A comprehensive review of the taxonomic diversity within the freshwater catfish genus Parauchenoglanis (Siluriformes, Auchenoglanididae)
- Authors: Sithole, Yonela
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/402992 , vital:69912
- Description: Thesis embargoed. To be released early 2026. , Thesis (PhD) -- Faculty of Science, Ichthyology & Fisheries Science, 2023
- Full Text:
- Authors: Sithole, Yonela
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/402992 , vital:69912
- Description: Thesis embargoed. To be released early 2026. , Thesis (PhD) -- Faculty of Science, Ichthyology & Fisheries Science, 2023
- Full Text:
A formative evaluation and critical analysis of an alcohol and pregnancy intervention in the Eastern Cape of South Africa
- Authors: Graham, Nicola Susan Jearey
- Date: 2023-10-13
- Subjects: Fetal alcohol spectrum disorders South Africa Eastern Cape , Foucauldian discourse analysis , Conversation analysis , Women Social conditions South Africa Eastern Cape , Sex role South Africa Eastern Cape , Cultural hegemony
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/432541 , vital:72879 , DOI 10.21504/10962/432541
- Description: Some communities in South Africa have the highest documented rates of Foetal Alcohol Spectrum Disorders (FASD) in the world. Interventions to reduce alcohol consumption during pregnancy are crucial, but evaluations of such interventions are sparse. Formative evaluations are indicated to assist in the development of interventions. Harmful alcohol consumption during pregnancy is undergirded by a range of social injustices, including those imposed by colonisation and patriarchy; a feminist, decolonial approach to evaluations is, therefore, important. A research project, consisting of three arms, examined alcohol use during pregnancy in an under-resourced urban area of the Eastern Cape, and this research was one of those arms. An intervention was being rolled out in this area and I gathered a range of data from it. I engaged in a formative evaluation of it, and I reflect on the difficulties that I encountered in this endeavour. In the bulk of this thesis, I examine the power apparatuses and technologies that were used during the intervention to discursively position pregnant women. My analysis was guided by Foucauldian and post-Foucauldian theories, using Foucauldian Discourse Analysis and simplified Conversation Analysis (CA). Power apparatuses of coloniality, patriarchy, and pastoral power were used in the intervention to construct positions for pregnant women who drink alcohol as ignorant children, sinners, criminals, or “Mommies”. The foetus was constructed as a precious, vulnerable baby, while the person with FASD was constructed as the defiled Other, responsible for societal dissolution. The intervention used various disciplinary techniques to exhort women to follow their dictates. Women were generally compliant with being positioned as ignorant children, which absolved them from any blame for pre-natal drinking. However, some resistance was evident. I then introduce an ethics of care and justice, and I argue that pregnant/newly parenting women need to be positioned within such an ethics, which acknowledges both the universal resources that they require for reproductive freedoms, as well as their particular care needs. I highlight the few times when women were positioned in this way in the data, and I look at how the common positions could be altered or expanded to promote such an ethics. I conclude by arguing that alcohol use during pregnancy cannot be separated from the larger context of the cultural hegemony of alcohol use in some communities, and the social injustices that potentiate this use. I provide suggestions for country-wide policies and interventions, as well as specific FASD prevention programmes, and I argue that a feminist decolonising approach, within an ethics of care and justice, should guide interventions at all levels. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Authors: Graham, Nicola Susan Jearey
- Date: 2023-10-13
- Subjects: Fetal alcohol spectrum disorders South Africa Eastern Cape , Foucauldian discourse analysis , Conversation analysis , Women Social conditions South Africa Eastern Cape , Sex role South Africa Eastern Cape , Cultural hegemony
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/432541 , vital:72879 , DOI 10.21504/10962/432541
- Description: Some communities in South Africa have the highest documented rates of Foetal Alcohol Spectrum Disorders (FASD) in the world. Interventions to reduce alcohol consumption during pregnancy are crucial, but evaluations of such interventions are sparse. Formative evaluations are indicated to assist in the development of interventions. Harmful alcohol consumption during pregnancy is undergirded by a range of social injustices, including those imposed by colonisation and patriarchy; a feminist, decolonial approach to evaluations is, therefore, important. A research project, consisting of three arms, examined alcohol use during pregnancy in an under-resourced urban area of the Eastern Cape, and this research was one of those arms. An intervention was being rolled out in this area and I gathered a range of data from it. I engaged in a formative evaluation of it, and I reflect on the difficulties that I encountered in this endeavour. In the bulk of this thesis, I examine the power apparatuses and technologies that were used during the intervention to discursively position pregnant women. My analysis was guided by Foucauldian and post-Foucauldian theories, using Foucauldian Discourse Analysis and simplified Conversation Analysis (CA). Power apparatuses of coloniality, patriarchy, and pastoral power were used in the intervention to construct positions for pregnant women who drink alcohol as ignorant children, sinners, criminals, or “Mommies”. The foetus was constructed as a precious, vulnerable baby, while the person with FASD was constructed as the defiled Other, responsible for societal dissolution. The intervention used various disciplinary techniques to exhort women to follow their dictates. Women were generally compliant with being positioned as ignorant children, which absolved them from any blame for pre-natal drinking. However, some resistance was evident. I then introduce an ethics of care and justice, and I argue that pregnant/newly parenting women need to be positioned within such an ethics, which acknowledges both the universal resources that they require for reproductive freedoms, as well as their particular care needs. I highlight the few times when women were positioned in this way in the data, and I look at how the common positions could be altered or expanded to promote such an ethics. I conclude by arguing that alcohol use during pregnancy cannot be separated from the larger context of the cultural hegemony of alcohol use in some communities, and the social injustices that potentiate this use. I provide suggestions for country-wide policies and interventions, as well as specific FASD prevention programmes, and I argue that a feminist decolonising approach, within an ethics of care and justice, should guide interventions at all levels. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2023
- Full Text:
Movement ecology of a West African sciaenid fish, Argyrosomus coronus, in southern Angola
- Authors: Parkinson, Matthew Cameron
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/432203 , vital:72851 , DOI 10.21504/10962/432203
- Description: Argyrosomus coronus is a large sciaenid species with a primary distribution between Cape Frio, in Namibia, and Luanda, in Angola, where it exists as a panmictic stock. Early juveniles (< 300 mm TL) occur on muddy offshore substrata (50–80 m deep) and at one year of age they recruit into the inshore zone. Adults are thought to predominantly occur inshore. Spawning occurs in the species during late spring. The species is heavily targeted by the recreational, subsistence, artisanal and commercial fisheries as juveniles through to adults and there are signs of population decline with declines in catch per unit effort (CPUE) and maximum size. A basic understanding of their movement ecology has emerged from previous studies, based on conventional tagging (mark-recapture) and CPUE monitoring from a shore-based recreational fishery. Juveniles were thought to be resident, with larger fish undertaking long distance migration southward in the austral summer and returning during the austral winter. In addition to the fishery-related threats faced by the species, the southern Angolan region has been identified to be an ocean warming hotspot, and this has been linked to a southward distribution shift and the recent hybridisation of A. coronus with its congener A. inodorus, in Namibia. This study aims to expand the knowledge of the movement ecology of A. coronus and to interrogate our current understanding of the movement patterns of the species using passive acoustic telemetry. Passive acoustic receivers were deployed at three study sites, Flamingo, where all tagging occurred, which lies ~ 200 km north of the Angolan border with Namibia, is a relatively exposed stretch of coastline; Tombua Bay, which lies 30 km south of Flamingo, is a small, sheltered natural embayment; and Baia dos Tigres, which lies 100 km south of Tombua Bay, is a sheltered lagoon in the lee of an island ~ 10 km from the mainland. Tagging occurred in two batches, one year apart. In the first batch, sub-adults (n = 3) and adults (n = 17) were tagged and monitored for two years. In the second batch, juveniles (n = 7) and sub-adults (n = 3) were tagged and monitored for one year. The first objective of this thesis (Chapter 3) was to examine the spatio-temporal dynamics of A. coronus at a regional-level (across study sites, to investigate the prevalence of the longshore migration), and at a local-level (within a study site), and to categorise the movement behaviour of juveniles, sub-adults and adults. Traditional seasons were not used in this thesis, as the study region alternates between ‘warm’ periods (up to ~ 26 °C mean daily water temperature), when Angola Current water covers the area, and ‘cold’ periods (down to ~ 15 °C mean daily water temperature), when Benguela Current water covers the area. A high degree of residency of tagged fish to the Flamingo study site, where tagging was conducted, was found, with juveniles and sub-adults never being detected outside of the Flamingo study site. Five adults (29 %) were detected haphazardly for between one and 36 days at Tombua Bay, following which they were typically detected again at the Flamingo study site. No fish were ever detected at the southernmost site, Baia dos Tigres, suggesting that none migrated to Namibia. Within the Flamingo study site, adults were found to group at the inshore mid-region of the study site during ‘cold’ periods, dispersing again during ‘warm’ periods, when there was a concomitant offshore shift in their area use. This explained the absence of the species from catches in the shore-based recreational fishery during ‘warm’ periods. These results challenge previous migration hypotheses for the species. Therefore, longshore return migrations which were evident from previously conducted conventional tagging, are probably not the norm for the species, but likely occur at a low frequency. The species exhibited a high degree of residency to their tagging site, despite the drastic seasonal changes in water temperatures and station-keeping was the dominant behaviour across all life stages. The constrained area-use noted in this study, relative to the known distribution of the species, suggests that A. coronus exists as a metapopulation, consisting of a network of subpopulations interconnected by gene flow that is most likely facilitated during their pelagic egg and larval phase. The second objective of this thesis was to examine the group formation observed at the Flamingo study site during ‘cold’ periods (Chapter 4). While this grouping of individuals was found to be correlated with water temperature, it was unlikely to be a causal relationship, as the water temperature was not dissimilar to adjacent areas. The area where individuals were concentrated is known to frequently attract large shoals of their dominant prey, Sardinella aurita. While the timing of this group formation aligns with a pre-spawning period, no studies have assessed the existence of local spawning. A. coronus were, however, likely utilising an abundant prey source, during the important pre-spawning period, in order to build up energy reserves. Group formation is a common feature of sciaenids, but literature on the subject is restricted to spawning congregations. Fish are not only more vulnerable to capture during these periods but may also be disturbed during these potentially important social periods. The third objective of this thesis was to investigate the presence of sociality in the species (Chapter 5). Evidence for sociality during and outside the seasonal group formation was explored using network analyses. There was evidence for sociality, with several groups, characterized by co-locations among individuals, identified. While these groups were fluid through time, there was evidence of persistent sociality, with two individuals in particular being consistently co-located over the entire study period. Due to the persistent nature of sociality, group foraging is suggested as an explanation for this, with anecdotal evidence of coordinated hunting supporting this. Acoustic telemetry vastly improved the knowledge of the movement ecology of A. coronus. Despite their panmictic population genetic structure, they were found to be largely resident, likely occurring as a metapopulation across their distribution, with egg and larval dispersal likely the primary mechanism for maintaining panmixia. Evidence for sociality was also found, which was previously unexplored in the species. The persistent nature of social groupings throughout the year, suggests that it may be linked with group foraging and is supported by anecdotal evidence of coordinated hunting by the species. While this study highlights the value of acoustic telemetry in studying movement ecology, it also shows the importance of drawing on multiple methods to fully understand a species’ spatial ecology, including mark-recapture, population genetics, and fishery catch and effort data. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Authors: Parkinson, Matthew Cameron
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/432203 , vital:72851 , DOI 10.21504/10962/432203
- Description: Argyrosomus coronus is a large sciaenid species with a primary distribution between Cape Frio, in Namibia, and Luanda, in Angola, where it exists as a panmictic stock. Early juveniles (< 300 mm TL) occur on muddy offshore substrata (50–80 m deep) and at one year of age they recruit into the inshore zone. Adults are thought to predominantly occur inshore. Spawning occurs in the species during late spring. The species is heavily targeted by the recreational, subsistence, artisanal and commercial fisheries as juveniles through to adults and there are signs of population decline with declines in catch per unit effort (CPUE) and maximum size. A basic understanding of their movement ecology has emerged from previous studies, based on conventional tagging (mark-recapture) and CPUE monitoring from a shore-based recreational fishery. Juveniles were thought to be resident, with larger fish undertaking long distance migration southward in the austral summer and returning during the austral winter. In addition to the fishery-related threats faced by the species, the southern Angolan region has been identified to be an ocean warming hotspot, and this has been linked to a southward distribution shift and the recent hybridisation of A. coronus with its congener A. inodorus, in Namibia. This study aims to expand the knowledge of the movement ecology of A. coronus and to interrogate our current understanding of the movement patterns of the species using passive acoustic telemetry. Passive acoustic receivers were deployed at three study sites, Flamingo, where all tagging occurred, which lies ~ 200 km north of the Angolan border with Namibia, is a relatively exposed stretch of coastline; Tombua Bay, which lies 30 km south of Flamingo, is a small, sheltered natural embayment; and Baia dos Tigres, which lies 100 km south of Tombua Bay, is a sheltered lagoon in the lee of an island ~ 10 km from the mainland. Tagging occurred in two batches, one year apart. In the first batch, sub-adults (n = 3) and adults (n = 17) were tagged and monitored for two years. In the second batch, juveniles (n = 7) and sub-adults (n = 3) were tagged and monitored for one year. The first objective of this thesis (Chapter 3) was to examine the spatio-temporal dynamics of A. coronus at a regional-level (across study sites, to investigate the prevalence of the longshore migration), and at a local-level (within a study site), and to categorise the movement behaviour of juveniles, sub-adults and adults. Traditional seasons were not used in this thesis, as the study region alternates between ‘warm’ periods (up to ~ 26 °C mean daily water temperature), when Angola Current water covers the area, and ‘cold’ periods (down to ~ 15 °C mean daily water temperature), when Benguela Current water covers the area. A high degree of residency of tagged fish to the Flamingo study site, where tagging was conducted, was found, with juveniles and sub-adults never being detected outside of the Flamingo study site. Five adults (29 %) were detected haphazardly for between one and 36 days at Tombua Bay, following which they were typically detected again at the Flamingo study site. No fish were ever detected at the southernmost site, Baia dos Tigres, suggesting that none migrated to Namibia. Within the Flamingo study site, adults were found to group at the inshore mid-region of the study site during ‘cold’ periods, dispersing again during ‘warm’ periods, when there was a concomitant offshore shift in their area use. This explained the absence of the species from catches in the shore-based recreational fishery during ‘warm’ periods. These results challenge previous migration hypotheses for the species. Therefore, longshore return migrations which were evident from previously conducted conventional tagging, are probably not the norm for the species, but likely occur at a low frequency. The species exhibited a high degree of residency to their tagging site, despite the drastic seasonal changes in water temperatures and station-keeping was the dominant behaviour across all life stages. The constrained area-use noted in this study, relative to the known distribution of the species, suggests that A. coronus exists as a metapopulation, consisting of a network of subpopulations interconnected by gene flow that is most likely facilitated during their pelagic egg and larval phase. The second objective of this thesis was to examine the group formation observed at the Flamingo study site during ‘cold’ periods (Chapter 4). While this grouping of individuals was found to be correlated with water temperature, it was unlikely to be a causal relationship, as the water temperature was not dissimilar to adjacent areas. The area where individuals were concentrated is known to frequently attract large shoals of their dominant prey, Sardinella aurita. While the timing of this group formation aligns with a pre-spawning period, no studies have assessed the existence of local spawning. A. coronus were, however, likely utilising an abundant prey source, during the important pre-spawning period, in order to build up energy reserves. Group formation is a common feature of sciaenids, but literature on the subject is restricted to spawning congregations. Fish are not only more vulnerable to capture during these periods but may also be disturbed during these potentially important social periods. The third objective of this thesis was to investigate the presence of sociality in the species (Chapter 5). Evidence for sociality during and outside the seasonal group formation was explored using network analyses. There was evidence for sociality, with several groups, characterized by co-locations among individuals, identified. While these groups were fluid through time, there was evidence of persistent sociality, with two individuals in particular being consistently co-located over the entire study period. Due to the persistent nature of sociality, group foraging is suggested as an explanation for this, with anecdotal evidence of coordinated hunting supporting this. Acoustic telemetry vastly improved the knowledge of the movement ecology of A. coronus. Despite their panmictic population genetic structure, they were found to be largely resident, likely occurring as a metapopulation across their distribution, with egg and larval dispersal likely the primary mechanism for maintaining panmixia. Evidence for sociality was also found, which was previously unexplored in the species. The persistent nature of social groupings throughout the year, suggests that it may be linked with group foraging and is supported by anecdotal evidence of coordinated hunting by the species. While this study highlights the value of acoustic telemetry in studying movement ecology, it also shows the importance of drawing on multiple methods to fully understand a species’ spatial ecology, including mark-recapture, population genetics, and fishery catch and effort data. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
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