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Book (series)Review of Tropical Reservoirs and Their Fisheries - The cases of Lake Nasser, Lake Volta and Indo-Gangetic Basin Reservoirs. 2011
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No results found.Freshwaters contribute 15 percent of the world’s reported fish catch, or about 10.1 million tonnes in 2006, most of which comes from tropical systems. The true contribution of tropical inland fisheries is likely to be higher, as less than half of the inland capture production is actually reported. While reservoir fisheries are already an essential component of this production, the potential of most of them may even exceed their current catch levels. Opportunities exist to increase prod uctivity, provided that environmentally and socially sustainable management systems can be adopted. To realize this untapped potential, it is necessary to improve understanding of the processes influencing reservoir productivity in such a way as to involve both biological principles and stakeholder participation, as each reservoir has different properties and different research and management institutions. Seen in isolation, catch and productivity data of individual reservoirs may be difficult to interpret. The present technical paper attempts to address this issue by reviewing the knowledge accumulated in reservoirs in some very different tropical river basins: the Indus and Ganges/Brahmaputra Basin in India, the Nile River Basin in Eastern Africa and the Volta River Basin in West Africa. In particular, it focuses on many of the reservoirs of northern India and Pakistan in the Indus and Ganges systems, Lake Nasser in the Nile River and Lake Volta in the Volta R iver. Information collated from grey and published literature on the three basins is synthesized and standardized with reference to wider knowledge and up-to-date information on tropical reservoir fisheries. A considerable quantity of data and information were collected on many aspects of the systems of the three reservoirs, including hydrological, biophysical and limnological features, primary production, and fish and fisheries data. This information was condensed and synthesized wi th the aim of providing a baseline against which the ecological changes that have taken place since impoundment can be described and analysed. Efforts are made to explain changes in fish catch in relation to climatic variations, ecological succession and fishing effort. The review shows that biological data and information are generally available. However, as is also common elsewhere, all three cases suffer from the general tendency to isolate and compartmentalize research into separ ate disciplines. Usually, there is very limited cross-disciplinary flow of information or recognition of how results of various disciplines can contribute to a more comprehensive understanding of the behaviour of fish populations, human communities and ecosystems and the productive activities that depend on them. This uniform tendency severely hampered the identification of relevant management actions. A more pragmatic and holistic understanding of reservoir ecosystems is needed in order to guide the choice of indicators and the development of monitoring systems that can inform management of changes in reservoir productivity and, hence, the potential catch. The next step would be to devise a hierarchy of indicators describing the different ecological and economic processes influencing fisheries catches and to organize monitoring systems around those indicators. Only by combining information across sectoral disciplines will it be possible to reach a better unders tanding of the processes that drive fish stocks, fisheries and reservoir productivity. -
Book (stand-alone)Mountain fisheries in developing countries 2003
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No results found.Mountains of the world cover about one-fifth of the land surface, are home to one-tenth of the world's population, and provide livelihood to some of the poorest communities in the world. Mountain lakes and streams are a source of freshwater for countless riparian human communities, support industries, provide water for irrigation and hydropower electricity production and for fish. Some countries situated in mountain areas are landlocked, with no access to marine fishery resources, hence the fish of lakes, streams, rivers and reservoirs are an important source of animal protein, always in short supply in mountain countries. The Fifty-third General Assembly of the United Nations declared the year 2002 the “International Year of Mountains”. With the present document, that reviews the current status of capture fisheries and aquaculture in mountains of developing countries of Asia, Latin America, Africa and the Pacific, the FAI Fisheries Department contributes to the efforts of the United N ations to promote sustainable mountain development. As fisheries play an important role in providing food and income to people in mountain areas, they must be integrated into the rural development and water resource development initiatives. Several problem areas are common to neighbouring countries in mountain regions and fishery resources, such as migratory fish stocks, may have to be shared. Specific action programmes for mountain countries, with collaborative actions on a regional scale, may become the most cost-effective way to address those common problems and share experiences. -
Book (series)Consequences of biomanipulation for fish and fisheries 2001
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No results found.The main goal of biomanipulation by fish reduction is not a change in the fish community but a change in the aquatic ecosystem. Fish reduction is a method to push the system in another state, usually a shift from algae domination to macrophyte domination. Intensive fish removal is done by one of the following methods: seining (the Netherlands, Germany, UK), trawling (Sweden, Finland), use of rotenone (Norway, USA, Poland) and stocking of piscivorous fish (USA, Germany). If circumstances allow it (reservoir, ponds) draining is combined with seining (the Netherlands, UK, Poland). The intensity and duration of fishing differs per case, but is quite important for the way the system changes. Fishing may be combined with stocking of predatory fish, mainly pike and pikeperch (or walleye)......
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