An examination of the spatial variation of surficial sediment characteristics in the Howison's Poort Reservoir
- Authors: Weaver, Alex van Breda
- Date: 1979
- Subjects: Howison's Poort Reservoir , South Africa , Sedimentation and deposition
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:4790 , http://hdl.handle.net/10962/d1001890
- Description: From Introduction: Lakes, estuaries and man-made water impoundments can be considered as intervening basins which provide for the temporary storage both of sediment and of water. Because of the potential energy of soil in elevated positions and because of the kinetic energy of water flowing under the influence of gravity, eroded material is eventually transported to the lowest possible level, i.e. the ocean deeps, or some intervening basin. This denudation process may be compared with Newton’s second law of thermodynamics which states that each system tends to move in the direction of lowest energy. Sedimentation in intervening basins may be seen as part of the natural process of landscape evolution. The rates at which sedimentation occurs may be strongly influenced by the activities of man.
- Full Text:
- Authors: Weaver, Alex van Breda
- Date: 1979
- Subjects: Howison's Poort Reservoir , South Africa , Sedimentation and deposition
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:4790 , http://hdl.handle.net/10962/d1001890
- Description: From Introduction: Lakes, estuaries and man-made water impoundments can be considered as intervening basins which provide for the temporary storage both of sediment and of water. Because of the potential energy of soil in elevated positions and because of the kinetic energy of water flowing under the influence of gravity, eroded material is eventually transported to the lowest possible level, i.e. the ocean deeps, or some intervening basin. This denudation process may be compared with Newton’s second law of thermodynamics which states that each system tends to move in the direction of lowest energy. Sedimentation in intervening basins may be seen as part of the natural process of landscape evolution. The rates at which sedimentation occurs may be strongly influenced by the activities of man.
- Full Text:
Anglican missionary policy in the diocese of Grahamstown under the first two bishops, 1853-1871
- Authors: Goedhals, Mary Mandeville
- Date: 1979
- Subjects: Anglican , Diocese , Grahamstown , Bishops , Missionary policy , Cattle Killing , Government , Education , Black people , John Armstrong , Henry Cotterill
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:1211 , http://hdl.handle.net/10962/d1001540
- Description: In 1843 a committee of the Colonial Bishroprics Fund appointed to investigate the state of the Church of England at the Cape of Good Hope, recommended the formation of a bishopric, and suggested that the bishop settle in the eastern districts of the colony, with an archdeacon in Cape Town. Three significant principles had been enunciated: the church was to grow under a bishop, the church would have a dual mission to blacks and whites, and the colony's eastern frontier, long a political and military headache, was seen as the focus of a new and spiritual battle. Contact between Nguni tribesmen and the eastward-moving European trekboer began in the region of the Fish River during the rule of the Dutch East India Company. Cattle and land were the main ingredients of the frontier conflict. From the point of view of the white settler, the growing cattle trade meant an increased need for pasture, but although the motive for expansion was economic, frontiersmen had come to regard large lands as their birthright. The semi-nomadic pastoral economy of the Nguni also required abundance of land, which was vested in the tribe. To the tribesmen, their cattle had a political, social and religious significance which transcended the economic. Cattle were sacrificed to the ancestors to propitiate the shades of the departed and to secure the prosperity of the tribe. The years of conflict, the constant threat to their herds and their land, undermined the basis of Nguni society, without providing it with a new foundation.
- Full Text:
- Authors: Goedhals, Mary Mandeville
- Date: 1979
- Subjects: Anglican , Diocese , Grahamstown , Bishops , Missionary policy , Cattle Killing , Government , Education , Black people , John Armstrong , Henry Cotterill
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:1211 , http://hdl.handle.net/10962/d1001540
- Description: In 1843 a committee of the Colonial Bishroprics Fund appointed to investigate the state of the Church of England at the Cape of Good Hope, recommended the formation of a bishopric, and suggested that the bishop settle in the eastern districts of the colony, with an archdeacon in Cape Town. Three significant principles had been enunciated: the church was to grow under a bishop, the church would have a dual mission to blacks and whites, and the colony's eastern frontier, long a political and military headache, was seen as the focus of a new and spiritual battle. Contact between Nguni tribesmen and the eastward-moving European trekboer began in the region of the Fish River during the rule of the Dutch East India Company. Cattle and land were the main ingredients of the frontier conflict. From the point of view of the white settler, the growing cattle trade meant an increased need for pasture, but although the motive for expansion was economic, frontiersmen had come to regard large lands as their birthright. The semi-nomadic pastoral economy of the Nguni also required abundance of land, which was vested in the tribe. To the tribesmen, their cattle had a political, social and religious significance which transcended the economic. Cattle were sacrificed to the ancestors to propitiate the shades of the departed and to secure the prosperity of the tribe. The years of conflict, the constant threat to their herds and their land, undermined the basis of Nguni society, without providing it with a new foundation.
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Extinction as consummation: an exposition of Virginia Woolf's mataphysic of visionary relation
- Authors: Ryan, Rory
- Date: 1979
- Subjects: Woolf, Virginia, 1882-1941 , Virginia Woolf
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2171 , http://hdl.handle.net/10962/d1001822
- Description: What follows is an attempt to circumscribe Virginia Woolf's ideas on life and death, the relation between self and all that which is not self, and the nature of reality, in short, Woolf's vision. I hope that whatever unity and structure may exist in the vision will not be overlooked, and moreover, I intend to avoid imposing a unity where none exists, whether the absence of unity is intentional or accidental
- Full Text:
- Authors: Ryan, Rory
- Date: 1979
- Subjects: Woolf, Virginia, 1882-1941 , Virginia Woolf
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2171 , http://hdl.handle.net/10962/d1001822
- Description: What follows is an attempt to circumscribe Virginia Woolf's ideas on life and death, the relation between self and all that which is not self, and the nature of reality, in short, Woolf's vision. I hope that whatever unity and structure may exist in the vision will not be overlooked, and moreover, I intend to avoid imposing a unity where none exists, whether the absence of unity is intentional or accidental
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Graaff-Reinet and the Great Depression (1929-1933)
- Authors: Minnaar, Anthony de V
- Date: 1979
- Subjects: Graaff-Reinet (South Africa) -- History , South Africa -- Economic conditions -- 1918-1961
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2518 , http://hdl.handle.net/10962/d1001847
- Description: The Depression of 1929-1933 was a world-wide phenomenon, in which "no aspect of the economy, no part of the world, escaped devastation". ¹ Accordingly the study of a medium sized rural town in South Africa during the period of the Depression, should show effects and reactions that were, in general, indicative of worldwide trends. In choosing Graaff- Reinet, I felt that being a close-knit community , with its urban and rural populations closely associated with each other, and the white, coloured and black sections of the population interdependent, it adequately represented a microcosm of South Africa as a whole. Then, too, Graaff- Reinet was ideally suited to illustrate the reality, that in South Africa during the Depression " the farmers were the most heavily hit of all". ² The single most significant product of the Graaff- Reinet district was wool, which at the time of the Depression was South Africa's second most important export, and consequently the well-being of the whole district depended largely on the market performance of this product . During the Depression the price of wool dropped drastically and the Graaff-Reinet farmers suffered in consequence . Graaff-Reinet also went, almost according to a blueprint, through the general phases of the Depression. The privations of the farming community led to the financial embarrassment of the local financial institutions causing their collapse , which in its turn led to the widespread hardship of everyone in the town. But these events all had a particular Graaff-Reinet quality, and the twists to the general outline are rooted deep in the local character of the district . Historically Graaff-Reinet is extremely interesting. It is the fourth oldest town in South Africa, being established in 1786, and in studying Graaf-Reinet one cannot but become conscious of the immense tradition and the awareness of history , which all its people have. The study itself starts with a general outline of the Worldwide Depre ssion, its causes and results, then moves on to the Depression in South Africa . The study of Graaff-Reinet in the Depression is divided into three basic sections, the Farmers, the Townspeople, and the Politics of Graaff-Reinet during the Depression. All three contain their own sub-divisions dealing with different aspects. In the Graaff-Reinet sections are included references to national events, tying them to, and explaining the course of, local happenings. In short the study becomes the story of how the Depression effected the people of Graaff-Reinet, how they suffered during this period and how they reacted to it. A final concluding section deals with their general recovery from the Depression. ¹ Heaton, H. : Kruger, D. W. The Economic History of Europe. p. 696. ²The Making of a Nation; a history of the Union of South Africa 19l0 - 1960. p. 158.
- Full Text:
- Authors: Minnaar, Anthony de V
- Date: 1979
- Subjects: Graaff-Reinet (South Africa) -- History , South Africa -- Economic conditions -- 1918-1961
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2518 , http://hdl.handle.net/10962/d1001847
- Description: The Depression of 1929-1933 was a world-wide phenomenon, in which "no aspect of the economy, no part of the world, escaped devastation". ¹ Accordingly the study of a medium sized rural town in South Africa during the period of the Depression, should show effects and reactions that were, in general, indicative of worldwide trends. In choosing Graaff- Reinet, I felt that being a close-knit community , with its urban and rural populations closely associated with each other, and the white, coloured and black sections of the population interdependent, it adequately represented a microcosm of South Africa as a whole. Then, too, Graaff- Reinet was ideally suited to illustrate the reality, that in South Africa during the Depression " the farmers were the most heavily hit of all". ² The single most significant product of the Graaff- Reinet district was wool, which at the time of the Depression was South Africa's second most important export, and consequently the well-being of the whole district depended largely on the market performance of this product . During the Depression the price of wool dropped drastically and the Graaff-Reinet farmers suffered in consequence . Graaff-Reinet also went, almost according to a blueprint, through the general phases of the Depression. The privations of the farming community led to the financial embarrassment of the local financial institutions causing their collapse , which in its turn led to the widespread hardship of everyone in the town. But these events all had a particular Graaff-Reinet quality, and the twists to the general outline are rooted deep in the local character of the district . Historically Graaff-Reinet is extremely interesting. It is the fourth oldest town in South Africa, being established in 1786, and in studying Graaf-Reinet one cannot but become conscious of the immense tradition and the awareness of history , which all its people have. The study itself starts with a general outline of the Worldwide Depre ssion, its causes and results, then moves on to the Depression in South Africa . The study of Graaff-Reinet in the Depression is divided into three basic sections, the Farmers, the Townspeople, and the Politics of Graaff-Reinet during the Depression. All three contain their own sub-divisions dealing with different aspects. In the Graaff-Reinet sections are included references to national events, tying them to, and explaining the course of, local happenings. In short the study becomes the story of how the Depression effected the people of Graaff-Reinet, how they suffered during this period and how they reacted to it. A final concluding section deals with their general recovery from the Depression. ¹ Heaton, H. : Kruger, D. W. The Economic History of Europe. p. 696. ²The Making of a Nation; a history of the Union of South Africa 19l0 - 1960. p. 158.
- Full Text:
Protest in fiction : an approach to Alex la Guma
- Cornwell, David Gareth Napier
- Authors: Cornwell, David Gareth Napier
- Date: 1979
- Subjects: La Guma, Alex , South African literature (English) -- Black authors -- History and criticism , Protest literature, South African (English) -- History and criticism
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2169 , http://hdl.handle.net/10962/d1001820
- Description: From Introduction: Thus for the black South African, the act of creative writing is inescapably a form of political action, and unless he turns his back on the reality which confronts him and retreats into a private imaginary world, it is also a form of social action, Yet Ezekiel Mphahlele has rightly cautioned that "creating an imaginary world" can never be an effective substitute for social act ion . Composing fictions about social and political problems is an indubitably oblique way of seeking a solution to them, and even the tendentious recreation of reality is only a metaphor for its actual transformation. Protest writing in South Africa is paradoxically a form of social action which is also only a parasitical imitation of social action, and therefore its avoidance . The freedom of literary creation described above is ambiguously not only a freedom to express reality, but also a freedom from the constraints of reality. And this suggests why the outlaw was such an important symbol to an earlier generation of rather more self-conscious writers.
- Full Text:
- Authors: Cornwell, David Gareth Napier
- Date: 1979
- Subjects: La Guma, Alex , South African literature (English) -- Black authors -- History and criticism , Protest literature, South African (English) -- History and criticism
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2169 , http://hdl.handle.net/10962/d1001820
- Description: From Introduction: Thus for the black South African, the act of creative writing is inescapably a form of political action, and unless he turns his back on the reality which confronts him and retreats into a private imaginary world, it is also a form of social action, Yet Ezekiel Mphahlele has rightly cautioned that "creating an imaginary world" can never be an effective substitute for social act ion . Composing fictions about social and political problems is an indubitably oblique way of seeking a solution to them, and even the tendentious recreation of reality is only a metaphor for its actual transformation. Protest writing in South Africa is paradoxically a form of social action which is also only a parasitical imitation of social action, and therefore its avoidance . The freedom of literary creation described above is ambiguously not only a freedom to express reality, but also a freedom from the constraints of reality. And this suggests why the outlaw was such an important symbol to an earlier generation of rather more self-conscious writers.
- Full Text:
Scientific theories : a philosophical analysis
- Authors: Schwerin, Alan Kenneth
- Date: 1979
- Subjects: Science -- Philosophy , Logical positivism , Realism
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2701 , http://hdl.handle.net/10962/d1001976
- Description: In this essay I have considered some of the philosophical problems involved in attempting to settle the question, What are scientific theories about? And in order to expose these problems, I have dealt with two influential responses to this question of the referents of scientific theories - namely, logical empiricism and realism.
- Full Text:
- Authors: Schwerin, Alan Kenneth
- Date: 1979
- Subjects: Science -- Philosophy , Logical positivism , Realism
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2701 , http://hdl.handle.net/10962/d1001976
- Description: In this essay I have considered some of the philosophical problems involved in attempting to settle the question, What are scientific theories about? And in order to expose these problems, I have dealt with two influential responses to this question of the referents of scientific theories - namely, logical empiricism and realism.
- Full Text:
The nature and function of setting in Jane Austen's novels
- Kelly, Patricia Marguerite Wyndham
- Authors: Kelly, Patricia Marguerite Wyndham
- Date: 1979
- Subjects: Austen, Jane, 1775-1817 , English fiction , Eighteenth century , Novel , Setting , Northanger Abbey , Pride and Prejudice , Mansfield Park , Emma
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2172 , http://hdl.handle.net/10962/d1001823
- Description: This study examines the settings in Jane Austen's six novels. Chapter I introduces the topic generally, and refers briefly to Jane Austen's aims and methods of creating her settings. Short accounts are given of the emphasis put on setting in the criticism of Jane Austen's work; of the chronology of the novels; and of the use made of this aspect of the novel in eighteenth-century predecessors. Chapter II deals with the treatment of place in Northanger Abbey, Sense and Sensibility, Pride and Prejudice, Mansfield Park and Emma. The consideration of five novels together makes it possible to generalize about aspects of place common to all , and to discuss particulars peculiar to individual novels without, I hope, excessive repetition. The chapter may be thought disproportionately long, but this aspect of setting is most prominent and important in the delineation of character. Chapter III discusses the handling of spatial detail and time in these five novels. Chapter IV offers a fuller analysis of what is the chief concern of this thesis, the nature and function of setting, in respect of the single novel Persuasion, and attempts to draw together into a coherent whole some of the points made in Chapters II and III. Persuasion separates conveniently from the other works, not only because it was written after them, but more importantly because in it there is a new development in Jane Austen's use of setting. Some critics, notably E.M. Forster and B.C. Southam, have found startlingly new qualities in the setting of Sanditon, and, certainly, the most striking feature of the fragment is the treatment of place. But Jane Austen left off writing Sanditon in March 1817 because of illness, and the twelve chapters make up too small and unfinished a piece to be considered in the same way as the other novels. The Watsons, too, except for some references to it in Chapter I, does not come within the scope of this dissertation. Another introductory point needs to be made briefly. Where it is necessary, the distinction between Jane Austen and the omniscient narrator is observed, but generally, partly because it is clear that Jane Austen's values are close to those of the narrator, and partly because it is convenient, traditional and sensible to do so, the name "Jane Austen" is used to refer both to the actual person and to the narrator of the novels.
- Full Text:
- Authors: Kelly, Patricia Marguerite Wyndham
- Date: 1979
- Subjects: Austen, Jane, 1775-1817 , English fiction , Eighteenth century , Novel , Setting , Northanger Abbey , Pride and Prejudice , Mansfield Park , Emma
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2172 , http://hdl.handle.net/10962/d1001823
- Description: This study examines the settings in Jane Austen's six novels. Chapter I introduces the topic generally, and refers briefly to Jane Austen's aims and methods of creating her settings. Short accounts are given of the emphasis put on setting in the criticism of Jane Austen's work; of the chronology of the novels; and of the use made of this aspect of the novel in eighteenth-century predecessors. Chapter II deals with the treatment of place in Northanger Abbey, Sense and Sensibility, Pride and Prejudice, Mansfield Park and Emma. The consideration of five novels together makes it possible to generalize about aspects of place common to all , and to discuss particulars peculiar to individual novels without, I hope, excessive repetition. The chapter may be thought disproportionately long, but this aspect of setting is most prominent and important in the delineation of character. Chapter III discusses the handling of spatial detail and time in these five novels. Chapter IV offers a fuller analysis of what is the chief concern of this thesis, the nature and function of setting, in respect of the single novel Persuasion, and attempts to draw together into a coherent whole some of the points made in Chapters II and III. Persuasion separates conveniently from the other works, not only because it was written after them, but more importantly because in it there is a new development in Jane Austen's use of setting. Some critics, notably E.M. Forster and B.C. Southam, have found startlingly new qualities in the setting of Sanditon, and, certainly, the most striking feature of the fragment is the treatment of place. But Jane Austen left off writing Sanditon in March 1817 because of illness, and the twelve chapters make up too small and unfinished a piece to be considered in the same way as the other novels. The Watsons, too, except for some references to it in Chapter I, does not come within the scope of this dissertation. Another introductory point needs to be made briefly. Where it is necessary, the distinction between Jane Austen and the omniscient narrator is observed, but generally, partly because it is clear that Jane Austen's values are close to those of the narrator, and partly because it is convenient, traditional and sensible to do so, the name "Jane Austen" is used to refer both to the actual person and to the narrator of the novels.
- Full Text:
The nouvelles of Henry James : a phenomeno-generic approach
- Authors: Bijker, Antony Jan
- Date: 1979
- Subjects: Novelists, American -- 19th century -- Diaries , James, Henry, 1843-1916 -- Notebooks, sketchbooks, etc. , James, Henry, 1843-1916 -- Diaries
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2168 , http://hdl.handle.net/10962/d1001819
- Description: From Introduction: The present work is about the nouvelles of Henry James and not about phenomenology. That is to say that I am more concerned with James's use of the form of the nouvelle than with the illustration of a method. But, as Roland Barthes has pointed out: "How can we tell the novel from the short story, the tale from the myth, suspense drama from tragedy ... without reference to a common model? Any critical attempt to describe even the most specific, the most historically orientated narrative form implies such a model. "I Hence, because phenomenology is somewhat alien to the Anglo-American critical sensibility, I must temporarily reverse this emphasis and discuss the phenomenological "model" that underlies my investigation of James and the nouvelle form. Elsewhere phenomenological theory will take precedence only when it throws light on what is a highly elusive genre.
- Full Text:
- Authors: Bijker, Antony Jan
- Date: 1979
- Subjects: Novelists, American -- 19th century -- Diaries , James, Henry, 1843-1916 -- Notebooks, sketchbooks, etc. , James, Henry, 1843-1916 -- Diaries
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2168 , http://hdl.handle.net/10962/d1001819
- Description: From Introduction: The present work is about the nouvelles of Henry James and not about phenomenology. That is to say that I am more concerned with James's use of the form of the nouvelle than with the illustration of a method. But, as Roland Barthes has pointed out: "How can we tell the novel from the short story, the tale from the myth, suspense drama from tragedy ... without reference to a common model? Any critical attempt to describe even the most specific, the most historically orientated narrative form implies such a model. "I Hence, because phenomenology is somewhat alien to the Anglo-American critical sensibility, I must temporarily reverse this emphasis and discuss the phenomenological "model" that underlies my investigation of James and the nouvelle form. Elsewhere phenomenological theory will take precedence only when it throws light on what is a highly elusive genre.
- Full Text:
A history of the Xhosa, c1700-1835
- Authors: Peires, J B (Jeffrey B)
- Date: 1977
- Subjects: Xhosa (African people) -- History
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2611 , http://hdl.handle.net/10962/d1013024
- Description: The boundaries of the territory occupied by the Xhosa fluctuated considerably, but in the period 1700-1835 they did not often extend west of the Sundays River, or east of the Mbashe River, along the coastal strip which separates the escarpment of South Africa's inland plateau from the Indian Ocean. It is an area of temperate grassland, permitting the cultivation of cereals and light crops, such as maize, millet, tobacco and pumpkins but better suited to stock-farming than intensive agriculture.
- Full Text:
- Authors: Peires, J B (Jeffrey B)
- Date: 1977
- Subjects: Xhosa (African people) -- History
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2611 , http://hdl.handle.net/10962/d1013024
- Description: The boundaries of the territory occupied by the Xhosa fluctuated considerably, but in the period 1700-1835 they did not often extend west of the Sundays River, or east of the Mbashe River, along the coastal strip which separates the escarpment of South Africa's inland plateau from the Indian Ocean. It is an area of temperate grassland, permitting the cultivation of cereals and light crops, such as maize, millet, tobacco and pumpkins but better suited to stock-farming than intensive agriculture.
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The biology of Clarias Gariepinus (Burchell, 1822) in Lake Sibaya, Kwazulu, with emphasis on its role as a predator
- Authors: Bruton, Michael N
- Date: 1977
- Subjects: Catfishes -- South Africa -- KwaZulu-Natal -- Lake Sibaya. , Clarias , Clariidae
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: vital:5886 , http://hdl.handle.net/10962/d1013313
- Description: Aspects of the biology of the sharptooth catfish, Clarias gariepinus (Burchell, 1822) were studied in a clear coastal lake (Lake Sibaya, KwaZulu.). Catfish reach maturity towards the end of the first year (total length 200-250mm) and breed in summer. Gonadal maturation is cyclical, and most fishes are ripe between September. and January e ach year. Maturation stages and fecundity are described. Twenty-two catfish spawning runs were witnessed. There were no large aggregations of catfish before the Summer rains, as reported in some impoundments and rivers, but catfish accumulated on the shallow terrace immediately before a spawning run. Spawning usually took place in flooded marginal areas after heavy rain on dark calm nights. Peak activity occurred between 20h00 and 02h30. Pre-nuptial aggression, courtship and mating are described and illustrated in detail for the first time from field observations. Gonadal products are released while in amplexus and fertilized externally. The eggs have an adhesive disc for attachment to plants, and develop rapidly. Early development and feeding are described. The growth rate of catfish was determined using rings on the pectoral spines, and validated using recent techniques. C.gariepinus in Lake Sibaya grow rapidly and remain in good condition to a length of 500mm, but larger catfish have a poor growth rate and condition, and few exceed 650mm. The modal length and weight of the Sibaya population is intermediate between that of other populations but the number and condition of larger catfish in Lake Sibaya is lower. Other studies on C.gariepinus growth are reviewed. Very high and low first year increments obtained previously may be due to methodological errors, but catfish do appear to have variable growth rates. The size reached by C.gariepinus is reviewed. Catfish are equipped morphologically and behaviourally to feed on a wide variety of·prey in different situations, but they usually feed at night on exposed, active benthic organisms. Social hunting facilitates the capture of prey which is too fast or manoevrable for a single predator. Food preferences are scored by three different methods and presented for the total catfish population and for different length groups, seasons, and habitats. Juveniles feed more often and on a greater variety of prey, and their condition is better than that of adults. The proportions of several food items in the diet changed at different lake levels as marginal areas became inundated. In particular, increasing lake levels resulted in a change in relative density of three cichlid prey in the shallow water feeding area of catfish. This situation provided the opportunity to study the effect of changing cichlid density on predation by catfish. The world literature on factors influencing the predator-prey relationship in fish is reviewed and several key factors are identified. The interaction of fish predators and prey in Africa, and particularly Lake Sibaya, is examined in detail, and prey density, modified by accessibility, is found to be an important factor. The effect of cichlid prey density on catfish predation was therefore investigated using field collections and experimental observations. Catfish prey on the cichlid species with greatest relative abundance, with some deviations which can be explained in terms of accessibility. The experimental results also describe feeding periodicity, imitative hunting and the effect of water depth , day-night light intensity changes and predator number on predation efficiency on cichlids. Catfish predation is discussed in terms of recent predation theory, and it is concluded that their ability to switch from one prey to another as prey availability (= density+ accessibility) changes , is an an important aspect of their success as predators. Catfish predate more efficiently on invertebrates, but feed largely on fishes after the first year. This preference for fish prey is probably related to food quality, as fishes contributed over 75% of the energy content of all ingested food, as well as abundant protein and the correct amino acid balance. Finally, I conclude that the role of C.gariepinus as a predator on S.mossambicus is three-fold: (a) to enhance species' fitness by removing enfeebled individuals i.e. to act as a 'cleanser' (b) to restrict the distribution of prey under certain conditions i.e. act as a 'restricter' (c) to dampen fluctuations in cichlid abundance i.e. act as a 'regulator'. The relative importance of these roles may alter at different lake levels in Lake Sibaya in response to changes in the vulnerability of fish prey.
- Full Text:
- Authors: Bruton, Michael N
- Date: 1977
- Subjects: Catfishes -- South Africa -- KwaZulu-Natal -- Lake Sibaya. , Clarias , Clariidae
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: vital:5886 , http://hdl.handle.net/10962/d1013313
- Description: Aspects of the biology of the sharptooth catfish, Clarias gariepinus (Burchell, 1822) were studied in a clear coastal lake (Lake Sibaya, KwaZulu.). Catfish reach maturity towards the end of the first year (total length 200-250mm) and breed in summer. Gonadal maturation is cyclical, and most fishes are ripe between September. and January e ach year. Maturation stages and fecundity are described. Twenty-two catfish spawning runs were witnessed. There were no large aggregations of catfish before the Summer rains, as reported in some impoundments and rivers, but catfish accumulated on the shallow terrace immediately before a spawning run. Spawning usually took place in flooded marginal areas after heavy rain on dark calm nights. Peak activity occurred between 20h00 and 02h30. Pre-nuptial aggression, courtship and mating are described and illustrated in detail for the first time from field observations. Gonadal products are released while in amplexus and fertilized externally. The eggs have an adhesive disc for attachment to plants, and develop rapidly. Early development and feeding are described. The growth rate of catfish was determined using rings on the pectoral spines, and validated using recent techniques. C.gariepinus in Lake Sibaya grow rapidly and remain in good condition to a length of 500mm, but larger catfish have a poor growth rate and condition, and few exceed 650mm. The modal length and weight of the Sibaya population is intermediate between that of other populations but the number and condition of larger catfish in Lake Sibaya is lower. Other studies on C.gariepinus growth are reviewed. Very high and low first year increments obtained previously may be due to methodological errors, but catfish do appear to have variable growth rates. The size reached by C.gariepinus is reviewed. Catfish are equipped morphologically and behaviourally to feed on a wide variety of·prey in different situations, but they usually feed at night on exposed, active benthic organisms. Social hunting facilitates the capture of prey which is too fast or manoevrable for a single predator. Food preferences are scored by three different methods and presented for the total catfish population and for different length groups, seasons, and habitats. Juveniles feed more often and on a greater variety of prey, and their condition is better than that of adults. The proportions of several food items in the diet changed at different lake levels as marginal areas became inundated. In particular, increasing lake levels resulted in a change in relative density of three cichlid prey in the shallow water feeding area of catfish. This situation provided the opportunity to study the effect of changing cichlid density on predation by catfish. The world literature on factors influencing the predator-prey relationship in fish is reviewed and several key factors are identified. The interaction of fish predators and prey in Africa, and particularly Lake Sibaya, is examined in detail, and prey density, modified by accessibility, is found to be an important factor. The effect of cichlid prey density on catfish predation was therefore investigated using field collections and experimental observations. Catfish prey on the cichlid species with greatest relative abundance, with some deviations which can be explained in terms of accessibility. The experimental results also describe feeding periodicity, imitative hunting and the effect of water depth , day-night light intensity changes and predator number on predation efficiency on cichlids. Catfish predation is discussed in terms of recent predation theory, and it is concluded that their ability to switch from one prey to another as prey availability (= density+ accessibility) changes , is an an important aspect of their success as predators. Catfish predate more efficiently on invertebrates, but feed largely on fishes after the first year. This preference for fish prey is probably related to food quality, as fishes contributed over 75% of the energy content of all ingested food, as well as abundant protein and the correct amino acid balance. Finally, I conclude that the role of C.gariepinus as a predator on S.mossambicus is three-fold: (a) to enhance species' fitness by removing enfeebled individuals i.e. to act as a 'cleanser' (b) to restrict the distribution of prey under certain conditions i.e. act as a 'restricter' (c) to dampen fluctuations in cichlid abundance i.e. act as a 'regulator'. The relative importance of these roles may alter at different lake levels in Lake Sibaya in response to changes in the vulnerability of fish prey.
- Full Text:
The chemistry of the wattle tannins
- Authors: Roux, David Gerhardus
- Date: 1953
- Subjects: Tannin plants , Tannins , Wattles (Plants)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: vital:4492 , http://hdl.handle.net/10962/d1013098
- Description: Four species of acacia of Auatralian origin are associated with the wattle industry in South Africa. Black wattle, Acacia mollissima willd., is the most important of these and is today almost exclusively cultivated. The tree grows successfully only in a limited area of rich soil and high rainfall and is easily affected by adverse conditions caused by insect pests, frost damage and drought. Expansion of the area under cultivation is therefore, not feasible, although the world demand for vegetable extracts far exceeds the available supply. The remaining species such as green (Acacia decurrrens willd.) and silver wattles (Acacia dealbata Link.) possess many desirable characteristics which resist such adverse factors. Their barks, however, give reddish extracts, which are considered unsuitable for tannery usage because of the red colour they impart to the leather. Hybridisation studies, involving the crossing of green and silver wattle with the black, and aimed at produc1ng progenies containing many of the desirable characterlstics of the parent plants, are thus a natural result and have been in progress for a considerable period. Summary, p. i.
- Full Text:
- Authors: Roux, David Gerhardus
- Date: 1953
- Subjects: Tannin plants , Tannins , Wattles (Plants)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: vital:4492 , http://hdl.handle.net/10962/d1013098
- Description: Four species of acacia of Auatralian origin are associated with the wattle industry in South Africa. Black wattle, Acacia mollissima willd., is the most important of these and is today almost exclusively cultivated. The tree grows successfully only in a limited area of rich soil and high rainfall and is easily affected by adverse conditions caused by insect pests, frost damage and drought. Expansion of the area under cultivation is therefore, not feasible, although the world demand for vegetable extracts far exceeds the available supply. The remaining species such as green (Acacia decurrrens willd.) and silver wattles (Acacia dealbata Link.) possess many desirable characteristics which resist such adverse factors. Their barks, however, give reddish extracts, which are considered unsuitable for tannery usage because of the red colour they impart to the leather. Hybridisation studies, involving the crossing of green and silver wattle with the black, and aimed at produc1ng progenies containing many of the desirable characterlstics of the parent plants, are thus a natural result and have been in progress for a considerable period. Summary, p. i.
- Full Text:
An investigation into the circumstances relating to the cattle-killing delusion in Kaffraria, 1856-1857
- Authors: Dowsley, Eileen D'Altera
- Date: 1932
- Subjects: Cattle Killing, 1856-1857 , Cape of Good Hope (South Africa) -- History -- 1853-1871 , Xhosa (African people) -- History , Grey, George, Sir, 1812-1898 , Nongqawuse, 1841-1898 , Mhlakaza -- Xhosa seer -- 1800?-1857 , Sarhili -- Xhosa paramount chief -- ca.1814-1892
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2538 , http://hdl.handle.net/10962/d1002390
- Description: Introductory: If the relations existing between the Native chiefs and the Colony which Sir George Grey found on his arrival are to be fully understood, a brief consideration of Cathcart’s policy and Frontier settlement is necessary. When Cathcart came out as Governor in 1852, he found the rebel chief Sandile, with associate chieftans’ and large bands of followers, still occupying their locations in the Amatola ranges. From this haunt no force had as yet been able to drive them. During the series of skirmishes known as the Eighth Kaffir War, their first crop of Indian corn was destroyed so early in the season as to allow of a second crop springing up. This unusual phenomenon inspired prophet Umlangeni to claim that he had worked a miracle. Fortunately later reverses and the expulsion of Sanailli from his mountain fastness discredited this thoughtful opportunist. Sandilli, as paramount chief of the Gaikas, might have held and influential position in the councils of the Kaffrarian chiefs, that he did not hold such a position, was due, in Charles Brownlee’s opinion, to his timid and suspicious nature and to the fact that his mental capacity was ‘hardly above mediocrity’. He was unable to fight owing to lameness, and he lacked ‘sufficient’ resciution and strength of mind to resist the evil influence of the bad advisers, nevertheless he could be obstinate and he never, to the end of his life, gave up on the idea of getting back to this old locations in the Amatolas. Macomo with some three thousand followers had likewise evaded all attempts to turn him out of this haunts in the mountain range. He, together with his associate the Tambookie chief Quesha, and diverse rebel Hotttentots, indulged in the frequent marauding forays into the surrounding country. Macomo was the eldest of Gaika’s sons and was “allowed by all to be the greatest politician and best warrior in Kaffraria’. During the minority of Sandilli Macomo had acted as his regent and had attained great influence over the tribe; this he afterwards lost for he moved to the neighbourhood of Fort Beaufort, where in a state of intoxication most of this time was passed. He had in Brownlee’s opinion, done more mischief in the war than any other chief. Great jealously was felt between Macomo and Sandilli, especially on the part of the former; this was shown through the cattle killing period in his efforts to involve Sandilli, while attempting to keep on the right side of the Government himself. Further south, indeed within the Colony itself, such petty chiefs as Seyolo and Botman, lurking in the Fish River bush, and the Keiskamma kloofs, rendered the main road dangerous, and even succeeded, for a time, in completely cutting the ling of communication between Kingwilliamstown and Grahamstown.
- Full Text:
- Authors: Dowsley, Eileen D'Altera
- Date: 1932
- Subjects: Cattle Killing, 1856-1857 , Cape of Good Hope (South Africa) -- History -- 1853-1871 , Xhosa (African people) -- History , Grey, George, Sir, 1812-1898 , Nongqawuse, 1841-1898 , Mhlakaza -- Xhosa seer -- 1800?-1857 , Sarhili -- Xhosa paramount chief -- ca.1814-1892
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2538 , http://hdl.handle.net/10962/d1002390
- Description: Introductory: If the relations existing between the Native chiefs and the Colony which Sir George Grey found on his arrival are to be fully understood, a brief consideration of Cathcart’s policy and Frontier settlement is necessary. When Cathcart came out as Governor in 1852, he found the rebel chief Sandile, with associate chieftans’ and large bands of followers, still occupying their locations in the Amatola ranges. From this haunt no force had as yet been able to drive them. During the series of skirmishes known as the Eighth Kaffir War, their first crop of Indian corn was destroyed so early in the season as to allow of a second crop springing up. This unusual phenomenon inspired prophet Umlangeni to claim that he had worked a miracle. Fortunately later reverses and the expulsion of Sanailli from his mountain fastness discredited this thoughtful opportunist. Sandilli, as paramount chief of the Gaikas, might have held and influential position in the councils of the Kaffrarian chiefs, that he did not hold such a position, was due, in Charles Brownlee’s opinion, to his timid and suspicious nature and to the fact that his mental capacity was ‘hardly above mediocrity’. He was unable to fight owing to lameness, and he lacked ‘sufficient’ resciution and strength of mind to resist the evil influence of the bad advisers, nevertheless he could be obstinate and he never, to the end of his life, gave up on the idea of getting back to this old locations in the Amatolas. Macomo with some three thousand followers had likewise evaded all attempts to turn him out of this haunts in the mountain range. He, together with his associate the Tambookie chief Quesha, and diverse rebel Hotttentots, indulged in the frequent marauding forays into the surrounding country. Macomo was the eldest of Gaika’s sons and was “allowed by all to be the greatest politician and best warrior in Kaffraria’. During the minority of Sandilli Macomo had acted as his regent and had attained great influence over the tribe; this he afterwards lost for he moved to the neighbourhood of Fort Beaufort, where in a state of intoxication most of this time was passed. He had in Brownlee’s opinion, done more mischief in the war than any other chief. Great jealously was felt between Macomo and Sandilli, especially on the part of the former; this was shown through the cattle killing period in his efforts to involve Sandilli, while attempting to keep on the right side of the Government himself. Further south, indeed within the Colony itself, such petty chiefs as Seyolo and Botman, lurking in the Fish River bush, and the Keiskamma kloofs, rendered the main road dangerous, and even succeeded, for a time, in completely cutting the ling of communication between Kingwilliamstown and Grahamstown.
- Full Text: