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DocumentAQUASTAT - Evaporation from artificial lakes and reservoirs 2015
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No results found.Dams and their associated reservoirs provide many services, including water storage, flow regulation, navigation, hydropower, in - stream and off - stream uses, flood protection, amongst others. However, these artificial lakes and reservoirs evaporate more water than the natural surface water flow before the dam was built, because dams generally increase the surface area of the body of water. This means that more water is exposed to air and direct sunlight, thus increasing ev aporation. This “lost” water is referred to as consumed, because it is removed from the system. In some cases, this water consumption can be quite substantial. AQUASTAT gathers country - level inform ation about dams and reservoirs (see Section 2), but information about evaporation from artificial lakes and reservoirs is rarely reported. Due to its importance, AQUASTAT has estimated the evaporation for all artificial lakes and reservoirs that are avai l able in the geo - referenced dam database it maintains. This exercise is a very rough estimation, the limitations of which are documented in Section 3 and Section 5, and it thus should be considered a s an 'order of magnitude' study. -
Book (stand-alone)Assessment of IUU activities on Lake Victoria 2012
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No results found.Fishing all over the world is a major source of food for humanity and a provider of employment and economic benefits to those engaged in the activity. However, with increased knowledge and the dynamic development of fisheries, it should be known that world living aquatic resources, although renewable, are not infinite and need proper management, if their continued contribution to the nutritional, economic and social well-being of the growing world’s population is to be sustained. Lake Victoria i s Africa’s largest and most important inland water body with a total water surface area of 68,800km2. Lake Victoria contributes significantly through its fishery and generation of electricity to the economic benefits of not only the riparian states, Kenya, Tanzania and Uganda, but also to the neighboring countries and the world at large. Lake Victoria is arguably the most important single source of freshwater fish on the African continent, contributing significantly to national and regional econ omies and livelihoods of the regions inhabitants. Although not often associated with inland fisheries, Illegal, Unreported and Unregulated (IUU) fishing and the trade of illegal fish has threatened the biological, social, financial and cultural integrity of the lakes resources and those that depend on them. Given that Lake Victoria’s living resources are shared amongst the three riparian states, a regional fisheries body, the Lake Victoria Fisheries Organization (LVFO) was formed in 1994 though the technical assistance of the FAO to manage the fisheries resources in Lake Victoria as a single ecological entity. Within the LVFO mandate, the identified areas of IUU fishing are considered in the form of: Illegal or misuse of fishing gears; illegal fishing, fish landing, processing and trading; unregulated fishing number of boats, fishers and gears (capacity); unregulated, unreported or undocumented domestic and regional fish trade; fishing and landing undersize fish in undesignated landing sites; and fishing during closed seasons or in the closed breeding areas or critical habitats. The decline of Nile perch stocks suggest that fisheries management and compliance structures within the three riparian states and at LVFO at the moment are at various levels of disarray, hence allowing IUU fishing to continue thriving unabated. Since the introduction of Nile perch into Lake Victoria in the 1950’s it has been the focus of an intensifying commercial fishery. In 1980, a total of 4 439 to ns of Nile perch were harvested, a decade later over 338 115 tons of Nile perch were landed annually. From 2000 to 2010, and average of 253 404 tons of Nile perch are caught. Despite relatively consistent landings reported by the LVFO, total biomass of Nile perch decreased from 1.4 million tons (92% of total biomass in Lake Victoria) in 1999 to it lowest recorded estimate of 298 394 tons in 2008 (14.9% of total biomass in Lake Victoria). Currently, as of 2010, the Nile perch biomass was estimate d at 18% of total biomass in Lake Victoria, which equates to 367 800 tons. Although a slight increase in biomass between 2008 and 2010 was observed, Nile perch biological indicators suggest that the fish is in a critical survival state. The average size of Nile perch has decreased from 51.7 cm TL to 26.6 cm TL, according to hydro acoustic surveys suggesting that a significant portion of total Nile perch biomass is less than 50 cm TL (legal size for export). It was reported by the LVFO stock asse ssment team that in 2006 and 2008, less than 2% of the Nile perch biomass was in fact greater than 50 cm TL. The size at first maturity of male and female Nile perch is also decreasing, this common amongst fish populations that are stressed (or overexploited). Despite the biological indicators, which suggest legal size Nile perch are less than 2% of total Nile perch biomass, the average number of fishermen increased by 33% between 2000 and 2008. During the same period, Frame survey and MCS compl iance missions noted a marked increase in the number of illegal gears being deployed to target undersize Nile perch. The number of vessels increased by 37% and the use of outboard engines increased by approximately 50%. It has been reported that motorized boats are more efficient, catching about 25 kg of fish per day, compared to 10 kg caught by non-motorized vessels. The increase in use of illegal gears, motorized vessels and fishermen suggests that fishing for Nile perch is still profitable. P reviously driven by lucrative export prices for Nile perch, fishers now target undersize illegal Nile perch for the lucrative domestic and regional trade, which is estimated to exceed the export trade by volume and value. This shift in fishing for undersize Nile perch will effect government revenues earned from the export fishery. The Nile perch fishery over the last decade contributed 0.6% less to the Tanzanian GDP, similarly, a decrease in export trade of Nile perch from Uganda of 14% occurred between 2007 and 2008, resulting in a 0.1% decrease in GDP contribution. By not controlling fishing effort targeting illegal, undersized and immature Nile perch, economic and social hardships will worsen. Current fisheries management both regionally through the LVFO, and nationally amongst the riparian states is inadequate, with respect to Monitoring, Control and Surveillance (MCS). MCS is a collection of activities and tools intended to support fisheries management in fighting IUU fishing, and forms the framework on which accurate, informative and dynamic fisheries management decisions can be made. MCS is critical at all levels of fisheries management. Within the Lake Victoria region, co-management has been implemented through the establishment of Beach Management Units (BMU’s). A BMU is a community-based organization, which is legally accepted as a representative of a fishing community and is mandated on a voluntary basis to engage in MCS initiatives. Lake Victoria has 1 087 registe red BMU’s according to the harmonized BMU guidelines, agreed upon amongst the member states and the LFVO. Although the inclusion of community based management and MCS is critical in contributing to effective management of Lake Victoria’s fisheries resources, many challenges exist, including amongst others; geographical isolation of fishing communities, social issues (families of BMU members may partake in illicit activities), political interference (revenue collections, or election voting), corr uption, conflict of interests (BMU members are often fishmongers and fish traders) and lack of representation in higher management committees. Although advances in MCS technology have revolutionized fisheries management amongst many ESA-IO countries, the sharing of regional resources and capacity is fragmented and not effectively harnessed by the LVFO. Database management systems are not working effectively, data collecting, analyzing and dissemination are unreliable and time inefficient, respec tively and appropriate MCS tools for example net gauges are not available. The RWG-MCS reported that between 2004 and the end of 2008, a total of 4 605 suspects were apprehended, 12 126 beach seines, 9 550 small seine nets, 27 703 monofilament nets, 248 843 kilograms of immature Nile perch (249 tons) and 254 589 illegal gillnets were confiscated. These data are unreliable; furthermore they were not quantified in terms of definition of the item (how long were the nets that were confiscated 80 met er, or one kilometer, this has a profound effect on CPUE), of financial loss to fishers and traders versus the opportunity costs of MCS. The valve of court fines are insignificant especially if one considers the amount of uncontrolled fishing effort, uncontrolled illegal gears used in Lake Victoria, and the increasing value in the trade of immature fish on domestic markets. Also, there is no indication as to whether the court penalties and fines imposed on the same offences in the three partner states have any reference to the same severity across the region, or are recycled back into MCS initiatives. It is therefore difficult to determine whether the RWG-MCS interventions from 2004 to the end of 2008 were beneficial, as little to no comparative data exists. The LVFO depends highly on donor funds to support MCS and management initiatives, including training, capacity building and technical expertise. When donor funds are not available, regional MCS stagnates, which is a major concern. Operation Save the Nile perch is one such example. The EAC Council of Ministers in 2009 launched the ‘Operation Save the Nile Perch’ (OSNP), which required each of the three member states to contribute US$ 600 000. The goal of the initiative was to target illegal fishing and to curb the trade in undersize Nile perch currently threatening the economic integrity of Lake Victoria. The target of OSNP, as ratified by the Council of Ministers was to have fisheries illegalities in the lake, based on th e 2008 frame survey data as bench mark, reduced by 50% in June and 100% by December 2009. Currently as of 2011, Kenya has paid the required funds, with Tanzania only contributing 31% and Uganda zero resulting in less than half of the required funds paid in by from the member states. This undermines the legitimacy of ‘Operation Save the Nile Perch’ and political will and MCS operational capacity. The aim of this report was to assess the state of IUU in Lake Victoria, and to support the SMARTFISH programme in assisting the LVFO and established MCS committees to implement joint regional MCS trainings, by conducting a short cost benefit analysis of enhancing existing regional MCS initiatives and by evaluating past and present regional action plans to deter IUU fishing on Lake Victoria. An action plan was developed through a participatory workshop between the LVFO, national states and the MCS-RWG, held in Jinja, Uganda from the 5th to the 7th of October 2011. -
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.
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