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Effect of water temperature on the biogeography of South African estuarine fishes associated with the subtropical/warm temperate subtraction zone

  • Authors: Maree, R C , Booth, Anthony J , Whitfield, Alan K
  • Date: 2000
  • Language: English
  • Type: text , Article
  • Identifier: vital:7133 , http://hdl.handle.net/10962/d1011776
  • Description: Estuarine biogeographical regions along the southeastern coast of South Africa were investigated in terms of fish distribution and abundance patterns, with particular emphasis on the role of water temperature in influencing these patterns. Qualitative and quantitative analyses were conducted upon the ichthyofaunal assemblages to determine whether the location of the subtropical/warm temperate boundary corresponds to that proposed by Whitfield.(n1) Analyses included the distribution ranges of species associated with estuaries according to presence/absence data, cluster analysis of gill net catches in eight estuaries along the southeastern coast and the relative proportion of tropical to temperate marine species within these eight systems. Quantitative analysis indicated that the ichthyofaunal biogeographical regions are indeed a reflection of water temperature regimes and that the subtropical/warm temperate boundary is located between the Great Kei and Mbashe estuaries. A strong negative correlation was found between the number of temperate fish species and the mean of the minimum monthly temperatures recorded in the systems studied. Qualitative analysis revealed that a barrier appears to exist in the vicinity of the Swartkops estuary, which prevents the westward migration of tropical 'vagrants'. The influence of the Agulhas Current along the east coast and its divergence from the coastline in the Algoa Bay region, as well as upwelling phenomena on the southeast and south coasts are identified as major factors that influence marine and estuarine temperature regimes and therefore the ichythyofauna of this region.
  • Full Text: false
  • Date Issued: 2000

Effect of wave exposure on growth and mortality rates of the mussel Perna perna: bottom up regulation of intertidal populations

  • Authors: McQuaid, Christopher D , Lindsay, Tracy L
  • Date: 2000
  • Language: English
  • Type: Article
  • Identifier: vital:6955 , http://hdl.handle.net/10962/d1011994
  • Description: The effect of wave exposure on the growth of low-shore populations of Perna perna (Linnaeus) was determined using 3 independent approaches at 6 sites on the south coast of South Africa: (1) Individual marking; notches were filed on the growing edges of mussels in situ. After 111 d, growth from the mark to the new growing edge was measured. (2) Internal shell-growth bands; mussels from the mark recapture experiment were used to establish that growth bands are laid down tidally. Unmarked individuals were then used to measure growth over the last 60 tides. (3) Shepherd¹s length-composition analysis (SLCA); growth rates were determined from length-frequency distributions in 11 samples collected at 6 wk intervals over 15 mo. All 3 approaches showed that growth rate was approximately twice as fast on exposed as on sheltered shores (ANCOVA, p < 0.05 in all cases). Mean length for the first year of growth (averaged for the 3 methods) was 47 and 22 mm, respectively. There were, however, considerable differences among methods. Marking provided the lowest estimates of growth rates, and SLCA the highest. The mean mortality index (Z yr-1) was significantly higher and annual survival rate lower for exposed shores, indicating faster turnover under exposed conditions. Mean longevity on exposed shores (2.6 yr) was only one-third of estimated longevity on sheltered shores (6.7 yr). These findings show that degree of exposure has important interactions with growth and mortality of mussels on the low shore, and that these effects are independent of the effects of exposure on density. The findings also indicate strong bottom up regulation of mussel populations.
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  • Date Issued: 2000

Effects of sustained elevated CO2 concentration and Nitrogen nutrition on wheat (Triticum aestivum L. cv Gamtoos)

  • Authors: Kgope, Barney Stephen
  • Date: 2000
  • Subjects: Wheat -- Growth , Wheat -- Nutrition , Nitrogen fertilizers , Nitrogen in agriculture
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4205 , http://hdl.handle.net/10962/d1003774 , Wheat -- Growth , Wheat -- Nutrition , Nitrogen fertilizers , Nitrogen in agriculture
  • Description: There is consensus that high CO2 results in enhanced growth and yield for most crop plants. However, most of these studies were carried out in the presence of adequate nutrients, which is also the case in agricultural systems (managed ecosystems). About 20% of the earth’s land mass have sufficiently low levels of nutrients to cause some kind of stress to plants. On the other hand, elevated [CO2] decreases foliar nutrient elements in plants and as a result partitioning of certain nutrient elements in plants is altered. Little data is available on the partitioning of most nutrient elements in plants, and this will definitely impact on growth and yield. To investigate this, wheat (Triticum aestivum L. c.v. Gamtoos) was grown in controlled environment cabinets at 360 and 700 µmol mol -1 CO2. The full Long-Ashton nutrient solution comprising of three-nitrogen concentrations ([N]) viz. (4,6 and 12 mM) was used to water plants everyday. The measurement of net assimilation rate (NAR), stomatal conductance (gs), transpiration rate (E), water use efficiency (WUE), foliar [N], nitrogen use efficiency (NUE) and growth parameters (total plant biomass (TPB), total plant height (TPH), leaf area (LA), shoot and root dry weight) were made 7 days after germination (7 DAG) till the onset of flowering. The increase in nitrogen supply in the order of 4, 6 and 12mM resulted in an increase in NAR, g_s_ , WUE and a decline in E under elevated [CO2]. Under elevated [CO2] NAR was observed to increase during the first two weeks reaching its maximum at 14 DAG, thereafter followed by a decline reaching its maximum at 28 DAG. This was later followed by an increase at 35 DAG onwards. Under elevated [CO2], NAR was increased significantly between the nitrogen regimes during the first (7-14 DAG) and the last two (35-42 DAG) weeks. The response of assimilation as a function of internal [CO2] (Ci), showed a decrease with age at ages 14, 28 and 35 DAG. This negatively affected the initial slope and the CO2 saturated photosynthetic rates under all treatments. This suggest that acclimation may have been as a result of both stomatal and biochemical limitations. All the photosynthetic pigment levels (chl_a_, chl_b_, chl_(a+b)_, and C_(x+c)_ ) increased with an increase in nitrogen supply from 4 to 6mM [N]. A 12mM [N] resulted in a significant decline in the photosynthetic pigment levels compared to a 6mM [N]. Chla remained higher than chlb under all treatments. Also, NAR was seen to increase and decrease concomitantly with the photosynthetic pigment levels. Foliar [N] was seen to decrease with an increase in nitrogen supply from 4 to 6 mM [N] under elevated [CO2] and the effects were adverse under the 4mM [N]. Under the 6mM N regime foliar [N] was positively correlated to NAR for elevated [CO2] grown plants. Similarly, E was positively correlated to foliar [N] under the same conditions. Elevated CO2 and increase in nitrogen supply had a pronounced effect on total plant height (TPH), total plant biomass (TPB), leaf area (LA), shoot and root dry weight and nitrogen use efficiency (NUE). The effects were more pronounced under a 6mM [N] as a result of high NUE. However, under 12mM [N] growth was not as expected as a result of lower NUE. Under all treatments shoot dry weight (SDW) was positively correlated to NUE. Anatomical studies revealed that total leaf and midrib thickness was significantly increased with an increase in nitrogen supply under elevated CO2 to support the larger leaf areas. There were no significant changes in the chloroplast ultrastructure as a result of the increase in nitrogen supply and CO2 enrichment. Starch grain surface area was seen to decline with an increase in nitrogen under both ambient and elevated CO2. Elevated CO2 and increase in nitrogen supply significantly increased total grain dry weight per plant by 47 and 46% respectively under 6 and 12mM [N]. In contrast, the increase was by about 21, 61 and 67% respectively under 4, 6 and 12mM [N] between the CO2 regimes.
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  • Date Issued: 2000

El hadji Diakali Toure

Electrocatalytic behavior of substituted cobalt phthalocyanines towards the oxidation of cysteine

  • Authors: Maree, Suzanne , Nyokong, Tebello
  • Date: 2000
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/293268 , vital:57070 , xlink:href="https://doi.org/10.1016/S0022-0728(00)00281-3"
  • Description: Ring substituted cobalt phthalocyanine complexes of the form CoPc(X)4, (where X=NH2, NO2, C(CH3)3, SO3H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the CoIII/CoII couple of the CoPc(X)4 complexes in acidic media and to the CoII/CoI couple in basic media. The catalytic currents and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive as the pH increases and the catalytic currents decreasing with increase in pH, for the same concentration of cysteine. The magnitudes of the catalytic currents (after ten scans) for cysteine oxidation at pH 8.3 and on electrodes modified with the CoPc(X)4 complexes increased with the nature of the ring substituent as follows: NO2 less than NH2 less than SO3H less than C(CH3)3 less than COOH.
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  • Date Issued: 2000

Electrocatalytic behavior of substituted cobalt phthalocyanines towards the oxidation of cysteine

  • Authors: Maree, Suzanne , Nyokong, Tebello
  • Date: 2000
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/293185 , vital:57063 , xlink:href="https://doi.org/10.1016/S0022-0728(00)00281-3"
  • Description: Ring substituted cobalt phthalocyanine complexes of the form CoPc(X)4, (where X=NH2, NO2, C(CH3)3, SO3H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the CoIII/CoII couple of the CoPc(X)4 complexes in acidic media and to the CoII/CoI couple in basic media. The catalytic currents and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive as the pH increases and the catalytic currents decreasing with increase in pH, for the same concentration of cysteine. The magnitudes of the catalytic currents (after ten scans) for cysteine oxidation at pH 8.3 and on electrodes modified with the CoPc(X)4 complexes increased with the nature of the ring substituent as follows: NO2 less than NH2 less than SO3H less than C(CH3)3 less than COOH.
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  • Date Issued: 2000

Electrocatalytic properties of vitamin B12 towards oxidation and reduction of nitric oxide

  • Authors: Vilakazi, Sibulelo Lea , Nyokong, Tebello
  • Date: 2000
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/293196 , vital:57064 , xlink:href="https://doi.org/10.1016/S0013-4686(00)00628-9"
  • Description: This paper reports on the catalytic behaviour of cyanocobalamin (VB12) towards the reduction and oxidation of nitric oxide. When VB12 is adsorbed on glassy carbon electrodes, it catalyses the reduction of nitric oxide (NO) in pH 4 and 9 buffers. In the absence of NO, cyclic voltammetry shows that VB12 is reduced by a one-step two-electron reduction from CoIII to the CoI species. Addition of NO at pH 9 to solutions of VB12 resulted in the splitting of the cyclic voltammetry peaks as a result of a consecutive one-electron reduction of the central CoIII metal in VB12 to CoII and finally to CoI. The catalytic peak for oxidation of NO on a glassy carbon electrode modified with VB12 was observed at 1.21 V versus Ag∣AgCl, at pH 9. The products of the catalytic reduction of nitric oxide include ammonia and hydroxylamine.
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  • Date Issued: 2000

Elle est occupee

Elle est occupee (remix maquis)

Environmental art and its contribution to establishing an awareness of the sacred in nature

  • Authors: Matthews, Elaine Katherine Simone
  • Date: 2000
  • Subjects: Installations (Art) Art, Modern -- 20th century Nature (Aesthetics)
  • Language: English
  • Type: Thesis , Masters , MFA
  • Identifier: vital:2413 , http://hdl.handle.net/10962/d1002209
  • Description: The introduction establishes the goal of the research, which is to discover that art concerned with re-evaluating the relationship to the environment and spirituality can serve to connect people to one another, and to the environment. The context of the research is the contemporary ecological and spiritual crisis of the postmodern world. The background places the discussion within the contexts of modernism and postmodernism. The historical background focuses on the period from the 1960s to the present day. Land and Environmental artists who work in a manner that is conscious of environmental issues and who suggest a sacred and creative attitude to ecology are discussed. My own creative work which is a response to both ancient and contemporary sites as well as to contemporary theories of art and spirituality is discussed. The four projects, are discussed in chronological order, they are: Quest - A journey into Sacred Space; Gaika's Kop - Sacred Mountain; Labyrinth - Journeys to the Centre; and Transforming the Centre. The conclusion shows that the multi-faceted, intertextual and relativistic philosophy of postmodernism has brought about a significant change in the attitude of humanity towards the environment. Artists who reject the modernist aesthetic and philosophy are making art that emphasises relationship to, rather than separation from the natural world.
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  • Date Issued: 2000

Environmental influences on the daytime vertical distribution of Cape hakes and implications for demersal trawl estimates of hake abundance off the west coast of South Africa

  • Authors: Maree, R C
  • Date: 2000
  • Subjects: Hake , Fisheries -- Environmental aspects -- South Africa , Fisheries -- South Africa , Trawls and trawling
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5278 , http://hdl.handle.net/10962/d1005122
  • Description: The demersal fishery off the west coast of South Africa experiences decreased catches per unit effort of hake, Merluccius capensis and M. paradoxus, following the onset of strong south easterly winds. Research has demonstrated that, during daylight hours, Cape hakes migrate vertically in the water column in response to strong south easterly winds, decreasing their availability to the bottom trawl. Hydroacoustic, trawl and environmental data were collected off the West Coast during both calm and wind-swept periods in an attempt to understand the forces that initiate this behaviour, its spatial variability and the implications for demersal trawl estimates of abundance. Near-bottom currents appear to be the primary factor influencing the vertical distribution of the demersal fish community, of which hake constitutes a large proportion, during daylight hours. Correlation between wind and near-bottom currents suggest that the poleward component of the currents increase in velocity within eight hours following the onset of south easterly winds. The fish avoid boundary layers where currents change direction and speed dramatically, and seem to concentrate in waters with relatively stable current regimes. This result questions the assumption of CPUE-based assessment models that hake availability to the bottom trawl is constant or varies randomly. The incorporation of acoustic assessment techniques to demersal surveys has potential, but may be most valuable by supplementing swept-area estimates of abundance, since the sampling efficiency of these methods varies within the water column. The incorporation of wind indices and gear performance data to Cape hake assessment models have been identified as useful considerations for the future.
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  • Date Issued: 2000

Environmental youth clubs in Namibia : what role do, could or should they play in environmental education?

  • Authors: Botma, Connie
  • Date: 2000
  • Subjects: Environmental education -- Namibia Environmental education -- Study and teaching -- Namibia Youth -- Societies and clubs Youth -- Namibia
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1519 , http://hdl.handle.net/10962/d1003401
  • Description: Although the existence of wildlife clubs in Africa dates back to the start of the environmental movement in the 1970s, youth involvement through environmental clubs only commenced in Namibia in 1992. I became involved with the clubs in 1995 when I was employed by the Rossing Foundation Environmental Education Project to encourage, support and coordinate environmental clubs in Namibia. During the last three years the number of Namibian clubs has increased from 20 to ±85, and they are now established in most geographical regions of the country. During my involvement with the clubs I became increasingly interested in the philosophical underpinnings of youth movements like clubs and started questioning what we could expect from the youth and what could be achieved through the clubs. One of my main concerns was whether youth could make a significant improvement to the quality of their lives and their environment through these clubs. The aim of my research was therefore to describe and reflect critically on the role of environmental youth clubs in environmental education in Namibia. My study was guided by a socially critical orientation which emphasises the construction of meaning through social dialogue and critical reflection. I chose an interpretative research strategy and generated data mainly through semi-structured interviews, participant observation, a focus-group discussion and a workshop. Due to the focus of the research I purposefully selected the sample of existing youth clubs to be included in the study. The iterative strategy of gathering and interpreting data in successive cycles allowed for continuous reflection throughout the research process. It also allowed me to identify key patterns and trends in analysing and interpreting the data. The study findings suggest that environmental clubs do playa role in learning about environmental issues; in developing personal and social identity, confidence and a sense of purpose in society; in establishing new and supportive relationships between teachers and learners and with other community resourde people; in creating opportunities and enabling exposure to diverse learning environments, options and alternatives; and ih fostering the orientation and skills needed to effect meaningful d1'inges in the environment. The findings also suggest that environmental clubs could make a significant contribution to environmental education, providing that they incorporate a socially critical orientation, gain greater recognition from significant adults and education officials, collaborate with other projects and organisations, and use guidelines of models such as the action research framework to ensure relevant and effective action projects. The main challenges to environmental clubs in Namibia include changing perceptions that youth do not have much to contribute; improving relationships between clubs, schools and communities; dealing with the tension between the possible disempowering effect of central control and the need for more formalised structures in order to gain official recognition; and developing strategies to ensure the clubs' sustainability in the future.
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  • Date Issued: 2000

Enzymes with biocatalytic potential from Sorghum bicolor

  • Authors: Nganwa, Patience Jennifer Kengyeya
  • Date: 2000
  • Subjects: Enzymes , Sorghum
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3908 , http://hdl.handle.net/10962/d1003967 , Enzymes , Sorghum
  • Description: Sorghum is a staple food in the semi-arid tropics of Asia and Africa, sustaining the lives of the poorest rural people. This project set out to improve the potential economic value of Sorghum bicolor as a crop. The task was undertaken by screening for selected enzymes in the plant that would have a potential market for use in industrial applications and in biotransformations, specifically proteases, polyphenol oxidases and peroxidases. Asurveywas conducted using standard enzyme assays and crude plant extracts, to determine whether the selected enzymes were present. Grain tissue did not appear to have significant protease or polyphenoloxidase activity, but high levels of peroxidases were detected, withthe young grain extracts showing more activity(4.63U/mL)thanripegrain extracts (0.62 U/mL). Leaf tissue extracts contained low levels of protease activity, a considerable amount of polyphenol oxidase (0.127 U/mL), and peroxidase (4.7 U/mL) activities comparable with that found in grain tissue. Root tissue extract was found to contain the highest levels of peroxidase activity (7.8 U/mL) compared to the other extracts. Therefore, sorghum peroxidase from the root was isolated, purified, characterized and applied to biotransformation reactions. Different sorghum strains,withvaryinggraincolour, (Zimbabwe - bronze, Seredo - brown and Epurpur - cream/white) were investigated for the presence of polyphenol oxidase and peroxidase activities. Results of spectrophotometric analysis showed that the enzymes did not appear to be strain specific. However, gel electrophoresis analysis revealed differences in band patterns among the strains. Partial purification of sorghum root peroxidase was achieved after centrifugation, extraction with polyvinylpolypyrrolidone (PVPP), ultrafiltration, and hydrophobic chromatography with phenyl Sepharose, followed by polyacrylamidegelelectrophoresis (PAGE). The specific activity of the 5-fold purified enzyme was found to be 122.3 U/mg. After PAGE analysis, two bands with molecular weights of approximately 30 000 and 40 000 were detected, which compares well with horse radish peroxidase (HRP) which has a molecular weight of approximately 44 000. The colour intensity of the bands in the activity gels indicated that sorghum root peroxidase had apparently higher levels of peroxidase activity than commercial horseradish peroxidase (HRP). Characterizationexperiments revealed that sorghumroot peroxidase is active over a broad temperature range and remains active at temperatures up to 100°C. It also has a broad substrate range. The optimum pH of the enzyme was found to be pH 5 - 6. Under standardized assay conditions, the optimal substrate concentration, using o-dianisidine as substrate, was 50 mM, and the optimal H2O2 concentration under these conditions was found to be 100 mM. Sorghum root peroxidase was applied in a preliminary investigation into the oxidative biotransformationof a number of aromatic compounds. The products obtained were comparable withthose whenthe compounds are reacted with HRP which is the most commonly used commercial peroxidase and has been extensively studied. However, HRP is relatively costly, and the use of peroxidase from sorghum roots as an alternative source, appears to be promising. A patent has been provisionally registered, covering application of sorghum root peroxidase for biotransformations.
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  • Date Issued: 2000

Epp Doole

Ethnic nationalism and democratisation in South Africa : political implications for the rainbow nation

  • Authors: Naidoo, Vinothan
  • Date: 2000
  • Subjects: Nationalism -- South Africa , Ethnicity -- South Africa , Democracy -- South Africa , South Africa -- Politics and government -- 1994-
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2815 , http://hdl.handle.net/10962/d1003025 , Nationalism -- South Africa , Ethnicity -- South Africa , Democracy -- South Africa , South Africa -- Politics and government -- 1994-
  • Description: Ethnic identities in South Africa have had a particularly contrived history, set within the constraints and motivations of population classification by race. A more democratic political environment emerged with the dismantling of apartheid, bringing with it a multitude of issues including the design and character of the country’s political institutions and framework. This thesis will address two principal questions. The first and primary one investigates what lies behind the initiation and development of ethnic bonds. The second concerns the political implications and management of ethnic expressions in a democratic South Africa. An analysis of Zulu ethnic nationalism will be undertaken, because it constituted the most prominent case of assertive communal interests during democratic transitional negotiations. This thesis argues that circumstantial and instrumental factors (based on conditions, and the actions of individuals and organizations respectively), have been predominately responsible for the initiation and formation of ethnic bonds, especially amongst those who identify with a Zulu identity. The “conditions” describe the increasingly segregationist direction in which successive South African government authorities were moving, especially after the 1948 election victory of the National Party and the subsequent introduction of apartheid. Secondly, the “actions” denote the motivations of both Zulu actors and governments in generating and elaborating an ethnic discourse where their desired interests could be more effectively supported and assured. It will also be argued that because of the instrumental and selective use of ethnicity, as well as the narrow interests being served by its popular and community-centred expressions, a developing South African democratic culture should seek to protect ethnic diversity rather than promote ethnic interests. To do so would be to deny the perpetuation of ethnic cleavages and the violence and instability perpetrated in its name in recent years. The “protection” of cultural diversity is consistent with a constitution that seeks non-discrimination among all South African identities. Finally, it is believed that an emphasis on the individual as individual, as well as member of a cultural group, will break from subordinating the individual to an ascribed racial and ethnic identity as in the past, and assist in reconstituting the state as equally reflective of all South Africans.
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  • Date Issued: 2000

Evaluation of the effectiveness of strategic planning in the blood transfusion services in South Africa

  • Authors: Van Heerden, Marchell
  • Date: 2000
  • Subjects: Strategic planning -- South Africa , Blood banks -- South Africa , Blood -- Transfusion -- South Africa
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:10835 , http://hdl.handle.net/10948/27 , Strategic planning -- South Africa , Blood banks -- South Africa , Blood -- Transfusion -- South Africa
  • Description: In this research paper, the effectiveness of Strategic Planning in Blood Transfusion Services in South Africa was investigated. A brief general overview of relevant aspects that specifically relate to the strategic planning of Services and not-for-gain organisations was presented. The literature study included an explanation of the steps involved in the strategic planning process and the guidelines to develop and implement each of these effectively. The research methodology consisted of three phases: Phase 1 - A literature study to determine the most effective strategic plan for a not-for-gain organisation. Phase 2 - An empirical study to determine the effectiveness of the strategic planning processes in practice by means of a survey among the Blood Transfusion Services in South Africa. Phase 3 - The findings from the literature study and empirical study were used to evaluate whether effective strategic planning is implemented in the Blood Transfusion Services in South Africa. The following recommendations and conclusions were made: The Blood Transfusion Services that have not yet started seeking the opinion of all the stakeholders involved in the organisation should strongly consider implementing this strategy as part of the services provided to the community. The services operate as individual organisations, but clearly influence each other within the industry and the changes within the external environment form part of the elements that are considered by the services when determining the strategic direction of the services. All the services identify the major areas for which objectives need to be set to assist the organisations in achieving long-term prosperity, but they do not all set objectives in these areas. When it comes to strategic issues, all the services state that they identify these, but not all pre-determine criteria for evaluating the strategic issues. Guidelines for the effective implementation of the strategies of choice by lower managers or supervisors are not developed by all the services, nor do most of the services have control mechanisms in place to assist in effective implementation of the strategic planning process.
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  • Date Issued: 2000

Evidence of Quaternary glaciation in Southern Africa : moraines on the Bastervoetpad of the eastern Cape Drakensberg, South Africa

  • Authors: Lewis, Colin A , Illgner, Peter M
  • Date: 2000
  • Language: English
  • Type: Article
  • Identifier: vital:6710 , http://hdl.handle.net/10962/d1006747
  • Description: This volume of Quaternary International comprises the Abstracts from the XVth INQUA Congress held in Durban,South Africa, 3–11 August 1999.
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  • Date Issued: 2000

Exploitation patterns of the multi species/gear hake (Merluccius capensis and paradoxus) fishery on South Africa's southeast coast

  • Authors: Sutton, Glen Robert
  • Date: 2000
  • Subjects: Fishing -- South Africa , Hake -- South Africa , Merluccius capensis -- South Africa , Merluccius paradoxus -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5280 , http://hdl.handle.net/10962/d1005124 , Fishing -- South Africa , Hake -- South Africa , Merluccius capensis -- South Africa , Merluccius paradoxus -- South Africa
  • Description: The motivation for this study was to examine the exploitation patterns of the M. capensis and M. paradoxus hake fisheries on the Southeast Coast, and determine the size and species of hake caught in each of the hand-line, long-line, and trawl methods. The handline hake fishery has increased substantially over the last several years and concerns are beginning to emerge about the impact this will have on the inshore resource collected on the South Coast between August 1998 and July 1999 was used to describe the hand-line method and estimate annual landings. Data on the size and species in longline catches of hake caught during 1997 were already available for this study. Size distributions in trawl catches were determined from commercial category landing data reported by catch weight and depth. The species composition in these catches determined by comparison using RV Afrikana survey data collected in the same depth regions. Location plays a significant role in determining the sizes and species of hake caught by each gear. Hand-lines catch smaller sizes on average than do long-lines, inshore trawls target mainly M. capensis while offshore trawls catch both hake species. A substantial amount of the hand-line hake caught on the South Coast is not reported. Examination of the exploitation patterns reveal that intense trawling pressure is directed at the smaller sized M. paradoxus inhabiting the depth region between 160-400-meters. Inshore trawls discard a large amount of small sized M. capensis within the 100-meter isobath. A preliminary stock assessment on the status of each hake species found that M. paradoxus appears to be over-exploited while M. capensis was in better shape. However, length-based pseudo-cohort analysis, used in this assessment, is critically reliant on having length frequency data from a steady state population in equilibrium. This limits the application of this model for management purposes and this finding is purely theoretical at this stage. Results suggest that each hake species is under a different pattern and level of exploitation and the multi-species nature of hake stocks on the South Coast should be considered in developing optimum management policies. Future work should focus on developing appropriate age/length keys so that an age-based VPA, which is more powerful than the length-based approach, can be applied towards stock assessments on the South Coast. Alternatively, length-data covering a longer period should be compiled and the equilibrium assumption further investigated so that the results from length-based models can be used with more confidence.
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  • Date Issued: 2000

Exploring the making of meaning: environmental education and training for industry, business and local government

  • Authors: Jenkin, Nicola Pat
  • Date: 2000
  • Subjects: Environmental education Corporations -- environmental aspects Local government -- environmental aspects Managerial economics -- environmental aspects
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1543 , http://hdl.handle.net/10962/d1003425
  • Description: The aim of this research was to explore how participants made meaning in an environmental education and training course for people from industry, business and local government in South Africa, and to identify and comment on any constraints to this meaning-making. I used a Symbolic Interactionist theoretical framework to explore and comment on the meaning-making process. I started my research by conducting a questionnaire to select participants for interviews. During the course the selected participants were interviewed, as well as the two course co-ordinators. Data was also gathered during the course from participant observation field notes ('captured talk'), photographs, participants' assignments and course evaluations. The data was analysed using an adapted form of discourse analysis and matrices. The research highlights that the opportunities provided on the course were adequate for encouraging meaning-making amongst both the co-ordinators and participants. However, recorded instances of meaning-making were low, which indicated that there were certain constraints during the meaning-making process. This research highlights and comments on identified constraints such as time and workplace support. The research supports similar findings which emerged from research conducted on the Gold Fields environmental education course for teachers and also offers recommendations for further research and practice into meaning-;making within the field of environmental education and industry, business and local government in South Africa.
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  • Date Issued: 2000

Exploring the needs and experiences of the social worker as an intermediary

  • Authors: Jarman, Renette
  • Date: 2000
  • Subjects: Social workers , Mediation
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:698 , http://hdl.handle.net/10962/d1006419 , Social workers , Mediation
  • Description: During this research an attempt was made to gain an understanding of the experiences and needs of the social workers acting as intermediaries for the sexually abused children in the criminal court during the trials of perpetrators. To achieve this, ten social workers that have performed the role of intermediary were interviewed. Research as well as literature on this topic is limited and it is believed that this study will present a valuable basis to pursue in further research as well as assist social workers already rendering intermediary services. Literature that was available was found to be critical of the adversarial system and the negative elements associated with the system, especially for the child witness. The study found that there are many problems associated with the intermediary system. The most important issue is the delay between the decision to prosecute and the trial as this impacts negatively on the child witness. In addition social workers acting as intermediaries are inadequately trained and are not supervised in this role. As a result very few are willing to continue with the procedure. Nevertheless the intermediary system is adjudged better than the adversarial system, especially as the child witness no longer has to face the alleged perpetrator in an open court. The thesis ends with recommendations for addressing the concerns of intermediaries in order to strengthen the system.
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  • Date Issued: 2000
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