Fishes of Southern African estuaries: from species to systems
- Authors: Whitfield, Alan K
- Date: 2022
- Subjects: Estuarine fishes -- South Africa , Estuarine fishes -- Africa, Southern , Fishes -- Africa, Southern -- Identification , Estuaries -- Africa, Southern
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/97933 , vital:31512
- Description: South Africa, despite its relatively small size, is often called “a world in one country”. This phrase arises mainly from the range of oceanographic and climatic features; geological and geomorphological attributes, the diversity of human cultures, languages, races and religions; the mix of developed and developing economies; the wide range in political opinion and parties; the vast array of mineral resources; and finally, what biologists find most interesting of all, the richness of the indigenous flora and fauna. Although southern African aquatic scientists cannot boast an equivalent of the Cape Floral Kingdom, the stretch of coast between northern Namibia and southern Mozambique has a particularly rich marine biota, accounting for almost 15% of all the coastal marine species known world-wide. The richness of the ichthyofauna is due to a number of factors, including the variety of habitats around the subcontinent, ranging from coral reefs, kelp beds, sheltered bays, sandy beaches, exposed rocky shores, coastal lakes to estuaries. In addition, southern Africa is the meeting place of three great oceans and is thus the recipient of species from each of these separate faunas. In comparison to land vertebrates, the world’s fish fauna is by no means well-known, either taxonomically or with regard to the biology of the component species. Apart from the very large number of fish species (estimated to be approximately 40 000), and the difficulties posed by the medium in which they live, there are other reasons for the above state of affairs. An obvious and universal reason is the shortage of funding available for taxonomic, biological and ecological studies, with increasing emphasis being placed on aquaculture, mariculture and fisheries related work. This situation is unlikely to improve and many research institutions around the world are operating on shrinking rather than expanding budgets. The onus of responsibility to disseminate information on the world’s fish faunas therefore rests squarely on the shoulders of those who are fortunate enough to be employed in the fascinating field of ichthyology. This book, which is a major revision and expansion of an earlier monograph (Whitfield 1998), is an attempt to synthesize the available information on fishes associated with southern African estuaries and to highlight the importance of conserving these systems for both fishes and people of the region. Limited reference is made to international estuarine fish research due to space constraints and readers are referred to global ichthyological reviews in this regard. The estuaries of southern Africa (defined as south of 26°S latitude for the purposes of this book) are highly diverse, both in terms of form and functioning. They range from the clear Kosi Estuary entering the coral rich subtropical Indian Ocean waters on the east coast, to the turbid Orange River flowing into the cool upwelled waters of the Atlantic Ocean on the west coast. The estuaries of the subcontinent are fed by catchments with a wide variety of climatic and geological characteristics. For example, the cool-temperate west coast is characterized by good winter rains and relatively dry summers, whereas on the subtropical east coast the opposite rainfall pattern prevails. While most south-western Cape estuaries are fed by rivers with low suspended sediment levels, those of KwaZulu-Natal normally carry high silt loads during the rainy season. Between Mossel Bay and St Francis Bay, rainfall patterns show no distinct seasonal peak and relatively acidic waters with low nutrient levels enter a variety of estuarine types along this section of the coast. The Eastern Cape is a region of transition between the subtropical and warm-temperate biogeographic provinces, and is prone to both droughts and floods occurring during any season of the year. The southern African estuarine environment is an unpredictable and often harsh habitat to occupy, yet each year millions of larval and juvenile fishes enter and thrive in these systems. The fish species that utilize estuaries as nursery areas exhibit great diversity in size, body form, salinity tolerance, diet, habitat preference and breeding behaviour. There is also a complete gradation in terms of the dependence that each species has on the estuarine environment. These and many other issues relating to the biology and ecology of estuary-associated fish species in southern Africa are explored in the chapters to follow. It is my sincere wish that our improved knowledge of these species and their environmental requirements will contribute to the wise management and conservation of these valuable ecosystems. , 2022 Edition
- Full Text:
- Date Issued: 2022
- Authors: Whitfield, Alan K
- Date: 2022
- Subjects: Estuarine fishes -- South Africa , Estuarine fishes -- Africa, Southern , Fishes -- Africa, Southern -- Identification , Estuaries -- Africa, Southern
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/97933 , vital:31512
- Description: South Africa, despite its relatively small size, is often called “a world in one country”. This phrase arises mainly from the range of oceanographic and climatic features; geological and geomorphological attributes, the diversity of human cultures, languages, races and religions; the mix of developed and developing economies; the wide range in political opinion and parties; the vast array of mineral resources; and finally, what biologists find most interesting of all, the richness of the indigenous flora and fauna. Although southern African aquatic scientists cannot boast an equivalent of the Cape Floral Kingdom, the stretch of coast between northern Namibia and southern Mozambique has a particularly rich marine biota, accounting for almost 15% of all the coastal marine species known world-wide. The richness of the ichthyofauna is due to a number of factors, including the variety of habitats around the subcontinent, ranging from coral reefs, kelp beds, sheltered bays, sandy beaches, exposed rocky shores, coastal lakes to estuaries. In addition, southern Africa is the meeting place of three great oceans and is thus the recipient of species from each of these separate faunas. In comparison to land vertebrates, the world’s fish fauna is by no means well-known, either taxonomically or with regard to the biology of the component species. Apart from the very large number of fish species (estimated to be approximately 40 000), and the difficulties posed by the medium in which they live, there are other reasons for the above state of affairs. An obvious and universal reason is the shortage of funding available for taxonomic, biological and ecological studies, with increasing emphasis being placed on aquaculture, mariculture and fisheries related work. This situation is unlikely to improve and many research institutions around the world are operating on shrinking rather than expanding budgets. The onus of responsibility to disseminate information on the world’s fish faunas therefore rests squarely on the shoulders of those who are fortunate enough to be employed in the fascinating field of ichthyology. This book, which is a major revision and expansion of an earlier monograph (Whitfield 1998), is an attempt to synthesize the available information on fishes associated with southern African estuaries and to highlight the importance of conserving these systems for both fishes and people of the region. Limited reference is made to international estuarine fish research due to space constraints and readers are referred to global ichthyological reviews in this regard. The estuaries of southern Africa (defined as south of 26°S latitude for the purposes of this book) are highly diverse, both in terms of form and functioning. They range from the clear Kosi Estuary entering the coral rich subtropical Indian Ocean waters on the east coast, to the turbid Orange River flowing into the cool upwelled waters of the Atlantic Ocean on the west coast. The estuaries of the subcontinent are fed by catchments with a wide variety of climatic and geological characteristics. For example, the cool-temperate west coast is characterized by good winter rains and relatively dry summers, whereas on the subtropical east coast the opposite rainfall pattern prevails. While most south-western Cape estuaries are fed by rivers with low suspended sediment levels, those of KwaZulu-Natal normally carry high silt loads during the rainy season. Between Mossel Bay and St Francis Bay, rainfall patterns show no distinct seasonal peak and relatively acidic waters with low nutrient levels enter a variety of estuarine types along this section of the coast. The Eastern Cape is a region of transition between the subtropical and warm-temperate biogeographic provinces, and is prone to both droughts and floods occurring during any season of the year. The southern African estuarine environment is an unpredictable and often harsh habitat to occupy, yet each year millions of larval and juvenile fishes enter and thrive in these systems. The fish species that utilize estuaries as nursery areas exhibit great diversity in size, body form, salinity tolerance, diet, habitat preference and breeding behaviour. There is also a complete gradation in terms of the dependence that each species has on the estuarine environment. These and many other issues relating to the biology and ecology of estuary-associated fish species in southern Africa are explored in the chapters to follow. It is my sincere wish that our improved knowledge of these species and their environmental requirements will contribute to the wise management and conservation of these valuable ecosystems. , 2022 Edition
- Full Text:
- Date Issued: 2022
The Fishes of Zimbabwe and their Biology
- Authors: Marshall, Brian
- Date: 2010
- Subjects: Estuarine fishes -- Zimbabwe , Estuarine fishes -- Africa, Southern , Fishes -- Africa, Southern -- Identification , Estuaries -- Africa, Southern
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/167948 , vital:41524
- Description: The first comprehensive book on the fishes of Zimbabwe appeared in 1961 and was written by Rex Jubb. He followed it with a major treatise on the fishes of southern Africa published in 1967. These books were published at a time when interest in fishes – partly stimulated by the creation of Lake Kariba –was growing, and they were welcomed by anglers and scientists alike. Zimbabwean ichthyology progressed rapidly during the years following their publication and knowledge about our fishes grew steadily. New insights and understanding of their systematics led to numerous taxonomic revisions, bringing with them inevitable changes to their scientific names. At the same time increased collecting meant that new species were being added to the Zimbabwean list. By the early 1970s Jubb’s books had become outdated and there was a clear need for a new volume on the fishes of this country. The National Museums and Monuments met this need by publishing Graham Bell-Cross’ The Fishes of Rhodesia in 1976. This book was available at a remarkably low price and such was its popularity that it was soon out of print. It rapidly became outdated as well and was revised by John Minshull as the Fishes of Zimbabwe, published in 1988. This version had a number of new features such as the inclusion of exotic species and species discovered in the country since 1976, as well as name changes brought about by new developments in taxonomy. It, too, was available at a very low price and has proved to be very popular; the demand was so great that it was reprinted without alteration in the 1990s. By this time, however, it had also become outdated and there was a need for yet another revision, or for a completely new type of book. I have chosen the latter option in preparing this book, since there seemed little point in attempting to revise the earlier ones within their original format. I felt that it would not be desirable to produce another field guide type of book that would have to compete with Paul Skelton’s superb volume, A Complete Guide to the Freshwater Fishes of Southern Africa, first published in 1993, with a second edition eight years later. Instead, I decided that I should try to summarise the existing data about fishes in Zimbabwe. My dealings with students and inexperienced fish biologists has made it clear that many of them do not know what work has been done, or not done, on Zimbabwe’s fishes and they are not familiar with the literature. Much of it is, in any case, to be found in obscure publications that are not readily available in Zimbabwean libraries, which have declined in recent years and no longer subscribe to major international journals or even to local ones. This makes it very difficult to keep up with information or to track it down. I am aware, of course, that such a book will never be complete and may already be outdated at the time of its publication, but I hope that it will supply the basic background information for anyone interested in Zimbabwean fishes and provide a platform from which further studies can be launched. Wherever possible, I have used only data from Zimbabwe, although there may be an extensive literature from other countries for widespread or economically important species, such as Clarias gariepinus or Oreochromis mossambicus. This was a conscious decision because I wanted to summarise what is known about the fish in this country, so that other workers can assess what still needs to be done. Nevertheless, I have used some data from outside Zimbabwe, especially for fish from the upper Zambezi because of its relevance to our situation. As far as possible I have tried to use only published works as references, with the exception of university theses and some institutional reports, since most unpublished work is generally difficult to locate and ephemeral. The scientific names of fishes often change as systematic knowledge advances and the reader will note that there have been many changes since Bell-Cross & Minshull (1988) was published. Common names are a problem because of local variations and anglers in particular have various names (or nicknames) for popular angling species; I have used the standard names with these other names included in brackets where necessary.
- Full Text:
- Date Issued: 2010
- Authors: Marshall, Brian
- Date: 2010
- Subjects: Estuarine fishes -- Zimbabwe , Estuarine fishes -- Africa, Southern , Fishes -- Africa, Southern -- Identification , Estuaries -- Africa, Southern
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/167948 , vital:41524
- Description: The first comprehensive book on the fishes of Zimbabwe appeared in 1961 and was written by Rex Jubb. He followed it with a major treatise on the fishes of southern Africa published in 1967. These books were published at a time when interest in fishes – partly stimulated by the creation of Lake Kariba –was growing, and they were welcomed by anglers and scientists alike. Zimbabwean ichthyology progressed rapidly during the years following their publication and knowledge about our fishes grew steadily. New insights and understanding of their systematics led to numerous taxonomic revisions, bringing with them inevitable changes to their scientific names. At the same time increased collecting meant that new species were being added to the Zimbabwean list. By the early 1970s Jubb’s books had become outdated and there was a clear need for a new volume on the fishes of this country. The National Museums and Monuments met this need by publishing Graham Bell-Cross’ The Fishes of Rhodesia in 1976. This book was available at a remarkably low price and such was its popularity that it was soon out of print. It rapidly became outdated as well and was revised by John Minshull as the Fishes of Zimbabwe, published in 1988. This version had a number of new features such as the inclusion of exotic species and species discovered in the country since 1976, as well as name changes brought about by new developments in taxonomy. It, too, was available at a very low price and has proved to be very popular; the demand was so great that it was reprinted without alteration in the 1990s. By this time, however, it had also become outdated and there was a need for yet another revision, or for a completely new type of book. I have chosen the latter option in preparing this book, since there seemed little point in attempting to revise the earlier ones within their original format. I felt that it would not be desirable to produce another field guide type of book that would have to compete with Paul Skelton’s superb volume, A Complete Guide to the Freshwater Fishes of Southern Africa, first published in 1993, with a second edition eight years later. Instead, I decided that I should try to summarise the existing data about fishes in Zimbabwe. My dealings with students and inexperienced fish biologists has made it clear that many of them do not know what work has been done, or not done, on Zimbabwe’s fishes and they are not familiar with the literature. Much of it is, in any case, to be found in obscure publications that are not readily available in Zimbabwean libraries, which have declined in recent years and no longer subscribe to major international journals or even to local ones. This makes it very difficult to keep up with information or to track it down. I am aware, of course, that such a book will never be complete and may already be outdated at the time of its publication, but I hope that it will supply the basic background information for anyone interested in Zimbabwean fishes and provide a platform from which further studies can be launched. Wherever possible, I have used only data from Zimbabwe, although there may be an extensive literature from other countries for widespread or economically important species, such as Clarias gariepinus or Oreochromis mossambicus. This was a conscious decision because I wanted to summarise what is known about the fish in this country, so that other workers can assess what still needs to be done. Nevertheless, I have used some data from outside Zimbabwe, especially for fish from the upper Zambezi because of its relevance to our situation. As far as possible I have tried to use only published works as references, with the exception of university theses and some institutional reports, since most unpublished work is generally difficult to locate and ephemeral. The scientific names of fishes often change as systematic knowledge advances and the reader will note that there have been many changes since Bell-Cross & Minshull (1988) was published. Common names are a problem because of local variations and anglers in particular have various names (or nicknames) for popular angling species; I have used the standard names with these other names included in brackets where necessary.
- Full Text:
- Date Issued: 2010
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