Fish utilization of surf-zones. Are they changing? A case study of the sheltered, warm-temperate King’s Beach
- Rishworth, Gavin M, Strydom, Nadine A, Potts, Warren M
- Authors: Rishworth, Gavin M , Strydom, Nadine A , Potts, Warren M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124504 , vital:35619 , https://doi.org/10.1080/15627020.2014.11407616
- Description: Surf-zone fish communities and their shifts over time are generally poorly understood. The aim of this study was to compare the current surf-zone fish assemblage at King’s Beach, South Africa, to a similar study conducted three decades ago, before the collapse of many exploited shore fishes in the region. Beach seine nets (mesh sizes of 10 and 50 mm) were used to target juvenile and adult fishes bimonthly from February to August 2011 over the high tide around sunset. A total of 14 species were recorded in both the 30mand 100mseine nets. The catch in these seine nets was dominated by Pomadasys olivaceus and Liza richardsonii, and this was significantly different to three decades ago, when P. olivaceus, Sarpa salpa and Diplodus capensis dominated the catch. Important linefish species belonging to the Sparidae and Sciaenidae families were significantly smaller and less abundant in this study. Two sparids, S. salpa and Lithognathus mormyrus, which made a large contribution to the surf-zone catch three decades ago were absent during this study. Reasons for the significant shifts in the surf-zone fish community, including overexploitation of the linefish and potential habitat modification, are discussed.
- Full Text:
- Date Issued: 2015
- Authors: Rishworth, Gavin M , Strydom, Nadine A , Potts, Warren M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124504 , vital:35619 , https://doi.org/10.1080/15627020.2014.11407616
- Description: Surf-zone fish communities and their shifts over time are generally poorly understood. The aim of this study was to compare the current surf-zone fish assemblage at King’s Beach, South Africa, to a similar study conducted three decades ago, before the collapse of many exploited shore fishes in the region. Beach seine nets (mesh sizes of 10 and 50 mm) were used to target juvenile and adult fishes bimonthly from February to August 2011 over the high tide around sunset. A total of 14 species were recorded in both the 30mand 100mseine nets. The catch in these seine nets was dominated by Pomadasys olivaceus and Liza richardsonii, and this was significantly different to three decades ago, when P. olivaceus, Sarpa salpa and Diplodus capensis dominated the catch. Important linefish species belonging to the Sparidae and Sciaenidae families were significantly smaller and less abundant in this study. Two sparids, S. salpa and Lithognathus mormyrus, which made a large contribution to the surf-zone catch three decades ago were absent during this study. Reasons for the significant shifts in the surf-zone fish community, including overexploitation of the linefish and potential habitat modification, are discussed.
- Full Text:
- Date Issued: 2015
Fluorescence behavior and singlet oxygen generating abilities of aluminum phthalocyanine in the presence of anisotropic gold nanoparticles
- Mthethwa, Thandekile, Nyokong, Tebello
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193598 , vital:45351 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
- Full Text:
- Date Issued: 2015
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193598 , vital:45351 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
- Full Text:
- Date Issued: 2015
Fluorescence behavior and singlet oxygen generating abilities of aluminum phthalocyanine in the presence of anisotropic gold nanoparticles
- Mthethwa, Thandekile, Nyokong, Tebello
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189865 , vital:44941 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
- Full Text:
- Date Issued: 2015
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189865 , vital:44941 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
- Full Text:
- Date Issued: 2015
Fluorescence Behaviour of an Aluminium Octacarboxy Phthalocyanine-NaYGdF 4
- Taylor, Jessica, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189503 , vital:44852 , xlink:href="https://doi.org/10.1007/s10895-015-1539-8"
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions).
- Full Text:
- Date Issued: 2015
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189503 , vital:44852 , xlink:href="https://doi.org/10.1007/s10895-015-1539-8"
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions).
- Full Text:
- Date Issued: 2015
Food on the Table: Human Responses and Changing Coastal Fisheries in Solomon Islands
- Albert, Simon, Aswani, Shankar, Fisher, Paul L, Albert, Joelle
- Authors: Albert, Simon , Aswani, Shankar , Fisher, Paul L , Albert, Joelle
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421887 , vital:71893 , xlink:href="https://doi.org/10.1371/journal.pone.0130800"
- Description: Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region’s fisheries in the future.
- Full Text:
- Date Issued: 2015
- Authors: Albert, Simon , Aswani, Shankar , Fisher, Paul L , Albert, Joelle
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421887 , vital:71893 , xlink:href="https://doi.org/10.1371/journal.pone.0130800"
- Description: Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region’s fisheries in the future.
- Full Text:
- Date Issued: 2015
FPGA Based Implementation of a High Performance Scalable NetFlow Filter
- Herbert, Alan, Irwin, Barry V W, Otten, D F, Balmahoon, M R
- Authors: Herbert, Alan , Irwin, Barry V W , Otten, D F , Balmahoon, M R
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427887 , vital:72470 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622948_FPGA_Based_Implementation_of_a_High_Perfor-mance_Scalable_NetFlow_Filter/links/5b9a17a192851c4ba8181ba5/FPGA-Based-Implementation-of-a-High-Performance-Scalable-NetFlow-Filter.pdf
- Description: Full packet analysis on firewalls and intrusion detection, although effec-tive, has been found in recent times to be detrimental to the overall per-formance of networks that receive large volumes of throughput. For this reason partial packet analysis algorithms such as the NetFlow protocol have emerged to better mitigate these bottlenecks. This research delves into implementing a hardware accelerated, scalable, high per-formance system for NetFlow analysis and attack mitigation. Further-more, this implementation takes on attack mitigation through collection and processing of network flows produced at the source, rather than at the site of incident. This research platform manages to scale out its back-end through dis-tributed analysis over multiple hosts using the ZeroMQ toolset. Fur-thermore, ZeroMQ allows for multiple NetFlow data publishers, so that plug-ins can subscribe to the publishers that contain the relevant data to further increase the overall performance of the system. The dedicat-ed custom hardware optimizes the received network flows through cleaning, summarization and re-ordering into an easy to pass form when given to the sequential component of the system; this being the back-end.
- Full Text:
- Date Issued: 2015
- Authors: Herbert, Alan , Irwin, Barry V W , Otten, D F , Balmahoon, M R
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427887 , vital:72470 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622948_FPGA_Based_Implementation_of_a_High_Perfor-mance_Scalable_NetFlow_Filter/links/5b9a17a192851c4ba8181ba5/FPGA-Based-Implementation-of-a-High-Performance-Scalable-NetFlow-Filter.pdf
- Description: Full packet analysis on firewalls and intrusion detection, although effec-tive, has been found in recent times to be detrimental to the overall per-formance of networks that receive large volumes of throughput. For this reason partial packet analysis algorithms such as the NetFlow protocol have emerged to better mitigate these bottlenecks. This research delves into implementing a hardware accelerated, scalable, high per-formance system for NetFlow analysis and attack mitigation. Further-more, this implementation takes on attack mitigation through collection and processing of network flows produced at the source, rather than at the site of incident. This research platform manages to scale out its back-end through dis-tributed analysis over multiple hosts using the ZeroMQ toolset. Fur-thermore, ZeroMQ allows for multiple NetFlow data publishers, so that plug-ins can subscribe to the publishers that contain the relevant data to further increase the overall performance of the system. The dedicat-ed custom hardware optimizes the received network flows through cleaning, summarization and re-ordering into an easy to pass form when given to the sequential component of the system; this being the back-end.
- Full Text:
- Date Issued: 2015
Gay men and fatherhood in South Africa: a discursive study
- Morison, Tracy, Lynch, Ingrid, Reddy, Vasu
- Authors: Morison, Tracy , Lynch, Ingrid , Reddy, Vasu
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143782 , vital:38282 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: There is little South African research on gender and sexual minorities’ reproductive decision-making and, to date, no published work explicitly focused on gay men. Motivated by the virtual absence of gay men in research, as well as their marginalisation more generally, we undertook a qualitative investigation of gay men’s thoughts, feelings and perspectives of fatherhood, fatherhood decisions, and experiences of pathways to parenthood. Framed by a reproductive justice perspective, the aim of the study was not only to generate new knowledge, but also to inform policy, services, and advocacy. In this paper we present some of the findings from our discursive analysis of participants’ accounts of their own experiences of the pathway to parenthood or remaining ‘childfree’. We locate our analysis within the broader South African context and show how the entanglement of various social identity markers - particularly gender, race, and class - come to bear on participants’ experiences.
- Full Text:
- Date Issued: 2015
- Authors: Morison, Tracy , Lynch, Ingrid , Reddy, Vasu
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143782 , vital:38282 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: There is little South African research on gender and sexual minorities’ reproductive decision-making and, to date, no published work explicitly focused on gay men. Motivated by the virtual absence of gay men in research, as well as their marginalisation more generally, we undertook a qualitative investigation of gay men’s thoughts, feelings and perspectives of fatherhood, fatherhood decisions, and experiences of pathways to parenthood. Framed by a reproductive justice perspective, the aim of the study was not only to generate new knowledge, but also to inform policy, services, and advocacy. In this paper we present some of the findings from our discursive analysis of participants’ accounts of their own experiences of the pathway to parenthood or remaining ‘childfree’. We locate our analysis within the broader South African context and show how the entanglement of various social identity markers - particularly gender, race, and class - come to bear on participants’ experiences.
- Full Text:
- Date Issued: 2015
Genetic and biological characterisation of a novel Plutella xylostella granulovirus, PlxyGV-SA
- Abdulkadir, Fatima, Knox, Caroline M, Marsberg, Tamryn, Hill, Martin P, Moore, Sean D
- Authors: Abdulkadir, Fatima , Knox, Caroline M , Marsberg, Tamryn , Hill, Martin P , Moore, Sean D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417971 , vital:71498 , xlink:href="https://doi.org/10.1007/s10526-015-9666-3"
- Description: Plutella xylostella granulovirus (PlxyGV) has been isolated from insect populations in many countries and is considered a potential biopesticide for sustainable control of P. xylostella (L.) (Lepidoptera: Plutellidae). Several PlxyGV isolates have been genetically characterised, and the full genome sequence of PlxyGV-Japan is available for comparison with novel isolates. A South African PlxyGV was recently recovered from an overcrowded laboratory P. xylostella colony and identified as a genetically distinct isolate by sequencing of the granulin gene and restriction endonuclease (REN) analysis of genomic DNA. In this report, PlxyGV-SA was further characterised by PCR amplification and sequencing of egt, lef-8 and lef-9 genes, and several amino acid substitutions were observed. The PstI REN profile of PlxyGV-SA was different from that of PlxyGV-Japan in terms of band size and number, thereby confirming its novel genetic identity. Surface dose bioassays showed that PlxyGV-SA is pathogenic to neonate but not late instar larvae at the same and higher virus doses, indicating that a biopesticide should be targeted at early larval stages in the field.
- Full Text:
- Date Issued: 2015
- Authors: Abdulkadir, Fatima , Knox, Caroline M , Marsberg, Tamryn , Hill, Martin P , Moore, Sean D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417971 , vital:71498 , xlink:href="https://doi.org/10.1007/s10526-015-9666-3"
- Description: Plutella xylostella granulovirus (PlxyGV) has been isolated from insect populations in many countries and is considered a potential biopesticide for sustainable control of P. xylostella (L.) (Lepidoptera: Plutellidae). Several PlxyGV isolates have been genetically characterised, and the full genome sequence of PlxyGV-Japan is available for comparison with novel isolates. A South African PlxyGV was recently recovered from an overcrowded laboratory P. xylostella colony and identified as a genetically distinct isolate by sequencing of the granulin gene and restriction endonuclease (REN) analysis of genomic DNA. In this report, PlxyGV-SA was further characterised by PCR amplification and sequencing of egt, lef-8 and lef-9 genes, and several amino acid substitutions were observed. The PstI REN profile of PlxyGV-SA was different from that of PlxyGV-Japan in terms of band size and number, thereby confirming its novel genetic identity. Surface dose bioassays showed that PlxyGV-SA is pathogenic to neonate but not late instar larvae at the same and higher virus doses, indicating that a biopesticide should be targeted at early larval stages in the field.
- Full Text:
- Date Issued: 2015
Guarded visions: walls, watchtowers and warped perspectives in the Israeli occupied West Bank Palestinian territory
- Authors: Baasch, Rachel M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147281 , vital:38611 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC176318
- Description: This paper examines the relationship between Israel's fortification of physical space and narratives of division in the Israeli occupied Palestinian West Bank Territory. I argue that the fortification and separation of physical space deepens segregation, and increases fear, hostility and disconnection between people living in this context. Furthermore, I suggest that this relationship between narratives of division and insecurity and structural mechanisms of control within the West Bank influences and impacts on individuals such that personal perspectives become guarded and defensive. The mediation of subjects through a defensive lens can prevent individuals from forming connections that acknowledge the permeability of seemingly impenetrable distinctions between inside and outside, or self and an-other. The looking, recording and representation of people in a place that is guarded and framed from a position of insecurity reduces the capacity of individuals to locate openings that traverse restrictive boundaries. In order to contextualise my discussion, I have included personal documentation of defensive structures photographed in the West Bank between 2013 and 2014. I position my observations and analyses in relation to discussions about the Oush Grab Military Base presented by the Decolonizing Architecture Art Residency (DAAR) in their recent publication Architecture after revolution (2013).
- Full Text:
- Date Issued: 2015
- Authors: Baasch, Rachel M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147281 , vital:38611 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC176318
- Description: This paper examines the relationship between Israel's fortification of physical space and narratives of division in the Israeli occupied Palestinian West Bank Territory. I argue that the fortification and separation of physical space deepens segregation, and increases fear, hostility and disconnection between people living in this context. Furthermore, I suggest that this relationship between narratives of division and insecurity and structural mechanisms of control within the West Bank influences and impacts on individuals such that personal perspectives become guarded and defensive. The mediation of subjects through a defensive lens can prevent individuals from forming connections that acknowledge the permeability of seemingly impenetrable distinctions between inside and outside, or self and an-other. The looking, recording and representation of people in a place that is guarded and framed from a position of insecurity reduces the capacity of individuals to locate openings that traverse restrictive boundaries. In order to contextualise my discussion, I have included personal documentation of defensive structures photographed in the West Bank between 2013 and 2014. I position my observations and analyses in relation to discussions about the Oush Grab Military Base presented by the Decolonizing Architecture Art Residency (DAAR) in their recent publication Architecture after revolution (2013).
- Full Text:
- Date Issued: 2015
Health Psychology and the framing of abortion in Africa: a critical review of the literature
- Macleod, Catriona I, Chiweshe, Malvern T, Mavuso, Jabulile
- Authors: Macleod, Catriona I , Chiweshe, Malvern T , Mavuso, Jabulile
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143871 , vital:38290 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Despite 97% of abortions performed in Africa being classifiable as unsafe, there has been virtually no engagement in knowledge production about abortion in Africa from psychologists, outside of South Africa. Taking a feminist health psychology approach, we conducted a systematic review of published research on this topic featured in PsycINFO over a six year period. We analysed the 39 articles included in the review in terms of countries in which the research was conducted, types of research, issues covered, framings, and main findings. The results show that apart from a public health framing, perspectives that foreground contextual, social, cultural, gendered perspectives dominate. While abortion services, unsafe abortion and the incidence of abortion were well researched, so too were attitudes and public discourses on abortion. Clinical psychological, reproductive justice or rights and medical framings received little attention. We outline the implications of this knowledge base for feminist health psychology in Africa.
- Full Text:
- Date Issued: 2015
- Authors: Macleod, Catriona I , Chiweshe, Malvern T , Mavuso, Jabulile
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143871 , vital:38290 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Despite 97% of abortions performed in Africa being classifiable as unsafe, there has been virtually no engagement in knowledge production about abortion in Africa from psychologists, outside of South Africa. Taking a feminist health psychology approach, we conducted a systematic review of published research on this topic featured in PsycINFO over a six year period. We analysed the 39 articles included in the review in terms of countries in which the research was conducted, types of research, issues covered, framings, and main findings. The results show that apart from a public health framing, perspectives that foreground contextual, social, cultural, gendered perspectives dominate. While abortion services, unsafe abortion and the incidence of abortion were well researched, so too were attitudes and public discourses on abortion. Clinical psychological, reproductive justice or rights and medical framings received little attention. We outline the implications of this knowledge base for feminist health psychology in Africa.
- Full Text:
- Date Issued: 2015
Host searching and oviposition behaviour of Agathis bishopi (Hymenoptera: Braconidae), a larval parasitoid of false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae): a potential proxy indicator for fruit infestation
- Zimba, Kennedy J, Heshula, LU, Moore, Sean D, Hill, Martin P
- Authors: Zimba, Kennedy J , Heshula, LU , Moore, Sean D , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407019 , vital:70330 , xlink:href="https://hdl.handle.net/10520/EJC195073"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae)is an arrhenotokous larval endoparasitoid of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (Gendall 2007; Hofmeyr et al. 2015) commonly known as false codling moth (FCM), a major pest of citrus in South Africa (Moore et al. 2004; Malan et al. 2011). Under field conditions, A. bishopi was identified attacking more than 34% of FCM larvae in fruit, showing good biocontrol potential (Gendall 2007). Preference by A. bishopi for parasitising the early instars of its concealed host suggests that the parasitoid has strong natural host location ability (Sishuba 2003; Gendall 2007).
- Full Text:
- Date Issued: 2015
- Authors: Zimba, Kennedy J , Heshula, LU , Moore, Sean D , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407019 , vital:70330 , xlink:href="https://hdl.handle.net/10520/EJC195073"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae)is an arrhenotokous larval endoparasitoid of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (Gendall 2007; Hofmeyr et al. 2015) commonly known as false codling moth (FCM), a major pest of citrus in South Africa (Moore et al. 2004; Malan et al. 2011). Under field conditions, A. bishopi was identified attacking more than 34% of FCM larvae in fruit, showing good biocontrol potential (Gendall 2007). Preference by A. bishopi for parasitising the early instars of its concealed host suggests that the parasitoid has strong natural host location ability (Sishuba 2003; Gendall 2007).
- Full Text:
- Date Issued: 2015
How can conversational analysis contribute to ‘doing’ critical work?: extending the methodological conversation
- Authors: du Toit, Ryan
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143904 , vital:38293 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Conversation analysis (CA) has been criticised as being overly obsessed with the intricate details of conversation and bracketing off the wider socio-structural power relations in which conversation is embedded. Many scholars regard CA as a methodology that is incompatible with, and thus incapable of doing, critical work. This paper seeks to contribute to the methodological conversation by proposing a dual analytical methodology that merges understandings of talk from CA and critical discursive approaches, and attends to both the conversational (turn-by-turn) context as well as the discursive resources that inhabit talk. This is accomplished through a triangulatory activity that takes different conceptualizations of ‘context’ into consideration and investigates how subject positions are worked up on a micro- (turnby-turn) and macro-level. The authors illustrate this approach using institutional talk collected at a UK diabetes clinic and from interviews investigating how employers talk about their domestic workers in South Africa.
- Full Text:
- Date Issued: 2015
- Authors: du Toit, Ryan
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143904 , vital:38293 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Conversation analysis (CA) has been criticised as being overly obsessed with the intricate details of conversation and bracketing off the wider socio-structural power relations in which conversation is embedded. Many scholars regard CA as a methodology that is incompatible with, and thus incapable of doing, critical work. This paper seeks to contribute to the methodological conversation by proposing a dual analytical methodology that merges understandings of talk from CA and critical discursive approaches, and attends to both the conversational (turn-by-turn) context as well as the discursive resources that inhabit talk. This is accomplished through a triangulatory activity that takes different conceptualizations of ‘context’ into consideration and investigates how subject positions are worked up on a micro- (turnby-turn) and macro-level. The authors illustrate this approach using institutional talk collected at a UK diabetes clinic and from interviews investigating how employers talk about their domestic workers in South Africa.
- Full Text:
- Date Issued: 2015
How general-purpose can a GPU be?
- Authors: Machanick, Philip
- Date: 2015
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61180 , vital:27988 , http://dx.doi.org/10.18489/sacj.v0i57.347
- Description: The use of graphics processing units (GPUs) in general-purpose computation (GPGPU) is a growing field. GPU instruction sets, while implementing a graphics pipeline, draw from a range of single instruction multiple datastream (SIMD) architectures characteristic of the heyday of supercomputers. Yet only one of these SIMD instruction sets has been of application on a wide enough range of problems to survive the era when the full range of supercomputer design variants was being explored: vector instructions. Supercomputers covered a range of exotic designs such as hypercubes and the Connection Machine (Fox, 1989). The latter is likely the source of the snide comment by Cray: it had thousands of relatively low-speed CPUs (Tucker & Robertson, 1988). Since Cray won, why are we not basing our ideas on his designs (Cray Inc., 2004), rather than those of the losers? The Top 500 supercomputer list is dominated by general-purpose CPUs, and nothing like the Connection Machine that headed the list in 1993 still exists.
- Full Text:
- Date Issued: 2015
- Authors: Machanick, Philip
- Date: 2015
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61180 , vital:27988 , http://dx.doi.org/10.18489/sacj.v0i57.347
- Description: The use of graphics processing units (GPUs) in general-purpose computation (GPGPU) is a growing field. GPU instruction sets, while implementing a graphics pipeline, draw from a range of single instruction multiple datastream (SIMD) architectures characteristic of the heyday of supercomputers. Yet only one of these SIMD instruction sets has been of application on a wide enough range of problems to survive the era when the full range of supercomputer design variants was being explored: vector instructions. Supercomputers covered a range of exotic designs such as hypercubes and the Connection Machine (Fox, 1989). The latter is likely the source of the snide comment by Cray: it had thousands of relatively low-speed CPUs (Tucker & Robertson, 1988). Since Cray won, why are we not basing our ideas on his designs (Cray Inc., 2004), rather than those of the losers? The Top 500 supercomputer list is dominated by general-purpose CPUs, and nothing like the Connection Machine that headed the list in 1993 still exists.
- Full Text:
- Date Issued: 2015
Human harvesting impacts on managed areas: ecological effects of socially-compatible shellfish reserves
- Aswani, Shankar, Flores, Carola F, Broitman, Bernardo R
- Authors: Aswani, Shankar , Flores, Carola F , Broitman, Bernardo R
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124664 , vital:35644 , https://doi.10.1007/s11160-014-9376-4
- Description: We examined how human harvesting impacts on managed areas affect the abundance and size distribution of the edible mangrove shellfish Anadara granosa and Polymesoda spp. in the Roviana Lagoon, Solomon Islands. We tested two hypotheses: (1) in areas permanently and temporally closed to human exploitation, abundance and size distribution of these shellfish species is significantly greater than in sites open to exploitation and (2) moderate human disturbance of shell beds, particularly of Polymesoda spp., increases their abundance. Firstly, we studied perceptions of environmental states and processes coupled to foraging and management interventions to assess sociocultural influences on harvesting practices and ascertain the types of management regime that people would consider in a context where poaching and interloping are common practices. Secondly, we compared shellfish abundance and shell size from areas that were permanently protected, temporally reserved for communal harvest, and permanently open for exploitation. Thirdly, drawing from women’s local knowledge, we measured the abundance of Polymesoda spp. in relation to mud compactness in quadrats across the three management regimes. Results showed that both species were significantly more abundant in permanent and temporally closed sites than in open sites. In the mud compactness study, however, while shell abundance was greater in moderately compacted quadrats, there was no statistical relationship between mud compactness and shell abundance within or across the three management regimes. Results suggest that even under the strong impacts of poaching, temporally closed areas have more clams than open areas and are as effective as areas that are permanently closed nominally. The results also suggest that human harvesting regimes can influence the effectiveness of local management decisions and thus are important when designing community-based conservation programs in the Solomon Islands and other Pacific Islands.
- Full Text:
- Date Issued: 2015
- Authors: Aswani, Shankar , Flores, Carola F , Broitman, Bernardo R
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124664 , vital:35644 , https://doi.10.1007/s11160-014-9376-4
- Description: We examined how human harvesting impacts on managed areas affect the abundance and size distribution of the edible mangrove shellfish Anadara granosa and Polymesoda spp. in the Roviana Lagoon, Solomon Islands. We tested two hypotheses: (1) in areas permanently and temporally closed to human exploitation, abundance and size distribution of these shellfish species is significantly greater than in sites open to exploitation and (2) moderate human disturbance of shell beds, particularly of Polymesoda spp., increases their abundance. Firstly, we studied perceptions of environmental states and processes coupled to foraging and management interventions to assess sociocultural influences on harvesting practices and ascertain the types of management regime that people would consider in a context where poaching and interloping are common practices. Secondly, we compared shellfish abundance and shell size from areas that were permanently protected, temporally reserved for communal harvest, and permanently open for exploitation. Thirdly, drawing from women’s local knowledge, we measured the abundance of Polymesoda spp. in relation to mud compactness in quadrats across the three management regimes. Results showed that both species were significantly more abundant in permanent and temporally closed sites than in open sites. In the mud compactness study, however, while shell abundance was greater in moderately compacted quadrats, there was no statistical relationship between mud compactness and shell abundance within or across the three management regimes. Results suggest that even under the strong impacts of poaching, temporally closed areas have more clams than open areas and are as effective as areas that are permanently closed nominally. The results also suggest that human harvesting regimes can influence the effectiveness of local management decisions and thus are important when designing community-based conservation programs in the Solomon Islands and other Pacific Islands.
- Full Text:
- Date Issued: 2015
Human, vector and parasite Hsp90 proteins: a comparative bioinformatics analysis
- Faya, Ngonidzashe, Penkler, David L, Tastan Bishop, Özlem
- Authors: Faya, Ngonidzashe , Penkler, David L , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148038 , vital:38704 , DOI: 10.1016/j.fob.2015.11.003
- Description: The treatment of protozoan parasitic diseases is challenging, and thus identification and analysis of new drug targets is important. Parasites survive within host organisms, and some need intermediate hosts to complete their life cycle. Changing host environment puts stress on parasites, and often adaptation is accompanied by the expression of large amounts of heat shock proteins (Hsps). Among Hsps, Hsp90 proteins play an important role in stress environments. Yet, there has been little computational research on Hsp90 proteins to analyze them comparatively as potential parasitic drug targets. Here, an attempt was made to gain detailed insights into the differences between host, vector and parasitic Hsp90 proteins by large-scale bioinformatics analysis.
- Full Text:
- Date Issued: 2015
- Authors: Faya, Ngonidzashe , Penkler, David L , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148038 , vital:38704 , DOI: 10.1016/j.fob.2015.11.003
- Description: The treatment of protozoan parasitic diseases is challenging, and thus identification and analysis of new drug targets is important. Parasites survive within host organisms, and some need intermediate hosts to complete their life cycle. Changing host environment puts stress on parasites, and often adaptation is accompanied by the expression of large amounts of heat shock proteins (Hsps). Among Hsps, Hsp90 proteins play an important role in stress environments. Yet, there has been little computational research on Hsp90 proteins to analyze them comparatively as potential parasitic drug targets. Here, an attempt was made to gain detailed insights into the differences between host, vector and parasitic Hsp90 proteins by large-scale bioinformatics analysis.
- Full Text:
- Date Issued: 2015
Immersive audio content creation using mobile devices and ethernet avb
- Rouget, Antoine, Foss, Richard
- Authors: Rouget, Antoine , Foss, Richard
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426786 , vital:72391 , https://www.aes.org/e-lib/browse.cfm?elib=18009
- Description: The goal of immersive sound systems is to localize multiple sound sources such that listeners are enveloped in sound. This paper describes an immersive sound system that allows for the creation of immersive sound content and real time control over sound source localization. It is a client/server system where the client is a mobile device. The server receives localization control messages from the client and uses an Ethernet AVB network to distribute appropriate mix levels to speakers with in-built signal processing.
- Full Text:
- Date Issued: 2015
- Authors: Rouget, Antoine , Foss, Richard
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426786 , vital:72391 , https://www.aes.org/e-lib/browse.cfm?elib=18009
- Description: The goal of immersive sound systems is to localize multiple sound sources such that listeners are enveloped in sound. This paper describes an immersive sound system that allows for the creation of immersive sound content and real time control over sound source localization. It is a client/server system where the client is a mobile device. The server receives localization control messages from the client and uses an Ethernet AVB network to distribute appropriate mix levels to speakers with in-built signal processing.
- Full Text:
- Date Issued: 2015
Impact of marine inundation after a period of drought on the lakeshore vegetation of Lake St Lucia, South Africa: resilience of estuarine vegetation
- Sieben, E J J, Ellery, William F N, Dullo, B W, Grootjans, A P
- Authors: Sieben, E J J , Ellery, William F N , Dullo, B W , Grootjans, A P
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144443 , vital:38346 , DOI: 10.2989/16085914.2015.1032208
- Description: The shore of Lake St Lucia in the vicinity of Catalina Bay, in the southern part of the lake, receives freshwater input as surface and groundwater seepage from the adjacent elevated coastal plain. Vegetation, water quality and landform were recorded on the lakeshore and on the dry lakebed near one of these seepage zones. This was done along a gradient perpendicular to the lakeshore and along the lakeshore away from the fluvial source of freshwater input. A number of plant communities were found along a gradient of water salinity from the shoreline (fresh water) towards the centre of the lake, and also away from the fluvial input of water (increasingly saline). Species richness decreased with increasing salinity. The first study was conducted in 2006 after a prolonged drought associated with low lake levels and closure of the mouth, and repeated again in 2010 three years after breaching of the estuarine mouth by a tropical cyclone at sea, which caused inundation of the partly dry lakebed with sea water. The vegetation of the lakeshore after these major disturbances was remarkably similar in the two time periods, suggesting rapid recovery near freshwater seepage zones, following an influx of sea water.
- Full Text:
- Date Issued: 2015
- Authors: Sieben, E J J , Ellery, William F N , Dullo, B W , Grootjans, A P
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144443 , vital:38346 , DOI: 10.2989/16085914.2015.1032208
- Description: The shore of Lake St Lucia in the vicinity of Catalina Bay, in the southern part of the lake, receives freshwater input as surface and groundwater seepage from the adjacent elevated coastal plain. Vegetation, water quality and landform were recorded on the lakeshore and on the dry lakebed near one of these seepage zones. This was done along a gradient perpendicular to the lakeshore and along the lakeshore away from the fluvial source of freshwater input. A number of plant communities were found along a gradient of water salinity from the shoreline (fresh water) towards the centre of the lake, and also away from the fluvial input of water (increasingly saline). Species richness decreased with increasing salinity. The first study was conducted in 2006 after a prolonged drought associated with low lake levels and closure of the mouth, and repeated again in 2010 three years after breaching of the estuarine mouth by a tropical cyclone at sea, which caused inundation of the partly dry lakebed with sea water. The vegetation of the lakeshore after these major disturbances was remarkably similar in the two time periods, suggesting rapid recovery near freshwater seepage zones, following an influx of sea water.
- Full Text:
- Date Issued: 2015
Improved triplet state parameters for indium octacarboxy phthalocyanines when conjugated to quantum dots and magnetite nanoparticles
- Tshangana, Charmaine, Nyokong, Tebello
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189337 , vital:44838 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: Fe3O4 magnetic nanoparticles (MNPs) and glutathione (GSH) capped CdSe@ZnS quantum dots (QDs) were separately coordinated to indium octacarboxy phthalocyanine (InPc(COOH)8) to form ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were determined for the conjugates. The triplet quantum yields increased from ΦT = 0.49 for InPc(COOH)8 alone to ΦT = 0.61 and 0.56 for InPc(COOH)8 in the conjugates: ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The lifetimes also became longer for the conjugates compared to Pc alone.
- Full Text:
- Date Issued: 2015
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189337 , vital:44838 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: Fe3O4 magnetic nanoparticles (MNPs) and glutathione (GSH) capped CdSe@ZnS quantum dots (QDs) were separately coordinated to indium octacarboxy phthalocyanine (InPc(COOH)8) to form ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were determined for the conjugates. The triplet quantum yields increased from ΦT = 0.49 for InPc(COOH)8 alone to ΦT = 0.61 and 0.56 for InPc(COOH)8 in the conjugates: ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The lifetimes also became longer for the conjugates compared to Pc alone.
- Full Text:
- Date Issued: 2015
Incipient genetic isolation of a temperate migratory coastal sciaenid fish (Argyrosomus inodorus) within the Benguela Cold Current system
- Henriques, Romina, Potts, Warren M, Sauer, Warwick H H, Shaw, Paul W
- Authors: Henriques, Romina , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124710 , vital:35652 , https://doi.10.1080/17451000.2014.952309
- Description: The Benguela Cold Current system, located in the south-eastern Atlantic, features cold sea surface temperatures, bounded to the north and south by tropical currents (the Angola and Agulhas Currents, respectively) and a perennial upwelling cell off central Namibia that divides the region into two sub-systems with different characteristics (Shannon 1985; Hutchings et al. 2009). The colder sea surface temperatures of the Benguela Current have been considered an important biogeographic barrier, isolating tropical and warm-temperate fauna of the Atlantic and Indo-Pacific Oceans (Avise 2000; Floeter et al. 2008). However, recent studies revealed that other oceanographic features, such as the perennial upwelling cell, may also play an important role in shaping the population structure of warm temperate fish populations within the Benguela system, as complete disruption of gene flow was documented both in Lichia amia (Linnaeus, 1758) and Atractoscion aequidens (Cuvier, 1830) (Henriques et al. 2012, 2014). Little is known, however, regarding the influence of the Benguela system on genetic population connectivity of cold-water-tolerant species.
- Full Text:
- Date Issued: 2015
- Authors: Henriques, Romina , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124710 , vital:35652 , https://doi.10.1080/17451000.2014.952309
- Description: The Benguela Cold Current system, located in the south-eastern Atlantic, features cold sea surface temperatures, bounded to the north and south by tropical currents (the Angola and Agulhas Currents, respectively) and a perennial upwelling cell off central Namibia that divides the region into two sub-systems with different characteristics (Shannon 1985; Hutchings et al. 2009). The colder sea surface temperatures of the Benguela Current have been considered an important biogeographic barrier, isolating tropical and warm-temperate fauna of the Atlantic and Indo-Pacific Oceans (Avise 2000; Floeter et al. 2008). However, recent studies revealed that other oceanographic features, such as the perennial upwelling cell, may also play an important role in shaping the population structure of warm temperate fish populations within the Benguela system, as complete disruption of gene flow was documented both in Lichia amia (Linnaeus, 1758) and Atractoscion aequidens (Cuvier, 1830) (Henriques et al. 2012, 2014). Little is known, however, regarding the influence of the Benguela system on genetic population connectivity of cold-water-tolerant species.
- Full Text:
- Date Issued: 2015
Influence of mouth status on population structure of southern African endemic estuarine-spawning ichthyofauna in a temperate, temporarily open/closed estuary
- Tweddle, Gavin P, Froneman, P William
- Authors: Tweddle, Gavin P , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68071 , vital:29195 , https://doi.org/10.2989/16085914.2015.1051940
- Description: Publisher version , The effect of mouth status on the population structure of three endemic estuarine-spawning fish species was assessed using seine nets from November 2005 to October 2007 in the temporarily open/closed Mpekweni Estuary, Eastern Cape, South Africa. Collectively, these three species accounted for more than 60% of the total fish abundance within the estuary. Monthly length frequency data were analysed. Two species, Gilchristella aestuaria and Glossogobius callidus, displayed normally distributed populations throughout, with recruitment/abundance peaks between spring and autumn, and were unaffected by open mouth and extended marine connection conditions. Atherina breviceps, however, displayed multiple modal peaks in its combined population distribution, suggesting a greater influence of mouth condition on its population structure. Retrospective analyses of the various cohorts for A. breviceps identified peaks in recruitment/abundance during summer, coinciding with open-mouth conditions and, to a lesser extent, with overwash events. This study highlights the importance of mouth phase, not only on the recruitment and population distribution of marine-spawning species, but also on estuarine-spawning fish in temporarily open/closed estuaries along the South African coastline.
- Full Text: false
- Date Issued: 2015
- Authors: Tweddle, Gavin P , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68071 , vital:29195 , https://doi.org/10.2989/16085914.2015.1051940
- Description: Publisher version , The effect of mouth status on the population structure of three endemic estuarine-spawning fish species was assessed using seine nets from November 2005 to October 2007 in the temporarily open/closed Mpekweni Estuary, Eastern Cape, South Africa. Collectively, these three species accounted for more than 60% of the total fish abundance within the estuary. Monthly length frequency data were analysed. Two species, Gilchristella aestuaria and Glossogobius callidus, displayed normally distributed populations throughout, with recruitment/abundance peaks between spring and autumn, and were unaffected by open mouth and extended marine connection conditions. Atherina breviceps, however, displayed multiple modal peaks in its combined population distribution, suggesting a greater influence of mouth condition on its population structure. Retrospective analyses of the various cohorts for A. breviceps identified peaks in recruitment/abundance during summer, coinciding with open-mouth conditions and, to a lesser extent, with overwash events. This study highlights the importance of mouth phase, not only on the recruitment and population distribution of marine-spawning species, but also on estuarine-spawning fish in temporarily open/closed estuaries along the South African coastline.
- Full Text: false
- Date Issued: 2015