Dissertations / Theses: 'South-east coast'

1

Thomson, Danielle, and n/a. "Arsenic and Selected Elements in Marine Photosynthetic Organisms,South-East Coast, NSW, Australia." University of Canberra. Resource, Environmental and Heritage Sciences, 2006. http://erl.canberra.edu.au./public/adt-AUC20070521.120826.

Full text

Abstract:

The cycling of arsenic in the marine photosynthetic plants and algae was examined by analysing total arsenic concentrations and arsenic species in selected marine photosynthetic organisms from the south-east coast, NSW, Australia. A range of elements required for metabolism in photosynthetic organisms were also analysed to determine if any relationship between these elements and arsenic concentrations occurred. Organisms were selected from salt marsh and mangrove ecosystems, marine inter-tidal and estuarine environments, and two species of marine phytoplankton cultured, to represent the different marine environments that primary producers inhabit. Organisms selected were compared to species within their own environment and then a comparison made between the varying ecosystems. In the salt marsh and mangrove ecosystems, the leaves of four species, the mangrove Avicennia marina, the samphire Sarcocornia quinqueflora, the seablight Suaeda australis, and the seagrass Posidonia australis were sampled from three locations from the south-east coast of NSW using nested sampling. Mean total arsenic concentrations (mean � sd) dry mass for all locations were A. marina (0.38 � 0.18 �g g-1 to 1.2 � 0.7 �g g-1), S. quinqueflora (0.13 � 0.06 �g g-1 to 0.46 � 0.22 �g g-1), S. australis (0.03 � 0.06 �g g-1 to 0.05 � 0.03 �g g-1)and P. australis (0.34 � 0.10 �g g-1 to 0.65 � 0.26 �g g-1). Arsenic concentrations were significantly different between species and locations but were consistently low compared to marine macroalgae species. Significant relationships between As and Fe concentrations for A. marina, S. quinqueflora and P. australis and negative relationship between As and Zn concentrations for S. quinqueflora could partially explain arsenic concentrations in these species. No relationship between As and P concentrations were found in this study. All terrestrial species contained predominantly inorganic arsenic in the water extractable and residue fractions with minor concentrations of DMA in the water-soluble fraction. P. australis also contained dimethylated glycerol and phosphate arsenoriboses. The presence of arsenobetaine, arsenocholine and trimethylated glycerol arsonioribose is most likely due to the presence of epiphytes on fronds on P. australis. In contrast, macroalgae contained higher total arsenic concentrations compared to marine terrestrial angiosperms. Total arsenic concentrations also varied between classes of algae: red macroalgae 4.3 �g g-1 to 24.7 �g g-1, green macroalgae 8.0 �g g-1 to 11.0 �g g-1 and blue green algae 10.4 �g g-1 and 18.4 �g g-1. No significant relations were found between As concentrations and concentrations of Fe, Co, Cu, Mn, Mo, Mg, P and Zn concentrations, elements that are required by macroalgae for photosynthesis and growth. Distinct differences between algal classes were found for the proportion of arsenic species present in the lipid and water-soluble fractions, with green algae having a higher proportion of As in lipids than red or estuarine algae. Acid hydrolysis of the lipid extract revealed DMA, glycerol arsenoribose and TMA based arsenolipids. Within water-soluble extracts, red and blue-green algae contained a greater proportion of arsenic as inorganic and simple methylated arsenic species compared to green algae, which contained predominantly glycerol arsenoribose. Arsenobetaine, arsenocholine and tetramethylarsonium was also present in water-soluble extracts but is not normally identified with macroalgae and is again likely due to the presence of attached epiphytes. Residue extracts contained predominantly inorganic arsenic, most likely associated with insoluble constituents of the cell. Mean arsenic concentrations in the green microalgae Dunaliella tertiolecta were 13.3 �g g-1 to 14.5 �g g-1, which is similar to arsenic concentrations found in green macroalgae in this study. Diatom Phaeodactylum tricornutum arsenic concentrations were 1.62 �g g-1 to 2.08 �g g-1. Varying the orthophosphate concentrations had little effect on arsenic uptake of microalgae. D. tertiolecta and P. tricornutum metabolised arsenic, forming simple methylated arsenic species and arsenic riboses. The ratio of phosphate to glycerol arsenoriboses was higher than that normally found in green macroalgae. The hydrolysed lipid fraction contained DMA arsenolipid (16-96%) with minor proportions of phosphate arsenoribose (4-23%). D. tertiolecta at f/10 phosphate concentration, however, contained glycerol arsenoribose and another arsenic lipid with similar retention as TMAO as well as DMA. The similarities between arsenic species in the water-soluble hydrolysed lipids and water-soluble extracts, especially for P. tricornutum, suggests that cells readily bind arsenic within lipids, either for membrane structure or storage, releasing arsenic species into the cytosol as degradation of lipids occurs. Inorganic arsenic was sequestered into insoluble components of the cell. Arsenic species present in D. tertiolecta at lower phosphate concentrations (f/10) were different to other phosphate concentrations (f/2, f/5), and require further investigation to determine whether this is a species-specific response as a result of phosphate deficiency. Although there are similarities in arsenic concentrations and arsenic species in marine photosynthetic organisms, it is evident that response to environmental concentrations of arsenic in uncontaminated environments is dependent on the mode of transfer from the environment, the influence of other elements in arsenic uptake and the ability of the organism to metabolise and sequester inorganic arsenic within the cell. It is not scientifically sound to generalise on arsenic metabolism in �marine plants� when species and the ecosystem in which they exist may influence the transformation of arsenic in higher marine organisms. There is no evidence to suggest that angiosperms produce AB as arsenic is mostly present as inorganic As, with little or no arsenic present in the lipids. However, marine macro- and microalgae both contain lipids with arsenic moieties that may be precursors for AB transformation. Specifically, the presence of TMA and dimethylated arsenoribose based arsenolipids both can transform to AB via intermediates previously identified in marine organisms. Further identification and characterization of As containing lipids is required.

APA, Harvard, Vancouver, ISO, and other styles

2

Mills, Simon Richard Stead. "The ritual music of South Korea's east coast shamans : inheritance, training and performance." Thesis, SOAS, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406536.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Vat, Laura Suzanne. "The growth and reproduction of Patella granularis (Mollusca : patellogastropoda) on the south-east coast of South Africa." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005388.

Full text

Abstract:

Aspects of the biology and ecology of Patella granularis were investigated along a 130km stretch of the south-east coast of South Africa. Distribution, biomass, density and population structure were investigated at seven localities. In addition, a more detailed study of the growth rate and reproductive biology of populations inhabiting three different substrata (aeolianite, quartzitic sandstone and mussel shells) was conducted. The genetic relationships between these three populations was also examined, as was the foraging behaviour of the limpets inhabiting an aeolianite and a quartzitic sandstone shore. Finally, differences in food availability on the different substrata were studied. On the south-east coast, P. granularis has a wide intertidal distribution, occurring from the upper Balanoid zone through to the Cochlear zone, where it is a common inhabitant of mussel shells. The mean shell length of P. granularis was found to decrease down the shore. The largest limpets (46.6 mm shell length) were found on an offshore island in Algoa Bay. At most localities investigated, the sex ratio deviated from a 1:1 ratio with more males than females being recorded on five shores. Both limpet density and biomass were lower on the south-east coast when compared to data published for west coast populations. On the south-east coast, both density and dry biomass were highest in the lower Balanoid zone. Allozyme electrophoresis indicated that P. granularis inhabiting aeolianite, quartzitic sandstone and mussel shells are all part of a single population. Extremely high genetic identity values (0.998), low levels of heterozygosities (0.035 - 0.061), low levels of polymorphisms (25% - 31%) and low FST values (0.021) all suggest that the three populations of P. granularis form a common breeding group, despite the high levels of phenotypic plasticity observed. On all shores, P. granularis was found to grow allometrically, increasing in shell height more rapidly than shell length. Estimation of the growth rate (determined by the Von Bertalanffy growth model) of P. granularis suggested that limpets inhabiting the mussel shells grew more slowly, and attained a smaller maximum size, than those inhabiting both the aeolianite and the quartzite (K = 0.25, 0.32 and 0.33 respectively; 27.12 mm, 31.89 mm and 32.96 mm respectively). Previous work has shown that west coast P. granularis grow more quickly (K = 0.7) and reach a greater size (. 40 mm). Translocation of limpets among sites suggested that limpet size in the mussel beds was spatially constrained. Shell microgrowth bands were deposited tidally, but could not be used for aging limpets due to shell erosion. Limpets from the aeolianite had the greatest reproductive fitness, producing more eggs (.366 000/limpet) than those inhabiting quartzite (.119 500/limpet) or mussel shell limpets (.85 800/limpet). Aeolianite limpets also spawned throughout the year, whereas those from the quartzite and mussel shells spawned twice a year (once in winter and once in summer) although a great deal of interannual variability was observed. The onset of sexual maturity occurred at a similar age in all limpets (1 - 2 years) and is probably genetically entrenched. P. granularis inhabiting both an aeolianite and a quartzitic shore were active during nocturnal low tides. All limpets returned to a home scar after foraging. Whilst foraging, limpets inhabiting the aeolianite shore moved shorter distances (.17 cm) at a slower rate than those from quartzite (.30 cm). Limpets that were translocated from one substratum to the other initially moved similar distances to the source group, but after a maximum period of one week, moved distances that mirrored those moved by the resident limpets. Neither season nor tidal phase influenced the distances foraged. No directionality in foraging was found. Wear of radula teeth, particularly the pluricuspid tooth, was greater in limpets from the quartzite. It is hypothesised that the observed differences in life-history parameters and foraging behaviour of limpets both within the south-east coast and between the west and south-east coasts are related to food abundance. Chlorophyll-a, and hence microalgal biomass, was consistently higher on aeolianite (.2.5 times) than on both quartzite and mussel shells. Estimates of chlorophyll-a were higher (although not significantly) in winter. Previous studies determined that primary productivity is also higher along the west coast. Finally, the lack of evidence for migration of limpets from the low-shore to high-shore in south-east coast P. granularis is discussed. It is suggested that this species settles opportunistically within its physiological tolerances and responds morphologically to localised environmental conditions.

APA, Harvard, Vancouver, ISO, and other styles

4

Blamey, Ross. "Numerical simulation of a mesoscale convective system over the east coast of South Africa." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/6463.

Full text

Abstract:

Includes bibliographical references (leaves 189-200).
Weather stations across the northern KwaZulu-Natal coastline recorded over 100 mm of rainfall over the 11112 February 2005, with Cape St. Lucia and Richards Bay measuring 111 mm and 96.8 mm, respectively. This heavy rainfall was associated with a mesoscale convective system (MCS) that initiated through small convective storms beginning early in the afternoon on 11 February 2005 and eventually decayed in the early morning hours on the 12th. The high-lying topography of the eastern escarpment and high diurnal surface heating possibly provided the trigger for the event. It was also identified that a combination of synoptic features in and around South Africa contributed to the evolution of the system. This particular MCS is investigated with a non-hydrostatic numerical model (MM5) to help determine which processes were important in its initiation and development, as well as what factors contributed to the associated heavy rainfall. The model is also used to conduct sensitivity tests to determine the role that local features, such as the regional topography and sea surface temperature, played in the evolution of the system. Through the various MM5 simulations, it was evident that the eastern escarpment played a key role in triggering the convective event, while it also had an influence on the low level winds that advected moisture into the region. A sea surface temperature sensitivity simulation highlighted the important role that the Agulhas Current plays in supplying moisture to fuel extreme precipitation events in South Africa. The significance of resolving large-scale features in the mid-latitudes in numerical simulations of weather events in South Africa was identified when excluding these features from the simulation. Through these simulations it was identified that the development of the MCS and the heavy nocturnal precipitation was due to a combination of the continuous moisture supply into the region, a conditionally unstable atmosphere, and uplift due to low level convergence and the local topography.

APA, Harvard, Vancouver, ISO, and other styles

5

Vosloo, Mathys Christiaan. "Network analysis of trophic linkages in two sub-tropical estuaries along the South-East coast of South Africa." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1010966.

Full text

Abstract:

Estuaries are some of the most productive yet threatened ecosystems in the world. Despite their importance they face significant threats through changes to river flow, eutrophication, rapid population growth long the caost and harvesting of natural resources. A number of international studies have been conducted investigating the structure and functioning of an array of ecosystems using ecological network analysis. Energy flow networks have been contsructed for coastal, lagoonal, intertidial and, most notably, permantently open estuaries. Despite the valualble insights contributed by these and other studies, a lack of information on the majority of estuarine ecosystems exists.

APA, Harvard, Vancouver, ISO, and other styles

6

Kaminsky, Alexander. "Social capital and fisheries co-management in South Africa: the East Coast Rock Lobster Fishery in Tshani Mankozi, Wild Coast, Eastern Cape." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1003110.

Full text

Abstract:

It is evident that natural fish stocks are in rapid decline and that millions of people around the world rely on these resources for food and for securing a livelihood. This has brought many social scientists, biologists and fisheries experts to acknowledge that communities need to take more control in managing their natural resources. The paradigm shift in fisheries management from a top-down resource orientated control to a participatory people-centred control is now being advocated in many maritime nations in facilitating community-based natural resource management. At the heart of these projects is the establishment of institutions and social networks that allow for clear communication and information sharing, based on scientific data and traditional knowledge which ultimately allow empowered communities to collectively manage their resources in partnership with government, market actors and many other stakeholders. Central to the problem is the issue of access rights. In many situations where co-management of natural resources through community-government partnerships is advocated, the failure of coastal states to provide adequate legislature and regulatory frameworks has jeopardised such projects. A second issue is the failure of many states to provide adequate investments in social and human capital which will enable communities to become the primary stakeholder in the co-management of their natural resources. Whilst investments like capacity building, education, skills training and development, communications and institution building can initially require high financial investments, the regulatory costs for monitoring, controlling and surveying fish stocks along the coastline will go down as communities take ownership of their resources under sustainable awareness. The main unit of investment therefore is social capital which allows for the increase in trust, cooperativeness, assertiveness, collective action and general capabilities of natural resource governance. High levels of social capital require good social relations and interactions which ultimately create a social network of fishers, community members and leaders, government officials, market players, researchers and various other stakeholders. Co-management thus has an inherent network structure made up of social relations on a horizontal scale amongst community members as well as on a vertical scale with government and fisheries authorities. These bonding relations between people and the bridging relations with institutions provide the social capital currency that allows for a successful co-management solution to community-based natural resource governance. The South African coastline is home to thousands of people who harvest the marine resources for food security and securing a basic income. Fishing is a major cultural and historical component of the livelihoods of many people along the coastline, particularly along the Wild Coast of South Africa located on its South-eastern shoreline. Due to the geopolitical nature of South Africa’s apartheid past many people were located in former tribal lands called Bantustans. The Transkei, one of the biggest homelands, is home to some of South Africa’s poorest people, many of whom rely on the marine resources. By 1998 the government sought to acknowledge the previously unrecognised subsistence sector that lived along the South African coastline with the promulgation of the Marine Living Resources Act. The act sought to legalise access rights for fishers and provide opportunities for the development of commercial fisheries. The act and many subsequent policies largely called for co-management as a solution to the management of the subsistence sector. This thesis largely explains the administrative and legislative difficulties in transporting the participatory components of co-management to the ground level. As such co-management has largely remained in rhetoric whilst the government provides a contradictory policy regarding the management of subsistence and small-scale fishers. This thesis attempts to provide qualitative ethnographic research of the East Coast Rock Lobster fishery located in a small fishing village in the Transkei. The fishery falls somewhere on the spectrum between the small-scale and subsistence sector as there are a basket of high and low value resources being harvested. It will be argued that in order to economically and socially develop the fishery the social capital and social networks of the community and various stakeholders needs to be analysed in order to effectively create a co-management network that can create a successful collective management of natural resources thereby sustaining these communities in the future.

APA, Harvard, Vancouver, ISO, and other styles

7

Brouwer, Stephen Leonard. "An assessment of the South African east coast linefishery from Kei Mouth to Stil Bay." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005076.

Full text

Abstract:

During the period April 1994 and February 1996 as part of an investigation into the national Iinefishery, the east coast shore fishery and the recreational and commercial ski-boat fisheries were surveyed, at eight sites between Kei Mouth in the East and Stil Bay in the West. Roving creel, access point and aerial surveys were used. A questionnaire was developed for each sector to gather data on catch and effort, fisher demographics, economics, fisher attitudes towards, and knowledge of, the current management regulations and assess the efficacy of the fisheries inspectorate. During the access point survey the catch of 3273 fishers was inspected and 1556 interviews were conducted. Questionnaires were conducted on 118 recreational ski-boaters and the catch of 165 boats was inspected. 96 commercial skippers were interviewed and 230 had their catch inspected. Three aerial surveys of the entire area were conducted during which a total of 1067 shore fishers were counted giving a shore fisher density of 0.39 fishers.km⁻¹. The majority (99%) of participants in all sectors of the linefishery were male. The greatest number of participants were white, shore fishery 77% recreational ski-boat 98% commercial skiboat 89%, followed by coloured, asian and black people. To a large extent this reflects the income of various racial groups. Most fishers supported the current linefish management plan. However, when tested on their knowledge of the size limits, bag limits and closed seasons of their target species many shore fishers (59%) did not know them and a high proportion of fishers in all sectors had disobeyed at least one of the regulations (shore 50%, recreational ski-boat 70%, commercial ski-boat 56%). When compared to historical data the present catch per unit effort (CPUE) in all sectors has decreased. Most interviewees in the various sectors did not accept responsibility for the decline in CPUE, but attributed it to three principal reasons vis their perceived direct competitors, trawling and pollution. Analysis of the catch revealed that all sectors were multispecies fisheries, with each sector being characterised by a small number of target species. Catch composition differed significantly between the shore and ski-boat sectors, but there was significant overlap between the two skiboat sectors. Analysis of the catch in comparison to that reported to the National Marine Linefish System (NMLS) revealed that there was a substantial degree of under-reporting. There was little seasonal difference in effort in the shore fishery while the recreational ski-boat effort was highest in the summer and the commercial ski-boat effort was high in the winter. Effort in the shore and recreational ski-boat fisheries was concentrated over weekends while the commercial ski-boat effort was highest during weekdays. Total effort for the entire area was estimated at 903 186 (±1913) fisher days per annum in the shore fishery, 24 357 (±685) recreational ski-boat fisher days and 64 266 (±1686) commercial ski-boat fisher days. Expenditure and capital investment in the various sectors was calculated, as were earnings of the participants in the commercial ski-boat sector. The linefishery in the Eastern Cape was estimated to have a minimum capital investment in excess of R210 million and more than R32 million is spent annually on running costs. The commercial ski-boat fishery directly employed an estimated 3184 people. The economic implications of changes in CPUE for the commercial ski-boat fishery are considered, as are the benefits of a recreational angling licence. Management of the linefishery is discussed in relation to the findings of this study.

APA, Harvard, Vancouver, ISO, and other styles

8

Dicken, Matthew Laurence. "Population dynamics of the raggedtooth shark (Carcharias taurus) along the east coast of South Africa." Thesis, Connect to this title online, 2006. http://eprints.ru.ac.za/247/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Heeps, Carolyn. "Sediment circulation in mixed gravel and shingle bayhead beaches on the South East Dorset coast." Thesis, Bournemouth University, 1986. http://eprints.bournemouth.ac.uk/454/.

Full text

Abstract:

This thesis investigates and attempts to clarify the morphological characteristics, processes and sedimentology of five local mixed gravel and shingle beaches. A conceptual framework of process response has been adopted which considers energy inputs, sediment transport and coastal morphology, under conditions of limited sediment supply and a "closed cell" situation. Onshore field investigations using conventional methods of surface sediment sampling, together with beach profiling, platform and cliff measurements provided quantitative data with respect to contemporary sediment inputs, sediment characteristics and transport. Extensive and intensive measurements of beach sections described spatial and temporal morphological and volumetric change and revealed a neutral sediment budget at the scale of 12-14 months. The beaches are in equilibrium with prevailing and dominant south westerly wave regimes; prolonged periods of south easterly wave climates influence the foci of wave energy and cause significant littoral drift and exposure of the chalk platform. The offshore data used were derived from available sources and supplemented by fieldwork by the author. Investigations in the nearshore zone by side-scan sonar and echosounder revealed the morphological and sedimentological nature of the seafloor along the northern shore of Weymouth Bay. Sediment distribution and bedforms suggested preferred sediment transport paths. Within each bay sediment sampling by grab and/or divers elucidated the nature of each sediment cell. The distinct differences of textural composition and the presence of natural offshore barriers to sediment movement highlighted the sedimentological/morphological containment of each bayhead unit. Theoretical considerations and field data have helped to gain a better understanding of the relationship between cliff, beach, platform and nearshore processes and illustrate that selected embayments along the northern shore of Weymouth Bay are morphologically contained sediment cells sharing the same hydrodynamic system.

APA, Harvard, Vancouver, ISO, and other styles

10

Proudfoot, Lee-Anne. "Population structure, growth and recruitment of two exploited infralittoral molluscs (Haliotis midae and Turbo sarmaticus) along the south east coast, South Africa." Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1005430.

Full text

Abstract:

The two most frequently exploited species along the south east coast of South Africa are the gastropods, Haliotis midae (abalone) and Turbo sarmaticus (alikreukel). H. midae is a high valued commercial species, and suffers intense levels of illegal fishing. T. sarmaticus however, has no commercial value but is the preferred food item for impoverished subsistence communities. Owing to the fact that no legal commercial fishery exists for either species along the south coast, very few studies have been undertaken, especially in the heavily exploited infralittoral. Infralittoral size frequency distributions for both species revealed significant variation in density and size among sites of varying exploitation pressure. Densities ranged between 0 – 2.23 m⁻² (H. midae) and 0.03 – 4.93 m⁻² (T. sarmaticus) and maximum shell lengths ranged from 49.4 – 153.5 mm (H. midae) and 28.3 – 104.4 mm (T. sarmaticus). Relatively high densities and large sizes were found in marine reserves and secluded areas, and low densities and small sizes at sites near to large population centres and within the former Ciskei homeland region. Mean size of the largest 10% of the population, total density and sexually mature density were significantly related to exploitation predictors for both species. In addition, densities of H. midae juveniles were significantly related to exploitation predictors, suggesting that recruitment may be suppressed at the most exploited sites. Exploitation of T. sarmaticus tended to be localized with refuge and subtidal populations persisting. H. midae exploitation was however, far more extensive and intense. Growth of H. midae was investigated using three methods; mark-recapture, cohort analysis and growth banding analysis at Kowie Rocks, Port Alfred. The most useful of these methods for determining growth was a new technique described for growth banding analysis; which was validated using cohort analysis and measurements of shells of known age. This technique was less time consuming and labour intensive than previously described methods. Abalone growth was best described by the Schnute (1981) growth function. Systematic geographic variation in growth was observed for 10 sites along the South African coastline. Significant differences in growth among sites existed for animals between 0-4 years (P < 0.0001) and 4-6 years (P < 0.0001), and in the mean maximum sizes attained (P < 0.001). In general, abalone from the south east/east coast were found to have faster growth rates, smaller mean maximum sizes and attained sexual maturity earlier than those along the south west/ west coast. Haliotis midae recruit and juvenile densities were found to differ significantly among sites of varying exploitation pressure (P < 0.0001) and among months for recruit densities (P < 0.001). Exploited sites had low recruit and juvenile densities compared to unexploited sites and peak recruitment occurred during October/ November 2005. Recruit densities were significantly related to infralittoral adult densities during two of the three sampling months (P<0.05), when recruitment was low. No relationship was observed during the period of high recruitment, with all sites receiving high recruit densities. It was concluded that variation in recruit densities was the result of a combination of both density-dependent relationships (i.e. local spawner density and temporal variability in recruitment intensity) and the possible dispersal capabilities of H. midae. In addition, it was concluded that at present recruitment overfishing was not occurring along the south east coast. Post-recruitment mortality rates were variable but relatively constant, with hypothetical percentage survival and density curves revealing high rates and similar mortality curves among sites. Variation in juvenile densities was consequently a result of initial recruit densities and not variation in post-recruitment mortality. T. sarmaticus populations were found to be regionally sustainable and persisted along the south east coast due to adjacent intertidal and subtidal refuge populations. However, H. midae populations are becoming decimated along the south east coast. From the information obtained in this study new management proposals were suggested and discussed, such as closed areas and region-based management fisheries together with stock enhancement. These suggestions may prove to be feasible alternatives to present management strategies.

APA, Harvard, Vancouver, ISO, and other styles

11

Le, Roux F. G. "The lithostratigraphy of Cenozoic deposits along the south-east Cape coast as related to sea-level changes." Thesis, Stellenbosch : Stellenbosch University, 1989. http://hdl.handle.net/10019.1/67134.

Full text

Abstract:

Thesis (MSc)--University of Stellenbosch, 1989.
AFRIKAANSE OPSOMMING: Senosoiese sedimente langs die suidooskus van die Kaapprovinsie is periodiek deur verskeie outeurs vir meer as 'n eeu bestudeer. In hierdie aanbieding word die Iiteratuur saamgevat en vele dubbelsinnige stratigrafiese onderverdelings en definisies opgeklaar. Die Senosoiese afsettings kan volgens oorsprong geklassifiseer word as marien, eolies en fluviaal. Die mariene afsettings, synde strand-, nabystrand-, estuarien of lagunale afsettings geassosieerd met transgressiewe/ regressiewe kusIyne, word nou op grond van kenmerkende litologiese, paleontologiese sowel as ouderdomsverskille onderverdeel in die Paleogeen Bathurst, Neogeen Alexandria en Kwaternere Salnova Foraasies. Die Laat-Plioseen tot Vroeg-Pleistoseen Nanaga Formasie, Middel- tot Laat- Pleistoseen Nahoon Formasie en die Holoseen Schel• Hoek Formasie vorm die kus-eoliese afsettings. AI die mariene en marienverwante (eoliese} formasies, gekenmerk deur kalkige klastiese afsettings, is saamgegroepeer in 'n nuutgedefinieerde Algoa Groep. Fluviale afsettings word onderverdeel in die Martindale, Kinkelbos, Bluewater Bay, Kudus Kloof en Sunland Formasies. Die onderskeie afsettings word gekorreleer met verskillende seevlakstande deur geologiese tye. Die vroegste Senosoiese transgressiewe/regressiewe siklus het in die Vroeg-Paleoseen begin en die hoogste aangetekende elevasie vir die era bereik. Die Bathurst Formasie is waarskynlik gedurende hierdie regressie afgeset. 'n Tweed~ kleiner transgressie/ regressiesiklus het plaasgevind gedurende die Laat-Eoseen tot Vroeg-Oligoseen. Sover tans bekend, kan geen afsetting in die dagsoomgebied van die Algoa Groep definitief met hierdie siklus in verband gebring word nie. Die volgende siklus, wat 'n transgressiewe maksimum van c. 250 m bereik het, het begin in die Middel-Mioseen en verstryk in die Vroee Plioseen. Mariene planasie van die kusplatform het gedurende die transgressie plaasgevind terwyl die Alexandria Formasie wat tans bo 120 m geleë is, gedurende die regressie afgeset is. Die Vroeg-Plioseen transgressie het waarskynlik 'n maksimum huidige hoogte van c. 120 m bereik, waartydens o.a. die 120 m branderstoep en "Humansdorpterras" gekerf is. Die Alexandria Formasie tans geleë tussen 60 en 120 m, is afgeset gedurende die Laat-Plioseen regressie. Hierdie regressie het verskeie relatief lang stilstande, wat waarskynlik die 106-m, 90- tot 100-m en 84-m branderstoepe verklaar, ondervind. Selfs die 60-m en 52-m kuslyne kon tydens hierdie regressie gevorm het. Voorlopige paleontologiese getuienis dui egter daarop dat die 60-m kuslyn 'n transgressiewe maksimum van 'n daaropvolgende siklus verteenwoordig, gevolg deur 'n regressie met minstens een beduidende stilstand by 52 m. Die Alexandria Formasie geleë tussen c. 60 en 30 m, is waarskynlik gedurende hierdie regressie gedeponeer, waartydens ook die Bluewater Bay, Kinkelbos en Kudus Kloof Formasies afgeset is. Gedurende die Kwaternêre transgressie/regressiesiklusse, waarvan minstens vier aangedui word, is die Salnova Formasie (afwesig bo 30 m) afgeset. Die Nahoon Formasie, wat ook op groot skaal op die kontinentale bank ontwikkel is, is gedeponeer gedurende die laaste twee Pleistoseen glasiale toe seevlakke tot benede -100 m gedaal het. Die Schelm Hoek Formasie wat tans nog afgeset word, het ontstaan uit die transgressiewe maksimum van die Flandriese transgressie aan die begin van die Holoseen.
ENGLISH ABSTRACT: Cenozoic sediments along the south-east coast of the Cape Province have been studied intermittently for more than a century by various authors. In this presentation the literature is reviewed and many ambiguous stratigraphic subdivisions and definitions are clarified. The Cenozoic deposits can be classified, according to origin, as marine, aeolian and fluvial. The marine deposits, being lagoonal deposits either beach, nearshore, estuarine or associated with transgressive/regressive shorelines, are now subdivided on the grounds of distinct lithological, palaeontological as well as age differences into the Palaeogene Bathurst, Neogene Alexandria and Quaternary Salnova Formations. The Late Pliocene to Early Pleistocene Nanaga Formation, the Hiddle to Late Pleistocene Nahoon Formation and the Holocene Schelm Hoek Formation constitute the coastal and marine-related aeolian deposits. All the marine (aeolian) formations, which are characterised by calcareous clastics, have been grouped together in a newly defined Algoa Group. Fluvial deposits are subdivided into the Martindale, Kinkelbos, Bluewater Bay, Kudus Kloof and Sunland Formations. The various deposits are correlated with different stands of sea-level through geological time. The earliest Cenozoic transgression/regression cycle started in the Early Palaeocene and reached the highest recorded altitude for the era. The Bathurst Formation was probably deposited during this regression. A second lesser transgression/regression cycle occurred in the Late Eocene to Early Oligocene. As far as is presently known, no deposit in the outcrop area of the Algoa Group can be definitely related to this cycle. The next cycle, which reached a transgressive maximum of c. 250 m, started in the Middle Miocene and terminated in the Early Pliocene. Marine planation of the coastal platform took place during the transgression, whilst the Alexandria Formation presently situated above 120 m, was deposited during the regression. The Early Pliocene transgression is considered to have reached a maximum present-day elevation of c. 120 m, during which the 120 m marine bench and "Humansdorp Terrace", amongst others, were carved. The Alexandria Formation presently situated between 60 and 120 m, was deposited during the Late Pliocene regression, which experienced several relatively long stillstands which probably account for the 106 m, 90 t.o 100 m and 8.4 m benches. Even the 60 m- and 52 m-shorelines could have been formed during this regression. Preliminary palaeontological evidence, however, suggests that the 60 m shoreline represents a transgressive maximum of a subsequent cycle followed by a regression with at least one significant stillstand at 52 m. The Alexandria Formation situated between c. 60 and 30 m, was probably deposited during this regression, which also saw the deposition of the Bluewater Bay, Kinkelbos and Kudus Kloof Formations. During the Quaternary transgression/regression cycles, of which at least four are indicated, the Salnova Formation (absent above 30 m) was deposited. The Nahoon Formation, which is also extensively developed on the continental shelf, was deposited during the last two Pleistocene glacials, when sea-levels receded to less than -100 m. The Schelm Hoek Formation, which is still being deposited, originated from the transgressive maximum of the Flandrian transgression at the start of the Holocene.

APA, Harvard, Vancouver, ISO, and other styles

12

Foxwell-Norton, Kerrie-Ann, and na. "Communicating the Australian Coast: Communities, Cultures and Coastcare." Griffith University. School of Arts, 2007. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070814.094758.

Full text

Abstract:

In Australia, Integrated Coastal Zone Management (ICM) is the policy framework adopted by government to manage the coastal zone. Amongst other principles, ICM contains an explicit mandate to include local communities in the management of the coastal zone. In Australia, the Coastcare program emerged in response to international acceptance of the need to involve local communities in the management of the coastal zone. This dissertation is a critical cultural investigation of the Coastcare program to discover how the program and the coastal zone generally, is understood and negotiated by three volunteer groups in SE Queensland. There is a paucity of data surrounding the actual experiences of Coastcare volunteers. This dissertation begins to fill this gap in our knowledge of local community involvement in coastal management. My dissertation considers the culture of Coastcare and broadly, community participation initiatives. Coastcare participants, government policymakers, environmental scientists, etc bring to their encounter a specific way of seeing the coast a cultural framework which guides their actions, ideas and priorities for the coastal zone. These cultural frameworks are established and maintained in the context of unequal relations of power and knowledge. The discourses of environmental science and economics as evidenced in the chief ICM policy objective, Ecologically Sustainable Development (ESD) are powerful knowledges in the realm of community participation policy. This arrangement has serious consequences for what governments and experts can expect to achieve via community participation programs. In short, the quest for power-sharing with communities and meaningful participation is impeded by dominant scientific and economic cultures which act to marginalise and discredit the cultures of communities (and volunteers). Ironically enough, the lack of consideration of these deeper relations of power and knowledge means that the very groups (such as policymakers, environmental scientists, etc) who actively seek the participation of local communities, contribute disproportionately to the relative failure of community participation programs. At the very least, as those in a position of power, policymakers and associated experts do little to enhance communication with local communities. To this situation add confusion wrought by changes in the delivery of the Coastcare program and a lack of human and financial resources. From this perspective, the warm and fuzzy sentiment of Coastcare can be understood as the Coastcare of neglect. However, the emergence of community participation as legitimate in environmental policymaking indicates a fissure in the traditional power relations between communities and experts. Indeed the entry of community participation policy is relatively new territory for the environmental sciences. It is this fissure which I seek to explore and encourage via the application of a cultural studies framework which offers another way of seeing community participation in coastal and marine management and thereby, offers avenues to improve relations between communities and experts. My fieldwork reveals a fundamental mismatch between the cultural frameworks which communities bring to the coast and those frameworks embodied and implemented by the Coastcare program. Upon closer examination, it is apparent that the Coastcare program (and community participation programs generally) are designed to introduce local lay communities to environmental science knowledge. Local coastal cultures are relegated to the personal and private realm. An excellent example of this is the scientifically oriented eligible areas for funding of the Coastcare program. The volunteers consulted for this project emphasized their motivation in terms of maintaining the natural beauty of the coast and protecting a little bit of coast from the rampant development of the coastal zone. Their motivations were largely the antithesis of ESD. They understood their actions as thwarting the negative impacts of coastal development this occurred within a policy framework which accepted development as fait daccompli. Australias nation of coastal dwellers may not know a lot about coastal ecologies but they do know the coast in other ways. Community knowledge of the coast can be largely accounted for in the phrase, Australian beach culture. Serious consideration of Australian beach culture in environmental policy is absent. The lack of attention to this central tenet of the Australian way of life is because, as a concept and in practice, beach culture lacks the seriousness and objectivity of environmental science knowledge it is about play, hedonism, holidays, spirituality, emotion and fun. The stories (including Indigenous cultural heritage) which emerge when Australians are asked about their beach cultural knowledge historical and contemporary experiences of the Australian coast await meaningful consideration by those interested in communicating with Australian communities living on the coast. This cultural geography is an avenue for policymakers to better communicate and engage with Australian communities in their quest to increase participation in, or motivate interest in community coastal management programs.

APA, Harvard, Vancouver, ISO, and other styles

13

Nsingi, Joseph Mayala. "Foraminiferal Biostratigraphy and Depositional Environment of the Early Cretaceous Drilled Succession in Durban Basin, East Coast, South Africa." University of the Western Cape, 2020. http://hdl.handle.net/11394/7266.

Full text

Abstract:

>Magister Scientiae - MSc
Durban Basin located on the eastern coast of South Africa has been a focus of interest for Petroleum Exploration for the last few decades. Only four exploratory wells have been drilled in this offshore basin without success. During the initial stage of its creation, the basin suffered major tectonic disturbance as evident from the presence extensional faults followed by intense igneous activities. This was followed by marine sedimentation in the late Mesozoic (late Jurassic-early Cretaceous). An attempt has been made in this work to understand the distribution of the rock in space and time for the early Cretaceous sediments considered most prospective for hydrocarbon exploration in Southern Africa. Temporal distribution of planktonic foraminifera helps in identification of the three early Cretaceous (Barremian to Albian) stages within the drilled intervals. Foraminiferal biostratigraphic studies integrated with sedimentology, log motif analysis and seismic data analysis helps to predict paleodepth and depositional environment during early Cretaceous in this research. The integrated analysis reveals that during the Barremian-early Aptian stages graben filled sediments were deposited in a marine shelf in the northern part of the studied area (site Jc-D1) whereas, in the central and southern part finer clastics were deposited in middle slope (site Jc-B1 and Jc-C1). The thick claystone section and presence of minor limestone lenses and their benthic foraminifera assemblage in late Aptian-Albian stage in the northern area indicates possibility of submarine fan. Overlying succession dated between late Aptian to Albian and early part of Cenomanian interval in the three studied exploratory wells shows serrated log signatures. The dominant claystone lithology with intermittent siltstone/sandstone units and the benthic foraminifera indicates fluctuating distal marine slope environment with periodic shallowness in the entire area.

APA, Harvard, Vancouver, ISO, and other styles

14

Mketsu, Qayiso K. "Comparative dietary analysis of four small pelagic fish species from presumed mixed shoals off South Africa's east coast." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/6493.

Full text

Abstract:

Includes abstract.
Includes bibliographical references (leaves 59-65).
Stomach contents of sardine (Sardinops sagax), anchovy (Engraulis encrasicolus), west coast redeye (Etrameus whiteheadi) and east coast redeye (E. teres) were collected from presumed mixed shoals off South Africa's east coast. The stomach contents were analysed to 1) determine the diet composition of each species in terms of dietary carbon, 2) assess whether resource partitioning by prey type and/or prey size occurs amont the four species, 3) compare results with what is known about the diet of these species on the west and south coasts of South Africa and 4) characterize diet of east coast redeye.

APA, Harvard, Vancouver, ISO, and other styles

15

Mann, Bruce Quintin. "Aspects of the biology of two inshore sparid fishes (Diplodus sargus capensis and Diplodus cervinus hottentotus) off the south-east coast of South Africa." Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1005065.

Full text

Abstract:

The blacktail, Diplodus sargus capensis and the zebra, Diplodus cervinus hottentotus, sparid fishes endemic to South Africa, are important components of the recreational shore-fishery. To provide a basis for the management of these fish, aspects of the biology of both species were investigated in the Tsitsikamma National Park (TNP). In particular, the role of the TNP was evaluated as a management option for the conservation of both species. Examination of stomach contents showed that juveniles of both species fed predominantly on amphipods, polychaetes and harpacticoid copepods. Adult !h. sargus were omnivorous and fed opportunistically on a wide variety of reef associated invertebrates and algae including echinoids, polychaetes, anthozoans, ascidians and rhodophytes. The diet of adult D. cervinus was more specialized with a preference shown for polychaetes and amphipods. Seasonal differences were apparent in the diets of both species where considerably more amphipods were consumed in winter than in summer. Feeding requirements of both species were reflected in their habitat preferences. Visual underwater assessment revealed that both species were most abundant on turbulent inshore reefs (1-10m). !h. sargus were observed over a wide variety of reef associated habitats. In the literature they have also been recorded in the surf zone of sandy beaches and in the lower reaches of estuaries. !h. cervinus, on the other hand, were more specific in their habitat requirements and were observed in greatest abundance on inshore reefs, often in close association with caves or overhangs. A comparison between the relative abundance and size structure of both species in the TNP with that of an exploited area immediately adjacent to the reserve, showed no significant differences. This was attributed to the low level of exploitation by rock-and-surf anglers occurring in the exploited study area, as well as the possibility of seeding of eggs and larvae, or emigration of adults from the TNP. An investigation of the reproductive biology of both fish showed that !h. sargus had an extended summer spawning season while in !h. cervi nus it was more restricted. Detailed histological examination of gonadal development showed that !h. sarqus were dygynous with partial protandry occuring in the male population. ~ cervinus were shown to be rudimentary hermaphrodites. Size at 50% maturity in ~ sargus and ~ cervinus was determined at 225 and 285mm fork length respectively, corresponding to ages of 4 and 6 years. An age and growth study based on the examination of sectioned otoliths showed that both species were slow growing capable of reaching ages in excess of 20 years. Growth in ~ sargus and ~ cervinus was described by the von Bertalanffy growth equations: L(t) = 309.44(1-e-0 . 247[t+l. 048 l) and L(t) = 396.85(1-e-0.146[t+2.148J) respectively. Life history characteristics of D. sargus and D. cervinus including slow growth, late maturation and occupation of a localised, demersal habitat showed that both species were vulnerable to the effects of over-fishing. Due to the present increase in the number of participants and the decrease in catch per unit effort in the recreational shore-fishery, more stringent management recommendations were proposed to ensure the adequate protection of both species. These included an increased minimum size limit and a decreased bag limit for both species. Based on the residency shown by both species and their high relative abundance in the TNP, marine reserves were considered to be a valuable addition to the suite of management options available for the conservation of these species . In this respect the reserve provided both protection for the spawner stock as well as the potential to seed adjacent areas.

APA, Harvard, Vancouver, ISO, and other styles

16

Wood, A. D. (Aidan David). "A contribution towards the taxonomy of the ichthyoplankton species community and an understanding of its dynamics along the south-east coast of South Africa." Thesis, Rhodes University, 1999. http://hdl.handle.net/10962/d1006124.

Full text

Abstract:

This study was prompted by the need to remedy the situation that existed with respect to the poor status of our knowledge regarding the ichthyoplankton assemblage of the nearshore region along the south-east Cape coast of South Africa. The first chapter provides a brief introduction to the field of ichthyoplankton research and includes a summary of the status of research in southern Africa and an explanation of early life history terminology. The selection of all sample sites, times and strategies is also outlined. The study area along the south-east Cape coast with respect to its location, climate and physical oceanography is described in the second chapter, as is the gear used, bongo nets and an RMT1x6. A sampling protocol for the use of bongos from a small ski-boat, and the RMT from the research vessels, and for the handling and processing of samples was established. The selection of Middlebank as the main monthly sampling site within the Tsitsikamma National Park (TNP) was based on taxonomic diversity as well as logistical and safety constraints. The effect of mesh size and time of sampling with bongo nets on the catchability of ichthyoplankton was investigated in chapter three. Most data was accumulated during Sea Fisheries research cruises, with additional collections coming from the National Parks vessel. Although the differences were not significant, the 505 μ mesh nets captured larger larvae, with catches comprising higher percentages of flexion and postflexion larvae. Larval concentration and size were consistently greater in samples from periods of reduced light intensity, but significant differences were the exception. It was decided that sampling with 505 μ mesh nets during daylight would provide a representative sample of the available ichthyoplankton assemblage, while at the same time being the most practical and least time consuming with respect to handling, clogging and backflushing. In chapter four, the early life history stages of thiny of the seventy-five taxa sampled are described, reflecting the paucity of information which existed on the ichthyoplankton of the nearshore zone in the south-east Cape. These descriptions are seen as an important contribution towards any future research efforts in the region, but as many of these descriptions are based on few or single specimens, it is realised that the description of egg and larval stages will be an ongoing process. Based upon the data collected during this study, an ichthyoplankton species checklist was established in chapter five. Seventy-five taxa of fish larvae were identified to either family, genus or species level. A number of squid para-larvae were also encountered. Similarities and discrepancies with a previous survey in the region are presented. The temporal distribution of eggs and larvae between August 1993 and October 1996 was established, and the spatial distribution of ichthyoplankton along an offshore transect was determined between January 1995 and May 1996. Only 7 species from Middlebank and twelve from all stations combined displayed seasonal trends, with most of these being prevalent during winter months. Egg production, both over Middlebank and from all stations combined, appeared to be consistent, with no seasonal trends. Based upon the results from the offshore transect samples, it would appear that a single ichthyoplankton assemblage exists from Storms River out to fifteen nautical miles. Although a variety of statistical methods were applied to the data during this study, low egg and larval concentrations and a low sampling frequency meant that results had to be interpreted carefully. Chapter six describes the preliminary investigation into the vertical distribution of eggs and larvae. During two research cruises, discrete depth sampling using an RMT1x6 net was performed, with the majority of samples being accompanied by physical data provided by a CTD rosette sampler. No definite patterns could be seen as larval concentrations were low, and the short time scale did not allow for the identification of any diel migratory patterns. The relationship between total larvae and the physical environment was poor. The only possible relationship was that between plankton volume and total egg and total larval concentrations. The TNP may play an important role in the conservation of reef fish and the seeding of nearby fishing grounds through the export of pelagic eggs and larvae. Chapter seven describes a preliminary investigation into the dispersal potential of ichthyoplankton from the TNP. Based upon longshore currents determined from drogues, ADCP vectors and current meter readings, it was clear that if larvae were passive drifters, the potential for their dispersal from the TNP did exist. This pilot study showed that future work should concentrate not only on the oceanographic aspects, but on behavioural aspects of larvae which may enhance or retard dispersal. In the final discussion, it is emphasised that while this study went a long way to increasing our knowledge of the nearshore ichthyoplankton community, the true picture of the temporal and spatial dynamics of the species assemblage may only be revealed once more intensive sampling has been performed. The resolution of the early life history stages of the sparids and the identification of eggs to species level are seen as priorities for the near future. A complete species checklist for the TNP is provided based upon previous surveys (both on adult and larval fishes), this work and personal observations. A total of 171 species of fish from 70 families were identified, illustrating that the eggs and larvae of many species in the TNP have yet to be sampled. A brief description of the collaborative effort which is envisaged for the TNP over the next few years is provided.

APA, Harvard, Vancouver, ISO, and other styles

17

Smith-Goodwin, Jacqueline Anne. "A molecular genetic assessment of the population structure and variation in two inshore dolphin genera on the east coast of South Africa." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1004067.

Full text

Abstract:

Coastal dolphins on the South African east coast are threatened by degradation and loss of habitat as a result of increasing coastal development, industrial effluent and agricultural runoff. In addition, dolphins off the coast of KwaZulu-Natal have, for more than four decades, been heavily exploited through unchecked incidental capture in shark nets set at 45 beaches. In light of the high rate of mortality and apparent depletion of both species, the persistence of bottlenose (Tursiops truncatus) and humpback (Sousa chinensis) dolphins in that region has been questioned. Genetic variation in south east African dolphin populations was determined as a means of assessing the fitness of the populations and their resilience to demographic disturbances. Furthermore, in order to determine the effects of continued mortality on the KwaZulu-Natal subpopulations, it was necessary to determine whether they are open or closed to immigration from the adjacent East Cape region, which represents a relatively unstressed region, characterised by a lack of shark nets and less intensive coastal activities. Genetic variation and differentiation in the maternal genome was assessed by determining the sequence of the first 400 bases of the mtDNA control region in bottlenose and humpback dolphins from KwaZulu-Natal and the East Cape. Nuclear variation and differentiation was estimated at six microsatellite loci and compared with earlier estimates determined from allozyme electrophoresis. Random amplified polymorphic DNA (RAPD) was assessed as a means of identifying population subdivisions and diagnostic population markers. Both bottlenose and humpback dolphins on the South African east coast are characterised by low nuclear and organellar genetic variation, consistent with a possible genetic bottleneck, the inferred date of which coincides with the onset of the last glacial period. Genetic variation in South African bottlenose dolphins was lower than that reported elsewhere for the species, while an intraspecific comparison supported lower genetic variation in South African humpback dolphins than in humpback dolphins sampled off Hong Kong. An analysis of molecular variance (AMOVA), performed on mtDNA haplotype frequency data indicated, for both species, significant genetic subdivision, concordant with geographic location. The data suggested female bottlenose dolphins demonstrate regional philopatry, displaying limited movement between KwaZulu-Natal and the East Cape. Female humpback dolphins tend towards strict local philopatry, with significant maternal differentiation evident both within and between regional subdivisions. Differentiation in microsatellite allele frequencies was also demonstrated between KwaZulu-Natal and the East Cape for both species, suggesting that the movement of male bottlenose and humpback dolphins may also be restricted. Nonetheless, considerably higher nuclear gene flow estimates suggested that males of both species represent the principal vectors of gene dispersal. The implications of historically low genetic variability and population subdivision in South African dolphins are important in view of the current rate of mortality in KwaZulu-Natal. The persistence of coastal dolphin populations relies on their ability to recover following a bottleneck event. Continued removal of demographically important age-sex classes such as occurs in shark nets, may not only further reduce the genetic variation, but would ultimately deplete dolphin populations in KwaZulu-Natal beyond a sustainable number, resulting in eventual local extinction. The differentiation of the two regions implies that, in the event of local extinction occurring, dolphins, particularly females, from adjacent regions will not readily re-colonise the area. This would result in fragmentation of the south east African populations and ensure reproductive isolation from neighbouring populations on the east African coast.

APA, Harvard, Vancouver, ISO, and other styles

18

Bishop, Amy Ruth. "Age, growth, reproduction and sexual dimorphism of the striped dolphin, Stenella coeruleoalba, off the south-east coast of southern Africa." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1011600.

Full text

Abstract:

The striped dolphin, Stenella coeruleoalba, is an oceanic dolphin found worldwide in tropical to warm temperate waters. Globally populations are threatened through direct fishing, bycatch and pollution. Little is known about the life history of this species in South African waters and it is currently listed as ‘Data Deficient’ by the International Union for Conservation of Nature (IUCN). Critical to the conservation and management of this species is an understanding of basic life history parameters. For the present study, metadata and tissues from 101 stranded S. coeruleoalba along the south-east coast of southern Africa between 1969 and 2012 were analyzed to examine age and growth, male and female reproduction and sexual dimorphism. Age and growth were determined by counting the number of growth layer groups (GLG’s) present in their teeth. A von Bertalanffy growth curve gave the best fit to the data and indicated that physical maturity was reached around 21 years in males and 18 years in females. Additionally, asymptotic lengths were reached at 231cm and 224cm in males and females, respectively. The maximum ages obtained were 21 years for males and 20 years for females. Length at birth was estimated to be between 116cm and 119cm for males and between 112cm and 114cm for females. The reproductive status of the adult dolphins was assessed by histological and macroscopic analyses of gonadal tissue. Sexual maturity was attained before physical maturity in both sexes. The males reached sexual maturity between 8 and 12 years of age and between 209 and 224cm in total body length. The maximum combined testis weight comprised about 0.24% of the total body weight and sexual maturity was reached between a combined testis weight of 16 and 41g, a mean testis length of 8 and 10cm, and a mean seminiferous tubule diameter of 44 and 70μm. Females attained sexual maturity between 7 and 8 years of age and between 213 and 216 cm in total body length. The ovulation rate was 0.32 per year and the majority of ovulations occurred in the left ovary, with ovulations occurring in the right ovary only in individuals older than 10 years of age. The annual pregnancy rate was calculated to be 26%. Reproductive seasonality could not be established due to the small sample size and the absence of samples throughout the year. However, both conceptions and births appear to occur in both August and December/January. Additionally, testis weight and seminiferous tubule diameters appear to fluctuate throughout the year, which could suggest reproductive seasonality in this species. Sexual size dimorphism in mature adults was evident for a number of external measurements, however, sexual shape dimorphism was not present in this species. Mature males had significantly longer and wider pectoral fins, dorsal fins and flukes than females (p<0.05 in all cases). It was suggested that the larger appendages are required for male on male combat during intraspecific competition for females. Additionally, larger appendages aid in thermoregulation, propulsion and maneuverability. Females had a significantly greater distance between the tip upper jaw and the genital aperture and anus, which was expected due to differences in anatomy between male and female genital openings. Overall, S. coeruleoalba did not exhibit distinct sexual dimorphism and together with the relatively small testes in relation to the total body weight (0.24%) it was proposed that this species demonstrates a less extreme form of polygyny. Additionaly, the results of this study are important to the understanding of the basic biology of the species.

APA, Harvard, Vancouver, ISO, and other styles

19

Mathagu, Tendamudzimu Titus. "Effects of small-scale water movement on the settlement and growth rates of the brown mussel Perna perna, on the south-east coast of South Africa." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1005368.

Full text

Abstract:

The effects of small scale (cm) water movement on the settlement and growth rates of the brown mussel Perna perna were investigated on the south-east coast of South Africa (33°28′S, 27°10′E). L-shaped metal baffles attached to the substratum decreased the erosion rates of cement balls and it was concluded that the baffles decreased the water flow rate around cement balls. These L-shaped baffles were then used to decrease water flow rates around mussel patches and pot-scouring pads used as artificial substrata for the settlement of P.perna larvae. Anova indicated that settlement rate varied by date and site while decreased water flow rate significantly increased larval settlement (p<0.05), only on the site and day that had the overall highest number of settlers. Mussels in the low zone had significantly higher growth rates than those in the high zone. Decreased water flow rate significantly increased mussel growth rate in the lower zone (Anova, p<0.05), while it did not have a significant effect on the mussel in the high zone. Thus water flow manipulation increased growth rates in the zone, which already had high growth rate. It was concluded that small-scale (cm) water flow patterns have an effect on both Perna perna settlement and growth rates, but only under specific conditions. Larval settlement rate was significantly increased by water flow manipulation on the site and day that had the highest number of settlers. Growth rates were significantly increased by decreased water flow rate only in the low zone, where growth rates are the highest. Although water flow was manipulated in both zones its effect in the high zone was insignificant (Anova) compared to other factors affecting growth rates at this tidal level.

APA, Harvard, Vancouver, ISO, and other styles

20

Tilney, Robin Lewis. "Aspects of the biology, ecology and population dynamics of Galeichthys feliceps (Valenciennes) and G. ater (Castelnau) (Pisces: Ariidae) off the south-east coast of South Africa." Thesis, Rhodes University, 1991. http://hdl.handle.net/10962/d1005064.

Full text

Abstract:

This thesis represents a detailed investigation into aspects of the biology, ecology and population dynamics of two endemic ariid species, Galeichthys feliceps and G. ater, off the southeast coast of South Africa. The two species are exploited as a by-catch in the commercial ski-boat fishery off Port Alfred, a fishery dominated by highly fecund sparid and sciaenid species. They collectively constitute approximately 10% of the total annual catch in terms of landed mass G. feliceps outnumber G. ater in the catches by a ratio of 3:1. The investigation was designed to provide the biological data required for stock assessment and to determine optimum management strategies for the two populations. The implications of their K-selected life-history styles for exploitation received particular attention. While the two species were sympatric and had similar depth distributions they were found to be allopatric with respect to their foraging habitats. G. feliceps foraged over sandy and muddy substrata in marine and estuarine environments. G. ater fed only on reef-associated species and did not utilise estuaries. Their feeding-associated morphologies were identical and both species preyed primarily on crustaceans (brachyuran crabs and isopods), echiurids, molluscs and polychaetes. The diet of G. ater was broader in terms of the number of species consumed. The two species are mouth-brooders with low fecundity. G. feliceps and G. ater produced a mean of 49 and 32 eggs each, per annum. The buccal incubation period was determined to be in the region of 140 days for G. feliceps. Embryos hatched after approximately 75-80 days and the young began exogenous feeding thereafter. The young fed intra-buccally on detritus provided by the parent. Adult buccal mucus may also have been used as a food source. Young were released at a total length of ± 55mm. Adult males ceased feeding whilst mouth-brooding. Body musculature, abdominal fat and liver reserves provided energy for basal metabolism and males lost approximately 28% of their body mass during buccal incubation. Females expended less reproductive energy than males. Catches were dominated by mature fish (76% in G. feliceps and 97% in G. ater). Females were significantly more abundant in catches during the spawning and mouth-brooding period. The female to male sex ratios were 1.65:1 and 2.23:1 for G. feliceps and G. ater respectively. Age and growth studies revealed that the two species mature at advanced ages (10 and 9 years for G. feliceps and 9 and 7 years for G. ater males and females respectively). They are long-lived, reaching ages in excess of 18 years in G. feliceps and in excess of 15 years in G. ater. Females live longer than males and grow larger. Yield-per-recruit and spawner biomass-per-recruit analyses demonstrated that G. ater were exploited below FO.1 at a level where spawner biomass-per-recruit was reduced to between 45% and 65% of the unexploited level. The G. ater stock was not adversely affected by current levels of fishing effort. For G. feliceps, both sexes were exploited beyond F₀.₁ where spawner biomass-per-recruit was reduced to between 30% and 22% of the unexploited level. G. feliceps were shown to be sensitive to relatively low levels of exploitation, a phenomenon attributed to their highly Kselected life-history style. Should the species become targeted for in the future, effort restrictions in the form of a closed season during the spawning and mouth-brooding period would prove effective in reducing effort and conserving the population sex ratio.

APA, Harvard, Vancouver, ISO, and other styles

21

Duba, Tania. "Climate and environmental change along the East Coast of South Africa: perspectives from a local marine resource- dependent community and scientific researchers." Master's thesis, Faculty of Science, 2019. http://hdl.handle.net/11427/31358.

Full text

Abstract:

Coastal areas are very susceptible to environmental problems such as sea-level rise, coastal flooding, increased frequency and intensity of extreme events, and changes in marine ecosystems that are arising from global climate change and variability. In the South African context, the Agulhas Current is important for its crucial role in regional climate and weather as well as the fishing livelihood of the coastal communities along the east coast of South Africa. Despite the efforts made to understand the Agulhas Current and the impacts of climate and environmental change, the shelf region remains poorly understood mostly due to the difficulties associated with observing and modelling such strong currents. The marine resource users in the fishing communities along the east coast of South Africa show long term dependence on the neighbouring ocean going back at least three generations. These communities provide long term, rich, detailed, and contextualized environmental knowledge from their daily interactions with the sea. This study seeks to investigate the local climate and environmental change knowledge of the fishers based on their own observations, perceptions, and experiences. The convergence/divergence of the marine resource user’s knowledge with the traditional scientific findings is explored using a broad, participatory methodology including desktop literature analysis, interviews and an adopted version of the Rapid Vulnerability Assessment (RVA). Results show that fishers in Tshani-Mankosi have observed changes in the rainfall, sea surface temperature and wind patterns in their community. According to the fishers, sea surface temperature and annual rainfall seem to have decreased while winds and rainfall related extreme events have increased. Similar observations were noticed in the scientific research at a larger spatial and temporal scale. Key differences and similarities between the two types of knowledge come from factors such as knowledge construction processes, scales, type of data output and parameters of interest. Finally, the study reveals opportunities and challenges of research collaboration between the community and scientific researchers.

APA, Harvard, Vancouver, ISO, and other styles

22

Vorsatz, Lyle Dennis. "Observations on the biology and seasonal variation in feeding of the East Coast redeye round herring (Etrumeus wongratanai) (Clupeiformes), off Scottburgh, KwaZulu-Natal, South Africa." University of the Western Cape, 2016. http://hdl.handle.net/11394/5545.

Full text

Abstract:

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol)
The basic biology and ecology of Etrumeus wongratanai was investigated from samples of fish collected by jigging off Scottburgh, Kwazulu-Natal throughout 2014 and 2015. A total of 516 otoliths, 401 gonads, 140 stomachs and 163 samples of white muscle tissue was examined, and length and weight data of 3 637 fish caught between 2013 and 2016 was also analysed. Counts of annuli deposited on sagittal otoliths indicate that sampled E. wongratanai ranged from 0 to 3 y. (year/s) of age. Length-at-age for males (females) was estimated at 15.5 cm (16.2 cm) for 1 y. olds, 17.7 cm (17.4 cm) for 2 y. olds and 19.6 cm (18.8 cm) for 3 y. olds. The length at 50% maturity was estimated to be 15.6 cm for males, and 16.1 cm for females. Etrumeus wongratanai showed high gonadosomatic index values from June to December indicating that the breeding season lasts for 6 and 8 months for males and females, respectively, and that spawning takes place from the onset of winter to early summer. Condition factor was lowest in May through to August and increased from September. The low condition factor values from May through to August could be due to the physiological strain before and during the spawning season. Fish larvae were the most important food item in samples collected in summer, whereas eucalanids were the most important prey item in autumn and winter. Overall, large copepods were the dominant prey items in terms of frequency and importance. Stable isotope data suggests that there are gradual changes in the trophic level and diet of E. wongratanai as it increases with size, and whilst δ¹⁵N values differed between seasons δ¹³C did not. The results obtained here are compared with other species of Etrumeus, regionally and globally.
National Research Foundation (NRF) and ACEP Phulisa

APA, Harvard, Vancouver, ISO, and other styles

23

Ott, Theresia. "The response of biological communities to spatial and temporal changes in a regenerating coastal dune forest along the north-east coast of South Africa." Thesis, University of Pretoria, 2013. http://hdl.handle.net/2263/26029.

Full text

Abstract:

Ecological restoration that aims to reinstate indigenous processes may be constrained by regional and local conditions, especially those that drive dispersal and colonisation. Local conditions can be managed, while regional conditions cannot. The management of costly rehabilitation programmes is considered best practice when scientifically informed. My thesis documents the responses of biological communities to a range of local conditions developing in coastal dune habitats in response to ecological restoration. Here, landscape-level (spatial structure of patches of tree canopies) local conditions were distinguished from site-level (topography, soil nutrient content, woody plant community richness, microclimatic variables) local conditions. The spatial structure of tree canopies varied over time and differed between the mining lease site and the relatively undisturbed benchmark site prior to (1937- 1970), and after (1990-2006) mining. For example, approximately 20% of the mining lease site and 40% of the benchmark site was covered by tree canopies prior to mining. However, after mining and rehabilitation, the structure of tree canopies began to converge towards that of the benchmark. The topographic profile of coastal dunes was less heterogeneous after mining and rehabilitation than before. Aspect, elevation and gradient of dune slopes were also different and had shifted in space. Variability in the structure of tree canopies could not explain variability in species richness, forest-associated species richness and proportion of benchmark species for the millipede, dung beetle and bird communities ashad been expected. However, species composition did change (though idiosyncratically) with age-related changes in soil nutrient availability and tree species diversity. Temperature, relative humidity and light intensity varied with dune topography, but soil nutrient content (C: N ratio and pH) was better accounted for by the age of the regenerating forest than by dune topography. Similarly, analysis of covariance suggested that tree canopy density, woody plant richness and millipede species richness only responded to the aspect, elevation and gradient of restored coastal dunes when age was taken into account as a covariate. However, the response of keeled millipedes to dune topography, regardless of regeneration age, suggested that the microclimatic variability brought about by topographic heterogeneity may provide these specialists with suitable microhabitats. Throughout my thesis, the age of regenerating patches of indigenous canopies was often more important as an explanatory variable than habitat conditions per se. Age itself is not a determinant of biological communities, but merely the axis along which habitat conditions change with succession, and later, patch dynamics. Therefore, as elsewhere, my thesis has highlighted age as a useful proxy for the response of biological communities to local conditions. It seems that managing local variables such as those considered in my assessment is not an avenue through which to enhance restoration. After kick-starting initial conditions, best practice rehabilitation management should therefore focus on minimizing external disturbances rather than interfering with natural processes.
Thesis (PhD)--University of Pretoria, 2013.
Zoology and Entomology
unrestricted

APA, Harvard, Vancouver, ISO, and other styles

24

Thompson, Bronwen Eleanor. "Occurrence of Theileria parva infection in cattle on a farm in KwaZulu-Natal, South Africa." Diss., Electronic thesis, 2007. http://upetd.up.ac.za/thesis/available/etd-11012007-133653/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Burns, Michael Edmund Reid. "A synecological study of the East London coast dune forests." Thesis, Rhodes University, 1987. http://hdl.handle.net/10962/d1006134.

Full text

Abstract:

Quantitative community descriptions, based on point quarter sample data, are made for a number of dune forest units along the East London coast. These are supported by multivariate classifications and ordinations which illustrate the inter community variation between the sampled seaward, landward and dune valley sites. Climax valley forest is floristically most characteristic and can be clearly distinguished from the seaward and landward thicket communities which tend to show a degree of similarity. Within-forest community differences are shown to be more significant than variation along the coast. This appears to indicate that climoedaphic gradients established laterally to the coast induce a greater floristic response than the rainfall gradient within the study area. The state of developnent within the dune soil profile and the rate and effect of salt spray deposition are considered to be important factors influencing dune forest succession and are discussed in some detail. An overview of certain other climatic variables as well as the geological features within the study area is also given. A phenology study of the dune forest, scrub-thicket and strand plant cornnunities shows some general patterns of flowering and fruiting phenorhythms. Although much variation was observed, there appears to be a bimodal hyperactive phenophase response which is thought to be related to rainfall or periods of favourable soil moisture conditions. A brief discussion of some of the positive and negative human influences on the coastline is given. This includes a description of the management activities carried out in the area as well as the demands placed on ·the coastal resource.

APA, Harvard, Vancouver, ISO, and other styles

26

MacHutchon, Keith Robert. "An introduction to multifractal geometry of wave sea states on the west and south-east coasts of South Africa." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96920.

Full text

Abstract:

Thesis (PhD)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: All of the Ports along the South African coastline are subject to bound infragravity wave action to a greater or lesser degree, for example, at the Ports of Saldanha Bay on the west coast and Ngqura on the south-east coast. Saldanha Bay harbour principally services loose- and liquid-bulk carriers and the Ngqura harbour mainly services container ships. The long wave actions when severe cause moorings to be broken, ships to leave the quay and loading to stop. This research has confirmed that the sea surface is a multifractal structure characterised by many singularities ranging from highly irregular or rough features to smooth or calm features. Any wave train is comprised of the full range of these features to various degrees and in varying percentages of occupancy. Notwithstanding this problem, relatively little is known about them in the South African context due to the fact that they cannot be visually detected and specialised, sophisticated equipment is required to physically measure them. The country is currently planning the development of a new port and the expansion of others for larger ships. Under these circumstances this research is seen to be appropriate from the point of view of obtaining a new method for the characterisation of these hazardous wave conditions. The objective of the research was achieved. This was to identify a set of fractal dimensions that describe the surface geometry of a hazardous bound infragravity wave sea state. In order to achieve the objective, a set of fractal dimensions was firstly determined from video imagery of an open water wave field, by analysing a set of single point time series data derived from the imagery. This has been done in order to be able to visually compare the derived set of fractal dimensions with video imagery of the sea surface that they represent. It also has the advantage of proving that fractal methods of analysis are applicable for the study of sea surface single point time series data. Secondly, periods when long wave action occurs at both Saldanha Bay and Ngqura harbours were identified by the presence of their actions in the harbours. Thirdly, single point time series data recorded by the Council for Scientific and Industrial Research (CSIR) were obtained during the identified periods as well as two days before these times and fractal sets of dimensions for the periods were determined. This was achieved by means of the following methods of analysis: ● The rescaled range (R/S) method, ● The Multifractal Detrended Fluctuation Analysis (MDFA) method, ● The Power Spectral Density (PSD) method in both the Fourier and the wavelet domains, and ● The Wavelet Transform method. Fourthly, the fractal data sets from each harbour were compared to confirm that the sets of dimensions for the hazardous sea state are clearly different from those of the non-hazardous sea state and can be used to describe the condition. Finally, the fractal sets of dimensions for hazardous sea states at both harbours were compared to identify any variances between them. During the research it was found that a hazardous sea state could be profiled for identification purposes and for complementing the currently determined significant wave height and peak period details by means of fractal indices. These indices were identified by comparison with a similar set of indices for nonhazardous sea states at the same location, as part of a ‘calibration’ process and clearly identified shifts in the Holder exponents of the sea states enabled the unambiguous identification of the hazardous condition. Having completed the research and analysis work, the author has identified other areas of coastal engineering, besides the identification of hazardous bound infragravity wave sea states, where a study of multifractal geometry could be applied advantageously.
AFRIKAANSE OPSOMMING: Alle hawens langs Suid Afrika se kuslyn is tot ‘n meerdere of mindere mate onderworpe aan gebonde infragravitasie golf aksie. Hierdie probleem is egter veral straf by die hawens van Saldanhabaai aan die weskus en Ngqura, aan die suidooskus. Saldanhabaai voorsien dienste hoofsaaklik aan massa draers van los stowwe en vloeistof, terwyl Ngqura hoofsaaklik houerskepe bedien. Die lang golf aksies veroorsaak dat ankertoue breek en die skepe die kaai verlaat, sodat laai van die skepe tot stilstand kom. In die loop van hierdie navorsing is gevind dat die seevlak ‘n multifraktale struktuur is, met singulariteitseienskappe wat wissel van hoogs onreëlmatig of rowwe eienskappe tot gladde, reëlmatige eienskappe. Enige golfreeks behels die volle omvang van hierdie eienskappe in verskillende grade en wisselende teenwoordigheids persentasies. Die navorsing is gefokus op die geometrie van gebonde infragravitasie golfaksie seetoestande, wat oral langs die Suid Afrikaanse kuslyn voorkom, en in twee hawens ‘n beduidende bedreiging vir vasgemaakte skepe is. Ondanks die probleem, is min bekend oor hierdie toestande in Suid Afrikaanse konteks, omdat hulle nie visueel bespeur kan word nie en spesiale gesofistikeerde gereedskap nodig is om hulle fisies te kan meet. Daar word tans beplan om ‘n nuwe hawe te ontwikkel, wat hierdie navorsing veral gepas maak, met die doel om ‘n meer volledige beskrywing van hierdie bedreigende golftoestande te weeg te bring. Die doel van die navorsing is om ‘n stel fraktale dimensies te identifiseer wat die oppervlakgeometrie van ‘n bedreigende gebonde infragravitasie golf-seetoestand omskryf. Hierdie dimensies kan dan gebruik word om ‘n indentifiserende profiel van die seetoestand te teken om die inligting tans beskikbaar oor beduidende golfhoogte en piektye, aan te vul. Om hierdie doel te bereik is ‘n stel fraktale dimensies eerstens bepaal deur middel van videobeelding van ‘n oopwater golfveld. ‘n Stel enkelpunt tydserie data, afgelei van die beelding, word dan ge-analiseer. Dit het visuele vergelyking tussen die afgeleide stel fraktale dimensies en die videobeelding van die seevlak wat dit verteenwoordig het, moontlik gemaak. ‘n Verdere voordeel is dat dit bewys het dat fraktale analisemetodes toepaslik is vir die bestudering van seevlak enkelpunt tydreeks data. Tweedens is die tye wanneer lang golfaksie teenwoordig was in die hawens by Saldanha en Ngqura, vasgestel deur die uitwerking daarvan in die hawens. Derdens is enkelpunt tydreeks data wat deur die WNNR aangeteken is vir die vasgestelde tydperke, sowel as twee dae voor elke tydperk, verkry en is fraktale dimensiestelle vir elke tydperk vasgestel. Vierdens is die fraktale datastelle van albei die hawens vergelyk om te bevestig dat die stelle dimensies vir bedreigende seetoestande duidelik verskil van die vir niebedreigende toestande, en dus geskik is om die seetoestand te beskryf. Ten slotte is die fraktale dimensiestelle vir bedreigende seetoestande in die twee hawens vergelyk om enige verskille tussen hulle te bepaal. Na voltooiing van die navorsing en analise is ander gebiede van kusingenieurswese behalwe die bepaling van bedreigende gebonde infragravitasie golf seetoestande, identifiseer waar multifraktale geometrie ook tot voordeel aangewend kan word.

APA, Harvard, Vancouver, ISO, and other styles

27

Kemp, J. O. G. "Mariculture as a means to add value to the east coast rock lobster Panulirus homarus rubellus subsistence fishery : a physiological approach to define transport and growout protocols for wild caught juveniles." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005144.

Full text

Abstract:

In a context of declining capture fisheries and public pressure for greater access to marine resources, marine aquaculture is receiving increasing interest from the South African government as a means to increase the diversity of economic activities in coastal regions, thereby providing employment and reducing poverty. The east coast rock lobster Panulirus homarus rubellus is currently harvested by subsistence fisherman along the former Transkei coastline of south-east South Africa and presents a possible opportunity for ongrowing wild juvenile lobsters in culture facilities. Lack of compliance coupled with poor enforcement of the minimum size limit (65 mm carapace length) has resulted in the ongoing harvest of undersize size lobsters by subsistence fishers. Generally, fishers either consume these undersize lobsters or sell them to tourists for low prices. In line with international trends in rock lobster aquaculture, interest has subsequently arisen in the possibilities of ongrowing these undersize lobsters as a means of adding value to the P. h rubellus resource for subsistence fishers. The aim of this physiological study was to assess the biological feasibility of harvesting, transporting and culturing wild caught juvenile lobsters, thereby provide empirical data to inform the development of suitable transport and culture protocols. The experimental objectives were to asses the effect of temperature on growth and survival of P. h. rubellus, as well as the effects of a suite of extrinsic and intrinsic factors on ammonia excretion and oxygen consumption. Juvenile lobsters were collected by hand from near-shore reefs (2-15 m depth) off Mdumbi in the former Transkei, Eastern Cape Province and transported by road (7 hours) to the Port Alfred Marine Research Laboratory where they were held in a recirculating culture system. The effect of temperature over a range of 9.7 °C (18.9±0.7 to 28.6±1.5 °C) on the growth and survival of juvenile P. h. rubellus fed a diet of fresh mussel flesh was investigated. Specific growth rate (SGR) was significantly different between temperatures (p = 0.01), with the highest values recorded for the 24 °C and 28 °C treatments. There was no significant difference in moult increment (MI) between temperatures, however, intermoult period (IMP) differed significantly between temperatures (p = 0.0015) with mean IMP lowest at 24 °C, although not significantly different from the means of the 26 °C and 28 °C treatments. IMP was highest at 19 °C and 21 °C. Apparent feed intake was significantly different between treatments (p < 0.0001) and exhibited a strong positive correlation with increasing temperature. Food conversion ratio (FCR) differed significantly between temperatures (p = 0.02) with 24 °C exhibiting the most efficient FCR. The results for growth rate and food conversion efficiency suggested that 24 °C is optimal for the growout of juvenile P. h. rubellus. In the second study, the effect of body weight, emersion, daily rhythm, feeding and ambient ammonia on the total ammonia nitrogen (TAN) excretion rate was investigated. Body weight (n = 16, range of 16.8 – 322 g) was positively correlated to daytime TAN excretion rate (mg h⁻¹). Re-immersion after one hour emersion in a moist environment was characterized by a significant increase in TAN excretion rate for the first hour compared to pre-immersion levels. The amount of TAN excreted during this period was as expected if basal TAN excretion rates were maintained during emersion. TAN excretion rates returned to pre-emersion levels by the end of the second hour. There was no evidence of a daily rhythm in TAN excretion rate for P. h. rubellus. TAN excretion rates were elevated following feeding. An initial peak in TAN excretion rate after seven hours (7.58 times pre-feeding rate) was followed by a smaller peak after 13 hours (6.69 times pre-feeding rate). TAN excretion rate dropped to levels not significantly different from pre-feeding levels after 23 hours and consistently returned to pre-feeding levels after 42 hours. The TAN excretion rates of lobster exposed for two hours to an ambient TAN concentration of 1.02±0.10 mg l⁻¹ and 2.3± 0.2 mg l⁻¹ were not significantly different from TAN excretion rates recorded at low ambient water TAN prior to exposure. Exposure to an ambient TAN concentration of 4.45±0.78 mg l⁻¹ had a significant effect on the TAN excretion rate, with pronounced ammonia uptake occurring for all animals at this concentration. The third study investigated the effects of body weight, diurnal rhythm, feeding and emersion on lobster oxygen consumption. Body weight was positively correlated to both standard and active oxygen consumption (mg O2 h⁻¹) while body weight was negatively correlated to mass-specific standard oxygen uptake (mg O2 g⁻¹ h⁻¹). Diurnal rhythm exhibited a strong effect on the lobsters oxygen consumption, with average night time values 67% greater than those recorded during the day. This was related to activity driven by intrinsic nocturnal foraging behaviour. Feeding resulted in a classic specific dynamic action (SDA) response, with postprandial oxygen consumption increasing to a peak before decreasing gradually to preprandial levels. Emersion resulted in a significant increase in oxygen consumption, with lobsters rapidly recovering to pre-emersion levels after four hours. Results from these studies suggest that the capture, transport and culture of juvenile P. h. rubellus is biologically feasible. Empirical data generated were used to provide recommendations regarding species optimised transport and culture protocols. A purge time of 48 hours before transport is suggested to ensure that ammonia excretion and oxygen consumption are at basal levels. Furthermore, emersed transport for a period of one hour is characterised by rapid recovery upon re-immersion. In order to prevent the accumulation of stressors, it is suggested that consecutive periods of emersion are interjected with recovery periods (five hours) in water to allow the removal of accumulated ammonia and repayment of the oxygen debt incurred. The recorded ammonia rates indicate that a biological filter size of 4.8 m³ is recommended for 1000 kg of fed lobsters in a culture situation, although this can be reduced considerably if lobsters are being held without feeding (0.72 m³). A flow rate of 112 l kg⁻¹ h⁻¹ is required to meet the metabolic requirements of lobsters. Bottlenecks to the viable commercial culture of P. h. rubellus, and the ability of this practice to provide the socio-economic benefits that were envisioned, are discussed.

APA, Harvard, Vancouver, ISO, and other styles

28

Choi, Young Rae. "Social coasts: Green growth, transformation of coastal space, and sea governance of East Asia." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440422456.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Nel, Johannes Hendrik. "An investigation of mine closure : gold mine case studies on the East Rand in South Africa / J.H. Nel." Thesis, North-West University, 2008. http://hdl.handle.net/10394/4088.

Full text

Abstract:

This research is on mines that struggle to obtain closure from the state departments. The closure process at the footprints of five Tailings Storage Facilities (TSFs) of a South African gold mine was investigated. They are situated in the Germiston, Brakpan, Springs and Nigel suburbs of the East Rand region of Johannesburg. Very limited scientific research has been done in South Africa on the management of mine closure. The most recent performed research was completed at Coal mines and only one was at an underground gold mine. The history of the case studies at a surface gold mine revealed similar problems, as confirmed in previous research, during the interviews with mine management and the review of operational documents. There is a whole array of causes giving rise to the struggle to obtain closure by a mine, that will be subsequently discussed. Major causes are the lack of estimation of closure costs and the lack of a proper Project Life Cycle (PLC) process for closure by mine management. Previous investigations indicated a general shortfall in estimated closure costs, mining operations that are not planned with closure in mind, closure objectives that are not set at all management levels, final land use after mine closure that is not defined properly, residual and latent impacts that are not dealt with, the post-closure period when the final impact will occur that is not defined and a proper risk assessment based on detailed information that is not properly done and communicated. Another cause is that the integrated process of making closure part of the Environmental Management Programme Report (EMPR) process is not followed. The result of not following the correct process is that mines do not obtain closure. Another reason why mines do not obtain closure is because of an underdeveloped mine infrastructure, e.g. tailings facilities, waste rock dumps, shafts and plants that are not constructed in an environmentally friendly way during the operational phases to facilitate closure. Therefore, these structures need to be changed in terms of their topography and growth medium to ensure an improvement in environmental parameters. This will assist in obtaining sustainability and final closure. Significantly more trust fund money than initially estimated during operations needs to be spent to ensure the above change. Specific issues defined from the case studies were the adaptation of the administration of the closure process, the management of risks, especially the differences in opinions, the management of the mine life cycle for closure and involvement of the land owners and Interested and Affected Parties (l&APs). This research was necessary because companies are uncertain and lack the competency to estimate and to correctly spend trust fund money in order to be sure of obtaining closure. This situation threatens the long-term survival of mining-companies by holding assets and profits back until closure is attained. The state departments also have to address the risks and have to rehabilitate the polluted mine sites if companies do not obtain closure. A proper PLC to facilitate closure was compiled from the above-mentioned data. An important fact to bear in mind is that the activities within the life cycle depend on one another. Therefore, when one activity is disregarded or not properly performed, it will influence the outcome of the remaining activities. The methodology of the research was as follows: Categories to evaluate the closure process of the selected case studies were determined from the project life cycle and the management principles of the literature review. Thereafter a questionnaire was developed from these categories. The questionnaire was subsequently used to guide interviews. After the interviews these categories and findings from the questionnaire were combined and summarised into key findings. The key findings of the research were: • The driving force behind obtaining closure must shift from the State Departments to the mining companies. They must realise there is an opportunity during the closure process to make money and to minimise their long-term liability. The mining company must thus drive the closure process to obtain environmental sustainability. • The gold mines do have problems in terms of cost estimation and trust fund expenditure at their TSF footprints during the closure process. The reasons were a mismanagement of the closure process and making use of a limited information system to make decisions. • A proper closure process does exist, but it can be improved to ensure all interested and affected parties have the same expectations from closure. • There are many activities in the closure process flow diagram which were not properly attended to according to the case studies. • A conceptual closure plan and a draft rehabilitation plan with broad objectives, policies and strategies with detailed descriptions were not compiled during the operational phase, because limited scientific monitoring information was gathered to do a proper risk assessment and some l&APs consultation was done mainly with the material and land owners on a one on one basis. From these key findings the following recommendations could be formulated: • Any mining operation should conduct a closure audit at least every second year and before mining activities change. • A searchable record keeping system must be established to keep track of the closure life cycle development. • Detailed conceptual and final closure plans need to capture the data from the audits and record keeping system. • A communication forum with company management and environmental specialists needs to be established.
Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2009.

APA, Harvard, Vancouver, ISO, and other styles

30

Cisneros, Kelly Ortega. "Ecosystem functioning of selected estuaries on the east coast of South Africa." Thesis, 2013. http://hdl.handle.net/10413/11207.

Full text

Abstract:

River inflow is one of the most important factors influencing the density and biomass of estuarine biotic communities. The aim of this study was to obtain an understanding of the ecosystem functioning of selected estuaries on the east coast of South Africa and to represent their dynamics through ecosystem models. The responses of water column nutrients, plankton density and biomass to inlet phase changes for 16 temporarily open/closed estuaries (TOCEs) in South Africa were first determined. This analysis demonstrated that inlet phase and the duration of mouth closure were the most important factors determining plankton density and biomass of the analysed TOCEs. Estimates of planktonic standing stocks for four of these estuaries revealed that stocks can be from 26 to 10 000 times higher during the closed compared to the open phase. Also, slightly higher variability of planktonic density and biomass was recorded during the closed phase of TOCEs. The second major thrust of this study was to analyse the variability and temporal stability of planktonic and macrobenthic invertebrate density and biomass in two KwaZulu-Natal estuaries over a dry/wet cycle. The results suggest that “stable” variability and species synchronization could be the mechanisms whereby the estuarine biota of these systems compensate for environmental changes and attain a degree of environmental homeostasis. The third major thrust involved an assessment of the spatio-temporal variations in the elemental composition and stoichiometry of suspended and sediment detritus, zooplankton and macrobenthic taxa from two estuaries over a dry/wet cycle. Significant seasonal variations in the elemental composition of detritus, zooplankton and macrobenthic species were found, with the variations in the elemental content of sediment and suspended detritus being related to the seasonal changes in river inflow, while the among-taxa variability was mainly explained by feeding mode. Finally, static seasonal carbon and nitrogen ecosystem network models were developed for the East Kleinemonde, Mlalazi and Mpenjati estuaries to investigate their nutrient dynamics and ecosystem functioning. The results indicated that the East Kleinemonde and Mpenjati estuaries were mainly dependent on primary producers during the dry season, especially the high standing stocks of phytoplankton and microphytobenthos. Similarly, the dependency on detritus was higher during the wet season due to the high riverine imports during this season. Consequently, higher detritivory was recorded in all three study systems during the wet season. Cycling of nitrogen was higher than of carbon on a seasonal basis, with higher recycling of nitrogen during the dry season implying a lower availability of this element due to reduced freshwater inflow and nutrient input during the low rainfall period. System indices indicated that the organization of these systems was higher during the dry season, while the overheads on imports and exports peaked during the wet season. The ecosystem models analysed here provide an initial insight into the overall carbon and nitrogen dynamics of estuaries on the east coast of South Africa.
M.Sc. University of KwaZulu-Natal, Durban 2013.

APA, Harvard, Vancouver, ISO, and other styles

31

Pillay, Yogesveri. "Ozone maxima off the East Coast of South Africa : the role of biomass burning." Thesis, 1993. http://hdl.handle.net/10413/5624.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Portwig, Heinrich Paul. "Documentary based evidence for sardine run events, east coast of South Africa: 1946-2012." Thesis, 2016. http://hdl.handle.net/10539/21704.

Full text

Abstract:

A dissertation submitted in the fulfilment of the requirements for the degree of Masters of Science (MSc) (Geography Archaeology and Environmental Studies) Faculty of Science. University of the Witwatersrand. Johannesburg, March 2016.
The southern African sardine run is an annually recurring phenomenon involving vast schools of sardines travelling northwards along the east coast of South Africa. Climate change is assumed responsible for recently observed changes in the occurrence of sardine runs, yet data have been absent to quantify any phenological changes over time. The National Library of South Africa has extensive archives of Kwa-Zulu Natal based newspapers which were scrutinized to determine the annual arrival of sardines at specific places along the east coast between 1946 and 2012. In particular, ‘The Natal Mercury’, ‘South Coast Herald’ and ‘South Coast Sun’ newspapers were consulted. This yielded an uninterrupted sardine run record spanning 66 consecutive years. This is the first such study examining historical fish phenology in the southern Hemisphere. A variety of environmental conditions is thought to influence the sardine runs and may include, oceanic temperatures, oceanic currents, visibility of the water, wind speed/direction and air temperature. We thus also demonstrate historical climate variability and change along the east coast for the period between 1936 and 2012, based on data obtained from the National Oceanic and Atmospheric Administration (NOAA) and the South African Weather Service. In particular, we examine the parameters: temperature, wind, the occurrence of westerly wave disturbances (i.e. cold fronts), the El Nino Southern Oscillation, and the Southern Oscillation Index. The sardine run data are then compared against the various climate parameters to ascertain which variables most influence their phenology. It is found that the sardine runs have become more temporally delayed during recent years, particularly since the late 1960s/early 1970s, and may be associated with considerable increases in Sea Surface Temperatures (SST) since that time.
TG2016

APA, Harvard, Vancouver, ISO, and other styles

33

Hugo, Victor Emmanuel. "A study of titanium-bearing oxides in heavy mineral deposits along the East Coast of South Africa." Thesis, 1993. http://hdl.handle.net/10413/5647.

Full text

Abstract:

Heavy mineral deposits along the east coast of South Africa represent the world's largest demonstrated resource of beach placer ilmenite. This mineral occurs as homogeneous, subrounded grains, with chemical compositions close to pure FeTi03• Concentrates contain between 48 and 52 per cent Ti02, with minor impurities of MnO, MgO, and Cr203. Most coastal ilmenites are unaltered or display only incipient alteration, but the entire spectrum of alteration products from ilmenite to rutile or anatase, is observed. Transmission electron microscopy of weathered ilmenites reveals that ilmenite commonly alters to pseudorutile and then to rutile or anatase, as described by Teufer and Temple (1966) and Grey and Reid (1975). Ilmenite may also alter directly to rutile (or anatase) in a single-stage process. In addition, ilmenite altered by high temperature oxidation and hydrothermal processes is found in the deposits. There is good mineralogical evidence that the alteration of ilmenites found in the coastal sediments is best described by a multi stage model, in which some ilmenite grains were altered prior to final deposition. Other common iron-titanium oxides in the deposits include magnetite, rutile and hematite, which may occur as discrete grains or as composite grains of two or more oxides. Ilmenite and magnetite in the coastal sediments are derived from rocks of both the Karoo Igneous Province and the Natal Basement, while rutile is derived solely from the latter. Ilmenites from certain rock groups may be distinguished on the basis of their chemical composition. However, magnetite chemistry is a better indicator of provenance, and magnetites from the above two sources can be clearly distinguished. The petrography of the iron-titanium oxides may be used as a provenance indicator, but may be misleading, as the proportions of the oxide intergrowths change with transport and weathering. Variations in the proportions and chemical compositions of iron-titanium oxides and other heavy minerals within the coastal sediments are caused by provenance, selective sorting during deposition, age of the deposit, weathering, and the recent geological history of the area. A model is proposed in this study which describes the formation of the heavy mineral deposits in relationship to the above influences.
Thesis (Ph.D.)-University of Natal, Durban, 1993.

APA, Harvard, Vancouver, ISO, and other styles

34

Fennessy, Sean Thomas. "Comparative life histories and stock assessments of rockcods (family Serranidae) from the east coast of South Africa." Thesis, 2000. http://hdl.handle.net/10413/4176.

Full text

Abstract:

The family Serranidae is a diverse group of fishes, of which the genus Epinephelus (rockcods or groupers) is the largest. Serranids are commonly caught in reef fisheries in tropical and warm-temperate latitudes, and are targeted because of their tasty flesh and high value. In South Africa, epinepheline serranids mainly occur in hook and line fisheries in the province of KwaZulu-Natal. Mostserranids are caught by the boat-based (skiboat) fishery, and the commonestspecies are the endemic catface rockcod (Epinephelus andersoni), thehalfmoon rockcod (E. rivulatus), the yellowbelly rockcod (E. marginatus) and the endemic white-edge rockcod (E. albomarginatus). Although serranids contribute about ten percent to catches by the commercial and recreational skiboat sectors in KwaZulu-Natal, representing an estimated total catch of around 200 mt per year, little is known about these fishes in South Africa. From the mid-1980s to the mid-1990s, the mean lengths of E. marginatus and E. albomarginatus in the region declined significantly. Over this period, lengths of E. andersoni remained the same, while those of E. rivulatus increased. Lengths of E. marginatus and E. albomarginatus from Mozambique, where fishing effort was low at the time of sampling, were significantly greater than in KwaZulu-Natal. Monthly biological data were mostly collected from commercial skiboat catches on the northern and southern coast of KwaZulu-Natal. Additional data for E. marginatus and E. albomarginatus were also collected irregularly from commercial catches made in Mozambique. Unless the fish had ripe ovaries, all gonads had to be sectioned to establish sex and stage. Histology revealed that all gonads had a female-like appearance, with lamellae and a central lumen. In E. andersoni, there was a complete overlap of male and female length frequencies, and their meanlengths were not significantly different. Some males and inactive bisexuals were both smaller and younger than the female size and age at first maturity. Together with the occurrence of mature bisexual fish (transitionals), these observations indicate that males are derived from immature or mature females, hence this species is a diandric protogynous hermaphrodite. The other three species exhibit typical signs of monandric protogynous hermaphroditism. Males and females had significantly different mean lengths, and age and length frequencies by sex werebimodal. Transitional individuals were recorded in E. rivulatus. E. andersoni and E. rivulatus matured at small sizes and early ages relative to E. marginatus and E. albomarginatus. Ripe ovaries were much larger than ripe testes in all four species. E. andersoni, E. marginatus and E. albomarginatus spawned in spring and summer, while E. rivulatus spawned in winter and spring. There were no indications of spawning in E. andersoni in the southern sampling region, and few ripe individuals of E. albomarginatus were encountered in KwaZulu-Natal samples. Size at maturity of this species was much smaller in Mozambique samples. Large, reproductively inactive individuals of E. andersoni were frequently observed in the spawning season. The lack of reproductive activity of E. andersoni and E. albomarginatus in KwaZulu-Natal may be because this area represents thesouthernmost limit of the distribution of these species. Ageing of the four species was undertaken using sectioned otoliths. Age validation was undertaken by a combination of tetracycline marking in captive fishes, and analysis of the marginal zone in otoliths. All four species are relatively long-lived, although estimates of maximum age may be under-estimated because of long-term harvesting. In all four species, fish from the southern sampling region were larger than fish from the northern region at the same age. Only in the case of E. rivulatus were these significant enough to warrant the fitting of two growth curves to the northern and southern populations. Males in all four species tended to be larger than females at the same age, suggesting that there may be a growth spurt following sex change, or that faster-growing females changed sex. A logistic growth curve was fitted to the age-length data for E. andersoni, while von Bertalanffy curves produced the best fit for the other species. Based on the rates at which L∞ attained in these four species, E. marginatus and E. albomarginatus are slow-growing species, while E. andersoni and, particularly, E. rivulatus arefaster growing. Rates of total mortality and natural mortality were estimated using length-converted catch curves and the Rikhter and Efanov equation, respectively. Stock assessments undertaken by yield per recruit and spawner biomass per recruit analyses indicate that E. andersoni in KwaZulu-Natal is currently optimally exploited, while E. rivulatus is lightly exploited. Both E. marginatus and E. albomarginatus are over-exploited. The potential problems in applying standard per recruit models to species with complex life histories are discussed. Support for the reduced stock status of the latter two species is provided by the observed changes in lengths of these species over a ten-year period, and their relatively small size in KwaZulu-Natal compared to the lightly-fished Mozambique populations. Local fishers in KwaZulu-Natal have also reported declines in sizes and reduced catches of these two species.The life history styles and other features of the four species are compared and discussed with reference to the resilience of these species to harvesting. Two of the species (E. marginatus and E. albomarginatus) are monandric protogynous hermaphrodites, which grow slowly, mature late and attain large sizes. E.andersoni and E. rivulatus grow faster, mature earlier and are smaller species. The normally deleterious effects of fishing on sex-changing species are not manifested in these two species, possibly because E. rivulatus is so small, that males are not selectively removed. In contrast, E. andersoni is a diandric protogynous hermaphrodite, and hence, does not rely on sex-change as a source of males. The current management methods for serranids in KwaZulu-Natal are presented, and suggestions for future approaches are discussed.
Thesis (Ph.D.)-University of Natal, Durban, 2000.

APA, Harvard, Vancouver, ISO, and other styles

35

Proudfoot, Lee-Anne. "Population structure, growth and recruitment of two exploited infralittoral molluscs (Haliotis midae and Turbo sarmaticus) along the south east coast, South Africa /." 2006. http://eprints.ru.ac.za/910/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Thabede, Mfanimpela Ishmael. "The impact of east coast fever on African homestead society in the Natal colony 1901-1910." Diss., 2006. http://hdl.handle.net/10500/2171.

Full text

Abstract:

This dissertation looks at the impact of East Coast Fever on African homestead society in Natal in the period 1901-1910. The disease broke out in Natal at the beginning of 1904. With the realization that East Coast Fever was another lethal epizootic, the Natal Colonial Government introduced measures to control the spread of the disease and finally eradicate it. The campaign was, however, not successful. The disease thus spread throughout the colony and led to the loss of many cattle owned by Africans. By 1909 not more than four divisions in the colony remained free of the disease. The death of many cattle deprived Africans of the means of extensive cultivation, the source of income for the payment of rents and taxes, and Ilobolo. Many African males were forced to leave their homesteads for the towns and the mining sector in search of work. This eventually changed the nature of the homestead society.
History
M.A. (History)

APA, Harvard, Vancouver, ISO, and other styles

37

Drummond, Anne E. "Studies on the biology of three species of sea urchin (Echinodermata : Echnoidea), on the South African east coast." Thesis, 1993. http://hdl.handle.net/10413/10544.

Full text

Abstract:

Ten species of shallow water echinoid are found on the subtropical east coast of South Africa. Although their distributions are patchy, the most common species, Echinometra mathaei, stomopneustes variolaris and Diadema savignyi, are nontheless conspicuous components of intertidal communities on this coast. As little was known about these three species, the overall intention of this study was to provide some fundemental information on their biology and ecology. For the purposes of achieving this aim a life history approach was adopted, where the relative investments by each species in growth, maintenance and reproduction were investigated and compared. These patterns of investment were then related to the habitat occupied by each species, in an attempt to identify the selective forces which may have been implicated in shaping their life histories. It was apparent from the results of investigations conducted between January 1991 and June 1993 that there were distinct differences in the patterns of investment in growth, maintenance and reproduction between the three species. The life history of S. variolaris, which occupied exposed habitats in the lower intertidal, was characterised by a large investment in maintenance, lower reproductive output, slower growth and a longer lifespan, relative to the other two species. In contrast, Q. savignyi, which inhabited less exposed mid-shore pools, had a relatively higher reproductive output, more rapid growth, a smaller investment in maintenance and a shorter lifespan. While selection ln S. variolaris and Q. savignyi appears to favour survival and reproduction respectively, the life history of E. mathaei, a species which also occupies mid-shore pools, was balanced between these two extremes, allocating sufficient resources to maintenance to permit tolerance of harsh physical conditions while still making a moderate investment in reproduction over a lifespan of intermediate duration. The predictions generated by the r-K selection and "bet hedging" theories of life history evolution, were applied in the process of speculating on the selective forces which may have shaped these life histories. However, it was found that neither set of predictions and associated selective forces could adequately explain the observed life histories. Rather, it seemed that the life histories of the three species represented evolved responses to the direct and indirect effects of exposure to wave action and sand movements which dominate the intertidal environment on the South African east coast. In the exposed lower intertidal, unpredictable recruitment, drag and impact forces associated with wave action, which impose limits to body size and necessitate a large investment in maintenance to ensure survival, select for slow growth, low reproductive output and high longevity. In contrast reproduction and growth of species occupying the more sheltered mid-shore pool habitats would be less effected by the demands of maintenance investment or limits to body size. In addition predictable recruitment in the mid-shore, would obviate the need for long life in order to ensure a contribution to future generations.
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1993.

APA, Harvard, Vancouver, ISO, and other styles

38

Arabi, Sumaiya. "Relationship between sediment structure and infaunal amphipod communities along the Durban outfalls region on the east coast of South Africa." Thesis, 2010. http://hdl.handle.net/10413/7337.

Full text

Abstract:

Increased human habitation brings associated pressures with it, such as the introduction of contaminants to coastal waters. The major sources of these occur along the KwaZulu-Natal coast via Sappi Saiccor discharge points, Tioxide, AECI, the Mlaas canal, Central Works Outfall and Southern Works Outfall. This study investigated the effects of sediment structure on benthic amphipod communities exposed to sewage and industrial waste from the Central Works and Southern Works Outfalls along the Durban coastline, and used a 4-year dataset of sediment grain size analysis, metal concentrations, Total Kjeldahl Nitrogen (TKN) and Chemical Oxygen Demand (COD) at impacted and reference sites. Results exhibited that the levels of effluent being discharged onto the Durban coast from the Southern Works and Central Works Outfalls do not accumulate in the fine grained sediments in sites where it would be expected. The Mdloti reference site which was dominated by coarse sediment showed the highest concentrations of metals. In addition, the outfalls do not have significant effects on the amphipod communities in the vicinity. Community structure between sites with similar grain sizes tends to be very similar thereby highlighting the possible influence of grain sizes on determining community patterns. Overall, there seemed to be no effect of pollutants on the biology or accumulation in the receiving environment.
Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

APA, Harvard, Vancouver, ISO, and other styles

39

David, Geraldine Michelle. "From idea to implementation : an evaluation of the East Coast radio corporate advertising campaign : how does the station construct its audience?" Thesis, 2001. http://hdl.handle.net/10413/5230.

Full text

Abstract:

The research will investigate the East Coast Radio Corporate Advertising Campaign which ran from early 1996 through until the end of March 1998. The 'catch phrase' or title of the campaign was "Hot Days, Cool Waves". The research will also focus on the station's constructs of its' audience. The thesis will follow through the agency's pitch to the client the end of the campaign. The campaign incorporates print, billboards, cinema and electronic media. The corporate advertising campaign preceded a large increase in East Coast Radio listenership. East Coast Radio began life as Radio Port Natal, part of the South African Broadcasting Corporation. Under the management of the South African Broadcasting Corporation, Radio Port Natal developed a particular image and specific audience profiles The new private station needed to establish an identity autonomous from the South African Broadcasting Company, in terms of both inherited and new listeners. The thesis will investigate the extent to which East Coast Radio retained the original audience after the transfer of ownership and the modality through which it was able to construct an extended audience for the station.
Thesis (M.A.)-University of Natal, Durban, 2001.

APA, Harvard, Vancouver, ISO, and other styles

40

Foulis, Alan. "A retrospective analysis of shark catches made by pelagic longliners off the east coast of South Africa and biology and life history of shortfin mako shark, Isurus oxyrinchus." Thesis, 2013. http://hdl.handle.net/10413/9987.

Full text

Abstract:

Oceanic pelagic shark species are under threat worldwide as fishing effort increases and they are taken as both targeted and bycatch. It is widely recognized that the life history characteristics of sharks make them inherently susceptible to overexploitation and as a result many shark-directed fisheries have collapsed. It is therefore essential that good-quality data are collected and analyzed in order to provide fisheries managers with the right information to manage these species sustainably. South Africa has a pelagic longline fishery which includes tuna-, swordfish-, and shark-directed vessels. This study analyzed logbook (1998 – 2010) and observer data (2002 – 2010) provided by the Department of Agriculture, Forestry and Fisheries in order to assess the catch composition and standardized catch-per-unit-effort (CPUE) of sharks captured as both targeted catch and bycatch. The study area consisted of four zones moving east of the 20°E meridian: the Agulhas Bank (20°E – 24°E), South Coast (25°E – 29°E), East Coast 1 (30°E – 32.8°E), and East Coast 2 (32.9°E – 36.5°E). The majority of fishing effort targeted at tuna was focused on the Agulhas Bank and consisted of foreign vessels which operated over the winter months, whereas local vessels targeted swordfish with consistent year-round effort along the upper east coast. Sharks made up 13% of total catches according to logbook data and catch composition was dominated by blue shark (Prionace glauca) and shortfin mako shark (Isurus oxyrinchus). Observer data identified a larger number of shark species than shown by logbooks, and notably, the crocodile shark (Pseudocarcharias kamoharai) made up 22.5% of shark bycatch on swordfish-directed vessels operating along the upper east coast. In addition, the observer data showed that although blue and mako shark dominated catches in the Agulhas Bank and South coast zones, carcharhinid sharks were more prevalent further east. Generalized linear models explained 54% of the variation in CPUE of shark bycatch, with year and target species being the two most important explanatory variables. The standardized CPUE index based on logbook data suggested a slightly increasing shark abundance trend between 1998 and 2010, but conversely, the index based on observer data suggested a decline between 2002 and 2010. Assuming that the observer data best reflected the actual CPUE trend (i.e. a declining trend), the increasing trend shown by logbooks over the same period most likely stems from initial under-reporting of shark capture events by skippers, followed by improved reporting in later years, thus masking the declining trend. Catch by target species revealed that swordfish vessels caught significantly more sharks per 1000 hooks than tuna vessels. The shortfin mako shark was one of the most common bycatch species, and also the primary target species of the shark-directed fishery. Generalized linear models of shortfin mako shark CPUE using the delta method produced similar trends than models of total shark bycatch; i.e. trends based on logbook data appeared stable but observer data showed a declining trend over time. Shortfin mako sharks were more abundant in the Agulhas Bank and South coast zones than along the East coast. A total of 817 shortfin mako shark samples were collected onboard a South African shark-directed pelagic longline vessel operating out of Cape Town and by the KwaZulu-Natal Sharks Board bather protection nets, set close inshore. Sharks collected inshore (from nets) were significantly larger than those collected offshore. More males than females were collected from the nets (2.3 males : 1 female), whereas the ratio for offshore samples was 1.1 : 1. Age and growth parameters were estimated from 89 sectioned vertebral samples consisting of 43 females and 46 males ranging in size from 90 cm to 299.4 cm fork length (FL). Annual band-pair deposition was assumed and growth was analyzed by fitting 3-parameter von Bertalanffy and Gompertz growth models. Parameter estimates for the Gompertz model were: K = 0.152 year¯¹ for males and 0.127 yearˉ¹ for females; L0 = 85 cm; L∞ = 295 cm for males and 315 cm for females; and longevity was 17 and 21 years for males and females respectively. Estimates for the von Bertalanffy model were: K = 0.08 yearˉ¹ for both sexes; L0 = 85 cm; L∞ = 354 cm for males and 321 cm for females; and longevity was 34 and 31 years for males and females respectively. Using these data, age and length at 50% maturity were calculated at 7 years and 199.1 cm FL for males, and 14 years and 252.8 cm for females. Litter size was in agreement with previous studies (9 to 14 pups). The gestation period was not estimated but parturition may be in late winter to spring. The stomach contents of 817 sharks showed that shortfin mako sharks are opportunistic feeders; elasmobranchs dominated in stomachs collected from sharks caught in nets near the shore (%F = 63.54%) whereas shark stomachs collected from the offshore contained mainly teleosts (70%). Length-frequency analyses revealed that large and reproductively active shortfin mako sharks were more common along the upper east coast and in the inshore environment, whereas juveniles and subadults preferred the oceanic environment, particularly over the Agulhas Bank and South Coast zones. The findings from the present study are a significant step forward towards developing a management strategy for protecting shortfin mako sharks in the South West Indian Ocean region.
Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2013.

APA, Harvard, Vancouver, ISO, and other styles

41

MartinPech and 裴馬丁. "A Study on Low Cost Airlines’ Perceived Service Quality in South-East Asia." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/fuqa2j.

Full text

Abstract:

碩士
國立成功大學
國際經營管理研究所
102
Service quality has become a paramount for every company, especially in airline industry. The last fifteen years have seen a rapid growth of low cost airlines in Asia. New routes are appearing and low cost air travel sees passenger numbers increasing every year. This study investigates perceived service quality of low cost airlines and their passengers’ behavioral intentions. With brand image as a perceived service quality’s antecedent, it furthermore introduces local-global identity and consumer affinity into the model and examines whether these marketing constructs have influence on perceived service quality’s and behavioral intentions; a relationship that has not yet been considered in the setting of low cost airlines industry. The partial least square method is applied to analyze the collected data sample. The results from this study indicate that consumer’s affinity has effect on behavioral intentions and that brand image and local-global identity influence the low cost airline’s perceived service quality. This could be utilized by low cost airline managers in their marketing strategy. This study contributes to the literature by affirming that the constructs of local-global identity and consumer affinity are also applicable in this setting.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'South-east coast'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles