest traded commodity in which many countries have gained economic advantage and stability, it is also a phenomenon of great economic and social significance. Tourism’s contribution, especially within developing countries and within emerging markets like South Africa, has become increasingly significant as it has created major economic growth and has highlighted areas of potential new sustainable development. The ultimate goal of achieving an increase in GDP and the creation of new employment opportunities is enhanced through the development of tourism. Considering the importance of the above and because the impact of tourism development in small towns is of significant economic benefit, research into this field is of value. This is the core of this study. As a result of tourism demand continually changing in small towns, mostly due to globalisation, demographic changes and agricultural changes, the need to continually update tourism data to ensure that tourism products remain highly rated is vital. This requires identifying tourists’ needs and supplying exactly what tourists demand. More specifically, evaluating tourist satisfaction and dissatisfaction will give accurate indications of a destination’s ability to satisfy its tourists, which is what will encourage repeat visits. The first objective of this dissertation was to qualitatively evaluate, through determining 27 product owners’ and 206 tourists’, opinions/perceptions of the tourism product offering in the Karoo. This study examined the accommodation sector of the tourism industry within 13 small towns in the Karoo. This is a fast growing and maturing industry. The study revealed that product owners and tourists expressed a positive attitude towards the growth of tourism in the Karoo, which they said was due to its heritage and authenticity, climate, desert tourism, natural beauty, ecotourism, remoteness, peace and quiet and acting as a refuge in an unspoilt natural environment. Amongst other recommendations, this result highlighted the importance of keeping closed the ‘gap’ between the expected product/level of service and the customer’s perception of the actual product/service received, by paying special attention to each of the identified tourist benefits. Most importantly, product owners, local tourism organisations (LTOs), municipalities, the government and all tourism stakeholders need to ensure that they work efficiently and effectively through transparent and collaborative relationships to ensure that they generate the highest possible returns from tourism investment through strategies that take cognizance of the above. The second objective of this dissertation was to quantitatively evaluate the economic impact of tourism through gathering and calculating 107 tourists’ spending data and 15 product owners’ expenditure data over a six month period between December 2010 and May 2011 in Graaff-Reinet. It was found that there was an increase over time in tourist spending, which led to an increase in direct income (net injection of visitor spending) and thus there was an increase in indirect income(affecting the level of product owners’ income)in the Graaff-Reinet economy. The key calculations in this study reflected a high multiplier of 1.2and a small amount of leakage (21%);and the final tourism economic impact of the accommodation sector in Graaff-Reinet wasR8940 982.00. This implies a positive economic contribution to this town. A focus on growing the tourist market is therefore a goal worth pursuing. This study provides up-to-date, statistically valid numerical/quantitative data as well as current qualitative data. However, gathering data for a longitudinal study would be highly beneficial to determine trends of how the tourism market in small towns is developing. This field has been given minimal attention, specifically within small towns. This dissertation was thus an attempt to initiate and motivate further ongoing efforts with regards to gathering, specifically economic, tourism data. Showing the positive economic contribution, and the multiple ripple effects that attracting tourists to an area can have, and the ultimate measurable economic benefit created through having a strong multiplier effect, will hopefully encourage all stakeholders to be confident and take the tourism industry more seriously. This highlights the need to recognise the economic impact potential of the tourism sector and to use the positive results identified in this study as a tool to lobby for tourism investment, which is unfortunately not reflected currently in many governmental programmes. Developing greater co-operation and co-ordination between the private and public sectors is needed: the most appropriate development model for the tourism industry being government led, private sector driven, community based and labour conscious in order for it to reap the benefits reflected in this tourism study. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2013
- Full Text:
- Date Issued: 2013-04-06
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