922 resultados para Irrigation districts
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The use of sustainability indicators for evaluating sanitation systems is applied to the Erdos Eco- Town Project (EETP) in China for illustration. The EETP is the largest urban settlement in the world employing ecological sanitation, which incorporates separation of waste streams, dry toilets, and resource recovery. The EETP’s dry sanitation system is compared against the Dongsheng District’s conventional sewer and centralised STP. The two systems are compared based on technological, environmental, economic, and societal indicators. Overall, the two systems perform reasonably well from a technological perspective. The conventional system performs significantly better than the dry system with regards to land and energy requirements, and global warming potential; it also performs better based on freshwater aquatic and terrestrial ecotoxicity potentials, but by a smaller margin. The dry system has superior environmental performance based on water consumption, eutrophication potential, and nutrient and organic matter recovery. The dry system is a more costly system as it requires greater infrastructure and higher operational costs, and does not benefit from economies of scale. The waterborne system performs better based on the societal indicators largely because it is a well-established system.
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Resumen: Este trabajo muestra que la dinámica Ejecutivo-Legislativo en la Argentina, para el período 1983-2007, ha sido una de las causas de la inestabilidad institucional en ese país (y, por ende, de los malos resultados económicos). Sin embargo, teniendo en cuenta que tanto el parlamentarismo como el semipresidencialismo, a priori, no serían opciones viables (según las creencias y valores de la sociedad argentina), la solución no sería cambiar de sistema de gobierno, sino reformarlo. La Argentina debería acotar la discrecionalidad presidencial, así como la influencia de los liderazgos partidarios provinciales sobre sus legisladores nacionales. La hipótesis subyacente es que este tipo de propuesta ayudaría a consolidar el clásico rol del Congreso bajo regímenes presidencialistas, con la consiguiente ganancia en estabilidad institucional (y en desempeño económico). Concretamente, las futuras investigaciones deberían estudiar la posible eliminación de la prerrogativa presidencial de legislar mediante decretos de necesidad y urgencia, y la reducción de la magnitud de los distritos electorales más grandes para la elección de diputados nacionales.
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*Table of Contents* Sustainable Aquaculture Fertilization, soil and water quality management in small-scale ponds part II:Soil and water quality management S. Adhikari Fisheries and aquaculture activities in Nepal Tek Gurung Peter Edwards writes on rural aquaculture: A knowledge-base for rural aquaculture Farmers as Scientists: Commercialization of giant freshwater prawn culture in India M.C. Nandeesha Aquaculture in reservoir fed canal based irrigation systems of India – a boon for fish production K.M. Rajesh, Mridula R. Mendon, K. N. Prabhudeva and P. Arun Padiyar Research and Farming Techniques Production and grow-out of the Black-lip pearl oyster Pinctada margaritifera Idris Lane Breeding of carps using a low-cost, small-scale hatchery in Assam, India: A farmer proven technology S.K. Das Genes and Fish: Hybridisation – more trouble than its worth? Graham Mair Breeding and culture of the sea cucumber Holothuria scabra in Vietnam R. Pitt and N. D. Q. Duy The potential use of palm kernel meal in aquaculture feeds Wing-Keong Ng Using a Simple GIS model to assess development patterns of small-scale rural aquaculture in the wider environment Simon R. Bush Aquaculture fundamentals: Getting the most out of your feed Simon Wilkinson Marine finfish section Status of marine finfish aquaculture in Myanmar U Khin Kolay Regional training course on grouper hatchery production Aquatic Animal Health Advice on aquatic animal health care: Problems in Penaeus monodon culture in low salinity areas Pornlerd Chanratchakool
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A large part of western Manatee County is devoted to the growing of winter vegetables and citrus fruits. As in most of peninsular Florida, rainfall in the county during the growing season is not sufficient for crop production and large quantites of artesian water are used for irrigation. The large withdrawals of artesian water for irrigation result in a considerable decline of the artesian head in the western part of the county. This seasonal decline of the artesian head has become larger as the withdrawal of artesian water has increased. The lowering of the fresh-water head in some coastal areas in the State has resulted in an infiltration of sea water into the water-bearing formations. The presence of salty water in the artesian aquifer in parts of the coastal area of Manatee County indicates that sea water may also have entered the waterbearing formations in this area as a result of the decline of artesian pressure during the growing season. The purpose of the investigation is to make a detailed study of the geology and ground-water resources of the county, primarily to determine whether salt-water encroachment has occurred or is likely to occur in the coastal area. (PDF contains 38 pages.)
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Variable watermilfoil (Myriophyllum heterophyllum Michx.) has recently become a problem in Bashan Lake, East Haddam, CT, USA. By 1998, approximately 4 ha of the 110 ha lake was covered with variable watermilfoil. In 1999, the milfoil was spot treated with Aquacide®, an 18% active ingredient of the sodium salt of 2,4-D [(2,4-dichlorophenoxy) acetic acid], applied at a rate of 114 kg/ha. Aquacide® was used because labeling regarding domestic water intakes and irrigation limitations prevented the use of Navigate® or AquaKleen®, a 19% active ingredient of the butoxyethyl ester of 2,4-D. Variable watermilfoil was partially controlled in shallow protected coves but little control occurred in deeper more exposed locations. 2,4-D levels in the treatment sites were lower than desired and offsite dilution was rapid. In 2000, the United States Environmental Protection Agency (USEPA) issued a special local need (SLN) registration to allow the use of Navigate ® or AquaKleen® in lakes with potable and irrigation water intakes. Navigate® was applied at a rate of 227 kg/ha to the same areas as treated in 1999. An additional 2 ha of variable watermilfoil was treated with Navigate® in 2001, and 0.4 ha was treated in mid-September. Dilution of the 2,4-D ester formulation to untreated areas was slower than with the salt formulation. Concentrations of 2,4-D exceeded 1000 μg/ L in several lake water samples in 2000 but not 2001. Nearly all of the treated variable watermilfoil was controlled in both years. The mid-September treatment appeared as effective as the spring and early summer treatments. Testing of homeowner wells in all 3 years found no detectable levels of 2,4-D.(PDF contains 8 pages.)
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In August 1999, giant salvinia ( Salvinia molesta Mitchell) was found along the lower Colorado River in irrigation drainages. To investigate the slow spread and apparent control of giant salvinia in this region, the herbivorous fish, tilapia (Oreochromis niloticus Trewavas), was examined as a biological control agent. The study was conducted in a 5,000-L recirculating system. (PDF contains 4 pages.)
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Results of recent field trials using the chelated copper formulation Clearigate® 4 showed that applying a 20% solution by volume was effective for controlling populations of giant salvinia in irrigation canals. 5 Lower rates may be efficacious, thereby reducing chemical use and cost; however, little is known about the dose-response effects of Clearigate® against giant salvinia. The objective of this study was to determine the effective rate range of chelated copper applied as Clearigate® for control of giant salvinia.
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Over the past four decades, the state of Hawaii has developed a system of eleven Marine Life Conservation Districts (MLCDs) to conserve and replenish marine resources around the state. Initially established to provide opportunities for public interaction with the marine environment, these MLCDs vary in size, habitat quality, and management regimes, providing an excellent opportunity to test hypotheses concerning marine protected area (MPA) design and function using multiple discreet sampling units. NOAA/NOS/NCCOS/Center for Coastal Monitoring and Assessment’s Biogeography Team developed digital benthic habitat maps for all MLCD and adjacent habitats. These maps were used to evaluate the efficacy of existing MLCDs for biodiversity conservation and fisheries replenishment, using a spatially explicit stratified random sampling design. Coupling the distribution of habitats and species habitat affinities using GIS technology elucidates species habitat utilization patterns at scales that are commensurate with ecosystem processes and is useful in defining essential fish habitat and biologically relevant boundaries for MPAs. Analysis of benthic cover validated the a priori classification of habitat types and provided justification for using these habitat strata to conduct stratified random sampling and analyses of fish habitat utilization patterns. Results showed that the abundance and distribution of species and assemblages exhibited strong correlations with habitat types. Fish assemblages in the colonized and uncolonized hardbottom habitats were found to be most similar among all of the habitat types. Much of the macroalgae habitat sampled was macroalgae growing on hard substrate, and as a result showed similarities with the other hardbottom assemblages. The fish assemblages in the sand habitats were highly variable but distinct from the other habitat types. Management regime also played an important role in the abundance and distribution of fish assemblages. MLCDs had higher values for most fish assemblage characteristics (e.g. biomass, size, diversity) compared with adjacent fished areas and Fisheries Management Areas (FMAs) across all habitat types. In addition, apex predators and other targeted resources species were more abundant and larger in the MLCDs, illustrating the effectiveness of these closures in conserving fish populations. Habitat complexity, quality, size and level of protection from fishing were important determinates of MLCD effectiveness with respect to their associated fish assemblages. (PDF contains 217 pages)
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Common carp is one of the most important cultured freshwater fish species in the world. Its production in freshwater areas is the second largest in Europe after rainbow trout. Common carp production in Europe was 146,845 t in 2004 (FAO Fishstat Plus 2006). Common carp production is concentrated mainly in Central and Eastern Europe. In Hungary, common carp has been traditionally cultured in earthen ponds since the late 19th century, following the sharp drop in catches from natural waters, due to the regulation of main river systems. Different production technologies and unintentional selection methods resulted in a wide variety of this species. Just before the intensification of rearing technology and the exchange of stocking materials among fish farms (early sixties), “landraces” of carp were collected from practically all Hungarian fish farms into a live gene bank at the Research Institute for Fisheries, Aquaculture and Irrigation (HAKI) at Szarvas (Bakos and Gorda 1995; Bakos and Gorda 2001). In order to provide highly productive hybrids for production purposes starting from 1964, different strains and crosses between Hungarian landraces were created and tested. During the last 40 years, approximately 150 two-, three-, and four-line hybrids were produced. While developing parental lines, methods of individual selection, inbreeding, backcrossing of lines, gynogenesis and sex reversal were used. This breeding program resulted in three outstanding hybrids: “Szarvas 215 mirror” and “Szarvas P31 scaly” for pond production, and “Szarvas P34 scaly” for angling waters. Besides satisfying the needs of industry, the live gene bank helped to conserve the biological diversity of Hungarian carp landraces. Fifteen Hungarian carp landraces are still maintained today in the gene bank. Through exchange programs fifteen foreign carp strains were added to the collection from Central and Eastern Europe, as well as Southeast Asia (Bakos and Gorda 2001). Besides developing the methodology to maintain live specimens in the gene bank, the National Carp Breeding Program has been initiated in cooperation with all the key stakeholders in Hungary, namely the National Association of Fish Producers (HOSZ), the National Institute for Agricultural Quality Control (OMMI), and the Research Institute for Fisheries, Aquaculture and Irrigation (HAKI). In addition, methodologies or technologies for broodstock management and carp performance testing have been developed. This National Carp Breeding Program is being implemented successfully since the mid-1990s.
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EXECUTIVE SUMMARY: The Coastal Change Analysis Programl (C-CAP) is developing a nationally standardized database on landcover and habitat change in the coastal regions of the United States. C-CAP is part of the Estuarine Habitat Program (EHP) of NOAA's Coastal Ocean Program (COP). C-CAP inventories coastal submersed habitats, wetland habitats, and adjacent uplands and monitors changes in these habitats on a one- to five-year cycle. This type of information and frequency of detection are required to improve scientific understanding of the linkages of coastal and submersed wetland habitats with adjacent uplands and with the distribution, abundance, and health of living marine resources. The monitoring cycle will vary according to the rate and magnitude of change in each geographic region. Satellite imagery (primarily Landsat Thematic Mapper), aerial photography, and field data are interpreted, classified, analyzed, and integrated with other digital data in a geographic information system (GIS). The resulting landcover change databases are disseminated in digital form for use by anyone wishing to conduct geographic analysis in the completed regions. C-CAP spatial information on coastal change will be input to EHP conceptual and predictive models to support coastal resource policy planning and analysis. CCAP products will include 1) spatially registered digital databases and images, 2) tabular summaries by state, county, and hydrologic unit, and 3) documentation. Aggregations to larger areas (representing habitats, wildlife refuges, or management districts) will be provided on a case-by-case basis. Ongoing C-CAP research will continue to explore techniques for remote determination of biomass, productivity, and functional status of wetlands and will evaluate new technologies (e.g. remote sensor systems, global positioning systems, image processing algorithms) as they become available. Selected hardcopy land-cover change maps will be produced at local (1:24,000) to regional scales (1:500,000) for distribution. Digital land-cover change data will be provided to users for the cost of reproduction. Much of the guidance contained in this document was developed through a series of professional workshops and interagency meetings that focused on a) coastal wetlands and uplands; b) coastal submersed habitat including aquatic beds; c) user needs; d) regional issues; e) classification schemes; f) change detection techniques; and g) data quality. Invited participants included technical and regional experts and representatives of key State and Federal organizations. Coastal habitat managers and researchers were given an opportunity for review and comment. This document summarizes C-CAP protocols and procedures that are to be used by scientists throughout the United States to develop consistent and reliable coastal change information for input to the C-CAP nationwide database. It also provides useful guidelines for contributors working on related projects. It is considered a working document subject to periodic review and revision.(PDF file contains 104 pages.)
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The aim of this working paper was to evaluate the potential of different fisheries enhancement and aquacultural systems to benefit marginal farmers who manage small rainfed irrigation systems in the lowland Dry zone of Sri Lanka. Analysis was based on secondary data and key informant interviews with professional fishermen and marginal farmers in N.W Province. [PDF contains 57 pages]
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Village tanks are put to a wide range of uses by the rural communities that depend on them for their survival. As the primacy of irrigation has decreased under these tanks due to a variety of climatic and economic reasons there is a need to reevaluate their use for other productive functions. The research presented in this paper is part of a programme investigating the potential to improve the management of living aquatic resources in order to bring benefits to the most marginal groups identified in upper watershed areas. Based on an improved typology of seasonal tanks, the seasonal changes and dynamics of various water quality parameters indicative of nutrient status and fisheries carrying capacity are compared over a period of one year. Indicators of Net (Primary) Productivity (NP): Rates of Dissolved Oxygen (DO) change, Total Suspended Solids (TSS): Total Suspended Volatile solids (TVSS) ratios are the parameters of principle interest. Based on these results a comparative analysis is made on two classes of ‘seasonal’ and ‘semi-seasonal’ tanks. Results indicate a broad correlation in each of these parameters with seasonal trends in tank hydrology. Highest productivity levels are associated with periods of declining water storage, whilst the lowest levels are associated with the periods of maximum water storage shortly after the NW monsoon. This variation is primarily attributed to dilution effects associated with depth and storage area. During the yala period, encroachment of the surface layer by several species of aquatic macrophyte also has progressively negative impacts on productivity. The most seasonal tanks show wider extremes in seasonal nutrient dynamics, overall, with less favourable conditions than the ‘semi-seasonal’ tanks. Never the less all the tanks can be considered as being highly productive with NP levels comparable to fertilised pond systems for much of the year. This indicates that nutrient status is not likely to be amongst the most important constraints to enhancing fish production. Other potential management improvements based on these results are discussed. [PDF contains 19 pages]
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Irrigation in the eleven River Basin Authorities and in particular in the South Chad Irrigation Project and the Baga Polder Project is increasing and demands high yearly investments for aquatic weed control in canals and drains. If the weeds are biologically controlled by the grass carp (Ctenopharyngodon idella Val.), the costs will be turned into profit, particularly when the fish production (resident fish plus grass carp) is harvested and sold for food. The use of irrigation canals and drains for aquaculture in the form of fish polyculture may be a wise step towards increased fish production. This paper highlights the concept of fish production from aquatic weed control and concludes that it is a proven profitable venture in several countries
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Various modern aquaculture practices applied in fish production especially in Asia are reviewed. The vast Nigerian aquatic medium of numerous water bodies like rivers, streams, lakes reservoirs, flood plains, irrigation canals, coastal swamps offer great potentials for aquaculture production, if optimally utilized. Constraints to modernization of aquaculture in Nigeria among other factors are: 1) a serious shortage of trained manpower; 2) lack of knowledge on profitability of aquaculture as an industry; 3) limited availability of fund (or capital); 4) non-recognition of indigenous trained aquaculture personnel; 5) inadequate data base on the biology and ecological requirements of endemic fish species with aquaculture potentials; 6) insufficient data on production and management techniques; and 7) lack of rational aquaculture development planning. Recommendations are made towards combating these constraints
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Sustainable aquaculture Peter Edwards writes on rural aquaculture Edwards, P. Mussel farming initiatives in North Kerala, India: A case of successful adoption of technology leading to rural livelihood transformation Laxmilatha, P., Thomas, S., Asokan, P.K., Surendranathan, V.G., Sivadasan, M.P., and Ramachandran, N.P. Selective study on the availability in indigenous fish species having ornamental value in some districts of West Bengal Panigrahi, A.K., Dutta, S. and Ghosh, I. Aquaculture livelihoods service centres in Aceh, Indonesia: A novel approach to improving the livelihoods of small scale fish farmers Ravikumar, B. and Yamamoto, K. Research and farming techniques e-Sagu Aqua - an innovative information and communication technology model for transfer of technology for aquaculture Vimala, D. D., Ravisankar, T., Mahalakshmi, P., and Kumaran, M. Freshwater pearl crop: an emerging enterprise in the Indian subcontinent Misra, G., Jena, J. and Kumar, K. Genetics and biodiversity Preliminary risk assessment of Pacific white leg shrimp (P. vannamei) introduced to Thailand for aquaculture Senanan, W., Panutrakul, S., Barnette, P., Chavanich, S., Mantachitr, V., Tangkrock-Olan, N., and Viyakarn, V. Farmer profile Aquatic animal health Asian fish health experts visit Australia Olsen, L. and Ingram, B. (Fisheries Victoria) Black gill disease of cage-cultured ornate rock lobster Panulirus ornatus in central Vietnam caused by Fusarium species Nha, V.V., Hoa, D.T. and Khoa, L.V. Marine Finfish Aquaculture Network Effects of the partial substitution fish oil by soybean oil in the diets on muscle fatty acid composition of juvenile cobia (Rachycentron canadum) Hung, P.D. and Mao, N.D. Growth response of cobia Rachycentron canadum (Pisces: Rachycentridae) under the hypersaline conditions of the Emirate of Abu Dhabi Yousif, O.M.*, Kumar, K.K. and Abdul-Rahman, A.F.A. NACA Newsletter