Henri J. Dumont – författare

This volume reports on the findings of experts on tropical zooplankton gathered at a meeting in Kariba, Zimbabwe, in 1991. Some basic questions were asked on community composition and biodiversity in the tropics versus the non-tropics. Old ideas on the nature of zooplankton, which were found to be wider than the `classical' rotifers, cladocerans and copepods, as well as on the number of species in tropical waters, are now beginning to break down accordingly as more and more blank spots in the tropics are explored and as more in-depth studies on the zooplankton of tropical lakes are becoming available. This volume contains a mix of papers discussing the two alternative controls (bottom-up and top-down) of zooplankton community structure and these constitute another step towards a coherent theory of tropical ecosystem theory.

Jellyfish, a group that includes scyphomedusae, hydromedusae, siphonophores and ctenophores, are important zooplankton predators throughout the world's estuaries and oceans. These beautiful creatures have come to public attention as featured exhibits in aquaria and in news headlines as invaders and as providers of genes used in biomedical research. Nevertheless, jellyfish are generally considered to be nuisances because they interfere with human activities by stinging swimmers, clogging power plant intakes and nets of fishermen and fish farms, and competing with fish and eating fish eggs and larvae. There is concern that environmental changes such as global warming, eutrophication, and over-fishing may result in increased jellyfish populations. The literature reviews and research papers in this volume explore the interactions between jellyfish and humans.Papers cover: the medical aspects of jellyfish stings; jellyfish as human food and jellyfish fisheries; interactions of jellyfish and fish; effects of environmental changes on jellyfish; effects of introduced ctenophores on the Black Sea ecosystem; factors causing increases or concentrations of jellyfish; and others aspects of jellyfish ecology. This is an important reference for students and professional marine biologists, oceanographers, fishery scientists, and aquarists.

The Mediterranean, Black, and Caspian Seas represent three fragments of the former Tethys Sea, and are thus of great interest to understanding the evolution of the entire region where Eurasia, Africa and the Arabian Peninsula meet. Fishing activity and maritime traffic through the Dardanelles and Bosporus, and via the Lenin Canal to the Caspian Sea, have greatly intensified. Moreover, all major European rivers are now linked by canals, meaning that ships can navigate from the mouth of the Volga to the Baltic, from the Danube to the Rhine, and from there to all other major European Rivers. Such an anastomosed system not only allows ships to pass between basins: biota follow in their wake, and thus the Black Sea and Caspian fauna and flora, long sequestered in their closed basins, are suddenly given an opportunity to "escape". On the other hand, alien invaders increasingly find their way to the three seas, as stowaways in ballast water tanks or attached to the hulls. Some of the newcomers expanded to enormous numbers in the receiving ecosystem, where they may cause great economic damage.The book provides an up-to-date overview of the situation in the Ponto-Caspian with regard to the jelly invasions that have been perturbing the local pelagic ecosystems since the early 1980s, contrasting that with biological invasions elsewhere, to try and identify general underlying principles.

The Mediterranean, Black, and Caspian Seas represent three fragments of the former Tethys Sea, and are thus of great interest to understanding the evolution of the entire region where Eurasia, Africa and the Arabian Peninsula meet. Fishing activity and maritime traffic through the Dardanelles and Bosporus, and via the Lenin Canal to the Caspian Sea, have greatly intensified. Moreover, all major European rivers are now linked by canals, meaning that ships can navigate from the mouth of the Volga to the Baltic, from the Danube to the Rhine, and from there to all other major European Rivers. Such an anastomosed system not only allows ships to pass between basins: biota follow in their wake, and thus the Black Sea and Caspian fauna and flora, long sequestered in their closed basins, are suddenly given an opportunity to "escape". On the other hand, alien invaders increasingly find their way to the three seas, as stowaways in ballast water tanks or attached to the hulls. Some of the newcomers expanded to enormous numbers in the receiving ecosystem, where they may cause great economic damage.The book provides an up-to-date overview of the situation in the Ponto-Caspian with regard to the jelly invasions that have been perturbing the local pelagic ecosystems since the early 1980s, contrasting that with biological invasions elsewhere, to try and identify general underlying principles.

What have we learnt about the Nile since the mid-1970s, the moment when Julian Rzóska decided that the time had come to publish a comprehensive volume about the biology, and the geological and cultural history of that great river? And what changes have meanwhile occurred in the basin? The human popu- tion has more than doubled, especially in Egypt, but also in East Africa. Locally, industrial development has taken place, and the Aswan High Dam was clearly not the last major infrastructure work that was carried out. More dams have been built, and some water diversions, like the Toshka lakes, have created new expanses of water in the middle of the Sahara desert. What are the effects of all this on the ec- ogy and economy of the Basin? That is what the present book sets out to explore, 33 years after the publi- tion of “The Nile: Biology of an Ancient River”. Thirty-seven authors have taken up the challenge, and have written the “new” book. They come from 13 different countries, and 15 among them represent the largest Nilotic states (Egypt, Sudan, Ethiopia, Uganda, and Kenya). Julian Rzóska died in 1984, and most of the - authors of his book have now either disappeared or retired from research. Only Jack Talling and Samir Ghabbour were still available to participate again.

Gaining some momentum in the early 18th century, accelerating in the 19th century, and culminating in the second half of the 20th century, a sharp increase in the number of non-native animal and plant species introduced to foreign ecosystems, terrestrial and aquatic alike, occurred. In marine systems, they appeared in the pelagic as well as in near-shore zones. Like an infection, this process rapidly spread globally. Currently, the “spontaneous” appearance of invasive, non-native species in various taxonomic groups, ranging from algae and protozoa to fishes, and their naturalization to new biotopes has become like an epidemic to coastal regions of the World Ocean, inland seas, and to brackish and freshwater systems as well.This book provides a comprehensive synthesis of all aspects regarding the non-native species in the Ponto-Caspian seas, including their introduction, naturalization, geographical distribution and consequences for native biota with special attention to gelatinous species. Highlighting important research findings, this book provides an overview of the invasion process from transportation patterns and reasons for establishment success to ecological impacts and role of abiotic factors and climate change.Increasing awareness of the problems associated with invasions of non-native species in Ponto-Caspian seas has led to rapid growth in research on this topic. This book provides updated summary of this fast-growing field of research, and is an essential text for established researchers, undergraduate and graduate students.

Our knowledge of the limnology of the waters situated, roughly, between the tropics of cancer and of capricorn, has depended for a long time on the expedition-approach, and therefore developed in a rather irregular, haphazard way, with the personal incentive of a small number of individuals as the main driving force. Things slowly started to change in the 1950s, and at an accelerating rate in the 1960s and 1970s. The IBP, and later the SCOPE and MAB programs, whatever their shortcomings are or may have been, promoted in-depth research of a small number of tropical lakes. For one thing, they showed the need for the creation of in situ limnological research institutes. When, in the 1970s, limnological research facilities or their nuclei began to appear in the tropical zones of all continents, an interesting phenomenon occurred: while most of the young native limnologists had received their training in advanced centres or courses held in the temperate (and developed) climatic zones, quite a few of their former supervisors or their associates became interested in warm lakes and rivers as well, using the new or newly expanded local institutes. We are, today, still in this phase and it is, apparently, expanding even further. Although not all experiments of this kind lead to happy marriages, a few were quite successful, and several papers contained in the present volume are hoped to reflect this.

Our knowledge of the limnology of the waters situated, roughly, between the tropics of cancer and of capricorn, has depended for a long time on the expedition-approach, and therefore developed in a rather irregular, haphazard way, with the personal incentive of a small number of individuals as the main driving force. Things slowly started to change in the 1950s, and at an accelerating rate in the 1960s and 1970s. The IBP, and later the SCOPE and MAB programs, whatever their shortcomings are or may have been, promoted in-depth research of a small number of tropical lakes. For one thing, they showed the need for the creation of in situ limnological research institutes. When, in the 1970s, limnological research facilities or their nuclei began to appear in the tropical zones of all continents, an interesting phenomenon occurred: while most of the young native limnologists had received their training in advanced centres or courses held in the temperate (and developed) climatic zones, quite a few of their former supervisors or their associates became interested in warm lakes and rivers as well, using the new or newly expanded local institutes. We are, today, still in this phase and it is, apparently, expanding even further. Although not all experiments of this kind lead to happy marriages, a few were quite successful, and several papers contained in the present volume are hoped to reflect this.

This book IS an attempt to review the state-of-the-art in the fields of limnology and of marine biology in the Sudan. The need for it became apparent while we were doing some joint field work in the Nile Valley and along the Red Sea coast. We feel that several reasons justify its publication. Firstly, a vast amount of information is being gathered year after year by the staff of the Hydrobiological Research U nit of the University of Khartoum, in conjunction with the faculties of Medicine and Agriculture of this university; much of this information fails to find an outlet to the scientific literature. Secondly, we did not want to restrict our book to the Nile Valley. The Nile is such a vital life artery to the Sudan that it has dominated limnological efforts in this country, to the neglect of other geographical areas. The same holds true for the field of marine biology, which lags far behind, despite the existence of a marine field laboratory at Suakin and a research institute at Port Sudan. It is hoped that both will develop considerably in the near future.

At the end of the first international Symposium on Rotifers diately accepted to do this, and kindly made an entire in Lunz, Austria, September 1976, entousiastic pleas were special volume of its Journal 'Hydrobiologia' available made for a second gathering of possibly the same format for this purpose. Also, arrangements were made to have and spirit that had made the first one such a great success. the proceedings out as quickly as possible. The proceedings include all papers that were presented One of us (HJD), 'supported' herein by his friends Charles E. King and Jens Petter Nilssen in particular, tentatively in Gent, and two communications by collegues who could suggested that Gent University might host a meeting of not attend in person. They thus amount to 23 original con­ this kind, having in mind that since the Xlth congress of tributions, including the summaries of the workshops. All SIL in 1950, no other SIL activity had take places in have been reviewed by the editors, and many, in addition Belgium. In view of the relatively large number of Be1gian by one or more referees. Manuscripts have been adjusted, rotifer workers, many among which are or were active in wherever needed, for grammar, clarity of meaning, and Gent, this proposal sounded acceptable to the attendance length. However, where possible, the flavor of some per­ of the Lunz meeting, who then gave each other rendez sonal styles was left unaltered.

`Jellyfish', a group that includes scyphomedusae, hydromedusae, siphonophores and ctenophores, are important zooplankton predators throughout the world's estuaries and oceans. These beautiful creatures have come to public attention as featured exhibits in aquaria and in news headlines as invaders and as providers of genes used in biomedical research. Nevertheless, jellyfish are generally considered to be nuisances because they interfere with human activities by stinging swimmers, clogging power plant intakes and nets of fishermen and fish farms, and competing with fish and eating fish eggs and larvae. There is concern that environmental changes such as global warming, eutrophication, and over-fishing may result in increased jellyfish populations. The literature reviews and research papers in this volume explore the interactions between jellyfish and humans. Papers cover the medical aspects of jellyfish stings, jellyfish as human food and jellyfish fisheries, interactions of jellyfish and fish, effects of environmental changes on jellyfish, effects of introduced ctenophores on the Black Sea ecosystem, factors causing increases or concentrations of jellyfish, and others aspects of jellyfish ecology. This is an important reference for students and professional marine biologists, oceanographers, fishery scientists, and aquarists.

This book contains a collection of papers dealing with various aspects of the biology and aquaculture of the large branchiopod crustacea; the Anostraca, Conchostraca, and Notostraca. Included are many of the papers presented at the Second International Large Branchiopod Symposium convened in Ulm, Germany, 30 July--3 August 1993. Additional manuscripts contributed by colleagues who were unable to attend are also included. A special feature of this volume is a checklist of the Anostraca, including information on distribution, location of type material, taxonomic problems, and literature references.

This volume reports on the findings of experts on tropical zooplankton gathered at a meeting in Kariba, Zimbabwe, in 1991. Some basic questions were asked on community composition and biodiversity in the tropics versus the non-tropics. Old ideas on the nature of zooplankton, which were found to be wider than the `classical' rotifers, cladocerans and copepods, as well as on the number of species in tropical waters, are now beginning to break down accordingly as more and more blank spots in the tropics are explored and as more in-depth studies on the zooplankton of tropical lakes are becoming available. This volume contains a mix of papers discussing the two alternative controls (bottom-up and top-down) of zooplankton community structure and these constitute another step towards a coherent theory of tropical ecosystem theory.