11 resultados para Productivity analysis

em Aquatic Commons


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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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Bi-weekly phytoplankton samples were collected at 0, 10, and 20 m and enumerated by the Utermöhl sedimentation technique; 14C productivity measurements at 10 m, oblique zooplankton tows, and routine hydrographic observations were also made. Northerly winds induce upwelling during December-April, followed by a rainy season; a slight resurgence in upwelling may occur during July and/or August. Annual variations in upwelling intensity and rainfall occur. During upwelling, the upper 50 m, about 30 per cent of the total volume of the Gulf of Panama, is replaced with water 5 to 10 C colder than the more stratified, turbid and nutrient impoverished watermass present during the rainy season. The mean annual runoff accompanying an average annual precipitation of 2731 mm is estimated to equal a layer of fresh water 3.2 m thick. About 10 per cent of the phytoplankton phosphate and inorganic nitrogen requirements during the rainy season are accreted. (PDF contains 260 pages.)

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In an effort to evaluate the production potential of an artificial impoundment, the phytoplankton of the Shen reservoir was sampled from November 1981 to June 1982 at three stations during three periods of distinct seasonal hydrographic characteristics. The samples were subsampled and quantified. Most of the phytoplankton were identified to the species level. There were in all 53 species comprising Chlorophyceae contributing 36.70% with species of Volvox, Pediastrum, Closterium, Staurodesmus and Ankistrodesmus as dominant species in this group. The Cyanophyceae contributed 30.00% with species of Microcystis, Nostoc , and Oscillatoria as the dominant species. An analysis of temporal and spatial changes in composition and abundance of the various groups showed that these were influenced by water temperature, sampling period and station. Based on the trophic status of the most abundant species, the composition of the phytoplankton is indicative of a tropical reservoir with a moderate productivity for fish culture

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Three fertilizer types (NPK, Super-phosphate and cow dung) were applied at two levels (Low, 0.3 kg/25m super(2)/2weeks and High, 0.7kg/25 m super(2)/2weeks) to 12 ponds with two ponds serving as control. Each pond had an area of 25 m super(2). Application of fertilizers and monitoring of plankton productivity and water quality parameters continued fortnightly for 52 days. Results obtained were subjected to Statistical Variance Analysis. The abundance of phytoplankton was in the order: Chlorophyceae > Bacillariophyceae > Cyanophyceae > Desmideaceae. While that of zooplankton followed the order: Crustacean > Rotifer > Protozoan. Primary productivity showed a variation between treatments with lowest value of 5592 mg/O sub(2)/m super(3)/day obtained in the control and cow dung low application rates (1.5 kg/25 m super(2)/2weeks). The highest value for primary productivity was obtained at M sub(2) (0.7 kg/25 m super(2)/2weeks, N.P.K) with primary productivity value of 7200 mg/O sub(2)/m super(3)/day, closely followed by M sub(4) (0.7 kg/25 m super(2)/2weeks, super phosphate) with 6792 mg/O sub(2)/m super(3)/day.

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Assessing the vulnerability of stocks to fishing practices in U.S. federal waters was recently highlighted by the National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration, as an important factor to consider when 1) identifying stocks that should be managed and protected under a fishery management plan; 2) grouping data-poor stocks into relevant management complexes; and 3) developing precautionary harvest control rules. To assist the regional fishery management councils in determining vulnerability, NMFS elected to use a modified version of a productivity and susceptibility analysis (PSA) because it can be based on qualitative data, has a history of use in other fisheries, and is recommended by several organizations as a reasonable approach for evaluating risk. A number of productivity and susceptibility attributes for a stock are used in a PSA and from these attributes, index scores and measures of uncertainty are computed and graphically displayed. To demonstrate the utility of the resulting vulnerability evaluation, we evaluated six U.S. fisheries targeting 162 stocks that exhibited varying degrees of productivity and susceptibility, and for which data quality varied. Overall, the PSA was capable of differentiating the vulnerability of stocks along the gradient of susceptibility and productivity indices, although fixed thresholds separating low-, moderate-, and highly vulnerable species were not observed. The PSA can be used as a flexible tool that can incorporate regional-specific information on fishery and management activity.

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The continental shelf adjacent to the Mississippi River is a highly productive system, often referred to as the fertile fisheries crescent. This productivity is attributed to the effects of the river, especially nutrient delivery. In the later decades of the 2oth century, though, changes in the system were becoming evident. Nutrient loads were seen to be increasing and reports of hypoxia were becoming more frequent. During most recent summers, a broad area (up to 20,000 krn2) of near bottom, inner shelf waters immediately west of the Mississippi River delta becomes hypoxic (dissolved oxygen concentrations less than 2 mgll). In 1990, the Coastal Ocean Program of the National Oceanic and Atmospheric Administration initiated the Nutrient Enhanced Coastal Ocean Productivity (NECOP) study of this area to test the hypothesis that anthropogenic nutrient addition to the coastal ocean has contributed to coastal eutrophication with a significant impact on water quality. Three major goals of the study were to determine the degree to which coastal productivity in the region is enhanced by terrestrial nutrient input, to determine the impact of enhanced productivity on water quality, and to determine the fate of fixed carbon and its impact on living marine resources. The study involved 49 federal and academic scientists from 14 institutions and cost $9.7 million. Field work proceeded from 1990 through 1993 and analysis through 1996, although some analyses continue to this day. The Mississippi River system delivers, on average, 19,000 m3/s of water to the northern Gulf of Mexico. The major flood of the river system occurs in spring following snow melt in the upper drainage basin. This water reaches the Gulf of Mexico through the Mississippi River birdfoot delta and through the delta of the Atchafalaya River. Much of this water flows westward along the coast as a highly stratified coastal current, the Louisiana Coastal Current, isolated from the bottom by a strong halocline and from mid-shelf waters by a strong salinity front. This stratification maintains dissolved and particulate matter from the rivers, as well as recycled material, in a well-defined flow over the inner shelf. It also inhibits the downward mixing of oxygenated surface waters from the surface layer to the near bottom waters. This highly stratified flow is readily identifiable by its surface turbidity, as it carries much of the fine material delivered with the river discharge and resuspended by nearshore wave activity. A second significant contribution to the turbidity of the surface waters is due to phytoplankton in these waters. This turbidity reduces the solar radiation penetrating to depth through the water column. These two aspects of the coastal current, isolation of the inner shelf surface waters and maintenance of a turbid surface layer, precondition the waters for the development of near bottom summer hypoxia.

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The effect of various factors on spawn and fingerlings production in government and private farms was measured in this study. Primary data were collected from 45 private and 11 government farms from 9 selected districts covering major fish seed producing areas of Bangladesh. Results from Cobb-Douglas production function analysis indicated that the included variables had some positive impacts on returns from spawn and fingerlings. No input was found to be over used and increasing returns to scale was observed. Tabular analysis indicated that higher amount of input use produced higher level of yield, gross return and net return. The government farms were under utilized. For increased supply of fish seeds in the country more amount of specified inputs (feed and fertilizer) should be used for producing spawn and fingerlings especially in government farms.

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The cost-benefit analysis of 23m and 22m trawlers operated from Visakhapatnam base is presented. The study indicated that the deep sea fishing in Indian waters is a profitable venture. The profit over capital investment for a 23m trawler worked out to about 18% whereas the same was about 10% for a 22m trawler. Catch per trawling operation, cost of production, productivity per man year, energy yield etc. establish the economic superiority of 23m vessel.

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This project was done during a one-year period (2006-2007) with the aim of assessing and evaluating the susceptible and vulnerable habitat of Tajan River estuarine region as well as identifying its ecological features. This region consists of Tajan estuarine region as one of the sub-basins of the Caspian Sea basin which covers a surface of 2km2. In this assessment, 6 riverine estuarine and marine stations were chosen in which non-biotic parameters such as temperature, salinity, dissolved oxygen, pH and nutrients, and biotic parameters such as variation, density, plankton, primary production by chlorophyll-a. Benthos variation density, silt and the organic materials of the sediments were sampled and measured monthly. The amount of chlorophyll-a concentration and primary production showed a lot of seasonal changes at these stations which ranged from0.3 to 96 mg/m3. The results from the primary productions indicated that the eastern station of the estuary had high concentrations of chlorophyll-a during all seasons (96mg/m3). The most important and dominant planktonic groups in this region included Bacillariophyta from plankton and copepoda from zooplankton. The most important Benthos communities consisted of Driessena polymorpha.Cerastoderma lamarki in estuarine region,Chironomus plumosus in riverine region and Hypaniola sp. In marine region. Assessing the annual variation in these three riverine, estuarine and marine regions, phytoplankton with 3.1, Zooplankton with 2.7 and Benthos with 1.9 Showed the most density in the estuarine region. Assessing the annual density, phytoplanktonic (6118967 no . in m3) and zooplanktonic (7272 no . in m3) communities showed the most density in the marine region. Assessing the statistical tests showed that the estuarine and riverine regions had a significant difference in planktonic density (p<0.005) compared with the marine region. Moreover, The zeoplanktonic density in the marine region had a significant difference (p<0.005) with estuarine and riverine regions. Tooki test and one-way variance Analysis showed that in assessing the planktonic groups (p<0.005) and Benthos (p<0.005), there was a significant difference in variation index between river with estuary, and estuary with the sea. The amount of the total annual live biomass of the Benthos resource in Tajan river estuarine region was estimated 757.66 g/m2.

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The objective of the current report produced for the CGIAR Research Program on Aquatic Agricultural Systems (AAS) is to provide basic information on key constraints driving poverty and vulnerability in aquatic agricultural systems in the Tonle Sap region in Cambodia. Six objectives and corresponding research themes are included in the program: sustainable increases in productivity; equitable access to markets; resilience and adaptive capacity; empowering policies and institutions; reduced gender disparity; and expanded benefits for the resource-poor. In this report, the authors review the main aquatic agricultural systems (status, specific policies and strategies, interventions, challenges, and options), then review the main drivers of change. This leads to an identification of plans and strategies important to AAS, with a particular focus on perspectives, gaps and opportunities in national policies, community engagement, increased benefits, adaptive capacity, and gender. This review, of potential interest to decision makers and all development partners, leads to conclusions and recommendations aimed at policymakers and institutional as well as private investors in development.

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There is increasing awareness that integrating gender into development frameworks is critical for effective implementation of development strategies. In working to alleviate rural poverty, the CGIAR Research Program on Aquatic Agricultural Systems (AAS) recognizes that “business as usual” gender integration approaches will not deliver lasting and widespread improvements in agricultural productivity, poverty reduction and food security. In response, AAS operationalized a gender transformative approach. The approach is informed by conceptual frameworks that explicitly recognize the potent influence of social relations on creating and perpetuating gender inequalities. In this way, AAS aims to address the underlying causes of rural poverty and gender inequality in Zambia’s Barotse Floodplain, where people rely extensively on riverine and wetland ecosystems for food and livelihood security. A central question guiding the research program is “How do social norms and gendered power relations influence agricultural development outcomes?” The findings presented in this report provide insights that help answer this question. The report presents a review of literature relevant to livelihoods, ecosystem services, and gender and social relations in Zambia, with a specific focus on Western Province, where AAS is currently implemented. It also presents a synthesis of findings of a social and gender analysis conducted in 2013 in 10 focal communities situated in and around the Barotse Floodplain.