Incidence of parasitic trematodes effects on the energetics and behaviour of Coryogalops sordidus (Family: Gobiidae) resident in microbialite pools, warm temperate South Africa
- Authors: Du Toit, Hendrik Daniël
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Gobiidae -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52458 , vital:43666
- Description: Coryogalops sordidus(Epaulette goby), is a cryptobenthic species of the Family Gobiidae that iscommonly foundoccupying turbulent surf zones, calm rock pools, and sand and mud flats, where they are generally carnivorous predators. The distribution of C. sordidushas been recorded for Kenya, Tanzania, Mozambique, and South Africa. The species is also resident in the microbialite pools on the temperate south east coast of South Africa. Recent reports indicated these gobies to be covered in numerous dark lesions, possibly suggesting that the microbialite pools are a sub-optimal habitat. Preliminary analyses have indicated that the dark lesions are a result of encysted metacercaria of a digenetic trematode (fluke). There werehowever,no current recorded parasiticspecies occurring within microbialite pool nor any records of any parasitic species utilizingC. sordidus as a host in South Africa. Therefore, the aim of this study was to investigate parasite-host interactions and parasite presence in and around themicrobialite pool systems of Algoa Bay using C. sordidusas a study species. Coryogalops sordiduswas identified to be parasitised by digenetic trematode metacercaria of the Family Diplostomidae Poirier, 1886, localised primarily to the host musculature, fins, eyes, and integument with no settlement on any of the visceral organs. Furthermore, C. sordidus was found additionally parasitised by a green leech (Class: Hirundinea) of the Family Piscicolidae Johnston, 1865, localised exclusively to the ventral body surface, underneath the pelvic fin of the host. Further investigation into the life cycle of the trematode, suggested that the most probable final hosts wereherons,namely Ardea cinereaand Egretta garzetta garzetta, and intermediate host likely being the freshwater gastropod Assimineacf.capensis, present inthe upper microbialite pools. In both the microbialite and neighbouring rock pools trematode prevalence was found to oscillate in response to seasonal chemical and climatic conditions, whereas the secondary piscicolid leech parasite was influencedmoreby host presence than environmental conditions. Greater prevalence and intensity were measured in the microbialite pools suggesting that these systems likely contained a suit of favourable conditions that allowed for greater trematode loads to be maintained as compared to neighbouring rock pools. As parasites often have deleterious effects on their hosts, the response can manifest as an altered host behaviour or an increased energetic debt due to elevated immune response activity and the associated cost of tissue repair at sites of parasite aggregation.This study further investigatedifgobies (C. sordidus) infected with metacercarial cysts display higher metabolic ratesordifferent swimming behaviour compared to non-infected individuals. The results indicated that the metacercarial load carried by infected hosts had on average no significant impact on energetics, swimming ability, or swimming behaviour, concluding that the average metacercarial intensity present on the gobies is therefore below the threshold of an altered host response. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Du Toit, Hendrik Daniël
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Gobiidae -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52458 , vital:43666
- Description: Coryogalops sordidus(Epaulette goby), is a cryptobenthic species of the Family Gobiidae that iscommonly foundoccupying turbulent surf zones, calm rock pools, and sand and mud flats, where they are generally carnivorous predators. The distribution of C. sordidushas been recorded for Kenya, Tanzania, Mozambique, and South Africa. The species is also resident in the microbialite pools on the temperate south east coast of South Africa. Recent reports indicated these gobies to be covered in numerous dark lesions, possibly suggesting that the microbialite pools are a sub-optimal habitat. Preliminary analyses have indicated that the dark lesions are a result of encysted metacercaria of a digenetic trematode (fluke). There werehowever,no current recorded parasiticspecies occurring within microbialite pool nor any records of any parasitic species utilizingC. sordidus as a host in South Africa. Therefore, the aim of this study was to investigate parasite-host interactions and parasite presence in and around themicrobialite pool systems of Algoa Bay using C. sordidusas a study species. Coryogalops sordiduswas identified to be parasitised by digenetic trematode metacercaria of the Family Diplostomidae Poirier, 1886, localised primarily to the host musculature, fins, eyes, and integument with no settlement on any of the visceral organs. Furthermore, C. sordidus was found additionally parasitised by a green leech (Class: Hirundinea) of the Family Piscicolidae Johnston, 1865, localised exclusively to the ventral body surface, underneath the pelvic fin of the host. Further investigation into the life cycle of the trematode, suggested that the most probable final hosts wereherons,namely Ardea cinereaand Egretta garzetta garzetta, and intermediate host likely being the freshwater gastropod Assimineacf.capensis, present inthe upper microbialite pools. In both the microbialite and neighbouring rock pools trematode prevalence was found to oscillate in response to seasonal chemical and climatic conditions, whereas the secondary piscicolid leech parasite was influencedmoreby host presence than environmental conditions. Greater prevalence and intensity were measured in the microbialite pools suggesting that these systems likely contained a suit of favourable conditions that allowed for greater trematode loads to be maintained as compared to neighbouring rock pools. As parasites often have deleterious effects on their hosts, the response can manifest as an altered host behaviour or an increased energetic debt due to elevated immune response activity and the associated cost of tissue repair at sites of parasite aggregation.This study further investigatedifgobies (C. sordidus) infected with metacercarial cysts display higher metabolic ratesordifferent swimming behaviour compared to non-infected individuals. The results indicated that the metacercarial load carried by infected hosts had on average no significant impact on energetics, swimming ability, or swimming behaviour, concluding that the average metacercarial intensity present on the gobies is therefore below the threshold of an altered host response. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-04
Performance management system at a public development corporation: success factors and challenges
- Authors: Saki, David Siphosethu
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's , text
- Identifier: http://hdl.handle.net/10948/52935 , vital:44733
- Description: Public sector organisations often lack effectiveness in the implementation of an organisational strategy and seek out means of utilising a performance management system to ensure the productive implementation of its strategy (Auditor General South Africa, 2017). Therefore, it is important for organisations to utilise tools and techniques to ensure that the performance management system is efficiently implemented. Performance management is defined as a strategic and integrated approach aimed at delivering sustained success by using tools and techniques to improve the performance of people by developing the capabilities of teams and individual contributors (Armstrong, 2006). The main purpose of the study was to identify success factors that contributed to the effective implementation of a performance management system and then determine the extent to which these factors have been successfully incorporated in the performance management system at the CDC. The literature review was conducted, highlighting the process of performance management, tools and techniques, success factors and challenges in order to effectively implement a performance management system. In this study, a positive correlation between the PM purpose, success factors and tools revealed that the various success factors in relation to systems, resources, staff and measurement linked with the PM purpose. In addition, it was also revealed that the human resources component was considered as very important in driving an effective performance management system. , Thesis (MA) -- Faculty of Business and Economic Sciences, Human Resources Management, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Saki, David Siphosethu
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's , text
- Identifier: http://hdl.handle.net/10948/52935 , vital:44733
- Description: Public sector organisations often lack effectiveness in the implementation of an organisational strategy and seek out means of utilising a performance management system to ensure the productive implementation of its strategy (Auditor General South Africa, 2017). Therefore, it is important for organisations to utilise tools and techniques to ensure that the performance management system is efficiently implemented. Performance management is defined as a strategic and integrated approach aimed at delivering sustained success by using tools and techniques to improve the performance of people by developing the capabilities of teams and individual contributors (Armstrong, 2006). The main purpose of the study was to identify success factors that contributed to the effective implementation of a performance management system and then determine the extent to which these factors have been successfully incorporated in the performance management system at the CDC. The literature review was conducted, highlighting the process of performance management, tools and techniques, success factors and challenges in order to effectively implement a performance management system. In this study, a positive correlation between the PM purpose, success factors and tools revealed that the various success factors in relation to systems, resources, staff and measurement linked with the PM purpose. In addition, it was also revealed that the human resources component was considered as very important in driving an effective performance management system. , Thesis (MA) -- Faculty of Business and Economic Sciences, Human Resources Management, 2021
- Full Text:
- Date Issued: 2021-04
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