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Sample records for modeling fish farm

  1. CH4 Emission Model from Bos Primigenius Waste in Fish-Water: Implications for Integrated Livestock-Fish Farming Systems

    Directory of Open Access Journals (Sweden)

    Joshua O. Okeniyi

    2013-07-01

    Full Text Available This paper studies a methane (CH4 emission model from the waste of cattle (B. primigenius based on trends in integrated livestock-fish farming adoption by farmers in Nigeria. Dung of B. primigenius was employed as substrate in fish-water, obtained from a fish-rearing farm, as a matrix medium for simulating a low-oxygen wastewater environment of an agriculture-aquaculture system. A substrate to fish-water mass ratio of 1:3 was used, developed in a laboratory-size digesting reactor system. Volumetric readings, at ambient temperature conditions and with a retention time of thirty-two days, were then subjected to the logistic probability density function, and tested against correlation coefficient and Nash-Sutcliffe coefficient of efficiency criteria. The readings show that a volume of CH4-containing gas as high as 65.3 x 10−3 dm3 was produced on the 13th day from the B. primigenius substrate. Also, production of 234.59 x 10−3 dm3/kg CH4-containing gas, totaling 703.76 x 10−3 dm3, was observed through the studied retention time. The 60% CH4 constituent model of the measured gas generation showed a potency of 2.0664 kg emission per animal, which is equivalent to 43.3944 CO2eq of global warming potential (GWP annually per animal. This bears environmental and climate change implications, and therefore alternative sustainable practices for integrated livestock-fish farming adoption are suggested.

  2. Development of a simple ecosystem model and its application to fish farms at Hazamaura

    Science.gov (United States)

    Yamamoto, Joji; Hirano, Tadahiko; Horiguchi, Fumio

    Fish farms often cause environmental degradation to the surrounding aquatic areas when they operate for a long time. In this study, a simple numerical model was developed to evaluate the water quality (dissolved inorganic nitrogen, dissolved oxygen) of fish farms. This model consisted of a conventional ecosystem model with an added "cultured fish" component. This model was applied to represent the material cycling in a red sea bream culture at Hazamaura, Gokasho Bay, Japan.The analysis was carried out on the basis of field data collected from 1986-1989. In order to verify the model, the simulated concentrations of dissolved inorganic nitrogen and dissolved oxygen were compared to observed concentrations. The simulated results were in good agreement with the observational data for the whole year. In the simulated nitrogen and dissolved oxygen cycle, we found that the factors causing water pollution (eutrophication, anoxia, etc.) were: excretion by the cultured fishes, river load and benthic regeneration in summer, an increase in organic substances from feed scraps and an increase in dissolved inorganic nitrogen through mineralization in winter.

  3. Modelling the fate of pesticides in paddy rice-fish pond farming system in Northern Vietnam

    Science.gov (United States)

    Lamers, M.; Nguyen, N.; Streck, T.

    2012-04-01

    During the last decade rice production in Vietnam has tremendously increased due to the introduction of new high yield, short duration rice varieties and an increased application of pesticides. Since pesticides are toxic by design, there is a natural concern on the possible impacts of their presence in the environment on human health and environment quality. In North Vietnam, lowland and upland rice fields were identified to be a major non-point source of agrochemical pollution to surface and ground water, which are often directly used for domestic purposes. Field measurements, however, are time consuming, costly and logistical demanding. Hence, quantification, forecast and risk assessment studies are hampered by a limited amount of field data. One potential way to cope with this shortcoming is the use of process-based models. In the present study we developed a model for simulating short-term pesticide dynamics in combined paddy rice field - fish pond farming systems under the specific environmental conditions of south-east Asia. Basic approaches and algorithms to describe the key underlying biogeochemical processes were mainly adopted from the literature to assure that the model reflects the current standard of scientific knowledge and commonly accepted theoretical background. The model was calibrated by means of the Gauss-Marquardt-Levenberg algorithm and validated against measured pesticide concentrations (dimethoate and fenitrothion) during spring and summer rice crop season 2008, respectively, of a paddy field - fish pond system typical for northern Vietnam. First simulation results indicate that our model is capable to simulate the fate of pesticides in such paddy - fish pond farming systems. The model efficiency for the period of calibration, for example, was 0.97 and 0.95 for dimethoate and fenitrothion, respectively. For the period of validation, however, the modeling efficiency slightly decreased to 0.96 and 0.81 for dimethoate and fenitrothion

  4. Consumer perceptions of farmed fish

    NARCIS (Netherlands)

    Reinders, Machiel J.; Banović, Marija; Guerrero, Lluis; Krystallis, Athanasios

    2016-01-01

    Purpose – The purpose of this paper is to investigate possible cross-cultural consumer segments
    in the EU aquaculture market and provide direction and focus for marketing strategies for farmed
    fish
    products.
    Design/methodology/approach – Selected psychographic constructs (i.e. category i

  5. Consumer perceptions of farmed fish

    NARCIS (Netherlands)

    Reinders, Machiel J.; Banović, Marija; Guerrero, Lluis; Krystallis, Athanasios

    2016-01-01

    Purpose – The purpose of this paper is to investigate possible cross-cultural consumer segments
    in the EU aquaculture market and provide direction and focus for marketing strategies for farmed
    fish
    products.
    Design/methodology/approach – Selected psychographic constructs (i.e. category

  6. 50 CFR 14.23 - Live farm-raised fish and farm-raised fish eggs.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Live farm-raised fish and farm-raised fish eggs. 14.23 Section 14.23 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF... Exportation at Designated Ports § 14.23 Live farm-raised fish and farm-raised fish eggs. Live farm-raised...

  7. Fish benefits from offshore wind farm development

    DEFF Research Database (Denmark)

    Leonhard, Simon B.; Stenberg, Claus; Støttrup, Josianne

    2013-01-01

    The studies up until 2006 showed few effects on the fish fauna that could be attributed to the establishment and operation of the wind farms. Fish abundance and diversity were not higher inside the wind farms than in the areas outside the wind farms. One obvious reason for this could be that the ...

  8. Biofilm responses to marine fish farm wastes

    Energy Technology Data Exchange (ETDEWEB)

    Sanz-Lazaro, Carlos, E-mail: carsanz@um.es [Departamento de Ecologia e Hidrologia, Facultad de Biologia, Universidad de Murcia, 30100 Murcia (Spain); Navarrete-Mier, Francisco; Marin, Arnaldo [Departamento de Ecologia e Hidrologia, Facultad de Biologia, Universidad de Murcia, 30100 Murcia (Spain)

    2011-03-15

    The changes in the biofilm community due to organic matter enrichment, eutrophication and metal contamination derived from fish farming were studied. The biofilm biomass, polysaccharide content, trophic niche and element accumulation were quantified along an environmental gradient of fish farm wastes in two seasons. Biofilm structure and trophic diversity was influenced by seasonality as well as by the fish farm waste load. Fish farming enhanced the accumulation of organic carbon, nutrients, selenium and metals by the biofilm community. The accumulation pattern of these elements was similar regardless of the structure and trophic niche of the community. This suggests that the biofilm communities can be considered a reliable tool for assessing dissolved aquaculture wastes. Due to the ubiquity of biofilms and its wide range of consumers, its role as a sink of dissolved wastes may have important implications for the transfer of aquaculture wastes to higher trophic levels in coastal systems. - Research highlights: > Biofilms can act as a trophic pathway of fish farm dissolved wastes. > Biofilms are reliable tools for monitoring fish farm dissolved wastes. > The influence of the fish farm dissolved wastes can be detected 120-350 m from farm. - Under the influence of fish farming biofilm accumulates organic carbon, nutrients, selenium and metals, regardless of the structure and trophic niche of the community.

  9. Current situation of fish farming in Togo

    African Journals Online (AJOL)

    practiced in ponds and water reservoirs and the semi intensive system (12.09%) implemented in tanks and ponds. ... The extensive fish farming system deserves to be improved and ..... yeast of beer, droppings of poultry, kitchen rests, maggots, blood meal, shell of oyster .... socio-economic welfare reasons made early.

  10. Health risks of workers fish farming center

    Directory of Open Access Journals (Sweden)

    Jorge L. Minchola Gallardo

    2013-12-01

    Full Text Available In this study we evaluated the ergonomic risks in workers' health Fish Farming Center. The sample universe consisted of the 15 workers of Motil Fish Farming Center, Department of La Libertad, Peru. Samples were taken every month. The methods used to assess ergonomic ergonomic risk were: Job Strain Index (JSI, Rapid Entire Body Assessment (REBA and Oako Working Analysis System (OWAS. The Results demonstrated by the methods of JSI and REBA that selection and maintenance activities are generating greater risks, and, according to the method OWAS, the activity that generates higher risks is that of selection, followed by selection activities of gravid females and maintenance. It was concluded that the activities that need immediate corrective measures are the selection and maintenance.

  11. THE INFORMATIONAL SYSTEM FOR RESOURSES ADMINISTRATION IN FISH FARMS

    Directory of Open Access Journals (Sweden)

    Adrian ZUGRAVU

    2005-01-01

    Full Text Available The informational system for aquaculture activities provide a financial planning and analysis tool.The software can also be of assistance to land-based farmers who want to more thoroughly utilizetheir water resources by developing small-scale fish farm systems to provide supplementary income.Informational model has been enhanced to produce a comprehensive software package foraquaculture feasibility modeling, financial planning, sales and harvesting planning and managementinformation tools.

  12. Fish farming and otters in Finland

    Directory of Open Access Journals (Sweden)

    Skarén U.

    1990-02-01

    Full Text Available The results of a questionnaire sent to all fishfarmers in Finland are presented; 45% replied. There appear to be good otter populations in Finland. Frequency and amount of damage to stocks is discussed. An electric fence system that has been found useful in excluding otters from fish farms is described. Only a few farmers consider otters a grave pest. The major threat to otters in Finland seems to be traffic accidents as car numbers increase. Further information is needed to confirm the findings, and to ensure confusion with mink does not occur.

  13. Fish farms at sea: the ground truth from Google Earth.

    Directory of Open Access Journals (Sweden)

    Pablo Trujillo

    Full Text Available In the face of global overfishing of wild-caught seafood, ocean fish farming has augmented the supply of fresh fish to western markets and become one of the fastest growing global industries. Accurate reporting of quantities of wild-caught fish has been problematic and we questioned whether similar discrepancies in data exist in statistics for farmed fish production. In the Mediterranean Sea, ocean fish farming is prevalent and stationary cages can be seen off the coasts of 16 countries using satellite imagery available through Google Earth. Using this tool, we demonstrate here that a few trained scientists now have the capacity to ground truth farmed fish production data reported by the Mediterranean countries. With Google Earth, we could examine 91% of the Mediterranean coast and count 248 tuna cages (circular cages >40 m diameter and 20,976 other fish cages within 10 km offshore, the majority of which were off Greece (49% and Turkey (31%. Combining satellite imagery with assumptions about cage volume, fish density, harvest rates, and seasonal capacity, we make a conservative approximation of ocean-farmed finfish production for 16 Mediterranean countries. Our overall estimate of 225,736 t of farmed finfish (not including tuna in the Mediterranean Sea in 2006 is only slightly more than the United Nations Food and Agriculture Organization reports. The results demonstrate the reliability of recent FAO farmed fish production statistics for the Mediterranean as well as the promise of Google Earth to collect and ground truth data.

  14. Fish farms at sea: the ground truth from Google Earth.

    Science.gov (United States)

    Trujillo, Pablo; Piroddi, Chiara; Jacquet, Jennifer

    2012-01-01

    In the face of global overfishing of wild-caught seafood, ocean fish farming has augmented the supply of fresh fish to western markets and become one of the fastest growing global industries. Accurate reporting of quantities of wild-caught fish has been problematic and we questioned whether similar discrepancies in data exist in statistics for farmed fish production. In the Mediterranean Sea, ocean fish farming is prevalent and stationary cages can be seen off the coasts of 16 countries using satellite imagery available through Google Earth. Using this tool, we demonstrate here that a few trained scientists now have the capacity to ground truth farmed fish production data reported by the Mediterranean countries. With Google Earth, we could examine 91% of the Mediterranean coast and count 248 tuna cages (circular cages >40 m diameter) and 20,976 other fish cages within 10 km offshore, the majority of which were off Greece (49%) and Turkey (31%). Combining satellite imagery with assumptions about cage volume, fish density, harvest rates, and seasonal capacity, we make a conservative approximation of ocean-farmed finfish production for 16 Mediterranean countries. Our overall estimate of 225,736 t of farmed finfish (not including tuna) in the Mediterranean Sea in 2006 is only slightly more than the United Nations Food and Agriculture Organization reports. The results demonstrate the reliability of recent FAO farmed fish production statistics for the Mediterranean as well as the promise of Google Earth to collect and ground truth data.

  15. Principles of fish welfare assessment in farm rearing conditions

    Directory of Open Access Journals (Sweden)

    Relić Renata R.

    2010-01-01

    Full Text Available For several decades fish welfare has been subject of many researches, and the interest for this subject is connected with the fact that fish can feel pain and suffering. In addition to this stressors’ mechanisms of action and their consequences are similar in mammals and fish. Assessment of welfare for farmed fish is based on the same principles as for terrestrial farm animals. However, special methods of collecting data are needed due to morphological characteristics of fish and properties of their environment. In the world and in our country, researches of different ways of fish welfare assessment are being conducted, especially based on non-invasive techniques such as monitoring of behaviour. In this paper a review of basic principles and methods used in assessment of farmed fish welfare is given.

  16. Consumer perception versus scientific evidence of farmed and wild fish

    DEFF Research Database (Denmark)

    Verbeke, Wim; Sioen, Isabelle; Brunsø, Karen

    2007-01-01

    capture fisheries. The consumer's subjective point of view is of overriding importance for the production system and product acceptance as well as for future market success. In this paper consumer perception in Belgium is explored and compared against scientific evidence of farmed versus wild fish......The increasing number of marketable fish being supplied from aquaculture is a response to the increasing demand for healthy food and is filling the gap left by depleting natural fish stocks. Little is known about the awareness and perception of the consumer in terms of farmed fish versus fish from...

  17. Survivorship of coral juveniles in a fish farm environment.

    Science.gov (United States)

    Villanueva, Ronald D; Yap, Helen T; Montaño, Marco Nemesio E

    2005-01-01

    Intensive fish farming is an emerging coastal activity that can potentially enhance sedimentation and promote eutrophication in fringing coral reefs. Here, we investigate the effect of fish farm effluent on the juvenile survivorship of the reef-building coral Seriatopora caliendrum. One-month old juvenile corals (on terracotta tiles) were deployed in fish farm and reference (reef) sites in Bolinao, the Philippines at a depth of 2m. After forty days, no survivor was recovered in the fish farm, while survivorship was low (11%) in the reference site, with the survivors' growth rate at 3.3polypsmo(-1) or 1.3mm(2)mo(-1). The fish farm deployed tiles were covered with muddy sediment and were colonized by barnacles, whereas those in the reference site were overgrown by a short stand of filamentous macroalgae. Environmental monitoring revealed higher nutrient levels (ammonia and phosphate), sedimentation rate, and organic matter flux, as well as diminished water transparency and dissolved oxygen levels in the fish farm compared to the reference site. Hence, intensive fish farming offers a suite of physical, chemical and biological modifications of the coastal marine environment which have a detrimental effect on the survivorship of coral juveniles.

  18. Dynamic emergy evaluation of a fish farm rearing process.

    Science.gov (United States)

    Vassallo, P; Beiso, I; Bastianoni, S; Fabiano, M

    2009-06-01

    The environmental sustainability of a fish farm rearing process was examined by means of emergy analysis. Many emergy analyses integrate data for a whole year smoothing short term variations and sometimes losing meaningful information (aliasing). For this reason we developed a model for an instantaneous emergy evaluation in an aquacultural system so that transformities, efficiency and effort spent at each moment during the fish rearing activity could be calculated. By means of the model and dynamic emergy calculations it is possible to recognize step by step the importance of the various emergy contributions and verify where and when to modify the system to move toward optimum production of a sustainable product. By the application of the model we confirmed that the emergy trends in a fish farm installation follow wide oscillations during a year due to variations in both internal and external emergy contributions. Among the fluxes considered, those due to the introduction of fingerlings represented the highest contributions to the total emergy budget. Thus, to improve the sustainability of the analyzed system the amount, frequency and timing of these fluxes must be carefully considered. For this purpose, a comparison between two different fry introduction schedules was performed to evaluate differences in the efficiency of the rearing process.

  19. Modelling Farm Animal Welfare.

    Science.gov (United States)

    Collins, Lisa M; Part, Chérie E

    2013-05-16

    The use of models in the life sciences has greatly expanded in scope and advanced in technique in recent decades. However, the range, type and complexity of models used in farm animal welfare is comparatively poor, despite the great scope for use of modeling in this field of research. In this paper, we review the different modeling approaches used in farm animal welfare science to date, discussing the types of questions they have been used to answer, the merits and problems associated with the method, and possible future applications of each technique. We find that the most frequently published types of model used in farm animal welfare are conceptual and assessment models; two types of model that are frequently (though not exclusively) based on expert opinion. Simulation, optimization, scenario, and systems modeling approaches are rarer in animal welfare, despite being commonly used in other related fields. Finally, common issues such as a lack of quantitative data to parameterize models, and model selection and validation are discussed throughout the review, with possible solutions and alternative approaches suggested.

  20. Modelling Farm Animal Welfare

    Directory of Open Access Journals (Sweden)

    Chérie E. Part

    2013-05-01

    Full Text Available The use of models in the life sciences has greatly expanded in scope and advanced in technique in recent decades. However, the range, type and complexity of models used in farm animal welfare is comparatively poor, despite the great scope for use of modeling in this field of research. In this paper, we review the different modeling approaches used in farm animal welfare science to date, discussing the types of questions they have been used to answer, the merits and problems associated with the method, and possible future applications of each technique. We find that the most frequently published types of model used in farm animal welfare are conceptual and assessment models; two types of model that are frequently (though not exclusively based on expert opinion. Simulation, optimization, scenario, and systems modeling approaches are rarer in animal welfare, despite being commonly used in other related fields. Finally, common issues such as a lack of quantitative data to parameterize models, and model selection and validation are discussed throughout the review, with possible solutions and alternative approaches suggested.

  1. Women in fish farming and gender perspectives | Singh | Nigerian ...

    African Journals Online (AJOL)

    Open Access DOWNLOAD FULL TEXT ... In fish farming, women are actively involved in production and other important activities like catching, cleaning, ... must be developed for successful operation and popularization of fishery activities.

  2. Establishing a benchmarking for fish farming

    DEFF Research Database (Denmark)

    Lasner, Tobias; Brinker, Alexander; Nielsen, Rasmus

    2016-01-01

    The promotion of Blue Growth in aquaculture requires an understanding of the economic drivers influencing the sector at farm level, but the collection of reliable and comparable data at this level is time-consuming and expensive. This study suggests an alternative strategy for qualitative sampling...... German farms profit from local market prices and advanced farm management. Danish farms using recirculating techniques remain competitive thanks to enhanced productivity and economy of scale. However, small traditional farms in Germany and Denmark may struggle to stay competitive in the long term....... Organic farms in both countries face challenges of high feed costs and comparatively low productivity with mixed success. Using edible protein energy return on investment (epEROI) as an indicator of ecological sustainability, all surveyed farms compared very favourably with the terrestrial systems...

  3. Economic and Environmental Impacts of Improving Growth Rate and Feed Efficiency in Fish Farming Depend on Nitrogen and Density Limitation

    NARCIS (Netherlands)

    Besson, M.; Komen, H.; Vandeputte, M.; Aubin, J.; Boer, de I.J.M.; Arendonk, van J.A.M.

    2014-01-01

    The aim of fish breeding is to increase profit by producing faster growing fish with lower feed intake. However, little is known about the economic and environmental impacts of selective breeding programs for fish. We modelled a fish farm producing African catfish in a Recirculating Aquaculture

  4. Ecology of Listeria spp. in a fish farm and molecular typing of Listeria monocytogenes from fish farming and processing companies.

    Science.gov (United States)

    Miettinen, Hanna; Wirtanen, Gun

    2006-11-01

    This study focused on the ecology of Listeria monocytogenes in a fish farm by following the changes in its occurrence in different types of samples for a three year period. In addition, L. monocytogenes isolates from different seafood industry areas were compared with pulsed field gel electrophoresis (PFGE) typing to discover possible associations between primary production, further processing and final products. Weather conditions were found to have a strong influence on the probability of finding Listeria spp. in a fish farm environment. The number of samples contaminated with Listeria spp. was typically bigger after rainy periods. Brook and river waters as well as other runoff waters seemed to be the main contamination source at the farm studied. The farmed fish originally found to carry L. monocytogenes become gradually Listeria free. The time needed for the purification of the fish was several months. The sea bottom soil samples were the ones that preserved the L. monocytogenes contamination the longest time. It can be stated that the fish and fish farm equipment studied did not spread listeria contamination. On the contrary, they were found to suffer from listeria contamination coming from outside sources like the brook water. There was a wide range of different L. monocytogenes PFGE-pulsotypes (30) found at 15 Finnish fish farms and fish processing factories. L. monocytogenes isolates from the final products often belonged to the same pulsotypes as did the isolates from the processing environment as well as from the raw fish. This suggests that, in addition to the fish processing factory environment, the fish raw materials are important sources of L. monocytogenes contamination in final products.

  5. Wind Farms: Modeling and Control

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam

    2012-01-01

    provides the state space form of the dynamic wind farm model. The model provides an approximation of the behavior of the flow in wind farms, and obtains the wind speed in the vicinity of each wind turbine. The control algorithms in this work are mostly on the basis of the developed wind farm model......The primary purpose of this work is to develop control algorithms for wind farms to optimize the power production and augment the lifetime of wind turbines in wind farms. In this regard, a dynamical model for wind farms was required to be the basis of the controller design. In the first stage......, a dynamical model has been developed for the wind flow in wind farms. The model is based on the spatial discretization of the linearized Navier-Stokes equation combined with the vortex cylinder theory. The spatial discretization of the model is performed using the Finite Difference Method (FDM), which...

  6. Economic and Environmental Impacts of Improving Growth Rate and Feed Efficiency in Fish Farming Depend on Nitrogen and Density Limitation

    OpenAIRE

    Besson, M.; Komen, H.; Vandeputte, M.; Aubin, J.; Boer, De; van Arendonk,

    2014-01-01

    The aim of fish breeding is to increase profit by producing faster growing fish with lower feed intake. However, little is known about the economic and environmental impacts of selective breeding programs for fish. We modelled a fish farm producing African catfish in a Recirculating Aquaculture System (RAS) to calculate economic values of growth rate and feed efficiency with production limited by fish density in rearing tanks and fish nitrogen emission. We also calculated “environmental value...

  7. Consumer perception versus scientific evidence of farmed and wild fish

    DEFF Research Database (Denmark)

    Verbeke, Wim; Sioen, Isabelle; Brunsø, Karen

    2007-01-01

    capture fisheries. The consumer's subjective point of view is of overriding importance for the production system and product acceptance as well as for future market success. In this paper consumer perception in Belgium is explored and compared against scientific evidence of farmed versus wild fish....... Primary data were collected through a consumer survey (April 2003) and focus group discussions (May 2004) with Belgian consumers. The majority of the consumer sample reported no perceived differences between farmed versus wild fish. However, mean perception scores were slightly in favour of wild fish...

  8. Effect of production quotas on economic and environmental values of growth rate and feed efficiency in sea cage fish farming

    NARCIS (Netherlands)

    Besson, M.; Boer, de I.J.M.; Vandeputte, M.; Arendonk, van J.A.M.; Quillet, E.; Komen, H.; Aubin, J.

    2017-01-01

    In sea cage fish farming, production quotas aim to constrain the impact of fish farming on the surrounding ecosystem. It is unknown how these quotas affect economic profitability and environmental impact of genetic improvement. We combined bioeconomic modelling with life cycle assessment (LCA) to

  9. Metanalysis of the fish farming and sale in Bahawalpur (Pakistan

    Directory of Open Access Journals (Sweden)

    H. R. Chaudhry,

    2011-02-01

    Full Text Available Fish Farming in the Cholistan is a growing industry despite the low water holding capacity of the desert sand terrain of the Cholistan desert. This is not the only problem lack of fresh water is also at large and the availability of brackish sub soil water adds to the insult. Despite all odds Bahawalpur district caters for the market in Multan by the help of interior sindh and 125 large scale mostly earthen fish farms. A Government fish farm has almost 20 ponds active throughout the year. The Islamia Uiversity of Bahawalpur has 2 ponds one 2 kanal 3-6ft deep nursery and another 500x108 ft farm which is 5-8ft deep earthen fish farms. The Bahwalpur District tastes the best in Rohu Carp, Mori Carp, and to a lesser extent Grass and Silver Carp and the Thela Carp is for the impoverished individuals. The seasons starts from October and continues till march but the peak sale and price are usually fetched in the months of December and January.Last years rate of Fish ranging from 1-2 kg was started at Rs. 140 and ended at a peak of Rs. 160. The fish above 2 kg was sold at Rs. 210-230. The retailers fetched a price higher by Rs. 30-40 on the previously mentioned price. Cooked, fried and Pakora Deep Fried fish rated at Rs. 150-200 per 250 grams. The present study highlights the various activities of the Fish Farming and Marketing.

  10. Checklists of Parasites of Farm Fishes of Babylon Province, Iraq

    Directory of Open Access Journals (Sweden)

    Furhan T. Mhaisen

    2016-01-01

    Full Text Available Literature reviews of all references concerning the parasitic fauna of fishes in fish farms of Babylon province, middle of Iraq, showed that a total of 92 valid parasite species are so far known from the common carp (Cyprinus carpio, the grass carp (Ctenopharyngodon idella, and the silver carp (Hypophthalmichthys molitrix as well as from three freshwater fish species (Carassius auratus, Liza abu, and Heteropneustes fossilis which were found in some fish farms of the same province. The parasitic fauna included one mastigophoran, three apicomplexans, 13 ciliophorans, five myxozoans, five trematodes, 45 monogeneans, five cestodes, three nematodes, two acanthocephalans, nine arthropods, and one mollusc. The common carp was found to harbour 81 species of parasites, the grass carp 30 species, the silver carp 28 species, L. abu 13 species, C. auratus one species, and H. fossilis one species. A host-parasite list for each fish species was also provided.

  11. Environmental impact assessment of fish farm hatcheries ...

    African Journals Online (AJOL)

    Water quality parameters were measured from site to site where alkalinity and ... noise, had insignificant impact (p > 0.05), while water pollution, insecurity as a ... impacts of pollution, erosion and degradation of farm lands and environment.

  12. Effects of fish farming on flavonoids in Posidonia oceanica.

    Science.gov (United States)

    Cannac, Magali; Ferrat, Lila; Pergent-Martini, Christine; Pergent, Gerard; Pasqualini, Vanina

    2006-10-15

    This work is a first approach to flavonoid responses (total proanthocyanidins and total and simple flavonols) in Posidonia oceanica in function of nutrient enrichment (aquaculture activities - fish farming), in the western Mediterranean Sea (Calvi-Corsica-France). The first result is the presence of total and simple flavonoids in P. oceanica. The second result shows an increase in total proanthocyanidin and total flavonol concentrations near cages, which would be linked to the high grazing pressure induced by meadow enrichment. Concerning simple flavonols, only quercetin shows a response to fish farming, which could be due to its strong antioxidant capacity. The presence of fish farming, which causes variations in environmental parameters, could affect the functioning of P. oceanica meadows. Flavonoid concentrations in P. oceanica seem to be a possible bioindicator of nutrient enrichment for the management of the littoral environment.

  13. THE POSSIBILITIES OF SMALL FAMILY FISH FARMS MANAGEMENT

    OpenAIRE

    2000-01-01

    The transitional changes in Central Europe significantly influenced the entire agriculutral production, Croatian fresh-water aquaculture included. The production in many countries fell down to only one third, while many bih fish farms reduced their production acreage. On the other hand, more alert sensitivity to ecological problems made water exploitation for angling, sport and recreation purposes, quite popular. Some small farms that have not been into fisheries yet, were influenced to chang...

  14. Health Categorisation of Fish Farms in Europe In 2011

    DEFF Research Database (Denmark)

    Olesen, Niels Jørgen; Nicolajsen, Nicole

    2012-01-01

    The Questionnaire on Surveillance and Diagnosis (S&D) included questions on how fish farms are health categorised according to Council Directive 2006/88/EC in the respective countries. More than half of the authorised farms in Europe are in category III for VHS and IHN and the remaining in category...... in or in proximity of a farm can it remain its Category I status? Some Member states do not include registered APBs in the categorisation but according to 2006/88/EC Annex III health categorisation comprise Member states, zone and compartments NOT single APBs. A new Animal Health Law is under preparation...

  15. Emergy evaluation and economic analysis of three wetland fish farming systems in Nansi Lake area, China.

    Science.gov (United States)

    Zhang, L X; Ulgiati, S; Yang, Z F; Chen, B

    2011-03-01

    Emergy and economic methods were used to evaluate and compare three fish production models, i.e., cage fish farming system, pond intensive fish rearing system and semi-natural extensive pond fish rearing system, in Nansi Lake area in China in the year 2007. The goal of this study was to understand the benefits and driving forces of selected fish production models from ecological and economic points of view. The study considered input structure, production efficiency, environmental impacts, economic viability and sustainability. Results show that the main difference among the three production systems was the emergy cost for fish feed associated with their feeding system, i.e., feeding on natural biomass such as plankton and grass or on commercial feedstock. As indicated by EYR, ELR and ESI, it can be clearly shown that the intensive production model with commercial feed is not a sustainable pattern. However, the point is that more environmentally sound patterns do not seem able to provide a competitive net profit in the short run. The intensive pond fish farming system had a net profit of 2.57E+03 $/ha, much higher than 1.27E+03 $/ha for cage fish farming system and slightly higher than 2.37E+03 $/ha for semi-natural fish farming system. With regard to the drivers of local farmer's decisions, the accessibility of land for the required use and investment ability determine the farmer's choice of the production model and the scale of operation, while other factors seem to have little effect. Theoretically, the development of environmentally sustainable production patterns, namely water and land conservation measures, greener feed as well as low waste systems is urgently needed, to keep production activities within the carrying capacity of ecosystems. Coupled emergy and economic analyses can provide better insight into the environmental and economic benefits of fish production systems and help solve the problems encountered during policy making.

  16. Market tntegration between farmed and wild fish

    DEFF Research Database (Denmark)

    Bronnmann, Julia; Ankamah Yeboah, Isaac; Nielsen, Max

    2016-01-01

    of these species, but more importantly by the much larger supplies of wild-caught cod and Alaska pollock. The implication of the presence of market integration is that the small-scale Asian farmers are secured against severe price reductions in Germany arising from farm productivity growth. However, market...

  17. Mercury exposure and source tracking in distinct marine-caged fish farm in southern China.

    Science.gov (United States)

    Xu, Xiaoyu; Wang, Wen-Xiong

    2017-01-01

    Coasts of South China have experienced an unprecedented growth in its marine-caged fish industry. We analyzed mercury concentrations and stable mercury isotope ratios in fourteen fish species from two cage-cultured farms in Southern China. Total mercury concentrations of all species were lower than the human health screening values, but the human exposures through consumption of several carnivorous fish exceeded the USEPA's reference dose. Isotopic compositions in the sediment (δ(202)Hg: -1.45‰ to -1.23‰; Δ(199)Hg: -0.04‰ to -0.01‰) suggested that mercury in these farms were from coal combustion and industrial inputs. Commercial food pellets and fresh fish viscera provided the major sources of methylmercury to the farmed fish and dominated their mercury isotopic signatures. Non-carnivorous fish presented lower δ(202)Hg and Δ(199)Hg values than the carnivorous fish. Using a mixing model, we demonstrated that the majority of mercury in non-carnivorous species came from pellets and in carnivorous fish came from combined diets of pellets and viscera. Meanwhile, methylmercury concentrations and % methylmercury in the fish were positively correlated with δ(202)Hg values but not with Δ(199)Hg values, mainly because fish eating similar feeds maintained similar Δ(199)Hg values. Environmental influences of cage farming such as fish feces and uneaten viscera that continuously provide organic mercury to the environments need to be considered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Impact of deep-water fish farms on benthic macrofauna communities under different hydrodynamic conditions.

    Science.gov (United States)

    Valdemarsen, Thomas; Hansen, Pia Kupka; Ervik, Arne; Bannister, Raymond J

    2015-12-30

    In this study the environmental impacts of two fish farms located over deep water (180-190 m) were compared. MC-Farm was located at a site with slightly higher water currents (mean current speed 3-5 cms(-1)) than LC-farm (fish farms should not be sited in low current areas (fish farming at slightly more dynamic sites can lead to stimulated benthic macrofauna communities and only moderate environmental impacts.

  19. Fish Farm Challenge Provides STEM Design Experiences for Youth

    Science.gov (United States)

    Horton , Robert L.; House, Patty L.

    2015-01-01

    In 2014, Monsanto Corporation partnered with National 4-H Council to help inspire and develop professional skills among young agriculturalists. The Ohio State University created Fish Farm Challenge, which engaged more than 8,000 youth across eight states. Youth were taught about worldwide food insecurity and the importance of aquaculture. They…

  20. Coping styles in farmed fish: consequences for aquaculture

    DEFF Research Database (Denmark)

    Castanheira, Maria Filipa; Conceição, Luís E.C.; Millot, Sandie

    2015-01-01

    on coping styles may contribute to improved sustainability of the aquaculture industry, including welfare and performance of farmed fish. Moreover, we will suggest areas for future research, where genetic basis (heritability/epigenetic) of coping styles, and the neuroendocrine mechanisms behind consistent...

  1. THE POSSIBILITIES OF SMALL FAMILY FISH FARMS MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Roman Safner

    2000-06-01

    Full Text Available The transitional changes in Central Europe significantly influenced the entire agriculutral production, Croatian fresh-water aquaculture included. The production in many countries fell down to only one third, while many bih fish farms reduced their production acreage. On the other hand, more alert sensitivity to ecological problems made water exploitation for angling, sport and recreation purposes, quite popular. Some small farms that have not been into fisheries yet, were influenced to change their business policy and take part in new viewpoints of fisheries. The possibilities of small family fish farm management in new conditions in particular as regard to commercial sport fisheries, to cyprinid as well as salmonid aquaculture are therefore discussed in this paper.

  2. Current and future prospects of commercial fish farming in Zambia

    Directory of Open Access Journals (Sweden)

    Confred G. Musuka

    2012-06-01

    Full Text Available According to the survey conducted, there were 15 land based commercial fish farms in Lusaka, Copperbelt and Northern provincesand 10 cage culture operators, mainly based on Lake Kariba. Fish production per hectare ranged between 13 and 18 tonnes while total productionwas estimated to be approximately 4971.37 metric tons. The weight of fish at harvest from ponds and tanks ranged from 250g to 350g per piecewhile under cage culture, where fish were regularly fed with floating pellets, ranged from 400 to 450g. Fish stocking density by most farmerswas 30,000 fingerlings per hectare and between 12,000 and 15,000 for cage culture. Those who operated fish hatcheries employed a technologythat manipulated genetic materials of Oreochromis andersonii and O. niloticus, resulting in production of all-male tilapia, simply referred to as“super males”. Environmental considerations remained a great challenge to the development of both land based commercial fish farms and cageculture on Lake Kariba. Higher fees were charged to do environmental impact assessment (EIA studies before commencement of operation.

  3. 7 CFR 760.204 - Eligible livestock, honeybees, and farm-raised fish.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Eligible livestock, honeybees, and farm-raised fish... for Livestock, Honeybees, and Farm-Raised Fish Program § 760.204 Eligible livestock, honeybees, and farm-raised fish. (a) To be considered eligible livestock for livestock feed losses and grazing...

  4. Environment and sex determination in farmed fish.

    Science.gov (United States)

    Baroiller, J F; D'Cotta, H

    2001-12-01

    A plasticity of gonadal sex differentiation was reported in the 1930s following exogenous steroid treatments in fish, but demonstration that environmental factors (temperature, pH, density and social interactions) could influence the sex ratio in gonochoristic species has been relatively recent. In fish, as in reptiles and amphibians displaying environmental sex determination, the main environmental factor influencing sex seems to be temperature (TSD=Temperature Sex Determination). In most thermosensitive species (some Atherinids, Poecilids, Cichlids: tilapias, goldfish, a Siluriform, a flatfishellipsis) male to female ratio increases with temperature and/or ovarian differentiation is induced by low temperatures. Conversely, in some rare species (Dicentrarchus labrax, Ictalurus punctatus), high temperatures may produce female-biased sex ratios and/or low temperatures promote male-biased sex ratios. In the hirame Paralichthys olivaceus, both high and low temperatures induce monosex male populations while intermediate temperatures yield a 1:1 sex ratio (U-shape curve). Fish show particularities in their TSD patterns since mono-sex populations are generally not produced at extreme temperatures, suggesting the existence of strong temperature/genotype interactions. In reptiles, amphibians and fish displaying TSD, temperature treatments must be applied at a critical sensitive period, relatively similar to the hormone sensitive period. In gonochoristic fish, steroid hormones with estrogens in females and 11-oxygenated androgens in males, are probably key physiological steps in the regulation of gonadal sex differentiation. Cytochrome P450-aromatase, enzyme catalysing conversion of androgens to estrogens, seems to be a critical enzyme for ovarian differentiation. Molecular mechanisms of thermosensitivity have been addressed in two species tilapia Oreochromis niloticus and the hirame, where aromatase gene expression is down-regulated by masculinizing temperature treatments

  5. Viral haemorrhagic septicaemia virus in marine fish and its implications for fish farming - a review

    DEFF Research Database (Denmark)

    Skall, Helle Frank; Olesen, Niels Jørgen; Mellergaard, Stig

    2005-01-01

    marine fish show no to low pathogenicity to rainbow trout and Atlantic salmon, although several are pathogenic for turbot. Marine VHSV isolates are so far serologically indistinguishable from freshwater isolates. Genotyping based on VHSV G- and N-genes reveals four groups indicating the geographical...... of possible transfer of virus from free-living marine fish to farmed fish are discussed, as are measures to prevent introduction of VHSV from the marine environment to aquaculture....

  6. Mediterranean Aquaculture: Marine Fish Farming Development

    OpenAIRE

    Basurco, B

    2001-01-01

    in many parts of the world, aquaculture production in the Mediterranean has been expanding rapidly over recent years. Total aquaculture production in the region reached 1,266,959 t in 1999, which represents approximately 6% of the world aquaculture production (3% in 1995). Although Mediterranean aquaculture still focuses more on mollusc production (53.9%), the share of fish production is progressing constantly (46% in 1999, and 35% in 1995), parallel to global trends of world a...

  7. Parasitic fauna in hybrid tambacu from fish farms

    Directory of Open Access Journals (Sweden)

    Ronilson Macedo Silva

    2013-08-01

    Full Text Available The objective of this work was to evaluate the parasitic fauna of hybrid tambacu (Colossoma macropomum x Piaractus mesopotamicus from fish farms and the host-parasite relationship. A hundred and fourteen fish were collected from four fish farms in Macapá, in the state of Amapá, Brazil, 80.7% of which were infected by: Ichthyophthirius multifiliis (Ciliophora; Piscinoodinium pillulare (Dinoflagellida; Anacanthorus spatulatus, Notozothecium janauachensis, and Mymarothecium viatorum (Monogenoidea; Neoechinorhynchus buttnerae (Acanthocephala; Cucullanus colossomi (Nematoda; Perulernaea gamitanae (Lernaeidae; and Proteocephalidae larvae (Cestoda. A total of 8,136,252 parasites were collected from the examined fish. This is the first record of N. buttnerae, C. colossomi, N. janauachensis, M. viatorum, and Proteocephalidae for hybrid tambacu in Brazil. Ichthyophthirius multifiliis was the most prevalent parasite, whereas endohelminths were the less. A positive correlation was observed between number of I. multifiliis and total length and weight of fish, as well as between number of P. gamitanae and total length. The infection by I. multifiliis had association with the parasitism by Monogenoidea. Low water quality contributes to high parasitism of hybrid tambacu by ectoparasites, which, however, does not influence the relative condition factor of fish.

  8. Potential retention effect at fish farms boosts zooplankton abundance

    Science.gov (United States)

    Fernandez-Jover, D.; Toledo-Guedes, K.; Valero-Rodríguez, J. M.; Fernandez-Gonzalez, V.; Sanchez-Jerez, P.

    2016-11-01

    Coastal aquaculture activities influence wild macrofauna in natural environments due to the introduction of artificial structures, such as floating cages, that provide structural complexity in the pelagic system. This alters the abundance and distribution of the affected species and also their feeding behaviour and diet. Despite this, the effects of coastal aquaculture on zooplankton assemblages and the potential changes in their abundance and distribution remain largely unstudied. Traditional plankton sampling hauls between the farm mooring systems entail some practical difficulties. As an alternative, light traps were deployed at 2 farms in the SW Mediterranean during a whole warm season. Total zooplankton capture by traps at farms was higher than at control locations on every sampling night. It ranged from 3 to 10 times higher for the taxonomic groups: bivalvia, cladocera, cumacea, fish early-life-stages, gastropoda, polychaeta and tanaidacea; 10-20 times higher for amphipoda, chaetognatha, isopoda, mysidacea and ostracoda, and 22 times higher for copepoda and the crustacean juvenile stages zoea and megalopa. Permutational analysis showed significant differences for the most abundant zooplankton groups (copepoda, crustacean larvae, chaetognatha, cladocera, mysidacea and polychaeta). This marked incremental increase in zooplankton taxa at farms was consistent, irrespective of the changing environmental variables registered every night. Reasons for the greater abundance of zooplankton at farms are discussed, although results suggest a retention effect caused by cage structures rather than active attraction through physical or chemical cues.

  9. Level of Aflatoxin in Some Fish Feeds from Fish Farming Processes, Feed Factories and Imported Feeds

    OpenAIRE

    ALTUĞ, Gülşen

    2014-01-01

    Aflatoxins that are toxic metabolites for human and animals were determined in some fish feed. Eighty-five unit samples taken from "fish farming processes", "feed factories" and "imported feeds" in 1998, 1999 and 2000 were analyzed. In the analysis, thin layer chromatography (TLC) and enzyme linked immunosorbent assay (ELISA) technique were used. Consequently, aflatoxin levels above 20 ppb were detected in 20 samples and from 21.2 to 42.4...

  10. THE NEED FOR DIVERSIFICATION IN FISH FARMING PRODUCTION

    Directory of Open Access Journals (Sweden)

    Krešimir Pažur

    1999-06-01

    Full Text Available One of the characteristics of developed economies in the world is a very rich and diversified offer of goods. There are many products of different assortment, of different quality and price on the market. In keeping with the marketing conception, the production is trying to satisfy all potential consumers. Croatian freshwater fish farming has not yet reached this stage. The assortment is very limited and includes mostly carp (up to 80%, Californian trout (up to 10%, grass carp (around 4%, wels, pike-perch and pike together up to 2.70%, while the rest are commercially insignificant and uninteresting fish species. In the last few years, an increasingly important type of consumers has emerged on the market sporting anglers whose importance is growing and bringing totally new, specific demands that the fish ponds at the moment cannot meet, except maybe in marginal quantities. There is a categorical imperative of a fast adjustment of the production assortment of our fishing farms to the tendencies in the nourishment of the population in developed countries that can also be observed in our country and to the demands and needs of sporting anglers.

  11. Differential response of fish assemblages to coral reef-based seaweed farming.

    Directory of Open Access Journals (Sweden)

    E James Hehre

    Full Text Available As the global demand for seaweed-derived products drives the expansion of seaweed farming onto shallow coral ecosystems, the effects of farms on fish assemblages remain largely unexplored. Shallow coral reefs provide food and shelter for highly diverse fish assemblages but are increasingly modified by anthropogenic activities. We hypothesized that the introduction of seaweed farms into degraded shallow coral reefs had potential to generate ecological benefits for fish by adding structural complexity and a possible food source. We conducted 210 transects at 14 locations, with sampling stratified across seaweed farms and sites adjacent to and distant from farms. At a seascape scale, locations were classified by their level of exposure to human disturbance. We compared sites where (1 marine protected areas (MPAs were established, (2 neither MPAs nor blast fishing was present (hence "unprotected", and (3 blast fishing occurred. We observed 80,186 fish representing 148 species from 38 families. The negative effects of seaweed farms on fish assemblages appeared stronger in the absence of blast fishing and were strongest when MPAs were present, likely reflecting the positive influence of the MPAs on fish within them. Species differentiating fish assemblages with respect to seaweed farming and disturbance were typically small but also included two key target species. The propensity for seaweed farms to increase fish diversity, abundance, and biomass is limited and may reduce MPA benefits. We suggest that careful consideration be given to the placement of seaweed farms relative to MPAs.

  12. Assessing a bioremediation strategy in a shallow coastal system affected by a fish farm culture--application of GIS and shellfish dynamic models in the Rio San Pedro, SW Spain.

    Science.gov (United States)

    Silva, C; Yáñez, E; Martín-Díaz, M L; DelValls, T A

    2012-04-01

    An integrated multi-trophic aquaculture assessment for Pacific oyster (Crassostrea gigas) aquaculture as a bioremediation strategy in areas impacted by fish farm effluents in Rio San Pedro was assessed by combining geographic information system with carrying capacity models. Sites of 0.44 km(2) were evaluated considering constraints; physical factors, growth and survival factors, environmental quality factors, water and sediment quality criteria, factor suitability ranges, and Multi-Criteria Evaluation. Isleta and Flamenco are promising sites for oyster production, and Dorada is of marginal interest. Carbon and nitrogen removal from the water by algae and through detritus filtration was estimated. The biodeposition of organic material from longline leases was found to have little negative impact on sediment. The eutrophication results indicate that phytoplankton removal had a positive impact on water quality at the Dorada. This case study quantified the direct profitability and bioremediative environmental service advantages that fish-shellfish farms can have relative to fish monocultures. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Economic values of growth and feed efficiency for fish farming in recirculating aquaculture system with density and nitrogen output limitations: a case study with African catfish (Clarias gariepinus)

    NARCIS (Netherlands)

    Besson, M.; Komen, H.; Aubin, J.; Boer, de I.J.M.; Poelman, M.; Quillet, E.; Vancoillie, C.; Vandeputte, M.; Arendonk, van J.A.M.

    2014-01-01

    In fish farming, economic values (EV) of breeding goal traits are lacking, even though they are key parameters when defining selection objectives. The aim of this study was to develop a bioeconomic model to estimate EV of 2 traits representing production performances in fish farming: the thermal gro

  14. Environmental impacts of coastal fish farming; Carbon and Nitrogen budgets for trout farming in Kaldbacksfjord, Faroe Islands

    DEFF Research Database (Denmark)

    Nordi, Gunnvor A; Glud, Ronnie N.; Gaard, Eilif

    2011-01-01

    Flow of organic carbon (OC) and nitrogen through a sea cage trout farm was calculated on the basis of detailed studies of the farming operation, water circulation, OC and nutrient transport and recycling processes in sediment. A third of the OC and nitrogen provided by fish food was incorporated......% of nitrogen derived from fish food settled on the seabed, where it was either mineralized or accumulated in the sediment. Based on transect measurements of diagenetic activity, the farm footprint was found to cover an area similar to 10 times the farm area. OC mineralization in the sediment increased linearly...

  15. Economic efficiency in fish farming: hope for agro-allied industries in Niagara

    Science.gov (United States)

    Kareem, R. O.; Dipeolu, A. O.; Aromolaran, A. B.; Williams, S. B.

    2008-02-01

    The challenge to increase the efficiency in food production level in Nigeria appears to be more urgent now than it has ever been in the history of the country. This is in view of the rapidly increasing population, the imminent decline in international economic and food aid and the need to conserve foreign exchange earnings through the production of raw materials to feed the growing industrial sector calls for urgent attention. The study was carried out in Ogun State. The descriptive statistics was used to determine the socio-economic characteristics of the respondents. The stochastic frontiers production analysis was applied to estimate the technical, allocative efficiency and economic efficiency among the fish farmers in the state. The results of economic efficiency revealed that fish farming is economically efficient with a range of between 55% and 84% efficiency level suggesting a favourable hope for the agro-allied industry such as poultry and cottage industries etc in the state. The result of hypothesis of inefficiency sources models showed that years of experience of fish farmers is significant at 1% probability level indicating the factor contributing to the fish farming experience in the state. Thus, the efficiency is due to the fact that farmers are experienced and fairly educated. On the basis of findings, policy is suggested to be directed towards the encouragement of entrepreneurs in fish farming in the state by providing enabling environment like credit facilities, public enlightenment programme and provision of social amenities like feeder roads, pipe-born water etc and given the fact that an increase in the level of formal education variable leads to less inefficiency, government policy should be focused on adopting the best technology (e.g. fast growing species and equipment) so as to improve the level of efficiency and investment which shall eventually lead to growth in output of fish farming and a lead to the establishment of agro

  16. Use of agent-based modelling to predict benefits of cleaner fish in controlling sea lice, Lepeophtheirus salmonis, infestations on farmed Atlantic salmon, Salmo salar L.

    Science.gov (United States)

    Groner, M L; Cox, R; Gettinby, G; Revie, C W

    2013-03-01

    Sea lice, Lepeophtheirus salmonis, are ectoparasites of farmed and wild salmonids. Infestations can result in significant morbidity and mortality of hosts in addition to being costly to control. Integrated pest management programmes have been developed to manage infestations, and in some salmon farming areas, these programmes include the use of wrasse. Wrasse prey upon the parasitic life stages of L. salmonis and can be stocked on farms at varying densities. Despite considerable variation in the usage of wrasse, there are few quantitative estimates of how well they can control sea lice and how best to optimize their use. To explore at what densities wrasse should be stocked in order to meet specific control targets, we built an individual-based model that simulates sea lice infestation patterns on a representative salmonid host. Sea lice can be controlled through the use of chemical treatments as well as by wrasse predators. We found that the wrasse can effectively control sea lice, and the densities of wrasse needed for effective control depend upon the source of the infestation and the targeted level of control. Effective usage of wrasse can result in decreased use of chemical treatments and improved control of sea lice.

  17. Appearance traits in fish farming: progress from classical genetics to genomics, providing insight into current and potential genetic improvement

    Science.gov (United States)

    Colihueque, Nelson; Araneda, Cristian

    2014-01-01

    Appearance traits in fish, those external body characteristics that influence consumer acceptance at point of sale, have come to the forefront of commercial fish farming, as culture profitability is closely linked to management of these traits. Appearance traits comprise mainly body shape and skin pigmentation. Analysis of the genetic basis of these traits in different fish reveals significant genetic variation within populations, indicating potential for their genetic improvement. Work into ascertaining the minor or major genes underlying appearance traits for commercial fish is emerging, with substantial progress in model fish in terms of identifying genes that control body shape and skin colors. In this review, we describe research progress to date, especially with regard to commercial fish, and discuss genomic findings in model fish in order to better address the genetic basis of the traits. Given that appearance traits are important in commercial fish, the genomic information related to this issue promises to accelerate the selection process in coming years. PMID:25140172

  18. Contaminants in popular farmed fish consumed in The Netherlands and their levels in fish feedContaminants in popular farmed fish consumed in The Netherlands and their levels in fish feed

    NARCIS (Netherlands)

    Leeuwen, van S.; Velzen, van M.; Swart, K.; Veen, van der I.; Traag, W.A.; Spanjer, M.; Scholten, J.; Rijn, van H.

    2008-01-01

    Onderzoek naar verontreinigende stoffen in veel geconsumeerde visproductenInvestigated is a wide range of pollutants in the top five consumed fish in the Netherlands (salmon, trout, tilapia, pangasius and shrimps). Farmed fish samples were collected from different sources (supermarkets, fish stores,

  19. Contaminants in popular farmed fish consumed in The Netherlands and their levels in fish feedContaminants in popular farmed fish consumed in The Netherlands and their levels in fish feed

    NARCIS (Netherlands)

    Leeuwen, van S.; Velzen, van M.; Swart, K.; Veen, van der I.; Traag, W.A.; Spanjer, M.; Scholten, J.; Rijn, van H.

    2008-01-01

    Onderzoek naar verontreinigende stoffen in veel geconsumeerde visproductenInvestigated is a wide range of pollutants in the top five consumed fish in the Netherlands (salmon, trout, tilapia, pangasius and shrimps). Farmed fish samples were collected from different sources (supermarkets, fish stores,

  20. Environmental impacts of coastal fish farming; Carbon and Nitrogen budgets for trout farming in Kaldbacksfjord, Faroe Islands

    DEFF Research Database (Denmark)

    Nordi, Gunnvor A; Glud, Ronnie N.; Gaard, Eilif

    2011-01-01

    Flow of organic carbon (OC) and nitrogen through a sea cage trout farm was calculated on the basis of detailed studies of the farming operation, water circulation, OC and nutrient transport and recycling processes in sediment. A third of the OC and nitrogen provided by fish food was incorporated...

  1. Effect of production quotas on economic and environmental values of growth rate and feed efficiency in sea cage fish farming

    Science.gov (United States)

    Besson, M.; de Boer, I. J. M.; Vandeputte, M.; van Arendonk, J. A. M.; Quillet, E.; Komen, H.; Aubin, J.

    2017-01-01

    In sea cage fish farming, production quotas aim to constrain the impact of fish farming on the surrounding ecosystem. It is unknown how these quotas affect economic profitability and environmental impact of genetic improvement. We combined bioeconomic modelling with life cycle assessment (LCA) to calculate the economic (EV) and environmental (ENV) values of thermal growth coefficient (TGC) and feed conversion ratio (FCR) of sea bass reared in sea cages, given four types of quota commonly used in Europe: annual production (Qprod), annual feed distributed (Qannual_feed), standing stock (Qstock), and daily feed distributed (Qdaily_feed). ENV were calculated for LCA impact categories climate change, eutrophication and acidification. ENV were expressed per ton of fish produced per year (ENV(fish)) and per farm per year (ENV(farm)). Results show that irrespective of quota used, EV of FCR as well as ENV(fish) and ENV(farm) were always positive, meaning that improving FCR increased profit and decreased environmental impacts. However, the EV and the ENV(fish) of TGC were positive only when quota was Qstock or Qdaily_feed. Moreover, the ENV(farm) of TGC was negative in Qstock and Qdaily_feed quotas, meaning that improving TGC increased the environmental impact of the farm. We conclude that Qstock quota and Qdaily_feed quota are economically favorable to a genetic improvement of TGC, a major trait for farmers. However, improving TGC increases the environmental impact of the farm. Improving FCR represents a good opportunity to balance out this increase but more information on its genetic background is needed to develop breeding programs improving FCR. PMID:28288179

  2. Association of health involvement and attitudes towards eating fish on farmed and wild fish consumption in Belgium, Norway and Spain

    NARCIS (Netherlands)

    Altintzoglou, T.; Vanhonacker, F.; Verbeke, W.; Luten, J.B.

    2011-01-01

    Consumers in many European countries do not equally meet the recommended daily intake levels for fish consumption. Various factors that can influence fish consumption behaviour have been identified but limited research has been performed on fish consumption behaviour, discriminating between farmed

  3. Association of health involvement and attitudes towards eating fish on farmed and wild fish consumption in Belgium, Norway and Spain

    NARCIS (Netherlands)

    Altintzoglou, T.; Vanhonacker, F.; Verbeke, W.; Luten, J.B.

    2011-01-01

    Consumers in many European countries do not equally meet the recommended daily intake levels for fish consumption. Various factors that can influence fish consumption behaviour have been identified but limited research has been performed on fish consumption behaviour, discriminating between farmed a

  4. Complex interactions mediate the effects of fish farming on benthic chemistry within a region of Scotland.

    Science.gov (United States)

    Mayor, Daniel J; Solan, Martin

    2011-07-01

    Fish farms typically generate a localised gradient of both organic and inorganic pollutants in the underlying sediments. The factors governing the extent of such impacts remain poorly understood, particularly when multiple sites are considered. We used regression-type techniques to examine the drivers of sediment chemistry patterns around five Scottish fish farms that ranged in size (120-2106 tonnes) and fish species, but were located within farm illustrate that between-site variability can be high, even at this regional-scale. These effects must be accounted for when comparing the effects of fish farming at different locations. All measured chemical parameters declined rapidly as a function of distance from the cage edge, with the rate of decline depending on local current speeds. Only phosphorus concentrations increased directly with farm size. Increasing current speeds at farms carbon in the underlying sediments, whereas the opposite occurred at larger farms. The counterintuitive effect of current speed at farms above the threshold size suggests that the physical properties of the seabed at these locations favour the accumulation of organic wastes and/or that the underlying communities have a lower assimilative capacity. These imply that the environmental efficiency of fish farming activities may be further optimised by taking into account the interaction between current speed, substrate complexity and the functional characteristics of the benthos. Collectively, our analyses demonstrate that the fate of fish farm-derived wastes is complex and highlight the need for site-specific management techniques.

  5. Factors affecting farmers' adoption of integrated rice-fish farming systems in the Mekong delta, Vietnam

    NARCIS (Netherlands)

    Bosma, R.H.; Nhan, D.K.; Udo, H.M.J.; Kaymak, U.

    2012-01-01

    This study investigated the determinants of the adoption of improved rice–fish farming systems in the Mekong delta to support policy making, agricultural land-use planning and extension of integrated rice–fish farming. Recently these systems have been referred to as adaptations to climate change, wh

  6. Semi-continuously addition of peracetic acid to a flow-through fish farm

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Henriksen, Niels Henrik

    2017-01-01

    •Demonstration of a safe and reliable practical method to reduce ectoparasites related mortality of farmed fish.•Central peracetic acid application caused even distribution to all ponds and considered suitable for organic fish farming.•Low dose and easy degradable peracetic acid is an alternative...... aquaculture management approach to formalin flush treatment....

  7. Marine Model Trout Farms: developments in marine RAS

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg

    2011-01-01

    . This development and demonstration unit in commercial scale will during the next four years hopefully provide scientific and practical basis and support for further development in coming generations of Marine Model Trout Farms for large salmonids. The unit consist in the recirculation loop of one large fish tank...

  8. Environmental health impacts of feeding crops to farmed fish.

    Science.gov (United States)

    Fry, Jillian P; Love, David C; MacDonald, Graham K; West, Paul C; Engstrom, Peder M; Nachman, Keeve E; Lawrence, Robert S

    2016-05-01

    Half of the seafood consumed globally now comes from aquaculture, or farmed seafood. Aquaculture therefore plays an increasingly important role in the global food system, the environment, and human health. Traditionally, aquaculture feed has contained high levels of wild fish, which is unsustainable for ocean ecosystems as demand grows. The aquaculture industry is shifting to crop-based feed ingredients, such as soy, to replace wild fish as a feed source and allow for continued industry growth. This shift fundamentally links seafood production to terrestrial agriculture, and multidisciplinary research is needed to understand the ecological and environmental health implications. We provide basic estimates of the agricultural resource use associated with producing the top five crops used in commercial aquaculture feed. Aquaculture's environmental footprint may now include nutrient and pesticide runoff from industrial crop production, and depending on where and how feed crops are produced, could be indirectly linked to associated negative health outcomes. We summarize key environmental health research on health effects associated with exposure to air, water, and soil contaminated by industrial crop production. Our review also finds that changes in the nutritional content of farmed seafood products due to altered feed composition could impact human nutrition. Based on our literature reviews and estimates of resource use, we present a conceptual framework describing the potential links between increasing use of crop-based ingredients in aquaculture and human health. Additional data and geographic sourcing information for crop-based ingredients are needed to fully assess the environmental health implications of this trend. This is especially critical in the context of a food system that is using both aquatic and terrestrial resources at unsustainable rates.

  9. Impact of integrated fish farming on antimicrobial resistance in a pond environment

    DEFF Research Database (Denmark)

    Petersen, Andreas; Andersen, Jens Strodl; Kaewmak, T.;

    2002-01-01

    investigated the impact of integrated fish farming on the levels of antimicrobial-resistant bacteria in a pond environment. One integrated broiler chicken-fish farm was studied for 2 months immediately after the start of a new fish production cycle. A significant increase over time in the resistance to six......-resistant bacteria from animal manure. Potential risks to human health were not addressed in this study and remain to be elucidated....

  10. On-farm trials with rice fish cultivation in the west Kano rice irrigation scheme, Kenya

    OpenAIRE

    Rasowo, J.; Auma, E.O.

    2006-01-01

    The viability of integrating rice farming with fish culture was studied in ten (10) rice plots. The on-farm research was done during one rice-growing season starting May 2003. The rice variety used was IR 2793-80-1 while the fish species was the Nile tilapia, Oreochromis niloticus. The fish culture period lasted 77 days. An average fish production of 132.4 kg/ha was obtained. The mean recovery rate of tilapia was 43 per cent. Total rice yield from the fields stocked with fish was lower than f...

  11. Farm-level risk factors for fish-borne zoonotic trematode infection in integrated small-scale fish farms in northern Vietnam.

    Directory of Open Access Journals (Sweden)

    Van Thi Phan

    Full Text Available BACKGROUND: Northern Vietnam is an endemic region for fish-borne zoonotic trematodes (FZT, including liver and intestinal flukes. Humans acquire the FZT infection by eating raw or inadequately cooked fish. The production of FZT-free fish in aquaculture is a key component in establishing a sustainable program to prevent and control the FZT transmission to humans. Interventions in aquaculture should be based on knowledge of the main risk factors associated with FZT transmission. METHODOLOGY/PRINCIPAL FINDINGS: A longitudinal study was carried out from June 2006 to May 2007 in Nam Dinh province, Red River Delta to investigate the development and risk factors of FZT infections in freshwater cultured fish. A total of 3820 fish were sampled six times at two-month intervals from 96 fish farms. Logistic analysis with repeated measurements was used to evaluate potential risk factors based on information collected through questionnaire interviews with 61 fish farm owners. The results showed that the FZT infections significantly increased from first sampling in June to July 2006 (65% to sixth sampling in April to May, 2007 (76%. The liver fluke, Clonorchis sinensis and different zoonotic intestinal flukes including Haplochis pumilio, H. taichui, H. yokogawai, Centrocestus formosanus and Procerovum varium were found in sampled fish. Duration of fish cultured (sampling times, mebendazole drug self-medication of household members, presence of snails in the pond, and feeding fish with green vegetation collected outside fish farms all had a significant effect on the development of FZT prevalence in the fish. CONCLUSIONS/SIGNIFICANCE: The FZT prevalence in fish increased by 11 percentage points during a one-year culture period and the risk factors for the development of infection were identified. Results also highlight that the young fish are already highly infected when stocked into the grow-out systems. This knowledge should be incorporated into control

  12. Hydroacoustic registration of fish abundance of offshore wind farms. Horns Rev offshore wind farm. Annual report 2004.

    Energy Technology Data Exchange (ETDEWEB)

    Hvidt, C.B.; Bruenner, L.; Reier Knudsen, F.

    2005-05-15

    Elsam Engineering AS has approved the implementation of a project concerning the registration of fish communities in Horns Rev Offshore Wind Farm with use of hydroacoustic methods. In a joint effort, Bio/consult as, Carl Bro as and SIMRAD AS have monitored the fish communities at Horns Rev Offshore Wind Farm using a new hydroacoustic methodology. The new hydroacoustic technique combines the use of scientific sonar acoustics with GPS to determine the density, diversity and location of fish. The objectives of this project were to test the possibility of using hydroacoustic techniques as alternative methods to traditional techniques to assess the fish assemblage inhabiting offshore wind farms and to investigate the possible effect from the wind farm and hard bottom substrates (turbine foundations) on fish abundance. The field study was carried out October 9-10, 2004 and consisted of four horizontal hydroacoustic survey transects each covering impact and reference areas. Transects were surveyed in order to achieve identical impact and reference transect pairs concerning environment, topography and time correspondence. The hydroacoustic equipment consisted of a SIMRAD EK60/EY60 echo sounder with a split-beam transducer (Simrad ES 120-4x10) mounted on a pan and tilt unit, a transceiver, a laptop extended with a GPS-receiver and additional large external hard discs. The raw data files from EK60 were converted to echogram files suitable for the post processing application, Sonar5-Pro. The Sonar5-Pro software makes it possible to filter out echo detections from the surface and the bottom, as well as perform cross filter detection. The validity of the results using the hydroacoustic method is high due to the cross filtering and single target tracking technique. From the hydroacoustic results, no or very little effect from the wind farm or from hard bottom substrates was found on the fish densities at Horns Rev Wind Farm at the time of the survey. The execution of the field

  13. Mercury in UK imported fish and shellfish and UK-farmed fish and their products.

    Science.gov (United States)

    Knowles, T G; Farrington, D; Kestin, S C

    2003-09-01

    Total mercury concentrations were measured in fish and shellfish and their products imported into the UK and also in UK-produced farmed salmon and trout. Three hundred and thirty-six samples were collected using a two-stage sampling plan. The sample plan was weighted to reflect consumption, but with some bias towards fish that might accumulate higher levels of mercury, such as large predatory fish at the top of the food chain. The highest levels of total mercury were found in billfish (swordfish and marlin) and shark. Mercury concentrations in the five samples of fresh/frozen shark ranged from 1.006 to 2.200 mg kg(-1), all above the European Commission limit for the species, and concentrations in 20 samples of fresh/frozen billfish ranged from 0.153 to 2.706 mg kg(-1) with 13 samples above the 1.0 mg kg(-1) limit for the species. One sample of Antarctic ice fish was collected and had a mercury concentration of 0.664 mg kg(-1). The limit for this species was 0.5 mg kg(-1). One sample of fresh/frozen tuna out of the 20 collected had a mercury concentration above the limit of 1.0 mg kg(-1) (1.5 mg kg(-1)), but all other fresh tuna samples were well within the regulatory limit (average 0.4 mg kg(-1)). Mercury concentrations in canned tuna were lower with concentrations on average half that measured in fresh/frozen tuna. Mercury concentrations in UK-farmed salmon and trout were relatively low. The maximum concentration found in 46 samples of fresh/frozen or smoked trout and salmon was 0.103 mg kg(-1).

  14. Empirical Analysis of Farm Credit Risk under the Structure Model

    Science.gov (United States)

    Yan, Yan

    2009-01-01

    The study measures farm credit risk by using farm records collected by Farm Business Farm Management (FBFM) during the period 1995-2004. The study addresses the following questions: (1) whether farm's financial position is fully described by the structure model, (2) what are the determinants of farm capital structure under the structure model, (3)…

  15. Empirical Analysis of Farm Credit Risk under the Structure Model

    Science.gov (United States)

    Yan, Yan

    2009-01-01

    The study measures farm credit risk by using farm records collected by Farm Business Farm Management (FBFM) during the period 1995-2004. The study addresses the following questions: (1) whether farm's financial position is fully described by the structure model, (2) what are the determinants of farm capital structure under the structure model, (3)…

  16. Growth of Tetraselmis suecica in a tubular photobioreactor on wastewater from a fish farm

    NARCIS (Netherlands)

    Michels, M.H.A.; Vaskoska, R.S.; Vermuë, M.H.; Wijffels, R.H.

    2014-01-01

    This study shows the feasibility of an integrated multi-trophic aquaculture approach where wastewater from the fish farms is used to produce feed for juvenile shellfish at high productivity and constant quality.

  17. A meta-analysis approach to the effects of fish farming on soft bottom polychaeta assemblages in temperate regions

    OpenAIRE

    Martinez-Garcia, Elena; Sanchez-Jerez, Pablo; Aguado Giménez, Felipe; Ávila, Pablo; Guerrero, Alejandro; Sánchez-Lizaso, José Luis; Fernandez-Gonzalez, Victoria; González, Nieves; Gairin Deulofeu, Joan Ignasi; Carballeira, Carlos; García García, Benjamín; Carreras, Jordi; Macías, José Carlos; Carballeira, Alejo; Collado, Cayetano

    2013-01-01

    Marine fish farms could cause environmental disturbances on the sediment due to uneaten food and fish faeces that impact the marine benthos. Polychaete assemblages are considered good indicators of environmental perturbations. The present study aimed to establish groups of polychaetes as potential indicators of fish farm pollution. This study was carried out in ten fish farms along the Spanish coast. Changes in polychaete assemblage were analyzed with meta-analysis and multivariate techniques...

  18. Distribution of fish species for the generic Appropriate Assessment for the construction of offshore wind farms.

    NARCIS (Netherlands)

    Hofstede, ter R.; Winter, H.V.; Os, O.G.

    2008-01-01

    The Dutch government aims at the production of 450 MW of electricity by offshore wind farms by 2010 and 6000 MW by 2020. Possibly the construction, exploitation and dismantlement of the wind farms will influence fish in the North Sea, which are protected under the European Habitat Directive or are c

  19. Proxy measures of fitness suggest coastal fish farms can act as population sources and not ecological traps for wild gadoid fish.

    Directory of Open Access Journals (Sweden)

    Tim Dempster

    Full Text Available BACKGROUND: Ecological traps form when artificial structures are added to natural habitats and induce mismatches between habitat preferences and fitness consequences. Their existence in terrestrial systems has been documented, yet little evidence suggests they occur in marine environments. Coastal fish farms are widespread artificial structures in coastal ecosystems and are highly attractive to wild fish. METHODOLOGY/PRINCIPAL FINDINGS: To investigate if coastal salmon farms act as ecological traps for wild Atlantic cod (Gadus morhua and saithe (Pollachius virens, we compared proxy measures of fitness between farm-associated fish and control fish caught distant from farms in nine locations throughout coastal Norway, the largest coastal fish farming industry in the world. Farms modified wild fish diets in both quality and quantity, thereby providing farm-associated wild fish with a strong trophic subsidy. This translated to greater somatic (saithe: 1.06-1.12 times; cod: 1.06-1.11 times and liver condition indices (saithe: 1.4-1.8 times; cod: 2.0-2.8 times than control fish caught distant from farms. Parasite loads of farm-associated wild fish were modified from control fish, with increased external and decreased internal parasites, however the strong effect of the trophic subsidy overrode any effects of altered loads upon condition. CONCLUSIONS AND SIGNIFICANCE: Proxy measures of fitness provided no evidence that salmon farms function as ecological traps for wild fish. We suggest fish farms may act as population sources for wild fish, provided they are protected from fishing while resident at farms to allow their increased condition to manifest as greater reproductive output.

  20. Logistic Regression Analysis on Factors Affecting Adoption of RiceFish Farming in North Iran

    Institute of Scientific and Technical Information of China (English)

    Seyyed Ali NOORHOSSEINI-NIYAKI; Mohammad Sadegh ALLAHYARI

    2012-01-01

    We evaluated the factors influencing the adoption of rice-fish farming in the Tavalesh region near the Caspian Sea in northern Iran.We conducted a survey with open-ended questions.Data were collected from 184 respondents (61 adopters and 123 non-adopters) randomly sampled from selected villages and analyzed using logistic regression and multiresponse analysis.Family size,number of contacts with an extension agent,participation in extension-education activities,membership in social institutions and the presence of farm workers were the most important socioeconomic factors for the adoption of rice-fish farming system.In addition,economic problems were the most common issue reported by adopters.Other issues such as lack of access to appropriate fish food,losses of fish,lack of access to high quality fish fingerlings and dehydration and poor water quality were also important to a number of farmers.

  1. Economic efficiency in fish farming:hope for agro-allied industries in Niagara

    Institute of Scientific and Technical Information of China (English)

    R.O.KAREEM; A.O.DIPEOLU; A.B.AROMOLARAN; S.B.WILLIAMS

    2008-01-01

    The challenge to increase the efficiency in food production level in Nigeria appears to be more urgent now than it has ever been in the history of the country.This is in view of the rapidly increasing population,the imminent decline in international economic and food aid and the need to conserve foreign exchange earnings through the production of raw materials to feed the growing industrial sector calls for urgent attention.The study was carried out in Ogun State.The descriptive statistics was used to determine the socio-economic characteristics of the respondents.The stochastic frontiers production analysis was applied to estimate the technical,allocative efficiency and economic efficiency among the fish farmers in the state.The results of economic efficiency revealed that fish farming is economically efficient with a range of between 55% and 84% efficiency level suggesting a favourable hope for the agro-allied industry such as poultry and cottage industries etc in the state.The result of hypothesis of inefficiency sources models showed that years of experience of fish farmers is significant at 1% probability level indicating the factor contributing to the fish fanning experience in the state.Thus,the efficiency is due to the fact that farmers are experienced and fairly educated.On the basis of findings,policy is suggested to be directed towards the encouragement of entrepreneurs in fish farming in the state by providing enabling environment like credit facilities,public enlightenment programme and provision of social amenities like feeder roads,prpe-born water etc and given the fact that an increase in the level of formal education variable leads to less inefficiency,government policy should be focused on adopting the best technology (e.g.fast growing species and equipment)so as to improve the level of efficiency and investment which shall eventually lead to growth in output of fish farming and a lead to the establishment of agro-allied industries in the state.

  2. Long-chain omega-3 from low-trophic-level fish provides value to farmed seafood.

    Science.gov (United States)

    Bibus, Douglas M

    2015-03-01

    Low-trophic-level fish are a crucial source of long-chain (LC) omega-3 fatty acids for farmed fish and humans. Many farm-raised fish species have a clear need for these nutrients. Farmed fish deposit the LC omega-3s in their flesh and transfer them up the food chain. However, the content of LC omega-3s in farm-raised seafood continues to decline, while the content of shorter-chain plant-sourced omega-3s, and pro-inflammtory omega-6s continue to increase. This reduces its nutritional worth. The value of low-trophic-level fish is often viewed merely as its price at the dock. Some reports and metrics steer public attention towards the mass balance between quantities of low-trophic-level fish and farmed seafood. However, the the nutritional value of seafood is more important than its mere quantities. The role of low-trophic-level fish in human nutrition, health, and wellbeing is a fundamental component of its economic value to society.

  3. Increasing the Economical Efficiency and Sustainability of Indoor Fish Farming by Means of Aquaponics - Review

    Directory of Open Access Journals (Sweden)

    Flavius Blidariu

    2011-10-01

    Full Text Available This review focuses on increasing economical efficiency and sustainability of indoor fish farming. Aspects like sustainability and economical efficiency were reviewed. In order to improve man`s health we must reconsider the agricultural sciences, by this we understand that we must develop technologies friendly for the environment. Sustainable indoor fish farming is the farming of the new millennium. Combining aquaculture with hydroponics we obtain a new innovation named aquaponics which respects principles of sustainable agriculture (wastewater biofiltration by plants and gives us the possibility to increase economical efficiency with an additional production (organic vegetables.

  4. Influence of water temperature on the economic value of growth rate in fish farming

    NARCIS (Netherlands)

    Besson, M.; Vandeputte, M.; Arendonk, van J.A.M.; Aubin, J.; Boer, de I.J.M.; Quillet, E.; Komen, H.

    2016-01-01

    In sea cage farming, fish are exposed to seasonal variations of water temperature, and these variations can differ from one location to another. A small increase in water temperature does not only stimulate growth of the fish (until an optimal level) but also lowers dissolved oxygen concentration

  5. Investigating the suitability of constructed wetlands for the treatment of water for fish farms

    NARCIS (Netherlands)

    Heijden, van der P.G.M.; Dien, van F.; El-Beshbishi, D.A.

    2015-01-01

    Many fish farms in Egypt rely on water of drainage canals to fill the fish ponds. There is a risk that this water is contaminated with pesticides and heavy metals. This report describes the results of a collaborative project that took place in 2012-2014 and that aimed to test the suitability of a

  6. Influence of water temperature on the economic value of growth rate in fish farming

    NARCIS (Netherlands)

    Besson, M.; Vandeputte, M.; Arendonk, van J.A.M.; Aubin, J.; Boer, de I.J.M.; Quillet, E.; Komen, H.

    2016-01-01

    In sea cage farming, fish are exposed to seasonal variations of water temperature, and these variations can differ from one location to another. A small increase in water temperature does not only stimulate growth of the fish (until an optimal level) but also lowers dissolved oxygen concentration

  7. [Aspects of animal welfare with regard to the production of farmed fish in aquaculture systems].

    Science.gov (United States)

    Kleingeld, D W

    2005-03-01

    The most important aspects on animal welfare with reference to fish are presented in this paper. World-wide a fast growing trend with regard to the production of aquatic organisms in aquaculture systems is observed. For the future an increase of the number of basic questions with relevance to animal welfare in this area is to be expected. The main precondition for the creation of appropriate welfare conditions with regard to the farmed fish species is the optimisation of the environmental quality. Careful handling in the course of necessary farming activities minimises the appearance of distrees and damages in live fish.

  8. Status and prospects of fish farming in Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.; Verlecar, X.N.

    In Goa, India, aquaculture is being practised from time immemorial. The methods of fish culture used are traditional and involve composite culture of wild stocks. Despite the ignorance of modern methods of aquaculture, the fish farmers of Goa seem...

  9. Performance of Azolla caroliniana Willd. and Salvinia auriculata Aubl. on fish farming effluent

    Directory of Open Access Journals (Sweden)

    JJ. Toledo

    Full Text Available The increasing release of untreated fish farming effluents into water courses that flow to the Pantanal wetlands in Mato Grosso (Brazil may drive this ecosystem to eutrophication. Therefore, the growth of Azolla caroliniana Willd. and Salvinia auriculata Aubl. in fish farming effluent and their effect on its quality were evaluated for 48 days in a greenhouse. The results were compared to those obtained in a nutrient rich solution (Hoagland ½ medium. Azolla caroliniana showed lower relative growth rate in fish farming effluent (0.020 d-1 than in Hoagland ½ medium (0.029 d-1. However, S. auriculata grew slightly better in fish farming effluent (0.030 d-1 than in Hoagland ½ medium (0.025 d-1. The species apparently contributed to reduce nitrate and phosphate concentration in Hoagland ½ medium. However, in fish farming effluent, only electrical conductivity and pH were reduced by plants compared to the control without plants. Thus, A. caroliniana and S. auriculata show low potential for improving effluent quality.

  10. Can energy willow (Salix sp.) remediate cadmium- and nickel-contaminated fish farm sludge?

    DEFF Research Database (Denmark)

    Pedersen, Marianne Bruus

    In Denmark, the sludge produced in fish farms is usually applied as agricultural fertiliser. However, in some areas of Denmark, the cadmium and nickel contents of the fish farm sludge exceed the Danish quality criteria for sludge, which means that the sludge has to be deposited or remedied until...... it meets the criteria. Phytoremediation by willow may combine accumulation of cadmium and nickel from the sludge with the production of an energy crop. The ability of eight selected willow clones to take up and tolerate cadmium and nickel was studied in pots under outdoor conditions. Fish farm sludge...... was added to the pots at different dosages, either on the soil surface, mixed into the soil or as pure sludge. The remediation potential of the single clones was estimated after one growing season by multiplying growth and heavy metal content. At leaf-fall leaves were collected for cadmium and nickel...

  11. A meta-analysis approach to the effects of fish farming on soft bottom polychaeta assemblages in temperate regions.

    Science.gov (United States)

    Martinez-Garcia, Elena; Sanchez-Jerez, Pablo; Aguado-Giménez, Felipe; Ávila, Pablo; Guerrero, Alejandro; Sánchez-Lizaso, Jose Luis; Fernandez-Gonzalez, Victoria; González, Nieves; Gairin, Joan Ignasi; Carballeira, Carlos; García-García, Benjamín; Carreras, Jordi; Macías, Jose Carlos; Carballeira, Alejo; Collado, Cayetano

    2013-04-15

    Marine fish farms could cause environmental disturbances on the sediment due to uneaten food and fish faeces that impact the marine benthos. Polychaete assemblages are considered good indicators of environmental perturbations. The present study aimed to establish groups of polychaetes as potential indicators of fish farm pollution. This study was carried out in ten fish farms along the Spanish coast. Changes in polychaete assemblage were analyzed with meta-analysis and multivariate techniques. Abundance, richness and diversity showed significant decreases under fish farm conditions. Distribution patterns of polychaetes responded to combinations of physicochemical variables. The main ones are sulfide concentration, silt and clays percentage, and stable nitrogen isotope ratio. The results showed that some families are tolerant, Capitellidae, Dorvilleidae, Glyceridae, Nereididae, Oweniidae and Spionidae; while others are sensitive to fish farm pollution, Magelonidae, Maldanidae, Nephtyidae, Onuphidae, Paralacydoniidae, Paraonide, Sabellidae and also Cirratulidae in spite of being reported as a tolerant family.

  12. Farming-up coastal fish assemblages through a massive aquaculture escape event.

    Science.gov (United States)

    Toledo-Guedes, Kilian; Sanchez-Jerez, Pablo; Benjumea, María E; Brito, Alberto

    2014-07-01

    We investigated the changes on the mean trophic level of fish assemblages across different spatiotemporal scales, before and after a massive escape event occurred off La Palma (Canary Islands), which resulted in the release of 1.5 million fish (mostly Dicentrarchus labrax) into the wild. The presence of escaped fish altered significantly the mean trophic level of fish assemblages in shallow coastal waters. This alteration was exacerbated by the massive escape. A nearby marine protected area buffered the changes in mean trophic level but exhibited the same temporal patterns as highly fished areas. Moreover, escaped fish exploited natural resources according to their total length and possibly, time since escapement. New concerns arise as a "farming up" process is detected in shallow coastal fish assemblages where marine aquaculture is established.

  13. The dinoflagellates Pfiesteria shumwayae and Luciella masanensis cause fish kills in recirculation fish farms in Denmark

    DEFF Research Database (Denmark)

    Moestrup, Øjvind; Hansen, Gert; Daugbjerg, Niels;

    2014-01-01

    are apparently the first RAS farms in which serious fish kills have been reported. In the marine farm (Luciella) fish mortality increased dramatically despite treatment of the water with peracetic acid and chloramine-T. The plant was temporarily closed down pending investigation into the cause of mortality...

  14. Space-time modelling of the spread of salmon lice between and within Norwegian marine salmon farms.

    Directory of Open Access Journals (Sweden)

    Magne Aldrin

    Full Text Available Parasitic salmon lice are potentially harmful to salmonid hosts and farm produced lice pose a threat to wild salmonids. To control salmon lice infections in Norwegian salmonid farming, numbers of lice are regularly counted and lice abundance is reported from all salmonid farms every month. We have developed a stochastic space-time model where monthly lice abundance is modelled simultaneously for all farms. The set of farms is regarded as a network where the degree of contact between farms depends on their seaway distance. The expected lice abundance at each farm is modelled as a function of i lice abundance in previous months at the same farm, ii at neighbourhood farms, and iii other, unspecified sources. In addition, the model includes explanatory variables such as seawater temperature and farm-numbers of fish. The model gives insight into factors that affect salmon lice abundance and contributing sources of infection. New findings in this study were that 66% of the expected salmon lice abundance was attributed to infection within farms, 28% was attributed to infection from neighbourhood farms and 6% to non-specified sources of infection. Furthermore, we present the relative risk of infection between neighbourhood farms as a function of seaway distance, which can be viewed as a between farm transmission kernel for salmon lice. The present modelling framework lays the foundation for development of future scenario simulation tools for examining the spread and abundance of salmon lice on farmed salmonids under different control regimes.

  15. To Safeguard Century-old Rice-fish Farming Practice

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ "… dig six mu of land into a pond … put 2,000 fry into the pond …sell the rest in the market," wrote ancient Chinese scholar Fan Li about 400 BC in The Canon for Fish Culture, the oldest known fish culture document.

  16. Copper, zinc and cadmium in marine cage fish farm sediments: An extensive survey

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Rebecca J. [Scottish Association for Marine Science, Ecology Department, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, Scotland (United Kingdom); Shimmield, Tracy M. [Scottish Association for Marine Science, Ecology Department, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, Scotland (United Kingdom); Black, Kenneth D. [Scottish Association for Marine Science, Ecology Department, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, Scotland (United Kingdom)]. E-mail: kenny.black@sams.ac.uk

    2007-01-15

    The diet of cage-farmed Atlantic salmon contains a range of trace metals, some of which have toxic properties, e.g. zinc, copper and cadmium. A survey of metal concentrations (ICP-MS analysis) in surface sediments of ca. 70 stations was carried out in both May and December 2000 around a Scottish fish farm. Additionally, at 13 stations on 2 orthogonal transects centered on the farm, sediments were analysed at 1 cm intervals to 8 cm depth. Maximum concentrations in surface sediments were 921, 805 and 3.5 {mu}g g{sup -1} for Zn, Cu and Cd, respectively, and were found at stations near the fish farm. The calculated losses from the farm (feed input minus fish output) were 87.0%, 4.3% and 14.0% of the background-corrected inventories for Zn, Cu and Cd, respectively, indicating that for Cu and Cd at least, the feed is not the only source. - Sediments around a salmon farm show extremely high levels of zinc, copper and cadmium contamination.

  17. Fish farming of native species in Colombia: current situation and perspectives

    DEFF Research Database (Denmark)

    Cruz-Casallas, P. E.; Medina-Robles, V. M.; Velasco-Santamaria, Y. M.

    2011-01-01

    . The Colombian pisciculture is based on red Tilapia Oreochromis sp. (Linnaeus), Rainbow trout Oncorhynchus mykiss (Walbaum) and cachama blanca Piaractus brachypomus (Cuvier), which currently represent around 96% of the total national production. The remaining 4% comes from other farmed species such as bocachico......, food conversion and disease resistance. The limited offer of Colombian fish farmed species determines its currently low competitiveness and restricted impact on the international markets; thus making necessary to explore the potential of new fish species in order to introduce them to the pisciculture...

  18. Tracing fish farm waste in the northern shrimp Pandalus borealis (Kroyer, 1838) using lipid biomarkers

    OpenAIRE

    Olsen, Siri Aaserud; Ervik, Arne; Grahl-Nielsen, Otto

    2012-01-01

    A large amount of organic effluents are released annually from coastal fish farming locations primarily in the form of faeces that settle to the seabed, where they become a substantial food source for benthic communities. The inclusion of marine and vegetable oils as sources of lipids in salmon feed has resulted in a fatty acid (FA) composition that differs markedly from marine-derived material, and thus they can be used as an efficient tracer for the distribution of fish farm waste in both s...

  19. Integrated Poultry-Fish Farming Systems for Sustainable Rural Livelihood Security in Kumaon Hills of Uttarakhand

    OpenAIRE

    2013-01-01

    The study has analyzed socio-economic impact of poultry based farming system on farmers for their livelihood security and women empowerment. The analysis is based on the data collected from 95 poultry farmers selected from three hill districts of Kumaon region for two production years, 2011-12 and 2012- 13. It has been observed that the farmers’ access to day-old chicks (DOCs)/fish seed/fingerlings plays the key role in popularization of integrated poultry-fish farming. The economics of pre...

  20. Wind Farm Decentralized Dynamic Modeling With Parameters

    DEFF Research Database (Denmark)

    Soltani, Mohsen; Shakeri, Sayyed Mojtaba; Grunnet, Jacob Deleuran;

    2010-01-01

    Development of dynamic wind flow models for wind farms is part of the research in European research FP7 project AEOLUS. The objective of this report is to provide decentralized dynamic wind flow models with parameters. The report presents a structure for decentralized flow models with inputs from...

  1. Aggregation of European storm-petrel (Hydrobates pelagicus ssp. melitensis) around cage fish farms. Do they benefit from the farmś resources?

    Science.gov (United States)

    Aguado-Giménez, F; Sallent-Sánchez, A; Eguía-Martínez, S; Martínez-Ródenas, J; Hernández-Llorente, M D; Palanca-Maresca, C; Molina-Pardo, J L; López-Pastor, B; García-Castellanos, F A; Ballester-Moltó, M; Ballesteros-Pelegrín, G; García-García, B; Barberá, G G

    2016-12-01

    Cage aquaculture aggregates wild fauna due to food provision. Several seabirds frequent fish farms, including the European storm-petrel (Hydrobates pelagicus melitensis). This work investigates the presence of storm-petrels around two aquaculture areas interspersed between breeding colonies in western Mediterranean Sea. Contribution of aquaculture-derived resources to their diet was assessed. Storm-petrels were mist-netted at the colonies and marked by bleaching feathers. Density around aquaculture areas was estimated through visual counts. Marks recognition was conducted visually and by photo-capture. Storm-petrel regurgitates were used as target tissue to estimate diet sources contribution. Contribution of surface zooplankton, ichthyoplankton and aquaculture wastes was estimated through Bayesian mixing modelling combining carbon and nitrogen stable isotopes and fatty acids as biomarkers. Storm-petrel density was high in open-sea aquaculture area, but not observed around near shore farms. Temporal variability of storm-petrels density during the breeding season was linked to their reproductive phenology. Within the open-sea aquaculture area, bluefin tuna farm was more attractive for storm-petrels than seabream/seabass farms. Visual identification of bleaching marks was not useful. Photo-capture showed that 8.3% of the storm-petrels watched around farms were firstly trapped in some of the nearby colonies, and 91.7% were unmarked. Qualitative evidence of aquaculture-derived wastes utilization was obtained. However, its estimated contribution was low (4.3%) when compared to ichthyoplankton (61.1%) or zooplankton (34.6%). The studied open-sea farms significantly aggregated storm-petrels along their entire breeding season. Storm-petrels got a slight profit from aquaculture resources. Nevertheless, some concerns arise regarding the cost/benefit balance of the interaction.

  2. Microbial and nutritional aspects on the production of live feeds in a fish farming industry.

    Science.gov (United States)

    De Donno, A; Lugoli, F; Bagordo, F; Vilella, S; Campa, A; Grassi, T; Guido, M

    2010-03-01

    Aquaculture is an enterprise in constant development, in particular relating to its effect on the environment and also the quality of its products. It represents a valid alternative to traditional fishing, facing the increasing demand for fish products. To guarantee to the consumer a product of high nutritional, organoleptic and hygienic quality, it is fundamental to monitor every phase of the fish farming industry, isolating the potential risk points. For this reason there has been a rapid evolution of productive technique, particularly in the technology, artificial reproduction and feed sectors. The aim of this research has been the monitoring of the evolution of certain microbial and nutritional quality indexes (total microbial counts and lipid analysis on suspensions of Rotifers and Artemia, used as live feed) in the larval phase of the productive cycle of the farm raised fish, in an intensive system. The study has shown an increment in the total microbial counts in the fish farming industry within the production of Rotifers and Artemia, more evident in the suspensions of Rotifers. In addition the study has demonstrated that the maintenance phase, in the enrichment protocol, can reduce the EPA and DHA content. The results confirm the importance of microbial and nutritional control of the live feeds before they get supplied to fish larvae.

  3. Wind farm models and control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Iov, F.; Blaabjerg, F.; Donovan, M.H.

    2005-08-01

    This report describes models and control strategies for 3 different concepts of wind farms. Initially, the potential in improvement of grid integration, structural loads and energy production is investigated in a survey of opportunities. Then simulation models are described, including wind turbine models for a fixed speed wind turbine with active stall control and a variable speed wind turbine with doubly-fed induction generator. After that, the 3 wind farm concepts and control strategies are described. The 3 concepts are AC connected doubly fed turbines, AC connected active stall turbines and DC connected active stall turbines. Finally, some simulation examples and conclusions are presented. (au)

  4. Calculation of the environmental capacity of cooling ponds for cage fish farming

    Directory of Open Access Journals (Sweden)

    N. Starco

    2016-12-01

    Full Text Available Purpose. The determination of a maximum annual amount of fish reared in cagesm which does not result in the deterioration of the ecological state of water cooling ponds of the Zmiev Thermal Power Plant and Kursk Nuclear Power Plant series Ι and ΙΙ. Methodology. The specific (per 1 ton of farmed fish nutrient intake necessary for calculations was determined according to the data of own studies. For this purpose, we perfrormed the determination of the input of suspended solids into cooling ponds from cage lines. The calculation of mean fish weight increase during the period of trap exposition bsed on fish farm data allowed calculating the specific input of suspended solids from cages. The effect of artificial feeds and a mixture of feed resideus and fish of fishes collected under cages on water quality were evaluated in the condoitins of laboratory experiments. The effect of fish metabolites on water quality was taken into account according to literature data. Findings. In the specific conditions of the investigated cooling ponds, the environmentally allowable concentrations of biogenic elements are established based on the mineral nitrogen content. With the mean volume of the Zmiev Thermal Power Plant of 40.5 million m3, the total amount of mineral nitrogen, which can be introduced with cage aquaculture residues, is 21.87 tons. When rearing one ton of fish in cages, 91.3 kg of mineral nitrogen get into the cooling pond. Thus, the environmental capacity of the Zmiev Thermal Power Plant cooling pond for cage fish farming is 281.7 tons. Accordingly, the allowable amounts of the production of cage fish farming for the Kursk NPP taking into account N content of 0.406 mgN/dm3 and volume of the cooling pond is 625.5 tons. Originality. For the first time, we calculated the ecological capacity of cooling ponds of the Zmiev TPP and Kursk NPP, series I–II. Practical value. Application of the results presented in the paper will allow creating and

  5. Modeling parasite dynamics on farmed salmon for precautionary conservation management of wild salmon.

    Directory of Open Access Journals (Sweden)

    Luke A Rogers

    Full Text Available Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis on domesticated populations of Atlantic salmon (Salmo salar in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity, local host density (measured as cohort surface area, and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March-June juvenile wild Pacific salmon (Oncorhynchus spp. migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions.

  6. Radiometric analysis of farmed fish (sea bass, gilthead bream, and rainbow trout) from Tenerife Island, Spain.

    Science.gov (United States)

    Jalili, A; López-Pérez, M; Karlsson, L; Hernández, F; Rubio, C; Hernández-Armas, J; Hardisson, A

    2009-09-01

    This study analyzed the content of gamma-emitting radionuclides in fish farmed on the island of Tenerife (Canary Islands, Spain). The fish species included in this study were sea bass, gilthead bream, and rainbow trout. The first two species are produced in offshore enclosures, while the third is produced in a freshwater fish farm. All measurements were performed using two high-purity germanium gamma-ray detectors. The content of gamma-emitting radionuclides in the fodder used to feed the different species of farmed fish studied was also determined. The following nuclides were often detected in the analyzed samples: 137Cs, 40K, 235U, 228Ac, 214Bi, 208Tl, 212Pb, and 214Pb. As a complement to this analysis, 210Po concentrations in two fish samples were determined by alpha spectrometry. The nuclide presenting the highest concentration was, as expected, the naturally occurring 40K, with an average concentration of 0.13 +/- 0.01 Bq/g (wet weight) (Bq/gww) in gilthead bream and sea bass and 0.12 +/- 0.01 Bq/gww in rainbow trout. The 235U concentrations determined in the same fish species were 0.6 +/- 0.5, 0.8 +/- 0.7, and 1.6 +/- 1.0 mBq/gww, respectively. This nuclide is seldom reported in fish samples. The concentrations of 137Cs (the only artificial nuclide determined in this study) in gilthead bream and sea bass were 0.026 +/- 0.006 and 0.044 +/- 0.01 mBq/gww, respectively. In addition to the radiometric analysis, the contribution of the analyzed nuclides to the effective dose from the mean daily intake of the fish was calculated. The calculated contribution, in terms of dose per person, produced by intake of the analyzed fish was 0.8 microSv/year. This value does not represent a significant risk to the local population.

  7. Yersiniosis outbreak in rainbow trout at fish farm in Oromia Regional ...

    African Journals Online (AJOL)

    the body, gasping at the surface of the water and finally death. When freshwa- ... of growing ponds: one big stony pond (divided into 2 parts) of 75 m3 located on ..... infected with Yersinia ruckeri in Turkey showed that an average 82.2% protec- tion level was ... as an option for fish protection in the farm in the future. Yersinia ...

  8. Physiological responses of the seagrass Posidonia oceanica as indicators of fish farm impact

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Marta [Departament d' Ecologia, Universitat de Barcelona Avda. Diagonal 645, 08028 Barcelona (Spain); Garcia, Tania [Departament d' Ecologia, Universitat de Barcelona Avda. Diagonal 645, 08028 Barcelona (Spain)], E-mail: irulagun@hotmail.com; Invers, Olga [Departament d' Ecologia, Universitat de Barcelona Avda. Diagonal 645, 08028 Barcelona (Spain); Ruiz, Juan Manuel [Instituto Espanol de Oceanografia C/Varadero 1, 30740 San Pedro del Pinatar, Murcia (Spain)

    2008-05-15

    The development of aquaculture along the Mediterranean coastline degrades the marine environment, in particular Posidonia oceanica meadows, which, in extreme cases, show high mortality. Here we studied the effects of organic matter and nutrient input from the effluents of three fish farms, located along the Mediterranean coast, on P. oceanica physiology. For this purpose, we measured physiological variables such as total nitrogen (N) content, free amino acid (FAA) concentration and composition, N stable isotope ratio ({delta}{sup 15}N), total phosphorus (P) content and total non-structural carbohydrate (TNC) content in plant tissues and epiphytes affected by organic discharges (highly impacted stations: HI, and less impacted stations: LI) and compared these results with those obtained in references sites (control stations: C). For all the descriptors analyzed in P. oceanica epiphytes, the values recorded in the vicinity of cages were, in general, much higher than those in C. Leaves did not respond consistently in any case. Total N content and {delta}{sup 15}N in epiphytes together with the total P content in rhizomes and epiphytes were the physiological descriptors that showed the most consistent responses to fish farm effluents. On the basis of these observations, we conclude that fish farm activities strongly affect the physiological parameters of nearby P. oceanica meadows. We propose that changes in these physiological parameters may be useful indicators of marine environmental degradation in studies that monitor the effects of fish farming.

  9. Stunning and killing of farmed fish: How to put it into pratice?

    NARCIS (Netherlands)

    Vis, van de J.W.; Abbink, W.; Lambooij, B.; Bracke, M.B.M.

    2014-01-01

    In this article an approach is presented to implement stunning and killing of farmed fish in practice. First, in a laboratory setting, the conditions need to be established to achieve an effective stun without causing avoidable distress and discomfort. Product quality is evaluated to assess the impa

  10. Using copper sulfate to control egg fungus at Keo Fish Farm

    Science.gov (United States)

    Keo Fish Farm is the biggest producer of hybrid striped bass fry in the world. The hatchery manager asked about treatments to control fungus on eggs which occurred fairly often. Our lab has been working on gaining FDA-approval to use copper sulfate to control fungus on catfish eggs, so we were con...

  11. Physiological responses of the seagrass Posidonia oceanica as indicators of fish farm impact.

    Science.gov (United States)

    Pérez, Marta; García, Tania; Invers, Olga; Ruiz, Juan Manuel

    2008-05-01

    The development of aquaculture along the Mediterranean coastline degrades the marine environment, in particular Posidonia oceanica meadows, which, in extreme cases, show high mortality. Here we studied the effects of organic matter and nutrient input from the effluents of three fish farms, located along the Mediterranean coast, on P. oceanica physiology. For this purpose, we measured physiological variables such as total nitrogen (N) content, free amino acid (FAA) concentration and composition, N stable isotope ratio (delta 15N), total phosphorus (P) content and total non-structural carbohydrate (TNC) content in plant tissues and epiphytes affected by organic discharges (highly impacted stations: HI, and less impacted stations: LI) and compared these results with those obtained in references sites (control stations: C). For all the descriptors analyzed in P. oceanica epiphytes, the values recorded in the vicinity of cages were, in general, much higher than those in C. Leaves did not respond consistently in any case. Total N content and delta 15N in epiphytes together with the total P content in rhizomes and epiphytes were the physiological descriptors that showed the most consistent responses to fish farm effluents. On the basis of these observations, we conclude that fish farm activities strongly affect the physiological parameters of nearby P. oceanica meadows. We propose that changes in these physiological parameters may be useful indicators of marine environmental degradation in studies that monitor the effects of fish farming.

  12. MOLECULAR GENETIC MARKERS AND METHODS OF THEIR IDENTIFICATION IN MODERN FISH-FARMING

    Directory of Open Access Journals (Sweden)

    I. Hrytsyniak

    2014-03-01

    Full Text Available Purpose. The application of molecular genetic markers has been widely used in modern experimental fish-farming in recent years. This methodology is currently presented by a differentiated approach with individual mechanisms and clearly defined possibilities. Numerous publications in the scientific literature that are dedicated to molecular genetic markers for the most part offer purely practical data. Thus, the synthesis and analysis of existing information on the general principles of action and the limits of the main methods of using molecular genetic markers is an actual problem. In particular, such a description will make it possible to plan more effectively the experiment and to obtain the desired results with high reliability. Findings. The main types of variable parts of DNA that can be used as molecular genetic markers in determining the level of stock hybridization, conducting genetic inventory of population and solving other problems in modern fish-farming are described in this paper. Also, the article provides an overview of principal modern methods that can be used to identify molecular genetic markers. Originality. This work is a generalization of modern ideas about the mechanisms of experiments with molecular genetic markers in fish-farming. Information is provided in the form of consistent presentation of the principles and purpose of each method, as well as significant advances during their practical application. Practical value. The proposed review of classic and modern literature data on molecular genetic markers can be used for planning, modernization and correction of research activity in modern fish-farming.

  13. The evaluation of fish farming impact by nutrient content and chlorophyll A in Mala Lamljana bay

    Directory of Open Access Journals (Sweden)

    Jelic-Mrcelic Gorana

    2013-01-01

    Full Text Available This paper offers a brief review of the impacts of fish farming on the nutrient content and chlorophyll a in Mala Lamljana Bay, Croatia. Local loading of nitrogen and phosphorous compounds in fish farms can be very significant and can represent the largest source of N and P in a given area. Low N and P concentrations, low chlorophyll a concentration and a great variety of phytoplankton species were found in the bay, despite the high nutrient loading during the long history of farming in the bay. The phytoplankton community consisted mostly of diatoms and partly of dinoflagellates. Skeletonema costatum and Chaetoceros compressus were the dominant species (90% in summer chlorophyll, which is typical for Middle Adriatic oligotrophic coastal waters. Nevertheless, further studies are required to determine changes in water column factors and planktonic communities in this area.

  14. Wind farm models and control strategies

    DEFF Research Database (Denmark)

    Sørensen, Poul Ejnar; Hansen, Anca Daniela; Iov, F.;

    2005-01-01

    models for a fixed speed wind turbine with active stall control and a variable speed wind turbine with doubly-fed induction generator. After that, the 3 wind farm concepts and control strategies are described.The 3 concepts are AC connected doubly fed turbines, AC connected active stall turbines and DC......This report describes models and control strategies for 3 different concepts of wind farms. Initially, the potential in improvement of grid integration, structural loads and energy production is investigated in a survey of opportunities. Then simulationmodels are described, including wind turbine...

  15. Parasites of marine, freshwater and farmed fishes of Portugal: a review

    Directory of Open Access Journals (Sweden)

    Jorge da Costa Eiras

    Full Text Available Abstract An extensive literature review is made of the parasites in marine and freshwater fish in mainland Portugal, the Portuguese archipelagos of the Azores and Madeira, as well as in farmed fish. The host(s of each parasite species, its location in the host, site of capture of the host, whenever possible, and all the available bibliographic references are described. The economic importance of some parasites and the zoonotic relevance of some parasitic forms are discussed. A general overview of the data is provided, and some research lines are suggested in order to increase and complement the current body of knowledge about the parasites of fish from Portugal.

  16. Total lipids and fatty acid profile in the liver of wild and farmed catla catla fish

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, M.; Shaihid chatha, S. A.; Tahira, I.; Hussain, B.

    2010-07-01

    This experimental work was aimed to study the moisture content, total lipids and fatty acid profile in the liver of wild and farmed freshwater major carp Catla catla of three different weight categories designated as W{sub 1} (601-900g), W{sub 2} (901- 1200)g and W{sub 3} (1201-1500g). Seven fish specimens of each of the three weight categories of wild and farmed Catla catla were obtained from Trimu Head, Jhang and Fish Hatchery, Satiana Road and Faisalabad, respectively. The fish were dissected to remove the liver and after weighing, liver samples were prepared and subjected to chemical analysis. Wild Catla catla liver had a significantly (p <0.05) higher moisture content as compared to the farmed species. Farmed Catla catla deposited significantly (p < 0.05) higher lipid contents in liver. Proportions of saturated fatty acids varied irregularly in the lipids of the liver from both wild and farmed Catla catla. Saturated fatty acids C12:0, C14:0, C16:0, C18:0, C20:0 and C22:0 were identified with considerable percentages in the liver of Catla catla from both habitats and monounsaturated fatty acid C18:1 was found in considerable amounts in the liver of both major carp. Polyunsaturated fatty acids such as C18:3 (n-6) and C20: 2 (n-6) were detected in the liver of the wild fish of W{sub 2} and W{sub 3} and was similar in the W{sub 3} weight category of the farmed species. (Author) 22 refs.

  17. Piscicultura. Productor Comercial de Peces. Guia Tecnica. Documento de trabajo, Programa de Educacion Agricola (Fish Farming. Commercial Fish Producer. Technical Guide. Curriculum Document, Agriculture Education Program).

    Science.gov (United States)

    Puerto Rico State Dept. of Education, Hato Rey. Area for Vocational and Technical Education.

    This curriculum guide begins with an introduction, course description, and description of the occupation of commercial fish farmer. A course outline covers five units: starting a business, establishing the fish farm, managing the enterprise, harvesting the fish, and administering the business. For each unit, the following are provided: terminal…

  18. Piscicultura. Productor Comercial de Peces. Guia Tecnica. Documento de trabajo, Programa de Educacion Agricola (Fish Farming. Commercial Fish Producer. Technical Guide. Curriculum Document, Agriculture Education Program).

    Science.gov (United States)

    Puerto Rico State Dept. of Education, Hato Rey. Area for Vocational and Technical Education.

    This curriculum guide begins with an introduction, course description, and description of the occupation of commercial fish farmer. A course outline covers five units: starting a business, establishing the fish farm, managing the enterprise, harvesting the fish, and administering the business. For each unit, the following are provided: terminal…

  19. From Farming to Fishing: Marine Resource Conservation and a New ...

    African Journals Online (AJOL)

    diversify their livelihoods, many coastal farmers are now also ... carry blocks from the quarry in Timboni, and bicycle taxis. Mombasa and Kilifi ... landing site, also known as Bandarini, and Uyombo proper which lies inland and is an agricultural area. The fishing ...... Capacity of Fisher Folk to Implement Beach. Management ...

  20. Risk formulation for the sonic effects of offshore wind farms on fish in the EU region.

    Science.gov (United States)

    Kikuchi, Ryunosuke

    2010-02-01

    In 2007, European leaders agreed to source 20% of their energy needs from renewable energy; since that time, offshore wind farms have been receiving attention in the European Union (EU). In 2008, the European Community submitted a proposal to the United Nations Environment Program (UNEP) in order to combat marine noise pollution. In consideration of these facts, the present paper aims to deduce a preliminary hypothesis and its formulation for the effect of offshore wind farm noise on fish. The following general picture is drawn: the short-term potential impact during pre-construction; the short-term intensive impact during construction; and the physiological and/or masking effects that may occur over a long period while the wind farm is in operation. The EU's proposal to UNEP includes noise databases that list the origins of man-made sounds; it is advisable that offshore wind farms should be listed in the noise databases in order to promote rational environment management.

  1. A survey on ectoparasite fauna of cold water fish farms in Mazandaran Province, Iran

    Directory of Open Access Journals (Sweden)

    Sara Mehdizadeh Mood

    2011-12-01

    Full Text Available the important areas of this industry in Iran. The present study was carried out to survey onectoparasite fauna of cold water fish farms in Mazandaran Province (Iran during a period of 12 months.For this aim 500 samples were obtained from 50 fish farms and after arriving to laboratory the parasiteexamination started immediately. From the total of 500 specimens, 182 fish (36.4% were infected withectoparasites. Through the parasitic examinations five species of parasites were detected, namely:Ichthyophthirius multifillis, Trichodina sp., Chilodonella sp., Gyrodactylus sp. and Dactylogyrus sp. Theresults showed that, from total percentage (36.4% of detection, 31.4% of detected parasites wereprotozoan (16.4% Ichthyophthirius multifillis, 14% Trichodina sp., and 1% Chilodonella sp. and 5% weremonogenean trematodes (3% Dactylogyrus sp. and 2% Gyrodactylus sp.. The highest prevalence ofparasites in our study belonged to the Ichthyophthirius multifiliis causative agent of White Spot Disease.

  2. An opinion paper: emphasis on white muscle development and growth to improve farmed fish flesh quality.

    Science.gov (United States)

    Videler, J J

    2011-06-01

    Due to rapid depletion of wild stocks, the necessity to cultivate fish is eminent. Current fish farming practices seek to improve flesh quality. The notion that white muscles are the main target of the fishing industry is emphasized. A novel approach is suggested based on the development of white muscles in wild fish from eggs to adults. A compilation of facts about white muscle structure, function and ontogeny is followed by an account of the changes in swimming behaviour and performance related to the use of white muscle during growth from larva to adult. Ecological data narrate early swimming performance with white muscle development and growth, unveiling some of the important natural selection factors eliminating weak swimmers and poor growers from the breeding stock. A comparison between fish culture practise and natural conditions reveals fundamental differences. New approaches following wild breeding processes promise several important advantages regarding the quality of white muscle.

  3. Tracing Asian seabass individuals to single fish farms using microsatellites.

    Directory of Open Access Journals (Sweden)

    Gen Hua Yue

    Full Text Available Traceability through physical labels is well established, but it is not highly reliable as physical labels can be easily changed or lost. Application of DNA markers to the traceability of food plays an increasingly important role for consumer protection and confidence building. In this study, we tested the efficiency of 16 polymorphic microsatellites and their combinations for tracing 368 fish to four populations where they originated. Using the maximum likelihood and Bayesian methods, three most efficient microsatellites were required to assign over 95% of fish to the correct populations. Selection of markers based on the assignment score estimated with the software WHICHLOCI was most effective in choosing markers for individual assignment, followed by the selection based on the allele number of individual markers. By combining rapid DNA extraction, and high-throughput genotyping of selected microsatellites, it is possible to conduct routine genetic traceability with high accuracy in Asian seabass.

  4. Wake effects and wind farm modelling

    Energy Technology Data Exchange (ETDEWEB)

    Crespo, A.; Gomez-Elvira, R. [Univ. Politecnica de Madrid, Dept. of Energy and Fluid Mechanic (Spain)

    1999-07-01

    A model has been developed to treat simultaneously the changes in wind characteristics due to the transition from land to sea, and the wake effects in offshore wind farms. There are beneficial effects both in an increase of power production and in a reduction of turbulence loads when the distance from the farm to the land coast is increased, however, particularly for the turbulence loads, this effect reaches a limit beyond a certain distance of the order of 1 to 2 km. A method has been proposed to estimate the performance of offshore wind farms, that has been applied to places of interest to the project. As it was observed in the project East Coast of the UK, wake effects are important and significant increases can be obtained in power production by increasing the distance between machines and a better disposition of them, i.e. alternating positions in contiguous rows normal to the prevailing wind direction. The most efficient wind farms from the point of view of wake interference are Gedser and Omo with an efficiency of 89% and 86% respectively. A large wind farm like Rodsand has lower efficiency because of the cumulative effect of the wakes of many turbines. The calculated value of the capacity factor of the three Danish wind farms is larger than 36%. The value of the added turbulence intensity, averaged over rows normal to the incident wind, increases suddenly in the first rows and then reaches an almost constant value in the downstream rows, that is of the order of 10%. A method to calculate the performance of very large wind farms, such that they can change the planetary boundary layer is presented. This method has been applied to the wind farms of interest in the project, and small reductions of the order of 5% or less in power production may occur. However, for very large wind farms (with a of the order of 100 km), that may perturb the whole planetary boundary layer, much more drastic reductions, of the order of 50%, may appear, particularly in the

  5. THE ENVIRONMENTAL IMPACTS OF MARINE FISH CAGE FARMS IN THE EASTERN ADRIATIC

    Directory of Open Access Journals (Sweden)

    Ivan Katavić

    2003-12-01

    Full Text Available Mariculture in Croatia could play a more important role in development of rural communities along coastline. However, by increase of fish farming, public concern over environmental issues has been raised, and the need for more responsible mariculture development and management has been asked. There are opportunities and challenges for effectively integrating mariculture into coastal zone management with equal rights and obligations. This is primarily because of its social and economic mission consisting in preventing de-population of rural coastal areas and islands and meeting the growing needs of tourist market for seafood. Although intensive mariculture production is accused of producing negative environmental effects, many of these effects still need to be scientifically documented. The effect of nitrogen and phosphorous releases from farmed fish faeces or uneaten food is not of significant issues for marine ecosystem, and it is generally of little importance compared to the inflow of nutrients from other coastal sources. The impact on sediment and benthic communities is mainly local and short-term ones, and depends on the number and extent of the farms and their location. Recovery of some benthic communities after the cessation of farming activities may be delayed over several years (i. e. Posidonia beds due to the accumulated organic matter. Bluefin tuna farming if not properly located and managed might cause pollution problems, either from uneaten feed and metabolic waste or from harvesting and processing the fish. In most cases the problem comes from smell pollution during the summer time and the oily water surface that may be widespread much outside of the farm areas. It will be important for sustainable development of Croatian mariculture to offer a healthy and good quality product in the quantities required by the market, while not degrading the marine environment.

  6. Statistical modelling of fish stocks

    DEFF Research Database (Denmark)

    Kvist, Trine

    1999-01-01

    for modelling the dynamics of a fish population is suggested. A new approach is introduced to analyse the sources of variation in age composition data, which is one of the most important sources of information in the cohort based models for estimation of stock abundancies and mortalities. The approach combines...... and it is argued that an approach utilising stochastic differential equations might be advantagous in fish stoch assessments....

  7. Statistical modelling of fish stocks

    DEFF Research Database (Denmark)

    Kvist, Trine

    1999-01-01

    for modelling the dynamics of a fish population is suggested. A new approach is introduced to analyse the sources of variation in age composition data, which is one of the most important sources of information in the cohort based models for estimation of stock abundancies and mortalities. The approach combines...... and it is argued that an approach utilising stochastic differential equations might be advantagous in fish stoch assessments....

  8. Status and future perspectives of vaccines for industrialised fin-fish farming.

    Science.gov (United States)

    Brudeseth, Bjørn Erik; Wiulsrød, Rune; Fredriksen, Børge Nilsen; Lindmo, Karine; Løkling, Knut-Egil; Bordevik, Marianne; Steine, Nils; Klevan, Are; Gravningen, Kjersti

    2013-12-01

    Fin fish farming is developing from extensive to intensive high industrial scale production. Production of fish in high-density growth conditions requires effective vaccines in order to control persistent and emerging diseases. Vaccines can also have significant positive impact on the reduced usage of antibiotics. This was demonstrated when vaccines were introduced in Norway for Atlantic salmon (Salmo salar) in the late eighties and early nineties, resulting in a rapid decline of antibiotics consumption. The present review will focus on current vaccine applications for farmed industrialized fish species such as Atlantic salmon, coho salmon (Oncorhynchus kisutch), rainbow trout (Oncorhynchus mykiss), ayu (Plecoglossus altivelis), cod (Gadus morhua), sea bass (Dicentrarchus labrax), gilt-head sea bream (Sparus aurata), yellowtail (Seriola quinqueradiata), great amberjack (Seriola dumerili), barramundi (Lates calcarifer), japanese flounder (Paralichythys olivaceus), turbot (Scophthalmus maximus), red sea bream (Pagrus major), rock bream (Oplegnathus fasciatus), seven band grouper (Epinephelus septemfasciatus), striped catfish (Pangasianodon hypophthalmus), channel catfish (Ictalurus punctatus) and tilapia (Oreochromis niloticus). This paper will review the current use of licensed vaccines in fin fish farming and describe vaccine administration regimes including immersion, oral and injection vaccination. Future trends for inactivated-, live attenuated - and DNA - vaccines will also be discussed.

  9. Energy profiling of demersal fish: a case-study in wind farm artificial reefs.

    Science.gov (United States)

    De Troch, Marleen; Reubens, Jan T; Heirman, Elke; Degraer, Steven; Vincx, Magda

    2013-12-01

    The construction of wind farms introduces artificial hard substrates in sandy sediments. As Atlantic cod (Gadus morhua) and pouting (Trisopterus luscus) tend to aggregate in order to feed around these reefs, energy profiling and trophic markers were applied to study their feeding ecology in a wind farm in the Belgian part of the North Sea. The proximate composition (carbohydrates, proteins and lipids) differed significantly between liver and muscle tissue but not between fish species or between their potential prey species. Atlantic cod showed to consume more energy than pouting. The latter had a higher overall energy reserve and can theoretically survive twice as long on the available energy than cod. In autumn, both fish species could survive longer on their energy than in spring. Polyunsaturated fatty acids were found in high concentrations in fish liver. The prey species Jassa and Pisidia were both rich in EPA while Jassa had a higher DHA content than Pisidia. Energy profiling supported the statement that wind farm artificial reefs are suitable feeding ground for both fish species. Sufficient energy levels were recorded and there is no indication of competition.

  10. Remote influence of off-shore fish farm waste on Mediterranean seagrass (Posidonia oceanica) meadows.

    Science.gov (United States)

    Ruiz, J M; Marco-Méndez, C; Sánchez-Lizaso, J L

    2010-04-01

    The aim of this study was estimating the remote influence of waste dispersed from a large off-shore fish farm complex (6197 ton year(-1)) on the near-shore Posidonia oceanica meadow (26-27 m deep) located at a distance of 3 km. Measurements of isotopic nitrogen content in epiphytes and seagrass leaf tissues, epiphyte biomass, shoot size, herbivory pressure, shoot density and seagrass meadow cover, performed in this meadow (FA area) were compared with those obtained in an undisturbed control meadow (CA area) to evaluate: (1) the remote influence of waste and (2) the impact of such influence on seagrass condition. In addition, delta(15)N measurements in particulate organic matter of natural and anthropogenic origin were used in a single-isotope mixing model to elucidate the relative contributions of these sources to the isotopic N signal measured in epiphytes and leaf tissues. Total tissue N content was similar between meadow areas, but delta(15)N signatures were significantly higher in the FA area than in the CA area both in epiphytes and seagrass leaf tissues. Results from the mixing model, together with available information on local currents and previous studies, support the conclusion that the dispersion of farm wastes over large areas (spanning kilometres) are responsible for the elevated delta(15)N signatures found in the FA meadow area. Despite this, no changes in meadow structure were detected and only some changes at the level of seagrass community (epiphytes abundances and herbivores activity) could be interpreted at the light of nutrient-induced effects in the FA area. Results from this study indicate that concentrating aquaculture facilities in off-shore areas is a strategy not totally exempt of environmental risk on near-shore sensitive habitats such as seagrass meadows.

  11. Assessment of the Impact of Extension Services on Fish Farming in Ekiti State, Nigeria

    Directory of Open Access Journals (Sweden)

    Agbebi, F. O.

    2012-03-01

    Full Text Available The study was carried out to assess the impact of access to extension services on fish farming in Ekiti State, Nigeria. Specifically, the study investigated the socio – economic characteristics of fish farmers, information disseminated to fish farmers, attributes of extension agents, and farmers’ access to extension services and farmers profitability. A well-structured questionnaire was used to collect information from the farmers and a sample size of 90 fish farmers was selected from the six local government selected. Analysis of data was carried out using frequency and percentage tables and Gross Margin analysis was used to determine the profitability of the farmers. There was relationship between farmers’ access to extension services and their profitability. It was recommended that extension agents should intensify their efforts in reaching farmers and passing useful information to them in order to increase farmers’ profitability.

  12. Epidemic and Endemic Malaria Transmission Related to Fish Farming Ponds in the Amazon Frontier.

    Directory of Open Access Journals (Sweden)

    Izabel Cristina Dos Reis

    Full Text Available Fish farming in the Amazon has been stimulated as a solution to increase economic development. However, poorly managed fish ponds have been sometimes associated with the presence of Anopheles spp. and consequently, with malaria transmission. In this study, we analyzed the spatial and temporal dynamics of malaria in the state of Acre (and more closely within a single county to investigate the potential links between aquaculture and malaria transmission in this region. At the state level, we classified the 22 counties into three malaria endemicity patterns, based on the correlation between notification time series. Furthermore, the study period (2003-2013 was divided into two phases (epidemic and post-epidemic. Higher fish pond construction coincided both spatially and temporally with increased rate of malaria notification. Within one malaria endemic county, we investigated the relationship between the geolocation of malaria cases (2011-2012 and their distance to fish ponds. Entomological surveys carried out in these ponds provided measurements of anopheline abundance that were significantly associated with the abundance of malaria cases within 100 m of the ponds (P < 0.005; r = 0.39. These results taken together suggest that fish farming contributes to the maintenance of high transmission levels of malaria in this region.

  13. DO-increasing effects of a microscopic bubble generating system in a fish farm.

    Science.gov (United States)

    Endo, Akira; Srithongouthai, Sarawut; Nashiki, Hisatsune; Teshiba, Ichiro; Iwasaki, Takaaki; Hama, Daigo; Tsutsumi, Hiroaki

    2008-01-01

    We have developed a "microscopic bubble generating system for the fish farm" and evaluated its ability to improve the quality of seawater and costs of it in marine cages of red sea bream (Pagrus major) in Kusuura Bay, Japan. Our results revealed that DO concentration of bubbling net pens increased and became significantly higher than the level outside the net pen (between 0.52 and 0.87 mg/L), and the whole water column was nearly saturated. Temperatures of the bubbling net pens decreased slightly between 0.08 and 0.12 degrees C in all the layers. Furthermore, micro-bubbles seemed to reach the deeper water due to the downward flow and diffusion. This study demonstrated that the microscopic bubble generating system developed in our research project could increase efficiently the dissolved oxygen concentration throughout all water layers of the fish farm. A capital and operation costs of the system is recoverable within a year.

  14. Monitoring of shrimp and farmed fish sold in Canada for cyanobacterial toxins.

    Science.gov (United States)

    Niedzwiadek, Barbara; Scott, Peter M; Lau, Ben P-Y

    2012-01-01

    Sixty-one samples of shrimp and 32 samples of farmed fish collected from retail markets across Canada were analyzed for cyanobacterial toxins, including microcystins, paralytic shellfish poisons (saxitoxins), cylindrospermopsin, and β-N-methylamino-L-alanine, using established methods of analysis. None of these toxins were detected in any of the samples. Some shrimp samples screened for paralytic shellfish poisons showed the presence of unknown peaks in the chromatogram after periodate oxidation.

  15. Experiences on ornamental fish farming in the Cooperative COOPESCA, Acacias - Meta

    OpenAIRE

    Sandra L. Parada-Guevara; Cooperativa Multiactiva de Pescadores del Municipio de Acacias-Meta. COOPESCA; Pablo E. Cruz-Casallas

    2012-01-01

    The ornamental fish farming species in Meta province is still incipient, although that can be a source of livelihood for many rural and urban families. However, to achieve growth of the business is essential and appropriate to generate the necessary knowledge on the biology, behavior and appropriate adaptation techniques and captive management of potentially cultivable species. The captive culture offers the possibility to diversify production, produce better quality animal husbandry and heal...

  16. MOLECULAR GENETIC MARKERS AND METHODS OF THEIR IDENTIFICATION IN MODERN FISH-FARMING

    OpenAIRE

    I. Hrytsyniak; O. Zaloilo; I. Zaloilo; N. Borysenko

    2014-01-01

    Purpose. The application of molecular genetic markers has been widely used in modern experimental fish-farming in recent years. This methodology is currently presented by a differentiated approach with individual mechanisms and clearly defined possibilities. Numerous publications in the scientific literature that are dedicated to molecular genetic markers for the most part offer purely practical data. Thus, the synthesis and analysis of existing information on the general principles of action...

  17. Dorso-ventral skin characterization of the farmed fish gilthead seabream (Sparus aurata)

    Science.gov (United States)

    Cordero, Héctor; Ceballos-Francisco, Diana; Cuesta, Alberto

    2017-01-01

    The skin is the first barrier of defence in fish, protecting against any external stressor and preserving the integrity and homeostasis of the fish body. The aim of this study was to characterise gilthead seabream skin by isolating cells and studying the cell cycle by flow cytometry, to study the skin histology by scanning electron microscopy and the transcription level of some immune-relevant genes by RT-PCR. Furthermore, the results obtained from samples taken from the dorsal and the ventral part of the specimens are compared. No differences were observed in the cell cycle of cells isolated from the dorsal and ventral zones of the skin or in the gene expression of the genes studied in both epidermal zones. However, the epidermis thickness of the ventral skin was higher than that of the dorsal skin, as demonstrated by image analysis using light microscopy. Besides, scanning electron microscopy pointed to a greater cell size and area of microridges in the apical part of the dorsal epidermal cells compared with ventral skin epidermal cells. This study represents a step forward in our knowledge of the skin structure of an important farmed teleost, gilthead seabream, one of the most commonly farmed fish worldwide. Furthermore, for functional characterization, experimental wounds were carried out comparing the wound healing rate between the dorsal and ventral regions of skin over the time. The results showed higher ratio of wound healing in the ventral region, whose wounds were closed after 15 days, compared to dorsal region of skin. Taking into account all together, this study represents a step forward in our knowledge of the skin structure and skin regeneration of an important farmed teleost, gilthead seabream, one of the most commonly farmed fish worldwide. PMID:28666033

  18. BACTERIOLOGICAL PROPERTIES OF MARINE WATER IN ADRIATIC FISH FARMS: ENUMERATION OF HETEROTROPHIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Emin Teskeredžić

    2012-12-01

    Full Text Available Aquaculture is currently one of the fastest growing food production sectors in the world. Increase in nutrients and organic wastes lead to general deterioration of water quality. The problem of water quality is associated with both physical and chemical factors, as well as microbiological water quality. Heterotrophic bacteria play an important role in the process of decomposition of organic matter in water environment and indicate eutrophication process. Here we present our experience and knowledge on bacterial properties of marine water in the Adriatic fish farms with European sea bass (Dicentrarchus labrax L., 1758, with an emphasis on enumeration of heterotrophic bacteria in marine water. We applied two temperatures of incubation, as well as two methods for enumeration of heterotrophic bacteria: substrate SimPlate® test and spread plate method on conventional artificial media (Marine agar and Tryptic Soy agar with added NaCl. The results of analysis of bacteriological properties of marine water in the Adriatic fish farms showed that enumeration of heterotrophic bacteria in marine water depends on the applied incubation temperature and media for enumeration. At the same time, the incubation temperature of 22C favours more intense growth of marine heterotrophic bacteria, whereas a SimPlate test gives higher values of heterotrophic bacteria. Volatile values of heterotrophic bacteria during this research indicate a possible deterioration of microbiological water quality in the Adriatic fish farms and a need for regular monitoring of marine water quality.

  19. An industry-scale mass marking technique for tracing farmed fish escapees.

    Directory of Open Access Journals (Sweden)

    Fletcher Warren-Myers

    Full Text Available Farmed fish escape and enter the environment with subsequent effects on wild populations. Reducing escapes requires the ability to trace individuals back to the point of escape, so that escape causes can be identified and technical standards improved. Here, we tested if stable isotope otolith fingerprint marks delivered during routine vaccination could be an accurate, feasible and cost effective marking method, suitable for industrial-scale application. We tested seven stable isotopes, (134Ba, (135Ba, (136Ba, (137Ba, (86Sr, (87Sr and (26Mg, on farmed Atlantic salmon reared in freshwater, in experimental conditions designed to reflect commercial practice. Marking was 100% successful with individual Ba isotopes at concentrations as low as 0.001 µg. g-1 fish and for Sr isotopes at 1 µg. g-1 fish. Our results suggest that 63 unique fingerprint marks can be made at low cost using Ba (0.0002 - 0.02 $US per mark and Sr (0.46 - 0.82 $US per mark isotopes. Stable isotope fingerprinting during vaccination is feasible for commercial application if applied at a company level within the world's largest salmon producing nations. Introducing a mass marking scheme would enable tracing of escapees back to point of origin, which could drive greater compliance, better farm design and improved management practices to reduce escapes.

  20. An industry-scale mass marking technique for tracing farmed fish escapees.

    Science.gov (United States)

    Warren-Myers, Fletcher; Dempster, Tim; Fjelldal, Per Gunnar; Hansen, Tom; Swearer, Stephen E

    2015-01-01

    Farmed fish escape and enter the environment with subsequent effects on wild populations. Reducing escapes requires the ability to trace individuals back to the point of escape, so that escape causes can be identified and technical standards improved. Here, we tested if stable isotope otolith fingerprint marks delivered during routine vaccination could be an accurate, feasible and cost effective marking method, suitable for industrial-scale application. We tested seven stable isotopes, (134)Ba, (135)Ba, (136)Ba, (137)Ba, (86)Sr, (87)Sr and (26)Mg, on farmed Atlantic salmon reared in freshwater, in experimental conditions designed to reflect commercial practice. Marking was 100% successful with individual Ba isotopes at concentrations as low as 0.001 µg. g-1 fish and for Sr isotopes at 1 µg. g-1 fish. Our results suggest that 63 unique fingerprint marks can be made at low cost using Ba (0.0002 - 0.02 $US per mark) and Sr (0.46 - 0.82 $US per mark) isotopes. Stable isotope fingerprinting during vaccination is feasible for commercial application if applied at a company level within the world's largest salmon producing nations. Introducing a mass marking scheme would enable tracing of escapees back to point of origin, which could drive greater compliance, better farm design and improved management practices to reduce escapes.

  1. Wind speed dynamical model in a wind farm

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2010-01-01

    , the dynamic model for wind flow will be established. The state space variables are determined based on a fine mesh defined for the farm. The end goal of this method is to assist the development of a dynamical model of a wind farm that can be engaged for better wind farm control strategies....

  2. Economic values of growth and feed efficiency for fish farming in recirculating aquaculture system with density and nitrogen output limitations: a case study with African catfish (Clarias gariepinus).

    Science.gov (United States)

    Besson, M; Komen, H; Aubin, J; de Boer, I J M; Poelman, M; Quillet, E; Vancoillie, C; Vandeputte, M; van Arendonk, J A M

    2014-12-01

    In fish farming, economic values (EV) of breeding goal traits are lacking, even though they are key parameters when defining selection objectives. The aim of this study was to develop a bioeconomic model to estimate EV of 2 traits representing production performances in fish farming: the thermal growth coefficient (TGC) and the feed conversion ratio (FCR). This approach was applied to a farm producing African catfish (Clarias gariepinus) in a recirculating aquaculture system (RAS). In the RAS, 2 factors could limit production level: the nitrogen treatment capacity of the biofilter or the fish density in rearing tanks at harvest. Profit calculation includes revenue from fish sales, cost of juveniles, cost of feed, cost of waste water treatment, and fixed costs. In the reference scenario, profit was modeled to zero. EV were calculated as the difference in profit per kilogram of fish between the current population mean for both traits (µt) and the next generation of selective breeding (µt+Δt) for either TGC or FCR. EV of TGC and FCR were calculated for three generations of hypothetical selection on either TGC or FCR (respectively 6.8% and 7.6% improvement per generation). The results show that changes in TGC and FCR can affect both the number of fish that can be stocked (number of batches per year and number of fish per batch) and the factor limiting production. The EV of TGC and FCR vary and depend on the limiting factors. When dissolved NH3-N is the limiting factor for both µt and µt+Δt, increasing TGC decreases the number of fish that can be stocked but increases the number of batches that can be grown. As a result, profit remains constant and EVTGC is zero. Increasing FCR, however, increases the number of fish stocked and the ratio of fish produced per kilogram of feed consumed ("economic efficiency"). The EVFCR is 0.14 €/kg of fish, and profit per kilogram of fish increases by about 10%. When density is the limiting factor for both µt and µt+Δt, the

  3. Fish schooling as a basis for vertical axis wind turbine farm design.

    Science.gov (United States)

    Whittlesey, Robert W; Liska, Sebastian; Dabiri, John O

    2010-09-01

    Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighboring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely spaced VAWTs may experience only small decreases (or even increases) in an individual turbine's power coefficient when placed in close proximity to neighbors, thus yielding much higher power outputs for a given area of land. A potential flow model of inter-VAWT interactions is developed to investigate the effect of changes in VAWT spatial arrangement on the array performance coefficient, which compares the expected average power coefficient of turbines in an array to a spatially isolated turbine. A geometric arrangement based on the configuration of shed vortices in the wake of schooling fish is shown to significantly increase the array performance coefficient based upon an array of 16 x 16 wind turbines. The results suggest increases in power output of over one order of magnitude for a given area of land as compared to HAWTs.

  4. Assessing farm innovations and responses to policies: a review of bio-economic farm models

    NARCIS (Netherlands)

    Janssen, S.J.C.; Ittersum, van M.K.

    2007-01-01

    Bio-economic farm models (BEFMs) are developed to enable assessment of policy changes and technological innovations, for specific categories of farming systems. A rapidly growing number of research projects is using these models and there is increasing interest for application. The paper critically

  5. Environmental impacts of genetic improvement of growth rate and feed conversion ratio in fish farming under rearing density and nitrogen output limitations

    NARCIS (Netherlands)

    Besson, M.; Aubin, J.; Komen, H.; Poelman, M.; Quillet, E.; Vandeputte, M.; Arendonk, Van J.A.M.; Boer, De I.J.M.

    2016-01-01

    Today, fish farming faces an increasing demand in fish products, but also various environmental challenges. Genetic improvement in growth rate and feed conversion ratio is known to be an efficient way to increase production and increase efficiency in fish farming. The environmental consequences o

  6. Simulation analysis of a wind farm with different aggregated models

    DEFF Research Database (Denmark)

    Li, H.; Wang, H.; Zhao, B.

    2011-01-01

    Based on a wind farm including wind turbines with squirrel cage induction generators (SCIGs), different aggregated models of a wind farm, such as a single weighted average model, a reduced-order re-scaled model, a parameter transformed model and a single weighted arithmetic model were presented......, as well as the detailed SCIG wind turbine model. Regarding for the two cases of a wind farm including SCIGs with identical parameters and different parameters, the dynamic characteristics and transient performances of the presented wind farm using different aggregated models were studied and compared...

  7. Eutrophic waters, algal bloom and fish kill in fish farming areas in Bolinao, Pangasinan, Philippines.

    Science.gov (United States)

    San Diego-McGlone, Maria Lourdes; Azanza, Rhodora V; Villanoy, Cesar L; Jacinto, Gil S

    2008-01-01

    The coastal waters of Bolinao, Pangasinan, Philippines experienced environmental changes over a 10-year period (1995-2005), the most significant effect of which was the major fish kill event in 2002 that coincided with the first reported Philippine bloom of a dinoflagellate Prorocentrum minimum. Days before the bloom, dissolved oxygen was < 2.0 mg/l in the waters that were stratified. These conditions may be linked to the uncontrolled proliferation of fish pens and cages to more than double the allowable limit of 544 units for Bolinao waters. Mariculture activities release organic matter from unconsumed feed and fecal material that accumulate in the water and sediments. In over 10 years, water quality conditions have become eutrophic with ammonia increasing by 56%, nitrite by 35%, nitrate by 90%, and phosphate by 67%. The addition of more fish pens and cages placed additional stress to this poorly flushed, shallow area that affected water quality due to changes in the water residence time.

  8. Eutrophic waters, algal bloom and fish kill in fish farming areas in Bolinao, Pangasinan, Philippines

    Energy Technology Data Exchange (ETDEWEB)

    San Diego-McGlone, Maria Lourdes [Marine Science Institute, University of the Philippines, Diliman, Quezon City 1101 (Philippines)], E-mail: mcglonem@upmsi.ph; Azanza, Rhodora V.; Villanoy, Cesar L.; Jacinto, Gil S. [Marine Science Institute, University of the Philippines, Diliman, Quezon City 1101 (Philippines)

    2008-07-01

    The coastal waters of Bolinao, Pangasinan, Philippines experienced environmental changes over a 10-year period (1995-2005), the most significant effect of which was the major fish kill event in 2002 that coincided with the first reported Philippine bloom of a dinoflagellate Prorocentrum minimum. Days before the bloom, dissolved oxygen was <2.0 mg/l in the waters that were stratified. These conditions may be linked to the uncontrolled proliferation of fish pens and cages to more than double the allowable limit of 544 units for Bolinao waters. Mariculture activities release organic matter from unconsumed feed and fecal material that accumulate in the water and sediments. In over 10 years, water quality conditions have become eutrophic with ammonia increasing by 56%, nitrite by 35%, nitrate by 90%, and phosphate by 67%. The addition of more fish pens and cages placed additional stress to this poorly flushed, shallow area that affected water quality due to changes in the water residence time.

  9. Life Cycle Assessment of Gilthead Seabream (Sparus aurata Production in Offshore Fish Farms

    Directory of Open Access Journals (Sweden)

    Benjamín García García

    2016-11-01

    Full Text Available Life cycle assessment is used in this study to evaluate the potential environmental impacts of producing gilthead seabream in an offshore sea farm exposed to storms in the Spanish Mediterranean Sea. The farming methods used can be considered as “basic” since no centralized or automatic food distribution system exists and there is no control system. This study aims to identify the main hotspots under these conditions and to propose and compare viable alternatives to them. Contribution analysis found that the component of the system with the greatest potential environmental impact (48% of the overall impact was fish feed, especially the raw material used. Other contributory factors were the fuel consumed by the vessels operating in the farm (35%, the dumping of N and P in the environment due to the metabolism of the fish (12%, the cages and their anchorage system (5%. A sensitivity analysis showed that a significant reduction in potential environmental impact can be achieved by increasing feeding efficiency. Feed formulation in raw materials is also an important factor and could serve to diminish overall adverse effects. A balance needs to be found between productive performance (growth, survival and feed conversion rate, feed price and its influence on production costs and the overall environmental consequences.

  10. Modelling worker physical health and societal sustainability at farm level: an application to conventional and organic dairy farming

    NARCIS (Netherlands)

    Calker, van K.J.; Berentsen, P.B.M.; Boer, de I.J.M.; Giesen, G.W.J.; Huirne, R.B.M.

    2007-01-01

    Farm-level modelling can be used to determine how farming systems and individual farm-management measures influence different sustainability indicators. Until now however, worker physical health and societal sustainability have been lacking in farm models. For this paper, we first selected attribute

  11. Phytoremediation Capabilities of Spirodela polyrhiza and Salvinia molesta in Fish Farm Wastewater: A Preliminary Study

    Science.gov (United States)

    Ng, Y. S.; Samsudin, N. I. S.; Chan, D. J. C.

    2017-06-01

    Fish farm wastewater needs to be treated as it contains considerably high loading of suspended solids and dissolved nutrients from accumulation of by-products e.g. fish excretions and uneaten feed. In this study, macrophytes, namely Spirodela polyrhiza and Salvinia molesta were examined for their phytoremediation efficiency in treating fish farm wastewater in a raceway pond rig. It was carried out indoor for 14 days under controlled environment. Water samples was collected once every 2 days for analysis of NO3 -- N, PO4 3-, NH3-N, COD, turbidity, MLVSS and pH. The results showed that there was decrement of phosphate in fish farm wastewater using either S. polyrhiza or S. molesta. Interestingly, S. polyrhiza was found to be more efficient in phosphate uptake as it removed 72% phosphate at day 4 and up to 95% in the end of the experiment whereas 72% phosphate removal was only achieved by S. molesta at day 10. Similar ammonia decrement was observed for both plants and most of the ammonia were not detected in the wastewater by day 10 for S. polyrhiza, while by day 8 for S. molesta. Nitrate showed increment for both plants which could be due to nitrification. Both plants achieved highest COD removal on day 12, whereby 68% for S. polyrhiza and 63% for S. molesta. They were able to reduce turbidity and total suspended solids (TSS) to very low level and significantly increase clarity of wastewater. S. polyrhiza reduced up to 96% of initial turbidity value and 86% of TSS. 82% reduction of initial turbidity and 79% TSS decrement were observed for S. molesta. pH fluctuations were minimum for both plants, with a range between 7.62 to 7.77. Both plants demonstrated biomass increment for fresh weight in which 84% for S. polyrhiza while 85% for S. molesta. This study proved that the macrophytes were able to treat fish farm wastewater by significantly removing phosphate, ammonia, turbidity and TSS. It aids in minimizing pollutants released to receiving waters and producing biomass

  12. Mercury concentrations in common carp (Cyprinus carpio) tissues, sediment and water from fish farm along the Karoun River in Iran

    OpenAIRE

    Maktabi, Payvand; Javaheri baboli, Mehran; Jafarnejadi, Ali Reza; Askary Sary, Abolfazl

    2015-01-01

    The Karoun River is major source of water for warm‌water fish culture industry in southwest of Iran. The aim of the present study was to investigate the distribution of mercury in tissues of marketable common carp and in bottom sediments of fish farms in Khouzestan province. This study was carried out on 45 fish farms that are located on the bank of the Karoun River in Khouzestan province, south-west Iran. Concentration of mercury (Hg) was determined using spectrophotometery in three tissues ...

  13. A model to predict the power output from wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Landberg, L. [Riso National Lab., Roskilde (Denmark)

    1997-12-31

    This paper will describe a model that can predict the power output from wind farms. To give examples of input the model is applied to a wind farm in Texas. The predictions are generated from forecasts from the NGM model of NCEP. These predictions are made valid at individual sites (wind farms) by applying a matrix calculated by the sub-models of WASP (Wind Atlas Application and Analysis Program). The actual wind farm production is calculated using the Riso PARK model. Because of the preliminary nature of the results, they will not be given. However, similar results from Europe will be given.

  14. Can the Global Adoption of Genetically Improved Farmed Fish Increase Beyond 10%, and How?

    Directory of Open Access Journals (Sweden)

    Ingrid Olesen

    2015-05-01

    Full Text Available The annual production from global aquaculture has increased rapidly from 2.6 million tons or 3.9% of the total supply of fish, shellfish and mollusks in 1970, to 66.7 million tons or 42.2% in 2012, while capture fisheries have more or less leveled out at about 90 million tons per year since the turn of the century. Consequently, the future seafood supply is likely to depend on a further increase of aquaculture production. Unlike terrestrial animal farming, less than 10% of the aquaculture production comes from domesticated and selectively bred farm stocks. This situation has substantial consequences in terms of poorer resource efficiency, poorer product quality and poorer animal welfare. The history of biological and technical challenges when establishing selective breeding programs for aquaculture is discussed, and it is concluded that most aquaculture species may now be domesticated and improved by selection. However, the adoption of selective breeding in aquaculture is progressing slowly. This paper reports on a study carried out in 2012 to identify key issues to address in promoting the development of genetically improved aquaculture stocks. The study involved semi structured interviews of 34 respondents from different sectors of the aquaculture society in East and Southeast Asia, where 76% of the global aquaculture production is located. Based on the interviews and literature review, three key factors are identified: (i long-term public commitment is often needed for financial support of the breeding nucleus operation (at least during the first five to ten generations of selection; (ii training at all levels (from government officers and university staff to breeding nucleus and hatchery operators, as well as farmers; and (iii development of appropriate business models for benefit sharing between the breeding, multiplier and grow-out operators (whether being public, cooperative or private operations. The public support should be invested in

  15. Resilience of coral-associated bacterial communities exposed to fish farm effluent.

    Science.gov (United States)

    Garren, Melissa; Raymundo, Laurie; Guest, James; Harvell, C Drew; Azam, Farooq

    2009-10-06

    The coral holobiont includes the coral animal, algal symbionts, and associated microbial community. These microbes help maintain the holobiont homeostasis; thus, sustaining robust mutualistic microbial communities is a fundamental part of long-term coral reef survival. Coastal pollution is one major threat to reefs, and intensive fish farming is a rapidly growing source of this pollution. We investigated the susceptibility and resilience of the bacterial communities associated with a common reef-building coral, Porites cylindrica, to coastal pollution by performing a clonally replicated transplantation experiment in Bolinao, Philippines adjacent to intensive fish farming. Ten fragments from each of four colonies (total of 40 fragments) were followed for 22 days across five sites: a well-flushed reference site (the original fragment source); two sites with low exposure to milkfish (Chanos chanos) aquaculture effluent; and two sites with high exposure. Elevated levels of dissolved organic carbon (DOC), chlorophyll a, total heterotrophic and autotrophic bacteria abundance, virus like particle (VLP) abundances, and culturable Vibrio abundance characterized the high effluent sites. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis, we observed rapid, dramatic changes in the coral-associated bacterial communities within five days of high effluent exposure. The community composition on fragments at these high effluent sites shifted towards known human and coral pathogens (i.e. Arcobacter, Fusobacterium, and Desulfovibrio) without the host corals showing signs of disease. The communities shifted back towards their original composition by day 22 without reduction in effluent levels. This study reveals fish farms as a likely source of pathogens with the potential to proliferate on corals and an unexpected short-term resilience of coral-associated bacterial communities to eutrophication pressure. These data highlight a need for

  16. Resilience of coral-associated bacterial communities exposed to fish farm effluent.

    Directory of Open Access Journals (Sweden)

    Melissa Garren

    Full Text Available The coral holobiont includes the coral animal, algal symbionts, and associated microbial community. These microbes help maintain the holobiont homeostasis; thus, sustaining robust mutualistic microbial communities is a fundamental part of long-term coral reef survival. Coastal pollution is one major threat to reefs, and intensive fish farming is a rapidly growing source of this pollution.We investigated the susceptibility and resilience of the bacterial communities associated with a common reef-building coral, Porites cylindrica, to coastal pollution by performing a clonally replicated transplantation experiment in Bolinao, Philippines adjacent to intensive fish farming. Ten fragments from each of four colonies (total of 40 fragments were followed for 22 days across five sites: a well-flushed reference site (the original fragment source; two sites with low exposure to milkfish (Chanos chanos aquaculture effluent; and two sites with high exposure. Elevated levels of dissolved organic carbon (DOC, chlorophyll a, total heterotrophic and autotrophic bacteria abundance, virus like particle (VLP abundances, and culturable Vibrio abundance characterized the high effluent sites. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE analysis, we observed rapid, dramatic changes in the coral-associated bacterial communities within five days of high effluent exposure. The community composition on fragments at these high effluent sites shifted towards known human and coral pathogens (i.e. Arcobacter, Fusobacterium, and Desulfovibrio without the host corals showing signs of disease. The communities shifted back towards their original composition by day 22 without reduction in effluent levels.This study reveals fish farms as a likely source of pathogens with the potential to proliferate on corals and an unexpected short-term resilience of coral-associated bacterial communities to eutrophication pressure. These data highlight a

  17. Fish welfare assurance system: initial steps to set up an effective tool to safeguard and monitor farmed fish welfare at a company level.

    Science.gov (United States)

    van de Vis, J W; Poelman, M; Lambooij, E; Bégout, M-L; Pilarczyk, M

    2012-02-01

    The objective was to take a first step in the development of a process-oriented quality assurance (QA) system for monitoring and safeguarding of fish welfare at a company level. A process-oriented approach is focused on preventing hazards and involves establishment of critical steps in a process that requires careful control. The seven principles of the Hazard Analysis Critical Control Points (HACCP) concept were used as a framework to establish the QA system. HACCP is an internationally agreed approach for management of food safety, which was adapted for the purpose of safeguarding and monitoring the welfare of farmed fish. As the main focus of this QA system is farmed fish welfare assurance at a company level, it was named Fish Welfare Assurance System (FWAS). In this paper we present the initial steps of setting up FWAS for on growing of sea bass (Dicentrarchus labrax), carp (Cyprinus carpio) and European eel (Anguilla anguilla). Four major hazards were selected, which were fish species dependent. Critical Control Points (CCPs) that need to be controlled to minimize or avoid the four hazards are presented. For FWAS, monitoring of CCPs at a farm level is essential. For monitoring purposes, Operational Welfare Indicators (OWIs) are needed to establish whether critical biotic, abiotic, managerial and environmental factors are controlled. For the OWIs we present critical limits/target values. A critical limit is the maximum or minimum value to which a factor must be controlled at a critical control point to prevent, eliminate or reduce a hazard to an acceptable level. For managerial factors target levels are more appropriate than critical limits. Regarding the international trade of farmed fish products, we propose that FWAS needs to be standardized in aquaculture chains. For this standardization a consensus on the concept of fish welfare, methods to assess welfare objectively and knowledge on the needs of farmed fish are required.

  18. Reduced carbon sequestration in a Mediterranean seagrass (Posidonia oceanica) ecosystem impacted by fish farming

    DEFF Research Database (Denmark)

    Apostolaki, E; Holmer, Marianne; Marbà, N;

    2011-01-01

    We studied the relationship between sediment nutrient enrichment and carbon sequestration, using the ratio of gross primary production to respiration (P/R), in a fish-farming impacted and an unaffected Mediterranean seagrass (Posidonia oceanica) ecosystem in the Aegean Sea, Greece. Carbon (C...... nutrient enrichment. Threshold values are given for C, N and P sedimentation rates and sediment pools, and for N and P concentrations in pore waters, after which P/R ratio in the seagrass meadow decreases below 1, indicating a shift from autotrophy to heterotrophy with sediment nutrient enrichment...

  19. Mercury concentrations in common carp (Cyprinus carpio) tissues, sediment and water from fish farm along the Karoun River in Iran.

    Science.gov (United States)

    Maktabi, Payvand; Javaheri Baboli, Mehran; Jafarnejadi, Ali Reza; Askary Sary, Abolfazl

    2015-01-01

    The Karoun River is major source of water for warm‌water fish culture industry in southwest of Iran. The aim of the present study was to investigate the distribution of mercury in tissues of marketable common carp and in bottom sediments of fish farms in Khouzestan province. This study was carried out on 45 fish farms that are located on the bank of the Karoun River in Khouzestan province, south-west Iran. Concentration of mercury (Hg) was determined using spectrophotometery in three tissues (muscles, liver and gills) of farmed common carp (Cyprinus carpio), water and bottom sediments of fish farms collected from three regions (North, center and south) of the Karoun River, in Khouzestan province, Iran. The concentrations of Hg in muscle tissue (2.71 mg kg(-1) dry matter) of fish from the south were significantly higher (p south sampling zones, Hg concentration in muscle was found to be above the maximum tolerable values provided by Food and Drug Administration standards. The Hg concentration of fish farm sediment and water samples were ranged as 0.46 to 0.48 mg kg(-1) dry matter and 3.10 to 4.11 μg Hg L(-1), respectively. Finally, Hg concentrations at downstream site were higher than upstream site.

  20. Preliminary aspects concerning phytoplankton structure in the Balta Mare – Carja 1 fish farm

    Directory of Open Access Journals (Sweden)

    Maria FETECAU

    2010-08-01

    Full Text Available The present paper presents information on the structure and the dynamics of the water ecosystem’s phytoplankton of the Carja 1 fish farm - Vaslui County, carps and Asian cyprinids are grown ascommon fish. To establish the structure and the dynamics of the phytoplankton, two samples from 6 stations were taken in the spring and in the autumn, using of a Garmin GPS 7- type navigation system.When analysing the number of individuals and the algae species present in the phytoplankton’s structure, one can notice the low development level of the vegetable plankton. From the quantity point of view, one can notice the numerical abundance of the clorophyceae in all the analysed samples. The dominant species were: Scenedesmus acuminatus, Scenedesmus quadricauda, Tetrastrum staurogenieforme. The small number of species and algae specimens determined in the phytoplankton’s structure emphasizes the reduced level of trophicity and biodiversity of the analysed ecosystem.

  1. Waste feed from coastal fish farms: A trophic subsidy with compositional side-effects for wild gadoids

    Science.gov (United States)

    Fernandez-Jover, Damian; Martinez-Rubio, Laura; Sanchez-Jerez, Pablo; Bayle-Sempere, Just T.; Lopez Jimenez, Jose Angel; Martínez Lopez, Francisco Javier; Bjørn, Pål-Arne; Uglem, Ingebrigt; Dempster, Tim

    2011-03-01

    Aquaculture of carnivorous fish species in sea-cages typically uses artificial feeds, with a proportion of these feeds lost to the surrounding environment. This lost resource may provide a trophic subsidy to wild fish in the vicinity of fish farms, yet the physiological consequences of the consumption of waste feed by wild fish remain unclear. In two regions in Norway with intensive aquaculture, we tested whether wild saithe ( Pollachius virens) and Atlantic cod ( Gadus morhua) associated with fish farms (F assoc), where waste feed is readily available, had modified diets, condition and fatty acid (FA) compositions in their muscle and liver tissues compared to fish unassociated (UA) with farms. Stomach content analyses revealed that both cod and saithe consumed waste feed in the vicinity of farms (6-96% of their diet was composed of food pellets). This translated into elevated body and liver condition compared to fish caught distant from farms for cod at both locations and elevated body condition for saithe at one of the locations. As a consequence of a modified diet, we detected significantly increased concentrations of terrestrial-derived fatty acids (FAs) such as linoleic (18:2ω6) and oleic (18:1ω9) acids and decreased concentrations of DHA (22:6ω3) in the muscle and/or liver of F assoc cod and saithe when compared with UA fish. In addition, the ω3:ω6 ratio clearly differed between F assoc and UA fish. Linear discriminant analysis (LDA) correctly classified 97% of fish into F assoc or UA origin for both cod and saithe based on the FA composition of liver tissues, and 89% of cod and 86% of saithe into F assoc or UA origin based on the FA composition of muscle. Thus, LDA appears a useful tool for detecting the influence of fish farms on the FA composition of wild fish. Ready availability of waste feed with high protein and fat content provides a clear trophic subsidy to wild fish in coastal waters, yet whether the accompanying side-effect of altered fatty

  2. Wind tunnel measurements of a large wind farm model approaching the infinite wind farm regime

    Science.gov (United States)

    Bossuyt, Juliaan; Howland, Michael; Meneveau, Charles; Meyers, Johan

    2016-11-01

    A scaled wind farm, with 100 porous disk models of wind turbines, is used to study the effect of wind farm layout on the wind farm power output and its variability, in a wind tunnel study. The wind farm consists of 20 rows and 5 columns. The porous disk models have a diameter of 0 . 03 m and are instrumented with strain gages to measure the thrust force, as a surrogate for wind turbine power output. The frequency response of the measurements goes up to the natural frequency of the models and allows studying the spatio-temporal characteristics of the power output for different layouts. A variety of layouts are considered by shifting the individual rows in the spanwise direction. The reference layout has a regular streamwise spacing of Sx / D = 7 and a spanwise spacing of Sy / D = 5 . The parameter space is further expanded by considering layouts with an uneven streamwise spacing: Sx / D = 3 . 5 & 10 . 5 and Sx / D = 1 . 5 & 12 . 5 . We study how the mean row power changes as a function of wind farm layout and investigate the appearance of an asymptotic limiting behavior as previously described in the literature by application of the top-down model for the spatially averaged wind farm - boundary layer interaction. Work supported by ERC (Grant No. 306471, the ActiveWindFarms project) and by NSF (OISE-1243482, the WINDINSPIRE project).

  3. The Implications of Ranaviruses to European farmed and wild freshwater fish

    DEFF Research Database (Denmark)

    Jensen, Ann Britt Bang

    fish species are susceptible to some or all of the ranaviruses tested, while other fish species were not found to be susceptible to infection with ranaviruses. Furthermore, virus could be re-isolated from several of the challenged fish even if no significant mortalities were observed. A separate study...... demonstrated that European stocks of the two fish species (redfin perch and rainbow trout) listed as susceptible to infection with epizootic haematopoietic necrosis virus did not show significant mortalities in bath challenges. These results are compared to published literature on ranavirus outbreaks...... fish from Asia. In the process of creating the model, a pathway for introduction was identified, and the potential risks of several ranaviruses were evaluated as part of a hazard identification process. This model used expert opinion to provide estimates of the probabilities of each step...

  4. Changes in fish communities on a small spatial scale, an effect of increased habitat complexity by an offshore wind farm.

    Science.gov (United States)

    van Hal, R; Griffioen, A B; van Keeken, O A

    2017-05-01

    The number of offshore wind farms (OWF) is increasing to meet the demands for renewable energy. The piles and hard substrate surrounding these piles creates new habitat for species with preference to hard substrates. We studied the impact of this hard substrate on the fish community in a Dutch OWF in the sandy southern North Sea, which had been in operation for five years. Multi-mesh gillnets were placed near the OWF structures on the hard substrate protection revetments and on the sandy bottom in the middle of the farm. The catches indicated attraction of cod, pouting, bullrout and edible and velvet crab, while attraction to the sandy habitat was shown for flatfish and whiting. Further, two species previously not caught in this area, goldsinny wrasse and grey trigger fish, were caught on the hard substrate. In addition a Dual-Frequency Identification Sonar (DIDSON) was used to record transects through the farm to observe individual fish in the water column throughout the farm and very near the OWF structures. High abundances of fish near the structure were observed during some days, while during other days equal distribution of fish in the area was observed. The area around the structures is thus only used temporarily for shelter or feeding. The DIDSON also allowed looking at the aggregation level of the fish. Seasonally the aggregation level differed most likely due to different species occurring in the area. In April, most fish were aggregated in schools, while in summer most observations were individual fish or loose aggregations. The wind farm structures had limited effect on the aggregation level compared to season or weather conditions.

  5. Impacts of fish farm pollution on ecosystem structure and function of tropical headwater streams.

    Science.gov (United States)

    Rosa, Rodrigo dos Santos; Aguiar, Anna Carolina Fornero; Boëchat, Iola Gonçalves; Gücker, Björn

    2013-03-01

    We investigated the impacts of effluent discharge from small flow-through fish farms on stream water characteristics, the benthic invertebrate community, whole-system nitrate uptake, and ecosystem metabolism of three tropical headwater streams in southeastern Brazil. Effluents were moderately, i.e. up to 20-fold enriched in particulate organic matter (POM) and inorganic nutrients in comparison to stream water at reference sites. Due to high dilution with stream water, effluent discharge resulted in up to 2.0-fold increases in stream water POM and up to 1.8-fold increases in inorganic nutrients only. Moderate impacts on the benthic invertebrate community were detected at one stream only. There was no consistent pattern of effluent impact on whole-stream nitrate uptake. Ecosystem metabolism, however, was clearly affected by effluent discharge. Stream reaches impacted by effluents exhibited significantly increased community respiration and primary productivity, stressing the importance of ecologically sound best management practices for small fish farms in the tropics.

  6. Natural Chemical Composition of Commercial Fish Species: Characterisation of Pangasius, Wild and Farmed Turbot and Barramundi

    Directory of Open Access Journals (Sweden)

    Monika Manthey-Karl

    2016-08-01

    Full Text Available To comply with the relevant legal requirements and correct labelling, it is necessary for business operators and inspection authorities to know the natural characteristics of the raw material. This study gives a comprehensive overview of muscle flesh composition of farmed and wild Atlantic turbot (Scophthalmus maximus and barramundi (Lates calcarifer and of farmed pangasius (Pangasianodon hypophthalmus. The proximate composition, di- and triphosphates and citric acid values are presented in order to evaluate possible indicators for a hidden treatment during processing to fillets. All moisture contents were ≤80%. Even for pangasius, protein values for deep skinned fillets of ≥18% were determined. Only small quantities of naturally occurring citric acid (up to 0.03 g·kg−1 were detectable. The lipid content was the most varying main component within the different species, ranging between 1.2% to 2.0% and 0.3% to 3.0% for farmed turbot and barramundi, respectively. Pangasius flesh had a mean lipid content of 7.8%. Trimming and separation of the red layer reduced the lipid content of the commercially sold white-flesh fillets to 2.7% to 3.5%. Fatty acids profiles, free amino acids, and minerals were analysed to show the nutritional quality of the aquaculture fish species and compared to wild turbot and barramundi. Despite some natural variation, these components can be considered as comparable.

  7. Natural Chemical Composition of Commercial Fish Species: Characterisation of Pangasius, Wild and Farmed Turbot and Barramundi.

    Science.gov (United States)

    Manthey-Karl, Monika; Lehmann, Ines; Ostermeyer, Ute; Schröder, Ute

    2016-08-30

    To comply with the relevant legal requirements and correct labelling, it is necessary for business operators and inspection authorities to know the natural characteristics of the raw material. This study gives a comprehensive overview of muscle flesh composition of farmed and wild Atlantic turbot (Scophthalmus maximus) and barramundi (Lates calcarifer) and of farmed pangasius (Pangasianodon hypophthalmus). The proximate composition, di- and triphosphates and citric acid values are presented in order to evaluate possible indicators for a hidden treatment during processing to fillets. All moisture contents were ≤80%. Even for pangasius, protein values for deep skinned fillets of ≥18% were determined. Only small quantities of naturally occurring citric acid (up to 0.03 g·kg(-1)) were detectable. The lipid content was the most varying main component within the different species, ranging between 1.2% to 2.0% and 0.3% to 3.0% for farmed turbot and barramundi, respectively. Pangasius flesh had a mean lipid content of 7.8%. Trimming and separation of the red layer reduced the lipid content of the commercially sold white-flesh fillets to 2.7% to 3.5%. Fatty acids profiles, free amino acids, and minerals were analysed to show the nutritional quality of the aquaculture fish species and compared to wild turbot and barramundi. Despite some natural variation, these components can be considered as comparable.

  8. TRANSGENIC FISH MODEL IN ENVIRONMENTAL TOXICOLOGY

    Directory of Open Access Journals (Sweden)

    Madhuri Sharma

    2012-05-01

    Full Text Available A number of experiments and the use of drugs have been performed in fish. The fish may be used as model organism in various biological experiments, including environmental toxicology. Aquatic animals are being engineered to increase aquaculture production, for medical and industrial research, and for ornamental reasons. Fish have been found to play an important role in assessing potential risks associated with exposure to toxic substances in aquatic environment. Hence, it has been thought that the development of transgenic fish can enhance the use of fish in environmental toxicology. India has developed experimental transgenics of rohu fish, zebra fish, cat fish and singhi fish. Genes, promoters and vectors of indigenous origin are now available for only two species namely rohu and singhi for engineering growth. Development of fish model carrying identical transgenes to those found in rodents is beneficial and has shown that several aspects of in vivo mutagenesis are similar between the two classes of vertebrates. Fish shows the frequencies of spontaneous mutations similar to rodents and respond to mutagen exposure consistent with known mutagenic mechanisms. The feasibility of in vivo mutation analysis using transgenic fish has been demonstrated and the potential value of transgenic fish as a comparative animal model has been illustrated. Therefore, the transgenic fish can give the significant contribution to study the environmental toxicity in animals as a whole.

  9. Dairy farm methane emissions using a dispersion model.

    Science.gov (United States)

    McGinn, S M; Beauchemin, K A

    2012-01-01

    There is a need to know whole-farm methane (CH(4)) emissions since confined animal facilities such as beef cattle feedlots and dairy farms are emission "hot spots" in the landscape. However, measurements of whole-farm CH(4) emissions can differ between farms because of differences in contributing sources such as manure handling, number of lactating and nonlactating cows, and diet. Such differences may limit the usefulness of whole-farm emissions for national inventories and mitigation purposes unless the variance between farms is taken into account or a large number of farms can be examined. Our study describes the application of a dispersion model used in conjunction with field measurements of CH(4) concentration and stability of the air to calculate whole-farm emissions of CH(4) from three dairy farms in Alberta, Canada, during three sequential campaigns conducted in November 2004 and May and July 2005. The dairy farms ranged in herd size from 208 to 351 cows (102 to 196 lactating cows) and had different manure handling operations. The results indicate that the average CH(4) emission per cow (mixture of lactating and nonlactating) from the three dairy farms was 336 g d(-1), which was reduced to 271 g d(-1) when the emission (estimated) from the manure storage was removed. Further separation of source strength yielded an average CH(4) (enteric) emission of 363 g d(-1) for a lactating cow. The estimated CH(4) emission intensities were approximately 15 g CH(4) kg(-1) dry matter intake and 16.7 L CH(4) L(-1) of milk produced. The approach of understanding the farm-to-farm differences in CH(4) emissions as affected by diet, animal type, and manure management is essential when utilizing whole-farm emission measurements for mitigation and inventory applications.

  10. Experimental infection of rainbow trout Oncorhynchus mykiss with viral haemorrhagic septicaemia virus isolates from European marine and farmed fishes

    DEFF Research Database (Denmark)

    Skall, Helle Frank; Slierendrecht, W.J.; King, J.A.

    2004-01-01

    The susceptibility of rainbow trout Oncorhynchus mykiss to infection with various isolates of viral haemorrhagic septicaemia virus (VHSV) was examined. A total of 8 experiments with rainbow trout ranging from 0.6 to 6.2 g was conducted for 139 isolates originating from wild marine fishes in Europ......The susceptibility of rainbow trout Oncorhynchus mykiss to infection with various isolates of viral haemorrhagic septicaemia virus (VHSV) was examined. A total of 8 experiments with rainbow trout ranging from 0.6 to 6.2 g was conducted for 139 isolates originating from wild marine fishes...... in European waters (115 isolates), farmed turbot from Scotland and Ireland (2 isolates), and farmed rainbow trout (22 isolates). The isolates were tested by immersion and/or intraperitoneal injection either as pooled or single isolates. The isolates from wild marine fishes did not cause mortality by immersion...... while some of the isolates caused mortality when injected. All VHSV isolates from farmed rainbow trout caused significant mortality by immersion. Currently, pathogenicity trials are the only way to differentiate VHSV isolates from wild marine fishes and farmed rainbow trout. The 2 farmed turbot isolates...

  11. Source apportionment of DDTs in maricultured fish: a modeling study in South China.

    Science.gov (United States)

    Fang, Shu-Ming; Bao, Lian-Jun; Yiruhan; Zeng, Eddy Y

    2016-04-01

    Fish is one of the most important nutrition sources for humanity. Contaminant exposure risk in fish farming will eventually deliver to the crowd through diet. China is the largest fish producing as well as exporting country, where mariculture plays an important role in fish production, especially in South China. Previous investigations indicated that a variety of compartments in farming areas of South China Sea were polluted by persistent organic pollutants, including DDT (dichlorodiphenyltrichloroethane) and its derivatives, some of which is designated as DDTs. In the present study, Hailing Bay and Daya Bay of Guangdong Province, China, were selected as the study sites and DDTs as the target compounds. A fish enrichment model was developed to assess the relative contributions of various pathways to the mass loadings of DDTs in the fish. Average concentrations (and concentration ranges) of DDTs in various environmental compartments of Hailing Bay and Daya Bay were included in modeling and analysis. Modeling results indicated that fish food and seawater contributed approximately the same proportions for the DDTs in maricultured fish. Antifouling paint was supposed to be the primary source of water DDTs in mariculture zone of Hailing Bay and Daya Bay, which contributed 69 % of the total DDTs to the mariculture water. We suggest that in order to protect people from consuming highly contaminated maricuture zone fish, the most effective and feasible methods are using environment-friendly antifouling paint and applying less polluted fish food in the fish reproduction process.

  12. Simulation analysis of a wind farm with different aggregated models

    DEFF Research Database (Denmark)

    Li, H.; Wang, H.; Zhao, B.

    2011-01-01

    , as well as the detailed SCIG wind turbine model. Regarding for the two cases of a wind farm including SCIGs with identical parameters and different parameters, the dynamic characteristics and transient performances of the presented wind farm using different aggregated models were studied and compared...

  13. Modelling Infectious Hematopoietic Necrosis Virus Dispersion from Marine Salmon Farms in the Discovery Islands, British Columbia, Canada.

    Directory of Open Access Journals (Sweden)

    Michael G G Foreman

    Full Text Available Finite volume ocean circulation and particle tracking models are used to simulate water-borne transmission of infectious hematopoietic necrosis virus (IHNV among Atlantic salmon (Salmo salar farms in the Discovery Islands region of British Columbia, Canada. Historical simulations for April and July 2010 are carried out to demonstrate the seasonal impact of river discharge, wind, ultra-violet (UV radiation, and heat flux conditions on near-surface currents, viral dispersion and survival. Numerical particles released from infected farm fish in accordance with IHNV shedding rates estimated through laboratory experiments are dispersed by model oceanic flows. Viral particles are inactivated by ambient UV radiation levels and by the natural microbial community at rates derived through laboratory studies. Viral concentration maps showing temporal and spatial changes are produced and combined with lab-determined minimum infectious dosages to estimate the infective connectivity among farms. Results demonstrate that neighbouring naïve farms can become exposed to IHNV via water-borne transport from an IHNV diseased farm, with a higher risk in April than July, and that many events in the sequence of farm outbreaks in 2001-2002 are consistent with higher risks in our farm connectivity matrix. Applications to other diseases, transfers between farmed and wild fish, and the effect of vaccinations are also discussed.

  14. Scrapie infectivity is quickly cleared in tissues of orally-infected farmed fish

    Directory of Open Access Journals (Sweden)

    Faoro Franco

    2006-06-01

    Full Text Available Abstract Background Scrapie and bovine spongiform encephalopathy (BSE belongs to the group of animal transmissible spongiform encephalopathy (TSE. BSE epidemic in the UK and elsewhere in Europe has been linked to the use of bovine meat and bone meals (MBM in the feeding of cattle. There is concern that pigs, poultry and fish bred for human consumption and fed with infected MBM would eventually develop BSE or carry residual infectivity without disease. Although there has been no evidence of infection in these species, experimental data on the susceptibility to the BSE agent of farm animals other than sheep and cow are limited only to pigs and domestic chicken. In the framework of a EU-granted project we have challenged two species of fish largely used in human food consumption, rainbow trout (Oncorhynchus mykiss and turbot (Scophthalmus maximus, with a mouse-adapted TSE strain (scrapie 139A, to assess the risk related to oral consumption of TSE contaminated food. In trout, we also checked the "in vitro" ability of the pathological isoform of the mouse prion protein (PrPSc to cross the intestinal epithelium when added to the mucosal side of everted intestine. Results Fish challenged with a large amount of scrapie mouse brain homogenate by either oral or parenteral routes, showed the ability to clear the majority of infectivity load. None of the fish tissues taken at different time points after oral or parenteral inoculation was able to provoke scrapie disease after intracerebral inoculation in recipient mice. However, a few recipient mice were positive for PrPSc and spongiform lesions in the brain. We also showed a specific binding of PrPSc to the mucosal side of fish intestine in the absence of an active uptake of the prion protein through the intestinal wall. Conclusion These results indicate that scrapie 139A, and possibly BSE, is quickly removed from fish tissues despite evidence of a prion like protein in fish and of a specific binding of Pr

  15. Large scale modelling of salmon lice (Lepeophtheirus salmonis infection pressure based on lice monitoring data from Norwegian salmonid farms

    Directory of Open Access Journals (Sweden)

    Anja B. Kristoffersen

    2014-12-01

    Full Text Available Infection by parasitic sea lice is a substantial problem in industrial scale salmon farming. To control the problem, Norwegian salmonid farms are not permitted to exceed a threshold level of infection on their fish, and farms are required to monitor and report lice levels on a weekly basis to ensure compliance with the regulation. In the present study, we combine the monitoring data with a deterministic model for salmon lice population dynamics to estimate farm production of infectious lice stages. Furthermore, we use an empirical estimate of the relative risk of salmon lice transmission between farms, that depend on inter-farm distances, to estimate the external infection pressure at a farm site, i.e. the infection pressure from infective salmon lice of neighbouring farm origin. Finally, we test whether our estimates of infection pressure from neighbouring farms as well as internal within farm infection pressure, predicts subsequent development of infection in cohorts of farmed salmonids in their initial phase of marine production. We find that estimated external infection pressure is a main predictor of salmon lice population dynamics in newly stocked cohorts of salmonids. Our results emphasize the importance of keeping the production of infectious lice stages at low levels within local networks of salmon farms. Our model can easily be implemented for real time estimation of infection pressure at the national scale, utilizing the masses of data generated through the compulsory lice monitoring in salmon farms. The implementation of such a system should give the salmon industry greater predictability with respect to salmon lice infection levels, and aid the decision making process when the development of new farm sites are planned.

  16. Accurate wind farm development and operation. Advanced wake modelling

    Energy Technology Data Exchange (ETDEWEB)

    Brand, A.; Bot, E.; Ozdemir, H. [ECN Unit Wind Energy, P.O. Box 1, NL 1755 ZG Petten (Netherlands); Steinfeld, G.; Drueke, S.; Schmidt, M. [ForWind, Center for Wind Energy Research, Carl von Ossietzky Universitaet Oldenburg, D-26129 Oldenburg (Germany); Mittelmeier, N. REpower Systems SE, D-22297 Hamburg (Germany))

    2013-11-15

    The ability is demonstrated to calculate wind farm wakes on the basis of ambient conditions that were calculated with an atmospheric model. Specifically, comparisons are described between predicted and observed ambient conditions, and between power predictions from three wind farm wake models and power measurements, for a single and a double wake situation. The comparisons are based on performance indicators and test criteria, with the objective to determine the percentage of predictions that fall within a given range about the observed value. The Alpha Ventus site is considered, which consists of a wind farm with the same name and the met mast FINO1. Data from the 6 REpower wind turbines and the FINO1 met mast were employed. The atmospheric model WRF predicted the ambient conditions at the location and the measurement heights of the FINO1 mast. May the predictability of the wind speed and the wind direction be reasonable if sufficiently sized tolerances are employed, it is fairly impossible to predict the ambient turbulence intensity and vertical shear. Three wind farm wake models predicted the individual turbine powers: FLaP-Jensen and FLaP-Ainslie from ForWind Oldenburg, and FarmFlow from ECN. The reliabilities of the FLaP-Ainslie and the FarmFlow wind farm wake models are of equal order, and higher than FLaP-Jensen. Any difference between the predictions from these models is most clear in the double wake situation. Here FarmFlow slightly outperforms FLaP-Ainslie.

  17. Relationship between sedimentation rates and benthic impact on Maërl beds derived from fish farming in the Mediterranean.

    Science.gov (United States)

    Sanz-Lázaro, Carlos; Belando, María Dolores; Marín-Guirao, Lázaro; Navarrete-Mier, Francisco; Marín, Arnaldo

    2011-02-01

    The aim of this work was to study the dispersion of particulate wastes derived from marine fish farming and correlate the data with the impact on the seabed. Carbon and nutrients were correlated with the physico-chemical parameters of the sediment and the benthic community structure. The sedimentation rates in the benthic system were 1.09, 0.09 and 0.13 g m⁻² day⁻¹ for particulate organic carbon (POC), particulate organic nitrogen (PON) and total phosphorus (TP), respectively. TP was a reliable parameter for establishing the spatial extent of the fish farm particulate wastes. Fish farming was seen to influence not only physico-chemical and biological parameters but also the functioning of the ecosystem from a trophic point of view, particularly affecting the grazers and the balance among the trophic groups. POC, PON and TP sedimentation dynamics reflected the physico-chemical status of the sediment along the distance gradient studied, while their impact on the benthic community extended further. Therefore, the level of fish farm impact on the benthic community might be underestimated if it is assessed by merely taking into account data obtained from waste dispersion rates. The benthic habitat beneath the fish farm, Maërl bed, was seen to be very sensitive to aquaculture impact compared with other unvegetated benthic habitats, with an estimated POC-carrying capacity to maintain current diversity of 0.087 g C m⁻² day⁻¹ (only 36% greater than the basal POC input). Environmental protection agencies should define different aquaculture waste load thresholds for different benthic communities affected by finfish farming, according to their particular degree of sensitivity, in order to maintain natural ecosystem functions.

  18. ESTIMATION OF VOLATILE CONSTITUENTS IN THE FISH FLESH FROM WILD AND FARMED CIRRHINA MRIGALA AND CYPRINUS CARPIO

    Institute of Scientific and Technical Information of China (English)

    Shahid Mahboob; Bilal Hussain; Zahid Iqbal; Abdul Shakoor Chaudhry

    2009-01-01

    Analysis of fish meat using gas chromatography is described. Flavor is the sensation arising from the interplay of the signals of sensing smell, taste and irritating stimuli from food stuff. For human, flavor and nutrition are inseparable. In fish, trace amount of volatile organic compounds (VOCs) are the major compounds to affect consumer's preference, which are produced during storage and spoilage. In the present study, volatile compounds were extracted by Likens-Nickerson con-current distillation apparatus from wild and farmed Cirrhina mrigala and Cyprinus carpio. The quantitative and qualitative estimation of volatiles was made by gas chromatography. Wild and farmed fish of different fish sizes were compared for these compounds (appearing in the form of peaks), which were identified from their retention time by comparing with the stand-ards. Fifteen major VOCs were found in these species which included hexadecane, 3-octanol, hexanal, decane, 3-hexene-1-ol, 2-undecanone, 2-heptanone, butanal, 2-nonanone, 1-heptanal, furaldehyde, 3-methyl-1-butanal, trans-3-hexene-1-ol, octanal and decanal. These compounds varied qualitatively and quantitatively in both wild and farmed fish of different fish sizes.

  19. A comparison of methane emissions following rice paddies conversion to crab-fish farming wetlands in southeast China.

    Science.gov (United States)

    Hu, Zhiqiang; Wu, Shuang; Ji, Cheng; Zou, Jianwen; Zhou, Quansuo; Liu, Shuwei

    2016-01-01

    Rice paddies and aquaculture wetlands are typical agricultural wetlands that constitute one of the important sources of atmospheric methane (CH4). Traditional transplanted rice paddies have been experiencing conversion to pond aquaculture wetlands for pursuing higher economic benefits over the past decades in southeast China. A parallel field experiment was carried out to compare CH4 emissions from a transplanted rice paddy and its converted crab-fish farming wetland in southeast China. Over the rice-growing season, CH4 fluxes averaged 1.86 mg m(-2) h(-1) from rice paddies, and 1.14 and 0.50 mg m(-2) h(-1) for the treatments with or without aquatic vegetation present in the crab-fish farming wetlands, respectively. When averaged across the treatments, seasonal CH4 emissions from crab-fish framing wetlands were 52% lower than those from rice paddies. The CH4 fluxes were negatively related to water dissolved oxygen (DO) concentration but positively related to soil/sediment dissolved organic carbon (DOC) content in crab-fish farming wetlands. Dependence of CH4 fluxes on DO or DOC was intensified by the aquatic vegetation presence. By extrapolating the present CH4 emission rate with the current rice paddy-converted aquaculture cultivation area, the seasonal CH4 emissions from inland aquaculture wetlands during the critical farming stage (20 June to 18 October) were estimated to be 33.6 Gg ha(-1) in southeast China in 2012. Rice paddies conversion to crab-fish farming wetlands might have reduced CH4 emissions by 22-54% in mainland China. Results of this study suggest that the conversion of transplanted rice paddies to crab-fish aquaculture wetlands for higher economic benefits would also lead to a lower ecosystem CH4 release rate.

  20. Micro-economic panel data models for Dutch dairy farming

    NARCIS (Netherlands)

    Ooms, D.L.

    2007-01-01

    Keywords:micro-economic models, panel data, GMM, CAP reform, dairy farmingIn The Netherlands, thedairy sector is the largest agricultural sub-sector based on both gross production value and number of farms

  1. Modeling and identification of harmonic instability problems in wind farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei;

    2016-01-01

    to identify harmonic instability problems in wind farms, where many wind turbines, cables, transformers, capacitor banks, shunt reactors, etc, typically are located. This methodology introduces the wind farm as a Multi-Input Multi-Outpur (MIMO) control system, where the linearized models of fast inner control...

  2. Comparing satellite SAR and wind farm wake models

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Vincent, P.; Husson, R.

    2015-01-01

    The aim of the paper is to present offshore wind farm wake observed from satellite Synthetic Aperture Radar (SAR) wind fields from RADARSAT-1/-2 and Envisat and to compare these wakes qualitatively to wind farm wake model results. From some satellite SAR wind maps very long wakes are observed. Th...

  3. Nitrogen cycling and community structure of proteobacterial ß-subgroup ammonia-oxidizing bacteria within polluted marine fish farm sediments

    NARCIS (Netherlands)

    McCaig, A.E.; Phillips, C.B.; Stephen, J.R.; Kowalchuk, G.A.; Harvey, S.M.; Herbert, R.A.; Embley, T.M.; Prosser, J.I.

    1999-01-01

    A multidisciplinary approach was used to study the effects of pollution from a marine fish farm on nitrification rates and on the community structure of ammonia-oxidizing bacteria in the underlying sediment. Organic content, ammonium concentrations, nitrification rates, and ammonia oxidizer most-pro

  4. Can energy willow (Salix sp.) remediate cadmium- and nickel-contaminated fish farm sludge?

    DEFF Research Database (Denmark)

    Pedersen, Marianne Bruus

    it meets the criteria. Phytoremediation by willow may combine accumulation of cadmium and nickel from the sludge with the production of an energy crop. The ability of eight selected willow clones to take up and tolerate cadmium and nickel was studied in pots under outdoor conditions. Fish farm sludge...

  5. Description age-3 brood rainbow trout bred in the conditions of the industral fish farm "Sloboda Banyliv"

    Directory of Open Access Journals (Sweden)

    P. Mendryshora

    2017-06-01

    Full Text Available Purpose. To analyze the results of cultivation and give fish-breeding and biological characteristics of age-3 brood rainbow trout grown using industrial technology in the conditions of the trout farm "Sloboda Banyliv." Methodology. Fish cultivation was carried in tank conditions of the trout farm "Sloboda Banyliv". The material for the study were age-3 brood rainbow trout obtained from eggs of the fall-spawning form of rainbow trout. Cultivation was carried out in a 216 m2 tank, stocking density of 255 fish/m2, using standard trout culture methods. Statistical analysis of the material was performed in Microsoft Office Excel (2003. Analysis of the variables was performed in the system of absolute values. The analysis criteria were their mean values mean deviations (M±m, standard error (σ, variability coefficient (Cv. Fish were fed with specialized feed manufactured by “BioMar” (Denmark with a high protein content (more than 40%. Findings. Based on the performed selective-breeding works aimed at creating brood stocks of rainbow trout, it was found that brood fish reared in the industrial conditions of the fish farm “Sloboda Banyliv”, despite instable culture conditions, were characterized by a moderate growth rate and had high values of productive and reproductive features. Mean weight of age-3 rainbow trout females was 1282.5 g, fecundity — 3.48 thousand eggs. Mean weight of produced eggs was 239.17 g, while individual parameters were 70.4 mg for the weight and 4.58 mm for the diameter. Originality. For the first time a study aimed at the formation of brood stocks of rainbow trout with analysis of phenotypic and productive features in the conditions of a fish farm with instable temperature and water regimes has been conducted. Practical value. The results of the performed work will allow selecting and forming a brood stock with high values of productive and reproductive features.

  6. Dynamic simulation of sustainable farm development scenarios using cognitive modeling

    Directory of Open Access Journals (Sweden)

    Tuzhyk Kateryna

    2017-03-01

    Full Text Available Dynamic simulation of sustainable farm development scenarios using cognitive modeling. The paper presents a dynamic simulation system of sustainable development scenarios on farms using cognitive modeling. The system incorporates relevant variables which affect the sustainable development of farms. Its user provides answers to strategic issues connected with the level of farm sustainability over a long-term perspective of dynamic development. The work contains a description of the model structure as well as the results of simulations carried out on 16 farms in northern Ukraine. The results show that the process of sustainability is based mainly on the potential for innovation in agricultural production and biodiversity. The user is able to simulate various scenarios for the sustainable development of a farm and visualize the influence of factors on the economic and social situation, as well as on environmental aspects. Upon carrying out a series of simulations, it was determined that the development of farms characterized by sustainable development is based on additional profit, which serves as the main motivation for transforming a conventional farm into a sustainable one. Nevertheless, additional profit is not the only driving force in the system of sustainable development. The standard of living, market condition, and legal regulations as well as government support also play a significant motivational role.

  7. Total lipids and fatty acid profile in the liver of wild and farmed Catla catla fish

    Directory of Open Access Journals (Sweden)

    Hussain, Bilal

    2010-03-01

    Full Text Available This experimental work was aimed to study the moisture content, total lipids and fatty acid profile in the liver of wild and farmed freshwater major carp Catla catla of three different weight categories designated as W1 (601-900g, W2 (901- 1200g and W3 (1201-1500g. Seven fish specimens of each of the three weight categories of wild and farmed Catla catla were obtained from Trimu Head, Jhang and Fish Hatchery, Satiana Road and Faisalabad, respectively. The fish were dissected to remove the liver and after weighing, liver samples were prepared and subjected to chemical analysis. Wild Catla catla liver had a significantly (p Catla catla deposited significantly (p Catla catla. Saturated fatty acids C12:0, C14:0, C16:0, C18:0, C20:0 and C22:0 were identified with considerable percentages in the liver of Catla catla from both habitats and monounsaturated fatty acid C18:1 was found in considerable amounts in the liver of both major carp. Polyunsaturated fatty acids such as C18:3 (n-6 and C20: 2 (n-6 were detected in the liver of the wild fish of W2 and W3 and was similar in the W3 weight category of the farmed species.Este trabajo experimental tiene como objetivo estudiar el contenido de humedad, lípidos totales y perfil de ácidos grasos de hígado de carpa de agua dulce Catla catla de tres categorías con peso diferentes designadas como W1 (601- 900g, W2 (901-1200g and W3 (1201-1500g. Siete muestras de pescados por cada una de las tres categorías de peso para Catla catla salvajes y criados fueron obtenidos de Trimu Head, Jhang and Fish Hatchery, Satiana Road y Faisalabad, respectivamente. Los pescados fueron diseccionados para obtener el hígado y las muestras de hígado fueron preparadas y sujetas a análisis químico. Catla catla salvaje tuvo un contenido de humedad significativamente mayor (p Catla catla criadas se depositaron mayores contenidos de lípidos en el hígado. La proporción de ácidos grasos saturados vario irregularmente en los l

  8. IEA-Task 31 WAKEBENCH: Towards a protocol for wind farm flow model evaluation. Part 2: Wind farm wake models

    DEFF Research Database (Denmark)

    Moriarty, Patrick; Rodrigo, Javier Sanz; Gancarski, Pawel;

    2014-01-01

    .windbench.net). This paper provides an overview of the building-block validation approach applied to wind farm wake models, including best practices for the benchmarking and data processing procedures for validation datasets from wind farm SCADA and meteorological databases. A hierarchy of test cases has been proposed...

  9. Modelling representative and coherent Danish farm types based on farm accountancy data for use in environmental assessments

    DEFF Research Database (Denmark)

    Dalgaard, Randi; Halberg, Niels; Kristensen, Ib Sillebak

    2006-01-01

    -oriented environmental assessment (e.g. greenhouse gas emissions per kg pork). The objective of this study was to establish a national agricultural model for estimating data on resource use, production and environmentally important emissions for a set of representative farm types. Every year a sample of farm accounts...... is established in order to report Danish agro-economical data to the ‘Farm Accountancy Data Network’ (FADN), and to produce ‘The annual Danish account statistics for agriculture’. The farm accounts are selected and weighted to be representative for the Danish agricultural sector, and similar samples of farm...... accounts are collected in most of the European countries. Based on a sample of 2138 farm accounts from year 1999 a national agricultural model, consisting of 31 farm types, was constructed. The farm accounts were grouped according to the major soil types, the number of working hours, the most important...

  10. INFLUENCE FISH FARMING IN TANKS ON STRUCTURAL AND FUNCTIONAL CHARACTERISTICS AND ACCUMULATION OF SEDIMENTS IN THE BASIN-COOLER

    Directory of Open Access Journals (Sweden)

    N. Starkо

    2013-09-01

    Full Text Available Purpose. Establishing change the basic structural and functional characteristics of the sediments under the influence of waste going fish farming in tanks. Methodology. Bottom sediment samples were collected using a 1 m of dirt tube (SOI-1, according to the standard requirements. Water-physical properties of sediments were investigated in accordance the recommendations of B. Novikov (1985 and A. Denisova et al. (1987. Determination of the gross content of organic matter carried by loss after calcining. Oxygen consumption in sediments was studied by the method V. І. Romanenko and V. A. Romanenko (1969. Determination of the amount of sediments, which are formed from waste fish farming, carried out in two different ways: by calculating the income from tanks suspended solids and by direct determination of the sediment under the tanks. Findings. Was established that intensive fish farming waste flow predetermines a significant (up to 4 increase the organic matter content. Thus, even 2 years after the reduction of volumes of fish farming tanks and even remove volumetric mass of the skeleton to the initial values of deposits are not refundable. The concentration of organic substances in the zone of the tanks lines causes increased intake of dissolved oxygen, which leads to deterioration in gas mode, especially in the bottom layers of water and may cause suffocation situations. According to our research, the role of tanks lines in shaping total volume of sediment rather low (up to 2%, but their effect on the structural characteristics of sediments allows to evaluate the role of this activity in the overall balance of production-destruction processes as significant. Originality. Was first quantified the role of fish farming in tanks on the quantitative and qualitative characteristics of sediments cooling ponds Zmievsk TPР and Kursk NPP. Practical value. The results will be used in the development of water conservation measures in the integrated use of

  11. Environmental and human health risk assessment of organic micro-pollutants occurring in a Spanish marine fish farm

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Ivan, E-mail: ivanmuno@ual.e [Departamento de Hidrogeologia y Quimica Analitica, Universidad de Almeria, 04120 Almeria (Spain); Martinez Bueno, Maria J., E-mail: mjbueno@ual.e [Departamento de Hidrogeologia y Quimica Analitica, Universidad de Almeria, 04120 Almeria (Spain); Agueera, Ana, E-mail: aaguera@ual.e [Departamento de Hidrogeologia y Quimica Analitica, Universidad de Almeria, 04120 Almeria (Spain); Fernandez-Alba, Amadeo R., E-mail: amadeo@ual.e [Departamento de Hidrogeologia y Quimica Analitica, Universidad de Almeria, 04120 Almeria (Spain)

    2010-05-15

    In this work the risk posed to seawater organisms, predators and humans is assessed, as a consequence of exposure to 12 organic micro-pollutants, namely metronidazole, trimethoprim, erythromycin, simazine, flumequine, carbaryl, atrazine, diuron, terbutryn, irgarol, diphenyl sulphone (DPS) and 2-thiocyanomethylthiobenzothiazole (TCMTB). The risk assessment study is based on a 1-year monitoring study at a Spanish marine fish farm, involving passive sampling techniques. The results showed that the risk threshold for irgarol concerning seawater organisms is exceeded. On the other hand, the risk to predators and especially humans through consumption of fish is very low, due to the low bioconcentration potential of the substances assessed. - Exposure and effects of twelve organic micro-pollutants are evaluated at a Spanish fish farm.

  12. Mediterranean fouling communities assimilate the organic matter derived from coastal fish farms as a new trophic resource.

    Science.gov (United States)

    Gonzalez-Silvera, D; Izquierdo-Gomez, D; Fernandez-Gonzalez, V; Martínez-López, F J; López-Jiménez, J A; Sanchez-Jerez, P

    2015-02-15

    Currently, the lipid content of fish feeds includes high amounts of terrestrial vegetable oils, rich in n-6 fatty acids and poor in n-3 fatty acids. Sinking organic matter in the shape of fragmented pellets and fish faeces could be ingested by the surrounding fauna attracted to the submerged structures of aquaculture facilities or living in natural benthic habitats. Fatty acids contained in feed pellets were used as trophic markers to shed light on the assimilation and incorporation of aquaculture wastes by the invertebrate fauna associated to sea-cages. Eighteen macroinvertebrate species, and zooplankton, seaweeds and sediments were collected from two fish farms, one of which (control) had not been used as such for two years. This study demonstrates that macroinvertebrate fauna present in fouling can take up sinking organic matter from farms. Further research should be directed at assessing the potential implications of aquaculture production for the surrounding ecosystem.

  13. Bacterial diversity in the intestine of young farmed puffer fish Takifugu rubripes

    Science.gov (United States)

    Li, Yanyu; Zhang, Tao; Zhang, Congyao; Zhu, Ying; Ding, Jianfeng; Ma, Yuexin

    2015-07-01

    The aim of the study was to examine the bacterial community associated with the intestinal mucus of young farmed puffer fish Takifugu rubripes. Polymerase chain reaction and partial 16S rDNA sequencing was performed on DNA from bacteria cultivated on Zobell 2216E medium. All the isolates were classified into two phyla—Proteobacteria and Firmicutes. Proteobacteria were the dominant, culturable intestinal microbiota (68.3%). At the genus level, Vibrio, Enterobacter, Bacillus, Pseudomonas, Exiguobacterium, Staphylococcus, Acinetobacter, Pseudoalteromonas and Shewanella were isolated from the intestine, with representatives of the genera Vibrio, Enterobacter and Bacillus accounting for 70.7% of the total. This is the first report of Enterobacter, Bacillus, Exiguobacterium and Staphylococcus as part of the intestinal bacterial microflora in T. rubripes. The profile of the culturable bacterial community differed between samples collected from the same tank at 2-month intervals, as indicated by Bray-Curtis and Sorensen indices, and the impact on the intestinal physiology and health of puffer fish requires further investigation.

  14. Fate of pesticides in combined paddy rice-fish pond farming systems in northern Vietnam.

    Science.gov (United States)

    Anyusheva, Maria; Lamers, Marc; La, Nguyen; Nguyen, Van Vien; Streck, Thilo

    2012-01-01

    During the last decades, high population growth and export-oriented economics in Vietnam have led to a tremendous intensification of rice production, which in turn has significantly increased the amount of pesticides applied in rice cropping systems. Since pesticides are toxic by design, there is a natural concern on the impact of their presence in the environment on human health and environmental quality. The present study was designed to examine the water regime and fate of pesticides (fenitrothion, dimethoate) during two consecutive rice crop seasons in combined paddy rice-fish pond farming systems in northern Vietnam. Major results revealed that 5 and 41% (dimethoate), and 1 and 17% (fenitrothion) of the applied mass of pesticides were lost from the paddy field to the adjacent fish pond during spring and summer crop seasons, respectively. The decrease of pesticide concentration in paddy surface water was very rapid with dissipation half-life values of 0.3 to 0.8 and 0.2 d for dimethoate and fenitrothion, respectively. Key factors controlling the transport of pesticides were water solubility and paddy water management parameters, such as hydraulic residence time and water holding period. Risk assessment indicates that the exposure to toxic levels of pesticides for aquaculture (, ) is significant, at least shortly after pesticide application.

  15. STATUS AND PROSPECTS OF BREEDING STURGEON AT JST "SHIROKOLSKI FISH FARM"

    Directory of Open Access Journals (Sweden)

    Akhmednabi Omarovich Shajhulislamov

    2015-01-01

    Full Text Available Aim. Tthe article presents the results of breeding broodstock of sturgeon in the Shirokolski fish farm. The volume of commodity output reached 50 tonnes of sturgeon, and two tones black caviar. After drilling termal well volume growth may reach 100 t, obtaining food caviar 5 t.Location. Russian Federation, Dagestan Republic.Methods. We used the standard ichthyological research methodology. Results. At the present time the plant formed one of the largest sturgeon broodstock total biomass of more than 50 t, which include clean lines: Beluga, Russian and Siberian sturgeon, sterlet, paddlefish, and hybrid forms. The plant research for the early detection of sex by ultrasound scan. The main role of bester, which is used to obtain the food caviar. The biomass of the herd is about 30 tonnes per year is about 10 tons of breeders. Mature females Bester in our conditions in 7-8 years. Sterlet is used as producers for the purpose of reproduction and food caviar. Maintenance of broodstock is 6000 fishes and approximately 2000 breeders of medium weight from 1.5 to 6.0 kg. Mature female starlet at age 4- 5 years.Main conclusions. The results convince us that the development of sturgeon aquaculture is one of the feasible ways not only to increase employment and reduce social poaching, but also stabilizing the feedstock, substantial improvements in the efficiency of hatcheries and processors.

  16. Wind farms model aggregation using probabilistic clustering

    Science.gov (United States)

    Fernandes, Paula Odete; Ferreira, Ángela Paula

    2013-10-01

    The main objective of this research is the identification of homogeneous groups within wind farms of a major operator playing in the energy sector in Portugal, based on two multivariate analyses: Hierarchical Cluster Analysis and Discriminant Analysis, by using two independent variables: annual liquid hours and net production. From the produced outputs there were identified three homogenous groups of wind farms: (1) medium Installed Capacity and Induction Generator based Technology, (2) high Installed Capacity and Synchronous Generator based Technology and (3) medium Installed Capacity and Synchronous Generator based Technology, which includes the wind farms with the higher annual liquid hours. It has been found that the results obtained by cluster analysis are well classified, with a total percentage of correct classification of 97,1%, which can be considered excellent.

  17. Towards a control model for the highly cybernetic farming ecosystems.

    Science.gov (United States)

    Liao, C M; Lin, W Z

    2000-11-01

    A dynamic model based on the linear systems theory is developed in designing a highly cybernetic farming strategy to efficiently manage residuals generated in farm ecosystems. A linear cybemetic model would be used to describe the dynamic behavior of resource flow in the farm ecosystem in which the state variables are resource quantities, and the control variables are residual quantities. The controlled process is defined as the controlled management strategy change. Cybemetic mechanism shows the application of residuals as control measures have determinate effects on the controlled process as along as the farming system is observable and controllable in the control sense. To illustrate the model algorithm the idea is applied to simulate the dynamic response of residual phosphorus concentrations in an integrated pig/corn farming system located in the south Taiwan region. General results show that the residual phosphorous concentration is influenced by farming activities which are controlled by a system of gross input and net output parameters. This paper demonstrates using input-output analysis technique that residuals generated in the farming system is the most important cybemetic variable,

  18. Modelling and transient stability of large wind farms

    DEFF Research Database (Denmark)

    Akhmatov, Vladislav; Knudsen, Hans; Nielsen, Arne Hejde

    2003-01-01

    The paper is dealing-with modelling and short-term Voltage stability considerations of large wind farms. A physical model of a large offshore wind farm consisting of a large number of windmills is implemented in the dynamic simulation tool PSS/E. Each windmill in the wind farm is represented...... by a physical model of grid-connected windmills. The windmill generators ate conventional induction generators and the wind farm is ac-connected to the power system. Improvements-of short-term voltage stability in case of failure events in the external power system are treated with use of conventional generator...... of dynamic reactive compensation demands. In case of blade angle control applied at failure events, dynamic reactive compensation is not necessary for maintaining the voltage stability....

  19. Improving farm management by modeling the contamination of farm tank milk with butyric acid bacteria

    NARCIS (Netherlands)

    Vissers, M.M.M.; Driehuis, F.; Giffel, te M.C.; Jong, de P.; Lankveld, J.M.G.

    2006-01-01

    Control of contamination of farm tank milk (FTM) with the spore-forming butyric acid bacteria (BAB) is important to prevent the late-blowing defect in semi-hard cheeses. The risk of late blowing can be decreased via control of the contamination level of FTM with BAB. A modeling approach was applied

  20. Improving farm management by modeling the contamination of farm tank milk with butyric acid bacteria

    NARCIS (Netherlands)

    Vissers, M.M.M.; Driehuis, F.; Giffel, te M.C.; Jong, de P.; Lankveld, J.M.G.

    2006-01-01

    Control of contamination of farm tank milk (FTM) with the spore-forming butyric acid bacteria (BAB) is important to prevent the late-blowing defect in semi-hard cheeses. The risk of late blowing can be decreased via control of the contamination level of FTM with BAB. A modeling approach was applied

  1. Marine and farmed fish on the Polish market: comparison of the nutritive value and human exposure to PCDD/Fs and other contaminants.

    Science.gov (United States)

    Szlinder-Richert, Joanna; Usydus, Zygmunt; Malesa-Ciećwierz, Małgorzata; Polak-Juszczak, Lucyna; Ruczyńska, Wiesława

    2011-12-01

    Chemical analyses were performed in nine fish species that are popular on the Polish market. These included Baltic fish (cod, herring, salmon), fish farmed in Poland (carp, trout), marine fish imported from China (Alaska pollock, sole), and farmed fish imported from Vietnam and China (sutchi catfish, tilapia). The nutritional composition (amino acid, micro- and macronutrients, fat-soluble vitamins - A(1), D(3), E) and certain contaminants (organochlorine pesticides, OCPs; indicator polychlorinated biphenyl, PCB(6); polychlorinated dibenzo-paradioxins and polychlorinated dibenzofurans, PCDD/Fs; dioxin-like polychlorinated biphenyls, dl-PCBs; organotin compounds, OCTs; dyes, malachite green and crystal violet; veterinary drug residues, nitrofurans and chloramphenicol; toxic metals, Cd, Pb, Hg) in the muscle tissues of fish were determined. It was confirmed that the fish species analyzed were excellent sources of amino acids, and were rich in phosphorous and selenium. Baltic Sea fish (salmon, herring), fish farmed in Poland (carp and trout), and tilapia were also rich in vitamin D(3). Traces of OCP, PCB(6), OCT, dyes, veterinary drug residues, and heavy metals were detected in concentrations which do not pose a threat to consumers at the current rate of fish consumption in Poland. However, the problem might arise from the content of PCDD/Fs and dl-PCBs in fatty Baltic fish. The fish species analyzed, differed in their nutritional values and degrees of contamination. We suggest that for optimum health and safety, it is advisable that consumers include a variety of different fish species in their diets.

  2. New host record of five Flavobacterium species associated with tropical fresh water farmed fishes from North India.

    Science.gov (United States)

    Verma, Dev Kumar; Rathore, Gaurav

    2015-01-01

    Yellow pigmented, filamentous, Gram-negative bacteria belonging to genus Flavobacterium are commonly associated with infections in stressed fish. In this study, inter-species diversity of Flavobacterium was studied in apparently healthy freshwater farmed fishes. For this, ninety one yellow pigmented bacteria were isolated from skin and gill samples (n = 38) of three farmed fish species i.e. Labeo rohita, Catla catla and Cyprinus carpio. Among them, only twelve bacterial isolates (13.18%) were identified as Flavobacterium spp. on the basis of morphological, biochemical tests, partial 16S rDNA gene sequencing and phylogenetic analysis. On the basis of 16S rDNA gene sequencing, all the 12 isolates were 97.6-100% similar to six different formally described species of genus Flavobacterium. The 16S rDNA based phylogenetic analysis grouped these strains into six different clades. Of the 12 isolates, six strains (Fl9S1-6) grouped with F. suncheonense, two strains (Fl6I2, Fl6I3) with F. indicum and the rest four strains (Fl1A1, Fl2G1, Fl3H1 and Fl10T1) clustered with F. aquaticum, F. granuli, F. hercynium and F. terrae, respectively. None of these species except, F. hercynium were previously reported from fish. All the isolated Flavobacterium species possessed the ability of adhesion and biofilm formation to colonize the external surface of healthy fish. The present study is the first record of tropical freshwater farmed fishes as hosts to five environmentally associated species of the Flavobacterium.

  3. Modelling seabird collision risk with off-shore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Mateos, Maria; Arroyo, Gonzalo Munoz; Rosario, Jose Juan Alonso del

    2011-07-01

    Full text: Recent concern about the adverse effects of collision mortality of avian migrants at wind farms has highlighted the need to understand bird-wind turbine interactions. Here, a stochastic collision model, based on data of seabird behaviour collected on- site, is presented, as a flexible and easy to take tool to assess the collisions probabilities of off-shore wind farms in a pre-construction phase. The collision prediction model considering the wind farm area as a risk window has been constructed as a stochastic model for avian migrants, based on Monte Carlo simulation. The model calculates the probable number of birds collided per time unit. Migration volume, wind farm dimensions, vertical and horizontal distribution of the migratory passage, flight direction and avoidance rates, between other variables, are taken into account in different steps of the model as the input variables. In order to assess the weighted importance of these factors on collision probability predictions, collision probabilities obtained from the set of scenarios resulting from the different combinations of the input variables were modelled by using Generalised Additive Models. The application of this model to a hypothetical project for erecting a wind farm at the Strait of Gibraltar showed that collision probability, and consequently mortality rates, strongly depend on the values of the avoidance rates taken into account, and the distribution of birds into the different altitude layers. These parameters should be considered as priorities to be addressed in post-construction studies. (Author)

  4. Wind farm density and harvested power in very large wind farms: A low-order model

    Science.gov (United States)

    Cortina, G.; Sharma, V.; Calaf, M.

    2017-07-01

    In this work we create new understanding of wind turbine wakes recovery process as a function of wind farm density using large-eddy simulations of an atmospheric boundary layer diurnal cycle. Simulations are forced with a constant geostrophic wind and a time varying surface temperature extracted from a selected period of the Cooperative Atmospheric Surface Exchange Study field experiment. Wind turbines are represented using the actuator disk model with rotation and yaw alignment. A control volume analysis around each turbine has been used to evaluate wind turbine wake recovery and corresponding harvested power. Results confirm the existence of two dominant recovery mechanisms, advection and flux of mean kinetic energy, which are modulated by the background thermal stratification. For the low-density arrangements advection dominates, while for the highly loaded wind farms the mean kinetic energy recovers through fluxes of mean kinetic energy. For those cases in between, a smooth balance of both mechanisms exists. From the results, a low-order model for the wind farms' harvested power as a function of thermal stratification and wind farm density has been developed, which has the potential to be used as an order-of-magnitude assessment tool.

  5. Description, systematics and ecology of a new tanaidacean (Crustacea, Peracarida) species from mediterranean fish farms

    Science.gov (United States)

    Esquete, P.; Fernandez-Gonzalez, V.

    2017-01-01

    An undescribed species of tanaidacean belonging to the genus Hexapleomera, tribe Pancolini, Hexapleomera bultidactyla sp. nov. was found in fouling community samples from off-coast fish farms cages in the western Mediterranean Sea. The species can be distinguished from other Hexapleomera species by the presence of a ventral apophysis on the dactylus of the chela in males. Other diagnostic characters (in combination) include a male antennule with five aesthetascs, the female with three, the maxillule palp with four terminal setae and maxilliped basis and coxa each with two setae; the male fixed finger with four ventral setae and proximal apophysis, the female chela fixed finger with a proximal triangular apophysis, an apophysis on the coxa of pereopod 1, a pleopod 3 basis with three outer setae, and an uropod of four segments. Although several substrata were investigated, the species was most abundant where the turf formed by Ceramiaceae algae and the hydroid Aglaophenia sp. was dominant. An updated identification key to all the species of Hexapleomera is provided.

  6. A hybrid wind farm parameterization for mesoscale and climate models

    Science.gov (United States)

    Pan, Y.; Archer, C. L.

    2016-12-01

    To better understand the potential impacts of wind farms on weather and climate at the local to regional scale, a new hybrid wind farm parameterization is proposed here for mesoscale models, such as the Weather Research and Forecasting Model (WRF), or climate models, such as the Community Atmosphere Model (CAM). All previous wind farm parameterizations treat all the wind turbines in the same grid cell as identical (i.e., they all share the same upstream wind velocity) and ignore the effect of wind direction. By contrast, the new hybrid model considers each individual wind turbine, based on its position in the layout and on wind direction. The new parameterization is developed starting from large eddy simulations (LES) of existing wind farms, in which the local flow around each wind turbine is directly simulated at high spatial ( 3.5 m) and temporal ( 0.1 s) resolutions and the effects of subgrid-scale processes are modeled. Based on analytic and statistical relationships between the LES results and several geometric properties of the wind farm layout (such as blockage ratio and blocking distance), the new hybrid parameterization predicts the local upstream wind speed of each individual wind turbine in the same grid cell, and thus successfully account for the effects of layout and wind direction with little computational cost. With the newly predicted upstream velocity, the turbine-induced forces and added turbulence kinetic energy (TKE) in the atmosphere are derived analytically. The wind speed, wind speed deficit, and TKE profiles and power production obtained with the hybrid parameterization for the test case (the 48-turbine Lillgrund wind farm in Sweden) are in better agreement with the LES results than previous parameterizations. Future work includes the insertion of the hybrid parameterization into the WRF code to assess impacts on near-surface properties, such as temperature and heat and momentum fluxes, in the region surrounding the wind farm.

  7. Occurrence of antibiotic resistance and characterization of resistant genes and integrons in Enterobacteriaceae isolated from integrated fish farms south China

    Science.gov (United States)

    Su, Hao-Chang; Ying, Guang-Guo; Tao, Ran; Zhang, Rui-Quan; Fogarty, Lisa R.; Kolpin, Dana W.

    2011-01-01

    Antibiotics are still widely applied in animal husbandry to prevent diseases and used as feed additives to promote animal growth. This could result in antibiotic resistance to bacteria and antibiotic residues in animals. In this paper, Enterobacteriaceae isolated from four integrated fish farms in Zhongshan, South China were tested for antibiotic resistance, tetracycline resistance genes, sulfonamide resistance genes, and class 1 integrons. The Kirby-Bauer disk diffusion method and polymerase chain reaction (PCR) assays were carried out to test antibiotic susceptibility and resistance genes, respectively. Relatively high antibiotic resistance frequencies were found, especially for ampicillin (80%), tetracycline (52%), and trimethoprim (50%). Out of 203 Enterobacteriaceae isolates, 98.5% were resistant to one or more antibiotics tested. Multiple antibiotic resistance (MAR) was found highest in animal manures with a MAR index of 0.56. Tetracycline resistance genes (tet(A), tet(C)) and sulfonamide resistance genes (sul2) were detected in more than 50% of the isolates. The intI1 gene was found in 170 isolates (83.7%). Both classic and non-classic class 1 integrons were found. Four genes, aadA5, aadA22, dfr2, and dfrA17, were detected. To our knowledge, this is the first report for molecular characterization of antibiotic resistance genes in Enterobacteriaceae isolated from integrated fish farms in China and the first time that gene cassette array dfrA17-aadA5 has been detected in such fish farms. Results of this study indicated that fish farms may be a reservoir of highly diverse and abundant antibiotic resistant genes and gene cassettes. Integrons may play a key role in multiple antibiotic resistances posing potential health risks to the general public and aquaculture.

  8. INFLUENCE FISH FARMING IN TANKS ON STRUCTURAL AND FUNCTIONAL CHARACTERISTICS AND ACCUMULATION OF SEDIMENTS IN THE BASIN-COOLER

    OpenAIRE

    N. Starkо

    2013-01-01

    Purpose. Establishing change the basic structural and functional characteristics of the sediments under the influence of waste going fish farming in tanks. Methodology. Bottom sediment samples were collected using a 1 m of dirt tube (SOI-1), according to the standard requirements. Water-physical properties of sediments were investigated in accordance the recommendations of B. Novikov (1985) and A. Denisova et al. (1987). Determination of the gross content of organic matter carried by loss...

  9. Occurrence of Antimicrobial Resistance in Fish-Pathogenic and Environmental Bacteria Associated with Four Danish Rainbow Trout Farms

    DEFF Research Database (Denmark)

    Schmidt, Anja S.; Bruun, Morten Sichlau; Dalsgaard, Inger

    2000-01-01

    Surveillance of bacterial susceptibility to five antimicrobial agents was performed during a 1-year period in and around four freshwater fish farms situated along a stream in western Denmark Besides assessing the levels of antibiotic resistance among the culturable fraction of microorganisms...... and outlet samples, the increase of the antibiotic-resistant proportions observed among the culturable microflora was more pronounced and statistically significant among the motile aeromonads. High levels of individual and multiple antimicrobial resistances were demonstrated within the collected...

  10. Wind farm electrical power production model for load flow analysis

    Energy Technology Data Exchange (ETDEWEB)

    Segura-Heras, Isidoro; Escriva-Escriva, Guillermo; Alcazar-Ortega, Manuel [Institute for Energy Engineering, Universidad Politecnica de Valencia, Camino de Vera, s/n, edificio 8E, escalera F, 2a planta, 46022 Valencia (Spain)

    2011-03-15

    The importance of renewable energy increases in activities relating to new forms of managing and operating electrical power: especially wind power. Wind generation is increasing its share in the electricity generation portfolios of many countries. Wind power production in Spain has doubled over the past four years and has reached 20 GW. One of the greatest problems facing wind farms is that the electrical power generated depends on the variable characteristics of the wind. To become competitive in a liberalized market, the reliability of wind energy must be guaranteed. Good local wind forecasts are therefore essential for the accurate prediction of generation levels for each moment of the day. This paper proposes an electrical power production model for wind farms based on a new method that produces correlated wind speeds for various wind farms. This method enables a reliable evaluation of the impact of new wind farms on the high-voltage distribution grid. (author)

  11. Modeling and Identification of Harmonic Instability Problems In Wind Farms

    DEFF Research Database (Denmark)

    Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

    2016-01-01

    to identify harmonic instability problems in wind farms, where many wind turbines, cables, transformers, capacitor banks, shunt reactors, etc, typically are located. This methodology introduces the wind farm as a Multi-Input Multi-Outpur (MIMO) control system, where the linearized models of fast inner control......In power electronics based power systems like wind farms, the interactions between the inner control systems of the power converters and the passive components may lead to high frequency oscillations, which can be called harmonic instability. In this paper, a simple methodology is presented...... loops of the grid-side converters are considered. Therefore, instability problems of the whole wind farm are predicted based on the poles of the introduced MIMO system. In order to confirm the effectiveness of the proposed analytical approach, time-domain simulations are performed in the PSCAD...

  12. The bottlenose dolphin Tursiops truncatus foraging around a fish farm: Effects of prey abundance on dolphins’ behavior

    Directory of Open Access Journals (Sweden)

    Bruno Díaz LÓPEZ

    2009-08-01

    Full Text Available The extent to which prey abundance influences both bottlenose dolphin foraging behavior and group size in the presence of human activities has not previously been studied. The primary aim of this study was to identify and quantify how wild bottlenose dolphins respond, individually and as groups, to the relative abundance of prey around a fish farm. Detailed views of dolphins’ behavior were obtained by focal following individual animals whilst simultaneously collecting surface and underwater behavioral data. A total of 2150 dive intervals were analyzed, corresponding to 342 focal samples, lasting over 34 hours. Bottlenose dolphins remained submerged for a mean duration of 46.4 seconds and a maximum of 249 seconds. This study provides the first quantified data on bottlenose dolphin diving behavior in a marine fin-fish farm area. This study’s results indicate that within a fish farm area used intensively by bottlenose dolphins for feeding, dolphins did not modify dive duration. Additionally, underwater observations confirmed that dolphins find it easier to exploit a concentrated food source and it appears that hunting tactic and not group size plays an important role during feeding activities. Thus, bottlenose dolphins appear capable of modifying their hunting tactics according to the abundance of prey. When top predators display behavioral responses to activities not directed at them, the task of studying all possible effects of human activities can become even more challenging [Current Zoology 55(4: 243–248, 2009].

  13. Application of “taxocene surrogation” and “taxonomic sufficiency” concepts to fish farming environmental monitoring. Comparison of BOPA index versus polychaete assemblage structure

    OpenAIRE

    Aguado Giménez, Felipe; Gairin Deulofeu, Joan Ignasi; Martinez-Garcia, Elena; Fernandez-Gonzalez, Victoria; Ballester-Moltó, Mateo; Cerezo-Valverde, Jesús; Sanchez-Jerez, Pablo

    2015-01-01

    “Taxocene surrogation” and “taxonomic sufficiency” concepts were applied to the monitoring of soft bottoms macrobenthic assemblages influenced by fish farming following two approaches. Polychaete assemblage evaluation through multivariate analysis and the benthic index BOPA were compared. Six fish farms along the Spanish Mediterranean coast were monitored. Polychaete assemblage provided a suitable picture of the impact gradient, being correlated with total free sulphides. BOPA did not support...

  14. Heavy metals levels in fish from aquaculture farms and risk assessment in Lhasa, Tibetan Autonomous Region of China.

    Science.gov (United States)

    Jiang, Dongsheng; Hu, Zhenzhen; Liu, Feng; Zhang, Rongfei; Duo, Bu; Fu, Jianjie; Cui, Yibin; Li, Mei

    2014-05-01

    Fish is consumed as a common food by humans due to its nutritional and therapeutic benefits. However, they can accumulate toxic chemicals (such as heavy metals, persistent organic pollutants) from water and food chain. Very few studies have been investigated on heavy metal contents in fish from Tibetan Autonomous Region of China. In order to study heavy metals levels in fish from aquaculture farms and evaluate the risk that human consume fish in this area, we collected four types of aquaculture fish species (6 big-head carps, 5 grass carps, 5 carps and 5 tilapias) from fisheries around Lhasa city in this study. 9 heavy metals (Cr, As, Cd, Pb, Cu, Ba, Co, Mn and V) in different tissues of fish were determined by an inductively coupled plasma mass spectrometer. Cr, Ba, Co, Mn and V could easily accumulate in the gill, and Cu was detected in the hearts of all the fishes. Toxic metal (As, Cd and Pb) contents were higher in the liver than those in other tissues, heavy metal levels were the lowest in the muscle among all tissues. Most of heavy metal concentrations in the tilapia tissues were higher than those in other fish tissues, especially arsenic. Arsenic content in the tilapia samples was ~2-4 times higher than the maximum levels (MLs) of contaminants in the national standard, and other metals were all lower than the MLs. Compared the estimated daily intake of heavy metals through fish consumption with tolerable daily intakes recommended by FAO, the metals daily intake of As, Cd and Pb from fish consumption might not pose serious health risk to the local inhabitants. It is therefore necessary to determine the dose level for human, which is considered to be taken daily over a lifetime without adverse effects.

  15. Monogenean parasites of the African catfish Clarias gariepinus from two fish farms in Calabar, Cross River State, Nigeria

    Directory of Open Access Journals (Sweden)

    Eyo Victor Oscar

    2015-06-01

    Full Text Available Objective: To determine the prevalence, mean intensity, and abundance of monogenean parasites in Clarias gariepinus (C. gariepinus from two selected fish farms in Calabar, Cross River State, Nigeria. Methods: Eighty specimens of C. gariepinus from the two farms (40 each were necropsied for parasitological analysis. Skin, gill and fin biopsies were prepared from each specimen following standard methods for microscopic analysis. Parasitological indices including dominance (D, prevalence, mean intensity and abundance were calculated according to standard formulae. Data were analyzed using the Fisher's exact test. Results: C. gariepinus from the two farms were infested with a total of ninety individuals of monogenean parasites belonging to three species including Macrogyrodactylus clarii (M. clarii, Gyrodactylus sp. and Dactylogyrus sp. D index showed that the three monogenean species were eudominant (D-value > 10%. Gyrodactylus sp. was more abundant (46 followed by Dactylogyrus sp. (23 while M. clarii was the lowest (21. Prevalence, meaning intensity and abundance of monogenean parasites in the two farms, varied insignificantly higher (P > 0.05. Prevalence in both farms were higher in female C. gariepinus than that in male. Monogenean parasites exhibited organ specificity as M. clarii and Dactylogyrus sp. were recovered from the gills while Gyrodactylus sp. colonized the skin and fin. Conclusions: High abundance of these parasites may lead to poor growth performance and high mortality in C. gariepinus, leading to huge monetary loss and low profit margin by increasing production cost due to the cost of treatments.

  16. Proteomics in farm animals models of human diseases.

    Science.gov (United States)

    Ceciliani, Fabrizio; Restelli, Laura; Lecchi, Cristina

    2014-10-01

    The need to provide in vivo complex environments to understand human diseases strongly relies on the use of animal models, which traditionally include small rodents and rabbits. It is becoming increasingly evident that the few species utilised to date cannot be regarded as universal. There is a great need for new animal species that are naturally endowed with specific features relevant to human diseases. Farm animals, including pigs, cows, sheep and horses, represent a valid alternative to commonly utilised rodent models. There is an ample scope for the application of proteomic techniques in farm animals, and the establishment of several proteomic maps of plasma and tissue has clearly demonstrated that farm animals provide a disease environment that closely resembles that of human diseases. The present review offers a snapshot of how proteomic techniques have been applied to farm animals to improve their use as biomedical models. Focus will be on specific topics of biomedical research in which farm animal models have been characterised through the application of proteomic techniques.

  17. IEA-Task 31 WAKEBENCH: Towards a protocol for wind farm flow model evaluation. Part 2: Wind farm wake models

    Science.gov (United States)

    Moriarty, Patrick; Sanz Rodrigo, Javier; Gancarski, Pawel; Chuchfield, Matthew; Naughton, Jonathan W.; Hansen, Kurt S.; Machefaux, Ewan; Maguire, Eoghan; Castellani, Francesco; Terzi, Ludovico; Breton, Simon-Philippe; Ueda, Yuko

    2014-06-01

    Researchers within the International Energy Agency (IEA) Task 31: Wakebench have created a framework for the evaluation of wind farm flow models operating at the microscale level. The framework consists of a model evaluation protocol integrated with a web-based portal for model benchmarking (www.windbench.net). This paper provides an overview of the building-block validation approach applied to wind farm wake models, including best practices for the benchmarking and data processing procedures for validation datasets from wind farm SCADA and meteorological databases. A hierarchy of test cases has been proposed for wake model evaluation, from similarity theory of the axisymmetric wake and idealized infinite wind farm, to single-wake wind tunnel (UMN-EPFL) and field experiments (Sexbierum), to wind farm arrays in offshore (Horns Rev, Lillgrund) and complex terrain conditions (San Gregorio). A summary of results from the axisymmetric wake, Sexbierum, Horns Rev and Lillgrund benchmarks are used to discuss the state-of-the-art of wake model validation and highlight the most relevant issues for future development.

  18. Measurements on and modelling of offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, S. [ed.

    1996-11-01

    The primary project component was measurement on the Vindeby Offshore Wind Farm. Also included are analyses of fatigue loading on the turbines, sea climate, performance of the wind farm and modelling of flow characteristics inside the wind farm. These individual analyses were made to meet the overall objective, which was to devise an adequate design tool to take into account the increased dynamic loading in wind farms. Measurements have been conducted for several years on the wind farm at Vindeby 2-3 km off the coast of the island of Lolland in the South Baltic Sea. The Vindeby Wind Farm consists of 11 Bonus machines with installed capacities of 450 kW, hub height 38 m and rotor diameter 35 m. The separations of the machines in the rows are 300 m (8.6D), and the distance between the rows is equally 300 m. Two machines, 4W and 5E are instrumented for structural measurements; tower base bending, yaw and tilt and edge and flapwise blade root bending moments are measured and statistics for 1/2 hourly consecutive time periods are stored. The statistics include minimum, maximum, mean, standard deviation and the so-called equivalent load widths. The equivalent load width is popularly speaking the amplitude of a sinusoidal load with frequency equal - in this case - to rotational frequency of the wind turbine rotor that would consume the same fatigue life as the actual load sequence. Modelling of fatigue loading in offshore wind farms and the offshore wind climate was carried out with good results. Also, computational flow modelling was performed. (au) 40 tabs., 130 ills., 114 refs.

  19. Fish farm and water quality management - doi: 10.4025/actascibiolsci.v35i1.10086

    Directory of Open Access Journals (Sweden)

    Lúcia Helena Sipaúba Tavares

    2012-12-01

    Full Text Available Normal 0 21 false false false MicrosoftInternetExplorer4 Fish farms’ water quality management is analyzed with regard to the management employed and the different trophic states are compared within the system during the dry and rainy seasons. Six sites were marked two in the water supply (P1 and P2, and four within the fish farm (P3 to P6 . Whereas sites P1 and P2 (water supply were characterized as oligotrophic, the others were mesotrophic and eutrotrophic sites. Environmental variables, mainly nutrients, conductivity, COD, BOD5 and TSS tended to increase as from P3 due to management and fertilization. Greater impact has been registered in the fish farm under analysis for variables COD, ammonia, total phosphorus and TSS during the discharge and pond emptying period. Frequent monitoring of water quality should be undertaken in fish breeding and plankton production ponds, especially in those close to P3 and P4. Removal of sediment in decantation lake or P5 is also recommended to decrease nutrient concentrations, especially phosphorus, accumulated on the bottom soil.

  20. Models for simulation of transient events in a wind farm

    DEFF Research Database (Denmark)

    Sørensen, P.; Hansen, A. D.; Bindner, H.

    2002-01-01

    with different tools with each other and with measurements. This present paper limits to describe the models including our reflections on which effects we expect to be essential for obtaining useful simulation results. The models comprise the substation, where the wind farm is connected, the power collection...

  1. Spectral coherence model for power fluctuations in a wind farm

    DEFF Research Database (Denmark)

    Vigueras-Rodriguez, A.; Sørensen, Poul Ejnar; Viedma, A.;

    2012-01-01

    This paper provides a model for the coherence between wind speeds located in a horizontal plane corresponding to hub height of wind turbines in a large wind farm. The model has been developed using wind speed and power measurements from the 72 Wind Turbines and two of the meteorological masts from...

  2. Modelling and measurements of wakes in large wind farms

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Rathmann, Ole; Frandsen, Sten Tronæs;

    2007-01-01

    The paper presents research conducted in the Flow workpackage of the EU funded UPWIND project which focuses on improving models of flow within and downwind of large wind farms in complex terrain and offshore. The main activity is modelling the behaviour of wind turbine wakes in order to improve...

  3. Modelling and measurements of wakes in large wind farms

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Rathmann, Ole; Frandsen, Sten Tronæs

    2007-01-01

    The paper presents research conducted in the Flow workpackage of the EU funded UPWIND project which focuses on improving models of flow within and downwind of large wind farms in complex terrain and offshore. The main activity is modelling the behaviour of wind turbine wakes in order to improve p...

  4. Ultrastructural description of Myxobolus cuneus (Myxosporea) in the skeletal muscle and kidney of tropical farmed fish Piaractus mesopotamicus (Characiformes: Characidae).

    Science.gov (United States)

    Manrique, Wilson Gómez; Figueiredo, Mayra Araguaia Pereira; de Andrade Belo, Marco Antonio; Martins, Maurício Laterça; Azevedo, Carlos

    2016-06-01

    This study characterizes by transmission electron microscopy (TEM) and morphometric features the myxozoan Myxobolus cuneus (Myxosporea) in Piaractus mesopotamicus and reports the skeletal muscle and kidney as site of infection. The register was based in 21 young fish from intensive fish farming in Southeast Brazil and the spores were analyzed in fresh-mounted slides of the infected organs stained with Toluidine blue and processed as usual for TEM. It differs from Myxobolus cunhai from the fish host and different polar capsule size, and from Myxobolus serrasalmi on the pyriform spore shape and an oval macrospore, differently to that reported in this study. Morphometric characteristics and TEM study confirmed the present material as M. cuneus.

  5. A piscicultura e o ambiente: o uso de alimentos ambientalmente corretos em piscicultura Fish farming and the environment: the use of environmental friendly feeds in fish culture

    Directory of Open Access Journals (Sweden)

    José Eurico Possebon Cyrino

    2010-07-01

    Full Text Available Embora a ciência da nutrição de peixes esteja longe de estabelecer um padrão geral de exigências nutricionais, a necessidade de desenvolvimento de alimentos de baixo impacto poluente há muito faz parte da agenda das comunidades científica e empresarial internacional da aqüicultura. Não só é absolutamente possível formular alimentos ambientalmente corretos, como é necessário modelar a formulação destes alimentos. Porém, é necessária absoluta acurácia para atender formulações espécie-específicas, considerando-se as interações da biologia e fisiologia nutricional das espécies com os alimentos e com as variações abióticas do meio. O conhecimento disponível sobre as mais de 200 espécies de peixe produzidas comercialmente no mundo é ainda incipiente e os sistemas de produção de peixe, nos diferentes regimes de exploração, estão implantados em todas as condições ecológicas possíveis. Neste cenário, produzir rações ambientalmente corretas é, senão impossível, pelo menos muito difícil e depende da ação coordenada e positiva de produtores, indústria da alimentação, agências regulatórias, e instituições de ensino e pesquisa para definir os parâmetros necessários à consecução deste objetivo.Although fish nutrition science is far from establishing general standards of nutritional requirements, the need for developing low impact feeds has long been included in the agenda of aquaculture's international scientific and business communities of. Not only is absolutely possible to formulate environmental friendly feeds, as it is necessary modeling the formulation of these feeds. However, it is necessary higher accuracy to develop species-specific formulations, considering interactions of the biology and nutritional physiology of the species with the feedstuffs and variations of abiotic environment. The knowledge on more than 200 species of commercially farmed fish is still incipient and fish production

  6. Correction of algocenosis by the preparation of komplezim in experimental ponds of fish-farm Nyvka

    Directory of Open Access Journals (Sweden)

    L. Dragan

    2016-01-01

    Full Text Available Purpose. To investigate the effect of the bacterial preparation "Komplezim", which is recommended for the prevention of mass reproduction of blue-green algae through algocoenosis correction, water cleaning and sanitary regime restoration, for the biological balance and self-purification of natural and farmed fish ponds of all sizes exposed to artificial or natural pollution. Methodology. The studies were carried out during 30 days in a 0.01 hectare pond with a depth of 1.0–1.5 m. The doses of the bacterial preparation "Komplezim" in the form of a solution were applied over the water surface of the experimental pond. The conventional techniques of hydrochemistry and hydrobiology were used to perform hydroecological studies. Findings. The study results showed that after the exposure of the bacterial preparation "Komplezim", pH level of water and oxidation rates were within the acceptable limits. Permanganate and dichromate oxidation decreased in the same manner in the middle and end of the experiment compared to initial values. Calcium, magnesium, and sulfate levels were lower compared to control values. This effect can be explained by the fact that bacteria from the “Komplezim” composition in aquatic medium started intensive metabolizing the products of organic decomposition enriched in calcium, magnesium and sulfates. The consequence of the application of "Komplezim" was an increase in the concentration of organic chlorides simultaneously with nitrites. The obtained results indicate that bacteria strains included in the “Komplezim” composition inhibit the processes of cyanobacteria reproduction by algocenosis correction and contributes to the optimization of hydrochemical conditions for pond fish rearing. Originality. The effect of the bacterial preparation "Komplezim" on the reproduction of blue-green algae and hydro-chemical composition of the water has been investigated for the first time. Practical value. Application of the

  7. An LP-model to analyse economic and ecological sustainability on Dutch dairy farms: model presentation and application for experimental farm "de Marke"

    NARCIS (Netherlands)

    Calker, van K.J.; Berentsen, P.B.M.; Boer, de I.J.M.; Giesen, G.W.J.; Huirne, R.B.M.

    2004-01-01

    Farm level modelling can be used to determine how farm management adjustments and environmental policy affect different sustainability indicators. In this paper indicators were included in a dairy farm LP (linear programming)-model to analyse the effects of environmental policy and management

  8. Infectious bacterial pathogens, parasites and pathological correlations of sewage pollution as an important threat to farmed fishes in Egypt.

    Science.gov (United States)

    Mahmoud, Mahmoud A; Abdelsalam, Mohamed; Mahdy, Olfat A; El Miniawy, Hala M F; Ahmed, Zakia A M; Osman, Ahmed H; Mohamed, Hussein M H; Khattab, A M; Zaki Ewiss, M A

    2016-12-01

    This paper is a part of a multi-disciplinary research "Application of Decentralized On-Site Water Treatment System in Egypt for Use in Agriculture and Producing Safe Fish and Animal Proteins". The project aimed to investigate the environmental impact of implementing sewage water before and after treatment using the effluent of the on-site decentralized Japanese' Johkasou system, in agriculture and producing fish protein. The aim is to establish such system in Egypt to strengthen the sanitary conditions of water resources. In the present study, the impact of the sewage pollution in some fish farms at El-Fayyum, Port Said and El-Dakahlia governorates in Egypt was carried out. Water and fish (Oreochromis niloticus and Mugil cephalus) samples were collected from private fish farms of such localities. Bacteriological and chemical examination of water samples revealed the existence of coliforms and many other bacterial species of significant human health hazards. The chemical parameters of water showed a marked deviation from normal levels while examination of fish flesh specimens indicated contamination with Streptococcus Sp., Staphylococcus Sp., and Salmonella in all examined localities. Other bacterial isolates of human health importance (Morganella morganii, Pseudomonas cepacia and Enterococcos durans) were identified. The parasitological examination revealed the presence of encysted metacercariae (EMC); Diplostomatidae, Prohemistomatidae and Heterphyidae. Moreover, two protozoan parasites (Mxyoboulus tilapiae and Ichthyophthirius multifilis) were also recorded. The histopathological examination revealed mild tissue reaction in case of bacterial infection and severe pathological lesions in different organs in case of EMC infection. Lamellar hyperplasia and mononuclear cell infiltration in branchial tissue was common findings. In skeletal muscles, atrophy of muscle fibres, myolysis and myophagia were detected.

  9. NOVEL TSUNAMI BARRIERS AND THEIR APPLICATIONS FOR HYDROELECTRIC ENERGY STORAGE, FISH FARMING, AND FOR LAND RECLAMATION

    Directory of Open Access Journals (Sweden)

    Hans J. Scheel

    2014-10-01

    Full Text Available The tsunami hazard can be mitigated if the destructive waves generated from earthquakes and landslides can be reflected by a stable submerged vertical barrier before striking coastal communities or important structures. Building such deep walls by conventional submarine technology is difficult. The present study describes the principle and the erection of such submarine defensive walls by a relatively simple efficient and economic technology. This technology is based on lowering high- strength steel fences with horizontal anchors, or two parallel steel fences with distance holders, into the sea and fixing them with rocks deposited from top. Dredged material like gravel or sand can be used for additional filling. This Tsunami-Flooding Barrier (TFB extends a few meters above sea level and carries on top a concrete supply and service road protected on both sides against storm waves by concrete walls. Replaceable surge stoppers (parapets, wave return walls prevent overtopping and erosion of the seaward barrier face. The TFBs protect the coastline against tsunami and the highest storm waves from hurricanes, but also can provide protection from oil spills or other contaminations from the ocean and thus protect flora, fauna, coral reefs and beaches. Channels and gates allow navigation and can be closed quickly upon a tsunami or storm warning. The construction costs can be eventually compensated by using the reservoirs between coast and barriers for hydroelectric energy storage (using pump-turbines in the barriers or for fish-farming, or alternatively the reservoir can be filled with rocks, rubble, gravel, sand and covered with soil in order to reclaim new land. Tidal energy can be generated by installing turbines within these barriers. Also, this submarine architecture may be applied to protect pillars of bridges and offshore platforms, and for erecting “roads” into the sea to connect near-shore platforms and wind-parks with the coast and

  10. Using the Monte Carlo method for the economic evaluation of polycultures of silver catfish, carps and tilapia-the-nile as an alternative model of fish farming for small properties

    Directory of Open Access Journals (Sweden)

    Filipe Ritter

    2014-11-01

    Full Text Available With a growing world population and increasing demand for quality food in sufficient quantities, the aquaculture fits in this context as a producer of high quality animal protein with high productivity. The fish production in ponds has practiced for over five decades in Rio Grande do Sul state. The fish culture system commonly used is the carp only polyculture, which consists in culturing different carp species aiming to improve the performance of each one and, therefore, achieve high productivity. The carp polyculture has a low technological level and the production obtained is considered small moreover, the release of effluents in natural water bodies may cause an imbalance in the natural aquatic environment. Some studies have been performed adding the silver catfish to the traditional polyculture. Also, several studies were performed about economic viability, but with a single species, or consortium, as is the case of polyculture of shrimp and Nile tilapia. We tested the polyculture with partial substitution of 25, 50 and 75% of carps by silver catfish and Nile tilapia. We analyzed the economic viability of all substitution rates by obtaining the Net Present Value (NPV, Annual Value (AV, Internal Rate of Return (IRR and Pay Back period. In conditions of uncertainty, we held on sensitivity analysis and evaluation through the Monte Carlo method. We concluded that substitution rate of 25% of carps by silver catfish and Nile tilapia has higher biomass production and better effluent quality. Regarding economic analysis, an investment in polyculture with vita useful 25 years is economically feasible for a fee Minimum Attractiveness (TMA of 6.17%.

  11. A noise generation and propagation model for large wind farms

    DEFF Research Database (Denmark)

    Bertagnolio, Franck

    2016-01-01

    A wind turbine noise calculation model is combined with a ray tracing method in order to estimate wind farm noise in its surrounding assuming an arbitrary topography. The wind turbine noise model is used to generate noise spectra for which each turbine is approximated as a point source. However......, the detailed three-dimensional directivity features are taken into account for the further calculation of noise propagation over the surrounding terrain. An arbitrary number of turbines constituting a wind farm can be spatially distributed. The noise from each individual turbine is propagated into the far......-field using the ray tracing method. These results are added up assuming the noise from each turbine is uncorrelated. The methodology permits to estimate a wind farm noise map over the surrounding terrain in a reasonable amount of computational time on a personal computer....

  12. An outbreak of myxozoan parasites in farmed freshwater fish Colossoma macropomum (Cuvier, 1818 (Characidae, Serrasalminae in the Amazon region, Brazil

    Directory of Open Access Journals (Sweden)

    Marcela Videira

    2016-05-01

    Full Text Available The tambaqui (Colossoma macropomum is a native fish species that is farmed most frequently and in the largest quantities throughout Brazil. The high production of this species from fish farms has contributed to the occurrence of emerging parasites, which may compromise fish health and productivity. In a batch of 2500 tambaqui fry acquired for experimental farming procedures in Brazil, a mortality rate of 80% was observed, with the fish swimming erratically and gasping for air at the water surface. From among the specimens that were still alive, 60 individuals were selected at random. Organs or fragments of organs containing lesions and/or cysts were examined under an optical microscope to investigate for the presence of parasitic spores. Of the 60 specimens of tambaqui analyzed, 83.3% were found to be infected in different organs, such as the gills, liver, and gallbladder with myxosporidian species belonging to four genera, namely, Myxobolus, Ellipsomyxa, Henneguya and Thelohanellus. The parasite with the greatest prevalence was Myxobolus sp., located in the gills (70%, followed by Henneguya sp. in the gills region (68.3%, Myxobolus sp. in the liver (63.3%, Thelohanellus sp. in the liver (58.3%, and Ellipsomyxa in the gallbladder (50%. This is the first report of parasitic infection caused by the genera Ellipsomyxa and Thelohanellus in C. macropomum. The present study reported the second incidence of the occurrence of the genus Thelohanellus in South America. This study suggested that the mortality among C. macropomum specimens was caused by the outbreak of myxosporidians.

  13. Including spatial data in nutrient balance modelling on dairy farms

    Science.gov (United States)

    van Leeuwen, Maricke; van Middelaar, Corina; Stoof, Cathelijne; Oenema, Jouke; Stoorvogel, Jetse; de Boer, Imke

    2017-04-01

    The Annual Nutrient Cycle Assessment (ANCA) calculates the nitrogen (N) and phosphorus (P) balance at a dairy farm, while taking into account the subsequent nutrient cycles of the herd, manure, soil and crop components. Since January 2016, Dutch dairy farmers are required to use ANCA in order to increase understanding of nutrient flows and to minimize nutrient losses to the environment. A nutrient balance calculates the difference between nutrient inputs and outputs. Nutrients enter the farm via purchased feed, fertilizers, deposition and fixation by legumes (nitrogen), and leave the farm via milk, livestock, manure, and roughages. A positive balance indicates to which extent N and/or P are lost to the environment via gaseous emissions (N), leaching, run-off and accumulation in soil. A negative balance indicates that N and/or P are depleted from soil. ANCA was designed to calculate average nutrient flows on farm level (for the herd, manure, soil and crop components). ANCA was not designed to perform calculations of nutrient flows at the field level, as it uses averaged nutrient inputs and outputs across all fields, and it does not include field specific soil characteristics. Land management decisions, however, such as the level of N and P application, are typically taken at the field level given the specific crop and soil characteristics. Therefore the information that ANCA provides is likely not sufficient to support farmers' decisions on land management to minimize nutrient losses to the environment. This is particularly a problem when land management and soils vary between fields. For an accurate estimate of nutrient flows in a given farming system that can be used to optimize land management, the spatial scale of nutrient inputs and outputs (and thus the effect of land management and soil variation) could be essential. Our aim was to determine the effect of the spatial scale of nutrient inputs and outputs on modelled nutrient flows and nutrient use efficiencies

  14. The fishing industry - toward supply chain modelling

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Nielsen, Jette; Larsen, Erling P.

    Mathematical models for simulating and optimizing supply chain aspects such as distribution planning and optimal use of raw materials are widely used. However, modelling based on a holistic chain view is less studied, and food-related aspects such as quality and shelf life issues enforce additional...... requirements onto the chains. In this paper, we consider the supply chain structure of the Danish fishing industry and illustrate the potential of using mathematical models to identify quality and value-adding activities. This is a first step toward innovative supply chain modelling aimed to identify benefits...... for actors along chains in the fishing industry....

  15. Pesticide pressure and fish farming in barrage pond in Northeastern France. Part II: residues of 13 pesticides in water, sediments, edible fish and their relationships.

    Science.gov (United States)

    Lazartigues, Angélique; Thomas, Marielle; Cren-Olivé, Cécile; Brun-Bellut, Jean; Le Roux, Yves; Banas, Damien; Feidt, Cyril

    2013-01-01

    Residues of pesticides in fish farming productions from barrage ponds are seldom studied in spite of increasing health questionings and environmental concerns. The purpose of this study is to establish the pesticide contamination profiles of sediments and edible fish from five ponds in Northeastern France. Multi-residues method and liquid chromatography-tandem mass spectrometry analysis were used to quantify 13 pesticides (azoxystrobin, carbendazim, clomazone, diflufenican, dimethachlor, fluroxypyr, iprodion, isoproturon, mesosulfuron-methyl, metazachlor, napropamid, quizalofop and thifensulfuron-methyl). Ten sediments and 143 muscles samples were analysed, corresponding to two successive fishing campaigns (first fishing date and second fishing date (P2), about 1 year later) on five sites (noted C-0, C-25, C-45, C-75 and C-85 to express the increasing gradient of crop area). Isoproturon was present in all sediments samples (1.8-56.4 μg/kg dry weight). During P2 period, carbendazim was quantified in the fish of site C-0 (0.09 ± 0.02, 0.2 ± 0.1 and 0.17 ± 0.06 μg/kg wet weight (ww) for roach, carp and perch, respectively). Metazachlor was only quantified in perch of the site C-25 (0.13 ± 0.02 μg/kg ww). Concentrations of isoproturon were similar for the sites C-45 and C-75 with 0.4 ± 0.1 and 0.75 ± 0.06 μg/kg ww for carp and perch, respectively. Contamination of fish reflected generally concentrations in surroundings. Isoproturon was the most concentrated and its main source was water for perch while carp was exposed through both water and sediments, highlighting their life strategies in pond.

  16. Modelling Options for Policy Impact Analysis on African Dairy Farms

    Directory of Open Access Journals (Sweden)

    Oghaiki Asaah NDAMBI

    2008-01-01

    Full Text Available Studies on the priorities for agricultural research in Eastern and CentralAfrica concluded that milk is the most important commodity for research anddevelopment in the region, based on its potential contribution to the agriculturalGDP. It has been presumed that, the right policies, marketing systems and technicalsupport must be sought for dairy development in Africa. In order to determine theright development pattern, appropriate analytical tools must be applied. The TIPICAL(Technology Impact Policy Impact model was used to analyse the impact ofdifferent policies on two typical dairy farming systems in Uganda, which accountfor more than 70% of milk produced in the country. Seven influential policy areaswere also identified: provision of veterinary services, consumption promotion,marketing promotion, input provision, credit access improvement, milk qualityimprovement and genetic improvement. In general, the policy impacts are very littleon farms with local cows but can be magnified up to threefold, if the farms havegraded cows. Policies which improve farmers’ accessibility to markets have thegreatest impacts. The results obtained from this model were compared to thoseusing the EXTRAPOLATE model. This comparison shows that both models couldcomplement each other in analysing policy impacts on African dairy farms.However, differences in results from the models indicate that more focus should bemade on farmers’ willingness to adopt new technology.

  17. Risk Analysis on Transmission of Avian Influenza in Integrated Fish Farming%水产立体养殖模式传播禽流感的风险分析

    Institute of Scientific and Technical Information of China (English)

    李宁求; 付小哲; 赖迎迢; 王亚军; 任燕; 石存斌; 吴淑勤

    2013-01-01

    Integrated fish farming is an important kind of aquaculture system and has long history in China.It was once as typical model of intelligent use of matter and energy to extend other countries.However,there are some worries about transmitting zoonosis in some outdated integrated fish farming.This may cause potential public health threat,especially integrated fish farming was suspected of transmission of avian influenza.Therefore,this paper reviewed the speculation of transmission avian influenza by aquaculture,and illustrated types and current sta-tus of integrated fish farming.Risk analysis was conducted about transmission of avian influenza in integrated fish farming,and some suggestions were made.%立体养殖模式是水产养殖的重要类型,在我国具有悠久的历史,曾被联合国粮农组织作为合理利用物质能量典型在全球进行推广。但现存落后的立体养殖模式存在传播人兽共患病的隐忧,对公共卫生造成威胁,特别是禽流感传播被疑与水产立体养殖模式有关。因此,论文对水产养殖可能传播禽流感的推测进行了总结,概述我国水产立体养殖模式类型与现状,并对其传播禽流感的风险进行了分析,提出了相关建议。

  18. A SIMULATION OF CONTRACT FARMING USING AGENT BASED MODELING

    Directory of Open Access Journals (Sweden)

    Yuanita Handayati

    2016-12-01

    Full Text Available This study aims to simulate the effects of contract farming and farmer commitment to contract farming on supply chain performance by using agent based modeling as a methodology. Supply chain performance is represented by profits and service levels. The simulation results indicate that farmers should pay attention to customer requirements and plan their agricultural activities in order to fulfill these requirements. Contract farming helps farmers deal with demand and price uncertainties. We also find that farmer commitment is crucial to fulfilling contract requirements. This study contributes to this field from a conceptual as well as a practical point of view. From the conceptual point of view, our simulation results show that different levels of farmer commitment have an impact on farmer performance when implementing contract farming. From a practical point of view, the uncertainty faced by farmers and the market can be managed by implementing cultivation and harvesting scheduling, information sharing, and collective learning as ways of committing to contract farming.

  19. Wind Farm parametrization in the mesoscale model WRF

    DEFF Research Database (Denmark)

    Volker, Patrick; Badger, Jake; Hahmann, Andrea N.

    2012-01-01

    The project’s objective is to investigate and develop methods for prediction of mesoscale climate, wake effects and atmospheric feedbacks, for scenarios where large portions of the sea are covered with wind farms. The atmospheric flow is simulated with the WRF mesoscale model, since it has signif...

  20. Molecular epidemiology of viral haemorrhagic septicaemia virus (VHSV) in British Columbia, Canada, reveals transmission from wild to farmed fish.

    Science.gov (United States)

    Garver, Kyle A; Traxler, Garth S; Hawley, Laura M; Richard, Jon; Ross, Jay P; Lovy, Jan

    2013-05-27

    Viral haemorrhagic septicaemia virus (VHSV) is a fish pathogen found throughout the Northern Hemisphere and is capable of infecting and causing mortality in numerous marine and freshwater hosts. In the coastal waters of British Columbia, Canada, the virus has been detected for 20 yr with many occurrences of mass mortalities among populations of Pacific herring Clupea pallasii (Valenciennes) and sardine Sardinops sagax as well as detections among cultured Atlantic Salmo salar and Chinook Oncorhynchus tshawytscha salmon. We compared nucleotide sequence of the full glycoprotein (G) gene coding region (1524 nt) of 63 VHSV isolates sampled during its recorded presence from 1993 to 2011 from 6 species and a total of 29 sites. Phylogenetic analysis showed that all isolates fell into sub-lineage IVa within the major VHSV genetic group IV. Of the 63 virus isolates, there were 42 unique sequences, each of which was ephemeral, being repeatedly detected at most only 1 yr after its initial detection. Multiple sequence types were revealed during single viral outbreak events, and genetic heterogeneity was observed within isolates from individual fish. Moreover, phylogenetic analysis revealed a close genetic linkage between VHSV isolates obtained from pelagic finfish species and farmed salmonids, providing evidence for virus transmission from wild to farmed fish.

  1. Monitoring- and Evaluation Program Near Shore Wind farm (MEP-NSW): Fish community

    NARCIS (Netherlands)

    Hal, van R.; Couperus, A.S.; Fassler, S.M.M.; Gastauer, S.; Griffioen, B.; Hintzen, N.T.; Teal, L.R.; Keeken, van O.A.; Winter, H.V.

    2012-01-01

    In 2006, the first Dutch offshore wind farm was built 10-18 km from the shore of Egmond aan Zee by a joint venture of Nuon and Shell Windenergy. A Monitoring and Evaluation Program accompanied the plans for the construction and exploitation of this farm. The program contained plans for the monitorin

  2. Multicriteria GIS modeling of wind and solar farms in Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Jason R. [Metropolitan State College of Denver, Department of Earth and Atmospheric Sciences, CB 22 P.O. Box 173362-22, Denver, CO 80217-3362 (United States)

    2010-10-15

    The majority of electricity and heat in Colorado comes from coal and natural gas; however, renewable energy sources will play an integral role in the state's energy future. Colorado is the 11th windiest state and has more than 250 sunny days per year. The objectives of this research are to: 1) determine which landcover classes are affiliated with high wind and solar potential; and 2) identify areas that are suitable for wind and solar farms using multicriteria GIS modelling techniques. Renewable potential (NREL wind speed measurements at 50 m above the ground and NREL annual insolation data), landcover, population density, federal lands, and distance to roads, transmission lines, and cities were reclassified according to their suitability. Each was assigned weights based on their relative importance to one another. Superb wind classes are located in high alpine areas. Unfortunately, these areas are not suitable for large-scale wind farm development due to their inaccessibility and location within a sensitive ecosystem. Federal lands have low wind potential. According to the GIS model, ideal areas for wind farm development are located in northeastern Colorado. About 41 850 km{sup 2} of the state has model scores that are in the 90-100% range. Although annual solar radiation varies slightly, inter-mountain areas receive the most insolation. As far as federal lands, Indian reservations have the greatest solar input. The GIS model indicates that ideal areas for solar development are located in northwestern Colorado and east of Denver. Only 191 km{sup 2} of the state had model scores that were in the 90-100% range. These results suggest that the variables used in this analysis have more of an effect at eliminating non-suitable areas for large-scale solar farms; a greater area exists for suitable wind farms. However, given the statewide high insolation values with minimal variance, solar projects may be better suited for small-scale residential or commercial

  3. Zebra fish: an uncharted behavior genetic model.

    Science.gov (United States)

    Gerlai, Robert

    2003-09-01

    The zebra fish has been a preferred subject of genetic analysis. It produces a large number of offspring that can be kept in small aquaria, it can be easily mutagenized using chemical mutagens (e.g., ethyl nitrosourea [ENU]), and high-resolution genetic maps exist that aid identification of novel genes. Libraries containing large numbers of mutant fish have been generated, and the genetic mechanisms of the development of zebra fish, whose embryo is transparent, have been extensively studied. Given the extensive homology of its genome with that of other vertebrate species including our own and given the available genetic tools, zebra fish has become a popular model organism. Despite this popularity, however, surprisingly little is known about its behavior. It is argued that behavioral analysis is a powerful tool with which the function of the brain may be studied, and the zebra fish will represent an excellent subject of such analysis. The present paper is a proof of concept study that uses pharmacological manipulation (exposure to alcohol) to show that the zebra fish is amenable to the behavioral genetic analysis of aggression and thus may allow us to reveal molecular mechanisms of this behavioral phenomenon relevant to vertebrates.

  4. First testing of an AUV mission planning and guidance system for water quality monitoring and fish behavior observation in net cage fish farming

    Directory of Open Access Journals (Sweden)

    D. Karimanzira

    2014-12-01

    Full Text Available Recently, underwater vehicles have become low cost, reliable and affordable platforms for performing various underwater tasks. While many aquaculture systems are closed with no harmful output, open net cage fish farms and land-based fish farms can discharge significant amounts of wastewater containing nutrients, chemicals, and pharmaceuticals that impact on the surrounding environment. Although aquaculture development has often occurred outside a regulatory framework, government oversight is increasingly common at both the seafood quality control level, and at baseline initiatives addressing the basic problem of pollution generated by culture operations, e.g. the European marine and maritime directives. This requires regular, sustainable and cost-effective monitoring of the water quality. Such monitoring needs devices to detect the water quality in a large sea area at different depths in real time. This paper presents a concept for a guidance system for a carrier (an autonomous underwater vehicle of such devices for the automated detection and analysis of water quality parameters.

  5. Perfluorinated compounds in fish and carryover from fishfeed to farmed rainbow trout

    DEFF Research Database (Denmark)

    Granby, Kit; Larsen, Bodil Katrine; Cederberg, Tommy Licht

    Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) bioaccumulate in humans and the half-life is around 4-6 years. As fish for many people is the largest source of PFOS exposure, the occurrence and the exposure of PFOS from fish was estimated. Today a significant proportion of the fish...... in an accumulation period of 12 weeks following an 8 weeks elimination period where unspiked feed were used. The feeding trials were carried out in tanks and the experiment included a control study of fish which were exposed only to unspiked feed. All feeding trials were conducted in duplicates. Fish were sampled 5...

  6. PORFLOW Modeling Supporting The H-Tank Farm Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, J. M.; Flach, G. P.; Westbrook, M. L.

    2012-08-31

    Numerical simulations of groundwater flow and contaminant transport in the vadose and saturated zones have been conducted using the PORFLOW code in support of an overall Performance Assessment (PA) of the H-Tank Farm. This report provides technical detail on selected aspects of PORFLOW model development and describes the structure of the associated electronic files. The PORFLOW models for the H-Tank Farm PA, Rev. 1 were updated with grout, solubility, and inventory changes. The aquifer model was refined. In addition, a set of flow sensitivity runs were performed to allow flow to be varied in the related probabilistic GoldSim models. The final PORFLOW concentration values are used as input into a GoldSim dose calculator.

  7. The fouling of fish farm cage nets as bioindicator of aquaculture pollution in the Adriatic Sea (Croatia).

    Science.gov (United States)

    Sliskovic, Merica; Jelic-Mrcelic, Gorana; Antolic, Boris; Anicic, Ivica

    2011-02-01

    A fouling assemblage (including density, species richness and diversity, and biomass) growing on netting of fish farm cages was investigated in Stracinska Bay--Location 1 and Peles Bay--Location 2 (Croatia) in order to test the efficiency of fouling as a bioindicator of organic pollution. A total number of 40 algal taxa in Location 1 and total number of 22 algal taxa in Location 2 were identified, with a dominance of opportunistic species (ESG II). We found domination of algal species over animal species and absolute dominance of Rhodophyta which are typical fouler in the Adriatic Sea. Low diversity and species richness with increase in value of the R/P index (occasionally higher than 6) were recorded in Location 2, indicating a certain impact of nutrient enrichment from fish culture facilities on a fouling community structure.

  8. CONDITIONS OF FISH FARMING IN NATURA 2000 AREAS, BASED ON THE EXAMPLE OF THE CATCHMENT OF BARYCZ

    Directory of Open Access Journals (Sweden)

    Katarzyna Tokarczyk-Dorociak

    2016-07-01

    Full Text Available One of the factors that contributed to the construction of approx.77 km2 offish ponds in the catchment of Barycz starting from the 13th century, which in turn transformed the woods into a mosaic of waters, forests and arable land, were the advantageous physiographic conditions. Fish farming operations conducted in this area led to the creation of a cultural landscape characterised by unique natural values, similar to the natural landscape.Approx.240 species of birds are observed here, of which 170 are nesting species. Due to its natural values, this area has been subject to natural reserve protection as part of the Landscape Park "Dolina Baryczy" (the Barycz Valley. It was entered in the "Living Lakes" list and it is protected under the Ramsar Convention as well as under the European nature protection network Natura 2000.The established forms of nature protection mean the introduction of a certain binding regime, pursuant to which the economic activity conducted in protected areas must take into account the prohibitions and orders introduced by documents that establish the said forms of protection. Additionally, there is a legal requirement to create a protection plan or conservation plan that constitutes a basis for the realisation of conservation-related objectives. A commercial company Stawy Milickie S.A. (public limited company operates in the area of this largest fish pond complex in Poland. The scope of its operations includes more than just the breeding and sale of freshwater fish (6500 ha of ponds but also environmental protection, environmental education and the development of tourism as well as stimulating the development and professional activation of local communities basing on the natural resources that exist in the catchment of Barycz. This study presents the conditions related to fish farming operations conducted in this area. Conducting an extensive management (i.e. often uneconomical from the economic point of view is a

  9. It is the economy, stupid! Projecting the fate of fish populations using ecological-economic modeling.

    Science.gov (United States)

    Quaas, Martin F; Reusch, Thorsten B H; Schmidt, Jörn O; Tahvonen, Olli; Voss, Rudi

    2016-01-01

    Four marine fish species are among the most important on the world market: cod, salmon, tuna, and sea bass. While the supply of North American and European markets for two of these species - Atlantic salmon and European sea bass - mainly comes from fish farming, Atlantic cod and tunas are mainly caught from wild stocks. We address the question what will be the status of these wild stocks in the midterm future, in the year 2048, to be specific. Whereas the effects of climate change and ecological driving forces on fish stocks have already gained much attention, our prime interest is in studying the effects of changing economic drivers, as well as the impact of variable management effectiveness. Using a process-based ecological-economic multispecies optimization model, we assess the future stock status under different scenarios of change. We simulate (i) technological progress in fishing, (ii) increasing demand for fish, and (iii) increasing supply of farmed fish, as well as the interplay of these driving forces under different scenarios of (limited) fishery management effectiveness. We find that economic change has a substantial effect on fish populations. Increasing aquaculture production can dampen the fishing pressure on wild stocks, but this effect is likely to be overwhelmed by increasing demand and technological progress, both increasing fishing pressure. The only solution to avoid collapse of the majority of stocks is institutional change to improve management effectiveness significantly above the current state. We conclude that full recognition of economic drivers of change will be needed to successfully develop an integrated ecosystem management and to sustain the wild fish stocks until 2048 and beyond. © 2015 John Wiley & Sons Ltd.

  10. Integrated watershed- and farm-scale modeling framework for targeting critical source areas while maintaining farm economic viability.

    Science.gov (United States)

    Ghebremichael, Lula T; Veith, Tamie L; Hamlett, James M

    2013-01-15

    Quantitative risk assessments of pollution and data related to the effectiveness of mitigating best management practices (BMPs) are important aspects of nonpoint source pollution control efforts, particularly those driven by specific water quality objectives and by measurable improvement goals, such as the total maximum daily load (TMDL) requirements. Targeting critical source areas (CSAs) that generate disproportionately high pollutant loads within a watershed is a crucial step in successfully controlling nonpoint source pollution. The importance of watershed simulation models in assisting with the quantitative assessments of CSAs of pollution (relative to their magnitudes and extents) and of the effectiveness of associated BMPs has been well recognized. However, due to the distinct disconnect between the hydrological scale in which these models conduct their evaluation and the farm scale at which feasible BMPs are actually selected and implemented, and due to the difficulty and uncertainty involved in transferring watershed model data to farm fields, there are limited practical applications of these tools in the current nonpoint source pollution control efforts by conservation specialists for delineating CSAs and planning targeting measures. There are also limited approaches developed that can assess impacts of CSA-targeted BMPs on farm productivity and profitability together with the assessment of water quality improvements expected from applying these measures. This study developed a modeling framework that integrates farm economics and environmental aspects (such as identification and mitigation of CSAs) through joint use of watershed- and farm-scale models in a closed feedback loop. The integration of models in a closed feedback loop provides a way for environmental changes to be evaluated with regard to the impact on the practical aspects of farm management and economics, adjusted or reformulated as necessary, and revaluated with respect to effectiveness of

  11. A Predictive Model for Wind Farms Using Dynamic Mode Decomposition

    Science.gov (United States)

    Thomas, Vaughan; Meneveau, Charles; Gayme, Dennice

    2016-11-01

    In this work we extend traditional dynamic mode decomposition (DMD) to develop a linear predictive model for the time evolution of the velocity field for a multiple-turbine wind farm. Traditional DMD identifies a set of DMD modes which can be used to produce a linear system that approximates the dynamics of the original system. Typically, these DMD modes consist of those that both grow and decay, but in order to develop a predictive model we need a system that evolves along a manifold that neither grows nor decays. Here we modify the DMD calculation to build such a model. We then apply this method to three dimensional large eddy simulations (LES) of a multi-turbine wind farm. Our predictive wind farm model is initialized with a small time series of data independent of the original data used to create the system. When initialized in this manner our DMD based model can reproduce the subsequent time evolution of the velocity field over ten inter-turbine convective timescales with a gradual falloff in performance. This work is supported by the National Science Foundation (Grants ECCS-1230788 and OISE-1243482, the WINDINSPIRE project).

  12. Modelling Waste Output from Trout Farms

    DEFF Research Database (Denmark)

    Frier, J. O.; From, J.; Larsen, Torben

    1995-01-01

    The aim of waste modelling in aquaculture is to provide tools for simulating input, transformation, output and subsidiary degradation in recipients of organic compounds, nitrogen, and phosphorus. The direct purpose of this modelling is to make it possible for caretakers and water authorities...... to calculate waste discharge from existing and planned aquaculture activities. A special purpose is simulating outcome of waste water treatment and altered feeding programmes. Different submodels must be applied for P, N, and organics, as well as for the different phases of food and waste treatment. Altogether...

  13. Modeling Fish Growth in Low Dissolved Oxygen

    Science.gov (United States)

    Neilan, Rachael Miller

    2013-01-01

    This article describes a computational project designed for undergraduate students as an introduction to mathematical modeling. Students use an ordinary differential equation to describe fish weight and assume the instantaneous growth rate depends on the concentration of dissolved oxygen. Published laboratory experiments suggest that continuous…

  14. Temporal and spatial dynamics of phytoplankton near farm fish in eutrophic reservoir in Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Ariadne do Nascimento Moura

    2012-06-01

    Full Text Available Spatial and temporal variations in phytoplankton communities in continental waters have received attention from limnologists, since they are differently influenced by many physico-chemical and biological factors. This study was undertaken with the aim to identify the environmental variables that influence the temporal and spatial dynamics of the phytoplankton near a fish farm in the Jucazinho reservoir, in a semi-arid region of Northeastern Brazil. Samples were taken from three sampling sites, at two depths during the rainy (Aug 2008, Feb and Mar 2009 and dry (Oct, Nov and Dec 2008 seasons. Phytoplankton was identified, density determined, and biomass values obtained. Concomitantly, abiotic analyses were performed for the characterization of the system. The reservoir was homogeneous with regard to the spatial-temporal variation in hydrological variables: water well oxygenated at the surface and anoxic at the bottom; pH ranging from neutral to alkaline; temperatures always above 25ºC; high turbidity; and high electrical conductivity at all sampling sites and both depths. For both seasons, there was limited nitrogen and high concentrations of phosphorus. Cyanophyta species were predominant, generally representing 80% of the phytoplankton biomass throughout practically the entire study, at all sampling sites and both depths. Co-dominance of cyanobacteria belonging to H1, MP, S1 and Sn associations was recorded in most of the months studied, except August 2008, when there was a substitution of the S1 association (Planktothrix agardhii by the P association (Aulacoseira granulata. Water temperature, precipitation and pH were the parameters with the greatest influence over the temporal variation in phytoplankton, whereas the vertical distribution of the phytoplankton biomass was directly related to the availability of light in the wáter column. There were no spatial or temporal differences in water quality, likely due to the fact that the sampling

  15. PRODUCTION AND BIOACTIVITY POTENTIAL OF THREE RECOMBINANT GROWTH HORMONES OF FARMED FISH

    Directory of Open Access Journals (Sweden)

    Alimuddin Alimuddin

    2010-06-01

    Full Text Available This study was aimed to produce recombinant growth hormone (rGH from giant grouper (Epinephelus lanceolatus, giant gouramy (Osphronemus gouramy and common carp (Cyprinus carpio and compare their bioactivity potential by means of inducing the growth hormone of juvenile Nile tilapia (Oreochromis niloticus as the model. DNA fragment encoding mature GH protein of giant grouper (El-mGH, giant gouramy (Og-mGH and common carp (Cc-mGH was amplified by PCR method. The purified PCR products were ligated to pCold-1 to generate pCold/El-mGH, pCold/OgmGH, and pCold/Cc-mGH protein expression vector, respectively. Each of the expression vectors was transformed into the Escherichia coli BL21. E. coli BL21 was cultured using 2xYT medium and protein production was induced by cold shock at 15±1oC for overnight. The inclusion bodies of E. coli transformants containing protein expression vector were isolated by sonication method, and rGH production was analyzed by SDS-PAGE. Juvenile of Nile tilapia of average body weight of 12.41±3.28 g was intramuscularly injected once a week for 4 weeks with 1 μg inclusion body containing rGH per gram fish body weight. The result showed that rGH in molecular weight of about 25 kDa was obtained. Fish injected with rGH of El-mGH, Cc-mGH and Og-mGH grew 20.94%, 18.09%, and 16.99% faster, respectively, compared with the control. This result indicated that the three rGH produced in E. coli possessed biological activity when tested on Nile tilapia and further research is needed to find its effect on the growth of other aquaculture fish species.

  16. Precaution or Integrated Responsibility Approach to Nanovaccines in Fish Farming? A Critical Appraisal of the UNESCO Precautionary Principle.

    Science.gov (United States)

    Myhr, Anne Ingeborg; Myskja, Bjørn K

    2011-04-01

    Nanoparticles have multifaceted advantages in drug administration as vaccine delivery and hence hold promises for improving protection of farmed fish against diseases caused by pathogens. However, there are concerns that the benefits associated with distribution of nanoparticles may also be accompanied with risks to the environment and health. The complexity of the natural and social systems involved implies that the information acquired in quantified risk assessments may be inadequate for evidence-based decisions. One controversial strategy for dealing with this kind of uncertainty is the precautionary principle. A few years ago, an UNESCO expert group suggested a new approach for implementation of the principle. Here we compare the UNESCO principle with earlier versions and explore the advantages and disadvantages by employing the UNESCO version to the use of PLGA nanoparticles for delivery of vaccines in aquaculture. Finally, we discuss whether a combined scientific and ethical analysis that involves the concept of responsibility will enable approaches that can provide a supplement to the precautionary principle as basis for decision-making in areas of scientific uncertainty, such as the application of nanoparticles in the vaccination of farmed fish.

  17. Stochastic modeling and performance monitoring of wind farm power production

    CERN Document Server

    Milan, Patrick; Peinke, Joachim

    2015-01-01

    We present a new stochastic approach to describe and remodel the conversion process of a wind farm at a sampling frequency of 1Hz. When conditioning on various wind direction sectors, the dynamics of the conversion process appear as a fluctuating trajectory around an average IEC-like power curve, see section II. Our approach is to consider the wind farm as a dynamical system that can be described as a stochastic drift/diffusion model, where a drift coefficient describes the attraction towards the power curve and a diffusion coefficient quantifies additional turbulent fluctuations. These stochastic coefficients are inserted into a Langevin equation that, once properly adapted to our particular system, models a synthetic signal of power output for any given wind speed/direction signals, see section III. When combined with a pre-model for turbulent wind fluctuations, the stochastic approach models the power output of the wind farm at a sampling frequency of 1Hz using only ten-minute average values of wind speed ...

  18. Sustainable Organic Farming For Environmental Health A Social Development Model

    Directory of Open Access Journals (Sweden)

    Ijun Rijwan Susanto

    2015-05-01

    Full Text Available ABSTRACT In this study the researcher attempted 1 to understand the basic features of organic farming in The Paguyuban Pasundans Cianjur 2 to describe and understand how the stakeholders were are able to internalize the challenges of organic farming on their lived experiences in the community 3 to describe and understand how the stakeholders were are able to internalize and applied the values of benefits of organic farming in support of environmental health on their lived experiences in the community 4 The purpose was to describe and understand how the stakeholders who are able to articulate their ideas regarding the model of sustainable organic farming 5 The Policy Recommendation for Organic Farming. The researcher employed triangulation thorough finding that provides breadth and depth to an investigation offering researchers a more accurate picture of the phenomenon. In the implementation of triangulation researchers conducted several interviews to get saturation. After completion of the interview results are written compiled and shown to the participants to check every statement by every participant. In addition researchers also checked the relevant documents and direct observation in the field The participants of this study were the stakeholders namely 1 The leader of Paguyuban Pasundans Organic Farmer Cianjur PPOFC 2 Members of Paguyuban Pasundans Organic FarmersCianjur 3 Leader of NGO 4 Government officials of agriculture 5 Business of organic food 6 and Consumer of organic food. Generally the findings of the study revealed the following 1 PPOFC began to see the reality as the impact of modern agriculture showed in fertility problems due to contaminated soil by residues of agricultural chemicals such as chemical fertilizers and chemical pesticides. So he wants to restore the soil fertility through environmentally friendly of farming practices 2 the challenges of organic farming on their lived experiences in the community farmers did not

  19. Wind farm production prediction - The Zephyr model

    Energy Technology Data Exchange (ETDEWEB)

    Landberg, L. [Risoe National Lab., Wind Energy Dept., Roskilde (Denmark); Giebel, G. [Risoe National Lab., Wind Energy Dept., Roskilde (Denmark); Madsen, H. [IMM (DTU), Kgs. Lyngby (Denmark); Nielsen, T.S. [IMM (DTU), Kgs. Lyngby (Denmark); Joergensen, J.U. [Danish Meteorologisk Inst., Copenhagen (Denmark); Lauersen, L. [Danish Meteorologisk Inst., Copenhagen (Denmark); Toefting, J. [Elsam, Fredericia (DK); Christensen, H.S. [Eltra, Fredericia (Denmark); Bjerge, C. [SEAS, Haslev (Denmark)

    2002-06-01

    This report describes a project - funded by the Danish Ministry of Energy and the Environment - which developed a next generation prediction system called Zephyr. The Zephyr system is a merging between two state-of-the-art prediction systems: Prediktor of Risoe National Laboratory and WPPT of IMM at the Danish Technical University. The numerical weather predictions were generated by DMI's HIRLAM model. Due to technical difficulties programming the system, only the computational core and a very simple version of the originally very complex system were developed. The project partners were: Risoe, DMU, DMI, Elsam, Eltra, Elkraft System, SEAS and E2. (au)

  20. Copper in the sediment and sea surface microlayer near a fallowed, open-net fish farm.

    Science.gov (United States)

    Loucks, Ronald H; Smith, Ruth E; Fisher, Clyde V; Fisher, E Brian

    2012-09-01

    Sediment and sea surface microlayer samples near an open-net salmon farm in Nova Scotia, were analysed for copper. Copper is a constituent of the feed and is an active ingredient of anti-foulants. The salmon farm was placed in fallow after 15 years of production. Sampling was pursued over 27 months. Elevated copper concentrations in the sediments indicated the farm site as a source. Bubble flotation due to gas-emitting sediments from eutrophication is a likely process for accumulating copper in the sea surface microlayer at enriched concentrations. Elevated and enriched concentrations in the sea surface microlayer over distance from the farm site led, as a result of wind-drift, to an enlarged farm footprint. The levels of copper in both sediments and sea surface microlayer exceeded guidelines for protection of marine life. Over the 27 months period, copper levels persisted in the sediments and decreased gradually in the sea surface microlayer. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Effects of exotic fish farms on bird communities in lake and marine ecosystems

    Science.gov (United States)

    Jiménez, Jaime E.; Arriagada, Aldo M.; Fontúrbel, Francisco E.; Camus, Patricio A.; Ávila-Thieme, M. Isidora

    2013-08-01

    Salmon farming is a widespread activity around the world, also known to promote diverse environmental effects on aquatic ecosystems. However, information regarding the impact of salmon farming on bird assemblages is notably scarce. We hypothesize that salmon farming, by providing food subsidies and physical structures to birds, will change their local community structure. To test this hypothesis, we conducted a seasonal monitoring of bird richness, abundance, and composition at paired salmon pen and control plots in two marine and two lake sites in southern Chile, from fall 2002 to summer 2004. Overall, salmon farming had no significant effects on species richness, but bird abundance was significantly and noticeably higher in salmon pens than in controls. Such aggregation was mainly accounted for by the trophic guilds of omnivores, diving piscivores, carrion eaters, and perching piscivores, but not by invertebrate feeders, herbivores, and surface feeders. Species composition was also significantly and persistently different between salmon pens and controls within each lake or marine locality. The patterns described above remained consistent across environment types and seasons indicating that salmon farming is changing the community structure of birds in both lake and marine habitats by promoting functional and aggregation responses, particularly by favoring species with broader niches. Such local patterns may thus anticipate potential threats from the ongoing expansion of the salmon industry to neighboring areas in Chile, resulting in regional changes of bird communities, toward a less diverse one and dominated by opportunistic, common, and generalist species such as gulls, vultures, and cormorants.

  2. The fish industry - toward supply chain modelling

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Nielsen, Jette; Larsen, Erling

    2010-01-01

    Mathematical models for simulating and optimizing aspects of supply chains such as distribution, planning, and optimal handling of raw materials are widely used. However, modeling based on a holistic chain view including several or all supply chain agents is less studied, and food-related aspects...... such as quality and shelf-life issues enforce additional requirements onto the chains. In this article, we consider the supply chain structure of the fish industry. We discuss and illustrate the potential of using mathematical models to identify quality and value-adding activities. The article provides a first...... step toward innovative supply chain modeling aimed to identify benefits for all agents along chains in the fish industry....

  3. The Sustainability of Aquaculture as a Farm Enterprise: Impacts and Consequences of Fish Culture in Rwanda.

    Science.gov (United States)

    Molnar, Joseph J.; And Others

    Rwanda, a small country in Africa, has experienced declines in per capita food production. Fish culture is one part of a many-stranded effort to increase food production and food security by intensifying the use of land resources to produce a much-needed protein crop. Beginning in 1983, the Rwanda National Fish Culture Project has assisted farmers…

  4. Stewardship and risk: An empirically grounded theory of organic fish farming in Scotland

    NARCIS (Netherlands)

    G. Georgakopoulos; P. Ciancanelli; A. Coulson; P.E. Kaldis

    2008-01-01

    It has long been assumed ownership gives farmers incentives to act as stewards of the land. On this basis, quasi-property rights are granted to fish farmers to encourage them to manage risks to the aquatic environment. This paper offers an empirically grounded theorisation of fish farmers’ perspecti

  5. Modelling impacts of offshore wind farms on trophic web: the Courseulles-sur-Mer case study

    Science.gov (United States)

    Raoux, Aurore; Pezy, Jean-Philippe; Dauvin, Jean-Claude; Tecchio, samuele; Degraer, Steven; Wilhelmsson, Dan; Niquil, Nathalie

    2016-04-01

    The French government is planning the construction of three offshore wind farms in Normandy. These offshore wind farms will integrate into an ecosystem already subject to a growing number of anthropogenic disturbances such as transportation, fishing, sediment deposit, and sediment extraction. The possible effects of this cumulative stressors on ecosystem functioning are still unknown, but they could impact their resilience, making them susceptible to changes from one stable state to another. Understanding the behaviour of these marine coastal complex systems is essential in order to anticipate potential state changes, and to implement conservation actions in a sustainable manner. Currently, there are no global and integrated studies on the effects of construction and exploitation of offshore wind farms. Moreover, approaches are generally focused on the conservation of some species or groups of species. Here, we develop a holistic and integrated view of ecosystem impacts through the use of trophic webs modelling tools. Trophic models describe the interaction between biological compartments at different trophic levels and are based on the quantification of flow of energy and matter in ecosystems. They allow the application of numerical methods for the characterization of emergent properties of the ecosystem, also called Ecological Network Analysis (ENA). These indices have been proposed as ecosystem health indicators as they have been demonstrated to be sensitive to different impacts on marine ecosystems. We present here in detail the strategy for analysing the potential environmental impacts of the construction of the Courseulles-sur-Mer offshore wind farm (Bay of Seine) such as the reef effect through the use of the Ecopath with Ecosim software. Similar Ecopath simulations will be made in the future on the Le Tréport offshore wind farm site. Results will contribute to a better knowledge of the impacts of the offshore wind farms on ecosystems. They also allow to

  6. Presence of lactobacilli in the intestinal content of freshwater fish from a river and from a farm with a recirculation system.

    Science.gov (United States)

    Bucio, Adolfo; Hartemink, Ralf; Schrama, Johan W; Verreth, Johan; Rombouts, Frans M

    2006-08-01

    Lactobacilli are Gram-positive and catalase negative rods commonly found in lactic acid fermented foods and in the gastrointestinal tract of mammals and birds. Few studies have described lactobacilli in freshwater fish. We analysed the presence of lactobacilli in the intestines of young and adult freshwater fish inhabiting a river environment and from fish reared in an aquaculture unit with a water recirculation system. Various species of lactobacilli were present in relatively high number in the intestines of edible fresh water fish from the river, especially in the warm season but in low numbers in the cold season. Lactobacilli were scarcely found in the intestines of edible farmed fish reared in a recirculation system in warm water. Lactobacilli are reported for the first time from the intestines of wild European eel, perch, rudd, ruffe, bleak, silver bream, chub, somnul and farmed African catfish. The two first fishes, and the last one are highly valuable species for fisheries and aquaculture. Additionally, improved methods for storage and bacteriological analysis of fish intestinal content are described. The natural presence of lactic acid bacteria in fish may be of great interest in producing fermented fish products worldwide.

  7. Whole-farm models to quantify greenhouse gas emissions and their potential use for linking climate change mitigation and adaptation in temperate grassland ruminant-based farming systems

    DEFF Research Database (Denmark)

    del Prado, A; Crosson, P; Olesen, Jørgen E;

    2013-01-01

    The farm level is the most appropriate scale for evaluating options for mitigating greenhouse gas (GHG) emissions, because the farm represents the unit at which management decisions in livestock production are made. To date, a number of whole farm modelling approaches have been developed to quant......The farm level is the most appropriate scale for evaluating options for mitigating greenhouse gas (GHG) emissions, because the farm represents the unit at which management decisions in livestock production are made. To date, a number of whole farm modelling approaches have been developed...

  8. Effect of EDTA enriched diets on farmed fish allergenicity; a proteomics approach

    OpenAIRE

    Raposo, Cláudia Sofia Ferreira

    2016-01-01

    Dissertação de mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016 A continuously increase of the world’s population has been registered over the last decades, along with an augment of fish consumption worldwide. Fish is one of the most common elicitors of food-allergies. The panallergen in fish, β-parvalbumin (β-PV), is responsible for the initiation of immunoglobulin-E (IgE)-mediated allergic reactions. PV is a calcium-binding mus...

  9. Coupled wake boundary layer model of wind-farms

    CERN Document Server

    Stevens, Richard J A M; Meneveau, Charles

    2014-01-01

    We present and test a coupled wake boundary layer (CWBL) model that describes the distribution of the power output in a wind-farm. The model couples the traditional, industry-standard wake expansion/superposition approach with a top-down model for the overall wind-farm boundary layer structure. The wake expansion/superposition model captures the effect of turbine positioning, while the top-down portion adds the interaction between the wind-turbine wakes and the atmospheric boundary layer. Each portion of the model requires specification of a parameter that is not known a-priori. For the wake model the wake expansion coefficient is required, while the top-down model requires an effective span-wise turbine spacing within which the model's momentum balance is relevant. The wake expansion coefficient is obtained by matching the predicted mean velocity at the turbine from both approaches, while the effective span-wise turbine spacing depends on turbine positioning and thus can be determined from the wake expansion...

  10. Mesoscale to microscale wind farm flow modeling and evaluation

    DEFF Research Database (Denmark)

    Sanz Rodrigo, Javier; Chávez Arroyo, Roberto Aurelio; Moriarty, Patrick

    2017-01-01

    of meteorological and wind engineering flow models and the definition of a formal model evaluation methodology, is a strong area of research for the next generation of wind conditions assessment and wind farm and wind turbine design tools. Some fundamental challenges are identified in order to guide future research...... design tools and meteorological models. The challenge is how to build the bridge between atmospheric and wind engineering model communities and how to establish a comprehensive evaluation process that identifies relevant physical phenomena for wind energy applications with modeling and experimental...... requirements. A framework for model verification, validation, and uncertainty quantification is established to guide this process by a systematic evaluation of the modeling system at increasing levels of complexity. In terms of atmospheric physics, 'building the bridge' means developing models for the so...

  11. Synthetic Musk fragrances in Trout from Danish fish farms and human milk

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Cederberg, Tommy Licht; Pedersen, K. H.

    2005-01-01

    /HRMS in Danish farmed trout and human milk from primiparous mothers are reported. The polycyclic musk, HHCB, dominated the synthetic musk compounds found in trout samples from 1999 with a median concentration of 5.0 mu g/kg fresh weight (n.d.-52.6 mu g/kg fresh weight) and in trout samples collected in 2003...

  12. Evaluation of Integrated Horticulture-Cum- Fish Farming in Malwa Region of Madhya Pradesh, India

    Directory of Open Access Journals (Sweden)

    Laxmi

    2015-08-01

    Full Text Available In India, the farming community accounts for 80% under marginal and small farmer’s category1. Farmers under these categories are economically poor working in diverse, risk prone environments and with hardly sufficient to sustain their family. The declining trend in land holding per capita poses a serious challenge to the sustainability and profitability of farming. Considering the efficacy of this viable production system, the study was conducted in purposively selected ponds of farmers which had available space of the pond bundh used for production of horticulture produce. The trial was conducted minimum 06 replications were taken under farm field condition. Vegetable growing in the trellis and dykes is an additional component which helps in maximizing profit from unit area. The data were collected from each treatment for consecutively 03 years to judge the economic profitability and sustainability of the practice. It was observed that better production and sustainable economic return can be achieved through integrated production technology or with dyke vegetable cultivation in pond based integrated farming practices.

  13. Fish Farm Inspections and Sampling Procedures: The Mediterranean Point of View

    DEFF Research Database (Denmark)

    Vendramin, Niccolò

    2012-01-01

    by peculiar health/disease management issues. First of all there are to be considered the hatcheries, this kind of farm are caracterised by having an extremely high level of technology and control of the water that; in these system biosecurity measures are generally high and the water quality parameters...

  14. Mathematical model of the Savannah River Site waste tank farm

    Energy Technology Data Exchange (ETDEWEB)

    Smith, F.G. III.

    1991-07-15

    A mathematical model has been developed to simulate operation of the waste tank farm and the associated evaporator systems at the Savannah River Site. The model solves material balance equations to predict the volumes of liquid waste, salt, and sludge for all of the tanks within each of the evaporator systems. Additional logic is included to model the behavior of waste tanks not directly associated with the evaporators. Input parameters include the Material Management Plan forecast of canyon operations, specification of other waste sources for the evaporator systems, evaporator operating characteristics, and salt and sludge removal schedules. The model determines how the evaporators will operate, when waste transfers can be made, and waste accumulation rates. Output from the model includes waste tank contents, summaries of systems operations, and reports of space gain and the remaining capacity to store waste materials within the tank farm. Model simulations can be made to predict waste tank capacities on a daily basis for up to 20 years. The model is coded as a set of three computer programs designed to run on either IBM compatible or Apple Macintosh II personal computers.

  15. Absence of viral hemorrhagic septicemia virus (VHSV) and infectious hemorrhagic necrosis virus (INHV) in a Tunisian fish farm: a case study.

    Science.gov (United States)

    Cherif, N; Hammami, S

    2012-01-01

    Beyond the obvious problems related to the sustainable management of wild stocks, current fish farming practices in the Mediterranean area entail important environmental risks and potential outbreaks of fish diseases linked to massive translocations across regional boundaries. Viral haemorrhagic septicaemia (VHS) and infectious hematopoietic necrosis (IHN) are well-known fish diseases caused by the VHSV and IHNV viruses, and positive cases are subject to obligatory reporting to the World Organisation for Animal Health (OIE). In August 2004, the OIE published the first record of a VHS outbreak in a sea bass (Dicentrarchus labrax) aquaculture facility on the coast of the Mediterranean Sea. However, D. labrax is not considered as a susceptible host species for viral hemorrhagic septicaemia according to OIE's International Aquatic Animal Health Code (2009) and VHSV was not previously reported in the Mediterranean. In this sense and given the high risk of disease translocation associated with farmed fish in marine aquaculture, the present study was aimed at investigating the presence of VHSV and IHNV in stocks of sea bass and sea bream (Sparus aurata) reared inside a Tunisian coastal fish farm. Cell culture, IFAT and RT-PCR were applied to screen for both VHSV and IHNV in 69 pooled samples of sea bass and 24 pooled samples of sea bream. All three techniques showed the absence of both viruses within fish at the selected site.

  16. Distributed Model Predictive Control for Active Power Control of Wind Farm

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Rasmussen, Claus Nygaard;

    2014-01-01

    This paper presents the active power control of a wind farm using the Distributed Model Predictive Controller (D- MPC) via dual decomposition. Different from the conventional centralized wind farm control, multiple objectives such as power reference tracking performance and wind turbine load can......-scale wind farm control....

  17. Aeolus Toolbox for Dynamics Wind Farm Model, Simulation and Control

    DEFF Research Database (Denmark)

    Grunnet, Jacob Deleuran; Soltani, Mohsen; Knudsen, Torben

    2010-01-01

    This paper presents the wind farm simulation modeldeveloped in the EU-FP7 project, AEOLUS. Theidea is to provide a publicly available simulationpackage for researchers developing farm level controlsolutions. With the software it is possible toauto generate a wind farm simulation model in Matlab/Simulink...

  18. Modelling the wind-borne spread of highly pathogenic avian influenza virus between farms

    NARCIS (Netherlands)

    Ssematimba, A.; Hagenaars, T.H.J.; Jong, de M.

    2012-01-01

    A quantitative understanding of the spread of contaminated farm dust between locations is a prerequisite for obtaining much-needed insight into one of the possible mechanisms of disease spread between farms. Here, we develop a model to calculate the quantity of contaminated farm-dust particles

  19. Global Aquaculture Performance Index (GAPI: The First Global Environmental Assessment of Marine Fish Farming

    Directory of Open Access Journals (Sweden)

    Jenna M.S. Stoner

    2013-09-01

    Full Text Available “Sustainable” is among the most sought after of all seafood product adjectives. Ironically it is also one of the most poorly defined and understood. The Global Aquaculture Performance Index (GAPI is the first tool to assess environmental performance of global marine aquaculture production, permitting direct comparison of disparate species, production methods and jurisdictions. Clear patterns emerge from this analysis; significant variation of environmental performance is driven by the species being farmed, significant room for improvement exists across the entire sector, the worst performing players are also the fastest growing, particularly within Asia, and perhaps most importantly, this work highlights the potential trap awaiting policy makers who focus too narrowly on farm production efficiency alone as a solution to diminishing seafood availability.

  20. Characteristics of Growth and Yield Formation of Rice in Rice-Fish Farming System

    Institute of Scientific and Technical Information of China (English)

    YANG Yong; ZHANG Hong-cheng; HU Xiao-jun; DAI Qi-gen; ZHANG Yong-jiang

    2006-01-01

    By using single rice cultivation as a control, the effect of rice-fish culture on growth dynamic, plant type and yield formation of rice was studied. The results showed as follows: rice-fish culture improved the physical-chemical properties of arable layer soil of paddy field, extended growth period of rice, increased dry matter and LAI of different growth stages,improved three top leaves area, deterred the degeneration of leaves function, increased the diameter of stem, promoted the growth of roots and the formation of roots in the extended stem. At the same time, rice-fish culture extended the length of basal internodes, increased the number of internodes, uplifted the gravity of plant, and depressed the root vigor. For the grain yield and yield structure of rice, rice-fish culture decreased ear/tillering ratio, spikelet/panicle and seed set percentage,increased grain weight. If variety choice and cultivation technology were controlled appropriately, rice-fish culture could increase the effective panicles and improve grain yield of rice.

  1. Environmental Adult Education for Mitigating the Impacts of Climate Change on Crop Production and Fish Farming in Rivers State of Nigeria

    Science.gov (United States)

    Eheazu, Caroline L.; Ezeala, Joy I.

    2017-01-01

    The threats of climate change to human society and natural ecosystems have become a devastating environmental problem for crop production and fish farming in Nigeria. This is partly because farmers and fisher folk are known to adopt age-old methods that do not counter current global warming and climate change effects. The purpose of this study was…

  2. ASSESSMENT OF THE DEVELOPMЕNT OF POND FORAGE BASE WHEN REARING CARP (CYPRINUS CARPIO CARPIO FISH SEEDS AT FISH FARM «MERKURIY»

    Directory of Open Access Journals (Sweden)

    B. Grishin

    2015-09-01

    comprehensive assessment of the natural forage base in nursery ponds when rearing carp fish seeds in the conditions of forest-steppe zone of Vinnitsa region at the fish farm “Merkuriy”. Practical value. The obtained data allow rearing high quality young-of-the-year Lubin few scale carp, Antoninsko-Zozulenets carp and their reciprocal crosses.

  3. Integrated assessment of runoff from livestock farming operations: analytical chemistry, in vitro bioassays, and in vivo fish exposures

    Science.gov (United States)

    Cavallin, Jenna E.; Durhan, Elizabeth J.; Evans, Nicola; Jensen, Kathleen M.; Kahl, Michael D.; Kolpin, Dana W.; Kolodziej, Edward P.; Foreman, William T.; LaLone, Carlie A.; Makynen, Elizabeth A.; Seidl, Sara M.; Thomas, Linnea M.; Villeneuve, Daniel L.; Weberg, Matthew A.; Wilson, Vickie S.; Ankley, Gerald T.

    2014-01-01

    Animal waste from livestock farming operations can contain varying levels of natural and synthetic androgens and/or estrogens, which can contaminate surrounding waterways. In the present study, surface stream water was collected from 6 basins containing livestock farming operations. Aqueous concentrations of 12 hormones were determined via chemical analyses. Relative androgenic and estrogenic activity was measured using in vitro cell assays (MDA-kb2 and T47D-Kbluc assays, respectively). In parallel, 48-h static-renewal in vivo exposures were conducted to examine potential endocrine-disrupting effects in fathead minnows. Mature fish were exposed to surface water dilutions (0%, 25%, 50%, and 100%) and 10-ng/L of 17α-ethynylestradiol or 50-ng/L of 17β-trenbolone as positive controls. Hepatic expression of vitellogenin and estrogen receptor α mRNA, gonadal ex vivo testosterone and 17β-estradiol production, and plasma vitellogenin concentrations were examined. Potentially estrogenic and androgenic steroids were detected at low nanogram per liter concentrations. In vitro estrogenic activity was detected in all samples, whereas androgenic activity was detected in only 1 sample. In vivo exposures to the surface water had no significant dose-dependent effect on any of the biological endpoints, with the exception of increased male testosterone production in 1 exposure. The present study, which combines analytical chemistry measurements, in vitro bioassays, and in vivo fish exposures, highlights the integrated value and future use of a combination of techniques to obtain a comprehensive characterization of an environmental chemical mixture. 

  4. Combination of Slag, Limestone and Sedimentary Apatite in Columns for Phosphorus Removal from Sludge Fish Farm Effluents

    Directory of Open Access Journals (Sweden)

    Florent Chazarenc

    2010-08-01

    Full Text Available Laboratory scale studies have repeatedly reported high P-retention in slag, a by-product of the steel manufacturing industry. Thus, it has emerged as a potential material to increase P-removal from constructed wetlands (CWs. However, several limitations were highlighted by field experiments, including the high pH of treated water and clogging. We hypothesized that the addition of sedimentary rocks to slag would preserve P-removal properties while reducing the pH of treated water. Four 2.5 L-columns were filled with 100% apatite (column A; a 50% weight each mixture of limestone with apatite (column B; 10% steel slag located at the inlet, plus 45% limestone mixed with 45% apatite (column C; and a mixture of steel slag (10%, limestone (45% apatite (45% (column D. A synthetic effluent (26 mg P/L and a reconstituted sludge fish farm effluent containing 97 mg/L total suspended solids (TSS, 220 mg/L chemical oxygen demand (COD and 23.5 mg P/L phosphorus (P were applied sequentially during 373 and 176 days, under saturated flow conditions and 12–24 hours hydraulic residence time (HRT, respectively. Treatment performance, P-removal, pH and calcium (Ca2+ were monitored. Results indicated that columns that contained 10% weight steel slag resulted in a higher P retention capacity than the columns without steel slag. The highest P removal was achieved in column C, containing a layer of slag in the inlet zone, 45% apatite and 45% limestone. Feeding the columns with a reconstituted fish farm effluent led to biofilm development, but this had little effect on the P-removal. A combination of slag and sedimentary rocks represents a promising filtration material that could be useful downstream of CWs to further increase P-removal.

  5. Summary Report: The Shadow effect of large wind farms: measurements, data analysis and modelling

    DEFF Research Database (Denmark)

    Frandsen, Sten Tronæs; Barthelmie, Rebecca Jane; Rathmann, Ole;

    It was the goal of the project – by means of data from the demonstration wind farms Horns Rev and Nysted, analyses of these data and modelling – to facilitate prediction of the power losses from a wind farm should a new wind farm be built upwind relative to the prevailing wind direction. Or conve......It was the goal of the project – by means of data from the demonstration wind farms Horns Rev and Nysted, analyses of these data and modelling – to facilitate prediction of the power losses from a wind farm should a new wind farm be built upwind relative to the prevailing wind direction....... The databases – one for each site – include production and operational statistics for the wind turbines and statistics for the meteorological measurements carries out in the vicinity of the wind farms. Several different modelling activities were carried out, which intentionally to some extent are redundant...

  6. Acid-base regulation in intensively farmed air-breathing fish

    DEFF Research Database (Denmark)

    Bayley, Mark; Damsgaard, Christian; Thomsen, Mikkel;

    Hypercapnia in slow moving organically loaded tropical waters is a natural occurrence with several records of pCO2 at 60 mm Hg. Despite this, studies on South American air-breathing fish have revealed a low capacity for extracellular pH (pHe) regulation. The two underlying reasons proposed are; 1...

  7. The 'Fish Trader+' model: reducing female fish traders' vulnerability to HIV.

    Science.gov (United States)

    Hüsken, Saskia Mc; Heck, Simon

    2012-03-01

    Analysis from research and practice in Africa shows that fishing communities are hardly reached by HIV-related services, education, and business services, partly because of the efforts and costs involved and a lack of good practice in reaching out to these often remote areas. At the same time, fish traders, especially women, travel regularly to remote fishing camps to purchase fish. Although female fish traders may be exposed to HIV, violence and abuse in their interactions and relationships with fishermen, economic necessity keeps them in this trade. Good health among fisherfolk is a basic mainstay of productive and sustainable fisheries, providing food and income to fishing communities and the nation at large. However, these benefits are severely at risk as per-capita fish supplies in several African countries are declining, and fisherfolk are among the populations most vulnerable to HIV and AIDS. Under the regional programme 'Fisheries and HIV/AIDS in Africa: Investing in sustainable solutions,' the WorldFish Center conducted a socioeconomic assessment in the Kafue Flats fishery in Zambia to identify factors related to HIV/AIDS vulnerability among people in the fishing communities, particularly female fish traders. The study identified a variety of factors, hence the 'Fish Trader+' model of intervention was developed to reduce female fish traders' vulnerability to HIV by building on their economic rationale through the formation of savings groups. This article outlines the implementation of the Fish Trader+ model in Zambia and examines its potential to empower female fish traders so as to reduce poverty and vulnerability to HIV in fishing communities.

  8. Stochastically modeling Listeria monocytogenes growth in farm tank milk.

    Science.gov (United States)

    Albert, Isabelle; Pouillot, Régis; Denis, Jean-Baptiste

    2005-10-01

    This article presents a Listeria monocytogenes growth model in milk at the farm bulk tank stage. The main objective was to judge the feasibility and value to risk assessors of introducing a complex model, including a complete thermal model, within a microbial quantitative risk assessment scheme. Predictive microbiology models are used under varying temperature conditions to predict bacterial growth. Input distributions are estimated based on data in the literature, when it is available. If not, reasonable assumptions are made for the considered context. Previously published results based on a Bayesian analysis of growth parameters are used. A Monte Carlo simulation that forecasts bacterial growth is the focus of this study. Three scenarios that take account of the variability and uncertainty of growth parameters are compared. The effect of a sophisticated thermal model taking account of continuous variations in milk temperature was tested by comparison with a simplified model where milk temperature was considered as constant. Limited multiplication of bacteria within the farm bulk tank was modeled. The two principal factors influencing bacterial growth were found to be tank thermostat regulation and bacterial population growth parameters. The dilution phenomenon due to the introduction of new milk was the main factor affecting the final bacterial concentration. The results show that a model that assumes constant environmental conditions at an average temperature should be acceptable for this process. This work may constitute a first step toward exposure assessment for L. monocytogenes in milk. In addition, this partly conceptual work provides guidelines for other risk assessments where continuous variation of a parameter needs to be taken into account.

  9. Trypanosoma epinepheli n. sp. (Kinetoplastida) from a farmed marine fish in China, the brown-marbled grouper (Epinephelus fuscoguttatus).

    Science.gov (United States)

    Su, Youlu; Feng, Juan; Jiang, Jingzhe; Guo, Zhixun; Liu, Guangfeng; Xu, Liwen

    2014-01-01

    An outbreak of trypanosomosis occurred in farmed Epinephelus fuscoguttatus in Xincun Bay, province of Hainan, South China Sea. The infected fish showed loss of appetite, lethargy, emaciation, severe anemia, and splenomegaly. Light and scanning electron microscopic examination of bloodstream trypomastigotes revealed morphological features typical for small-sized marine fish trypanosomes. The trypanosome possesses a short body length (mean 22.3 μm, range 17.6-25.9 μm) and narrow body width (mean1.7 μm, range 1.3-2.0 μm), a central nucleus, a narrow but distinct undulating membrane, and a relatively long free flagellum (mean 10.1 μm, range 7.4-13.3 μm). The kinetoplast is situated at approximately one quarter of body length from posterior extremity. The division process of this trypanosome was observed in the peripheral blood of the host, and occurred by transverse constriction at a point between the kinetoplasts. Comparison of the small subunit rDNA (SSU rDNA) sequences revealed that the trypanosome from E. fuscoguttatus showed 93.4-97.1% identity with the available sequences from Trypanosoma spp. from other piscine hosts. Phylogenetic analysis supported the existence of an aquatic clade, and the present trypanosome grouped with other marine fish trypanosomes, in a subclade together with Trypanosoma senegalense. Based on the differences in morphological characteristics, host species, and molecular data, the trypanosome infecting E. fuscoguttatus is considered to be a new species, for which we propose the name Trypanosoma epinepheli n. sp.

  10. Interaction model of artificial fish in virtual environment

    Institute of Scientific and Technical Information of China (English)

    Meng Xiangsong; Ban Xiaojuan; Yin Yixin

    2008-01-01

    Conventional artificial fish has some shortages on the interaction with environment,other fish,and the animator.This article proposes a multi-tier interaction control model of artificial fish,realizes the interaction model through integration of virtual reality technology and Markov sequence,and provides a virtual marine world to describe the interaction between artificial fish and the virtual environment and the interaction between the artificial fish and the animator.Simulation results show that the interaction model owns not only the basic characteristics of virtual biology,but also has high trueness interaction function.

  11. BASIC PARAMETERS FOR DESIGNING PHYSICAL SEPARATION TREATMENTS FROM AN INTENSIVE ON-SHORE FISH FARM

    Directory of Open Access Journals (Sweden)

    Biagio Bianchi

    2012-06-01

    Full Text Available The pollutant load was monitored in an intensive on-shore plant; evaluation especially concerned one basin,during a period of time in which the water temperature (21-23°c, the stocking density (25 kg/m3, the loading and unloading flow (40 dm3/s remained steady at the highest values. The results show that the maximum pollution levels are characterized by high concentrations of suspended organic materials, as well as by high BOD5/COD rates; moreover, more than 60% of the suspended solid waste consists of particles with a maximum dimension ranging from 200 μm to more than 500 μm. Tests show that an effluent channel is not efficient in reducing the pollutant load of waste water. The laboratory sedimentation trials showed – for a period of about 3 hours – minimum and maximum solid particle sedimentation speeds of 2.56 mm/s and 46.8 mm/s respectively, which should be considered when deciding the turbid speed and the dimensions of basins for this type of effluent. In any case, the sedimentation process carried out in the laboratory was only just sufficient to bring the farm effluent within the legal limits. Therefore a mechanical filtration treatment may suit the specific requirements of the farm waste water used for the experimental trials. A 50 μm mesh would be considered sufficient for any critical situation.

  12. Long-term monitoring of fish farms: application of Nematode/Copepod index to oligotrophic conditions.

    Science.gov (United States)

    Riera, Rodrigo; Sanchez-Jerez, Pablo; Rodríguez, Myriam; Monterroso, Oscar; Ramos, Eva

    2012-04-01

    Interannual variability (2003-2008) of meiofaunal assemblages were analyzed in sediments beneath fish cages (Impact group) and in areas not affected by aquaculture activities (Control group). Organisms responded with spatial and seasonal variation in meiofauna assemblages, with an abrupt increase of abundances in locations beneath fish cages throughout the study period. This increase was greater during the last sampling year (2008) and mainly due to high abundances of nematodes. Univariate analyses showed differences between control and impacted sites at both sites, however, only significant variations were found in Los Gigantes, which are consistent with seasonal meiofauna variations throughout the study period. These results are partially explained by differences in current velocity between both sampling areas. The Ne/Co index showed the same trend and it seems to be a reliable index in sediment slightly affected by aquaculture wastes. This index is especially recommended in oligotrophic areas (e.g. Canary Islands) where meiofaunal assemblages are poorly represented in terms of abundances.

  13. Trial of Growth Control of Farm-raised Fish by Plasma-generated Reactive Species

    Science.gov (United States)

    Motomura, Hideki; Kubota, Yoshiki; Fukushima, Ryo; Ikeda, Yoshihisa; Jinno, Masafumi

    2016-09-01

    As one of the biological applications of plasmas, growth control of agricultural products attracts attentions. There are many papers on growth enhancement of crops by plasma treatment. However, there are few published papers concerning growth enhancement of fishery products excepting reports of goldfish growth enhancement in 1980s. In this study, growth characteristics of edible fish (tilapia) under the plasma treatment has been investigated. An arc discharge reactor was employed and plasma treated air was introduced to two aquariums with a flow rate of 2.5 L/min. Measured concentrations of main reactive species were 43 ppm for NO, 23 ppm for NO2 and 7.5 ppm for O3. Each aquarium had 60 L capacity and contained 15 tilapia fish. The plasma treated air was supplied to an aquarium once a day and to the other aquarium twice a day with total duration of 10 min. Compared to no plasma treatment case, the growth rate decreased by 18% by once a day plasma treatment, whereas almost same growth rate was observed by twice a day plasma treatment. A possible reason of growth suppression is excess concentrations of nitrite and nitrate in water. The relationship between their concentrations and growth characteristics under several treatment conditions will be shown at the conference. Tirapia fish was supplied from SEFREC of Ehime University.

  14. MORPHOMETRIC CHARACTERISTICS OF THE REPLACEMENT-BROOD STOCK OF RAINBOW TROUT (ONCORHYNCHUS MYKISS (WALBAUM, 1792 REARED IN THE CONDITIONS OF THE INDUSTRIAL FISH FARM "SLOBODA-BANYLIV”

    Directory of Open Access Journals (Sweden)

    P. Mendrishora

    2017-09-01

    Full Text Available Purpose. To analyze the results of morphometric measurements and dates of aquaculture-biological characteristics of the young-of-the-year and age-1+ rainbow trout reared under industrial technology at instable conditions of the fish farm “Sloboda-Banyliv”. Methodology. The study has been performed at the industrial fish farm “Sloboda-Banyliv”, Chernivtsi region. The materials for the study were young-of-the-year and age-1+ rainbow trout obtained from the eggs of autumn-spawning form rainbow trout. The young-of-the-year were reared in a 216 m2 tank with stocking density of 255 ind./m2, age-1+ fish were reared in 108 m2 tank with a stocking density of 33 ind./m2 according to generally accepted methods in trout culture. Morphometric measurements of fish were performed according to I.F. Pravdin. Statistical processing of data was carried out in Microsoft Office Excel (2003. The analysis of values was done in the system of absolute values. The analyzed criteria of the measured parameters were their mean values and standard errors (M±m, deviation (σ, variability coefficient (Cv. Fish were fed with the artificial feed with high protein content manufactured by “Biomar” (Denmark. Findings. The studies on rainbow trout rearing under industrial conditions showed that fish body proportions did not change with age, however, the length of their fins decreased. The slenderness coefficient in age-1+ fish decreased insignificantly that is typical with increasing body depth. Despite instable rearing conditions, both young-of-the-year and age-1+ fish were characterized by moderate growth rate and high feed-conversion efficiency. Originality. For the first time, in conditions of Ukraine, a study on the formation of rainbow trout brood stocks in a fish farm with instable rearing conditions was performed with the use of the analysis of phenotypical and productive features. Practical value. The results of the performed work will provide an opportunity to

  15. Modeling large offshore wind farms under different atmospheric stability regimes with the Park wake model

    DEFF Research Database (Denmark)

    Peña, Alfredo; Réthoré, Pierre-Elouan; Rathmann, Ole

    2013-01-01

    Here, we evaluate a modified version of the Park wake model against power data from a west-east row in the middle of the Horns Rev I offshore wind farm. The evaluation is performed on data classified in four different atmospheric stability conditions, for a narrow wind speed range, and a wide ran....... The simulations do not approach the limits of the infinite wind farm under any stability condition as winds are not parallel to the row....

  16. Investigation on the integral output power model of a large-scale wind farm

    Institute of Scientific and Technical Information of China (English)

    BAO Nengsheng; MA Xiuqian; NI Weidou

    2007-01-01

    The integral output power model of a large-scale wind farm is needed when estimating the wind farm's output over a period of time in the future.The actual wind speed power model and calculation method of a wind farm made up of many wind turbine units are discussed.After analyzing the incoming wind flow characteristics and their energy distributions,and after considering the multi-effects among the wind turbine units and certain assumptions,the incoming wind flow model of multi-units is built.The calculation algorithms and steps of the integral output power model of a large-scale wind farm are provided.Finally,an actual power output of the wind farm is calculated and analyzed by using the practical measurement wind speed data.The characteristics of a large-scale wind farm are also discussed.

  17. An analytical canopy-type model for wind farm-atmosphere interaction

    Science.gov (United States)

    Markfort, C. D.; Zhang, W.; Porte-Agel, F.

    2013-12-01

    We present a new model for the interactions between large-scale wind farms and the atmospheric boundary layer (ABL) based on similarity to canopy flows. Wind farms capture momentum from the atmospheric boundary layer both at the leading edge and from above. Based on our recent findings that turbulent flow in and above wind farms is similar to canopy-type flows, we examine this further with an analytical model that can predict the development length of the wind farm flow as well as vertical momentum absorption. Within the region of flow development, momentum is advected into the wind farm and wake turbulence draws excess momentum in from between turbines. This is characterized by large dispersive fluxes of momentum. Once the flow within the farm is developed, the area-averaged velocity profile exhibits an inflection point, characteristic of canopy-type flows. The inflected velocity profile is associated with the presence of a dominant characteristic turbulence scale, which may be responsible for a significant portion of the vertical momentum flux. Prediction of this scale is useful for determining the amount of available power for harvesting. The new model is tested with results from wind tunnel experiments, which characterize the turbulent flow in and above model wind farms. The model is useful for representing wind farms in meteorological and wind resource assessment models, for optimizing wind turbine spacing and layout, and for assessing the impacts of wind farms on nearby wind resources and the environment.

  18. Fish behavior in relation to modeling fish passage through hydropower turbines: A review

    Energy Technology Data Exchange (ETDEWEB)

    Coutant, C.C. [Oak Ridge National Lab., TN (United States); Whitney, R.R.

    1997-06-01

    We evaluated the literature on fish behavior as it relates to passage of fish near or through hydropower turbines. The goal was to foster compatibility of engineered systems with the normal behavior patterns of fish species and life stages such that entrainment into turbines and injury in passage are minimized. We focused on aspects of fish behavior that could be used for computational fluid dynamics (CFD) modeling of fish trajectories through turbine systems. Downstream-migrating salmon smolts are generally surface oriented and follow flow. Smolts orient to the ceilings of turbine intakes but are horizontally distributed more evenly, except as affected by intake-specific turbulence and vortices. Smolts often enter intakes oriented head-upstream. Non-salmonids are entrained episodically, suggesting accidental capture of schools (often of juveniles or in cold water) and little behavioral control during turbine passage. Models of fish trajectories should not assume neutral buoyancy throughout the time a fish passes through a turbine, largely because of pressure effects on swim bladders. Fish use their lateral line system to sense obstacles and change their orientation, but this sensory-response system may not be effective in the rapid passage times of turbine systems. A Effects of pre-existing stress levels on fish performance in turbine passage are not well known but may be important. There are practical limits of observation and measurement of fish and flows in the proximity of turbine runners that may inhibit development of information germane to developing a more fish-friendly turbine. We provide recommendations for CFD modelers of fish passage and for additional research. 20 refs., 2 figs.

  19. Effects of Changes in Food Supply at the Time of Sex Differentiation on the Gonadal Transcriptome of Juvenile Fish. Implications for Natural and Farmed Populations

    Science.gov (United States)

    Díaz, Noelia; Ribas, Laia; Piferrer, Francesc

    2014-01-01

    Background Food supply is a major factor influencing growth rates in animals. This has important implications for both natural and farmed fish populations, since food restriction may difficult reproduction. However, a study on the effects of food supply on the development of juvenile gonads has never been transcriptionally described in fish. Methods and Findings This study investigated the consequences of growth on gonadal transcriptome of European sea bass in: 1) 4-month-old sexually undifferentiated fish, comparing the gonads of fish with the highest vs. the lowest growth, to explore a possible link between transcriptome and future sex, and 2) testis from 11-month-old juveniles where growth had been manipulated through changes in food supply. The four groups used were: i) sustained fast growth, ii) sustained slow growth, iii) accelerated growth, iv) decelerated growth. The transcriptome of undifferentiated gonads was not drastically affected by initial natural differences in growth. Further, changes in the expression of genes associated with protein turnover were seen, favoring catabolism in slow-growing fish and anabolism in fast-growing fish. Moreover, while fast-growing fish took energy from glucose, as deduced from the pathways affected and the analysis of protein-protein interactions examined, in slow-growing fish lipid metabolism and gluconeogenesis was favored. Interestingly, the highest transcriptomic differences were found when forcing initially fast-growing fish to decelerate their growth, while accelerating growth of initially slow-growing fish resulted in full transcriptomic convergence with sustained fast-growing fish. Conclusions Food availability during sex differentiation shapes the juvenile testis transcriptome, as evidenced by adaptations to different energy balances. Remarkably, this occurs in absence of major histological changes in the testis. Thus, fish are able to recover transcriptionally their testes if they are provided with enough food

  20. Effects of changes in food supply at the time of sex differentiation on the gonadal transcriptome of juvenile fish. Implications for natural and farmed populations.

    Directory of Open Access Journals (Sweden)

    Noelia Díaz

    Full Text Available Food supply is a major factor influencing growth rates in animals. This has important implications for both natural and farmed fish populations, since food restriction may difficult reproduction. However, a study on the effects of food supply on the development of juvenile gonads has never been transcriptionally described in fish.This study investigated the consequences of growth on gonadal transcriptome of European sea bass in: 1 4-month-old sexually undifferentiated fish, comparing the gonads of fish with the highest vs. the lowest growth, to explore a possible link between transcriptome and future sex, and 2 testis from 11-month-old juveniles where growth had been manipulated through changes in food supply. The four groups used were: i sustained fast growth, ii sustained slow growth, iii accelerated growth, iv decelerated growth. The transcriptome of undifferentiated gonads was not drastically affected by initial natural differences in growth. Further, changes in the expression of genes associated with protein turnover were seen, favoring catabolism in slow-growing fish and anabolism in fast-growing fish. Moreover, while fast-growing fish took energy from glucose, as deduced from the pathways affected and the analysis of protein-protein interactions examined, in slow-growing fish lipid metabolism and gluconeogenesis was favored. Interestingly, the highest transcriptomic differences were found when forcing initially fast-growing fish to decelerate their growth, while accelerating growth of initially slow-growing fish resulted in full transcriptomic convergence with sustained fast-growing fish.Food availability during sex differentiation shapes the juvenile testis transcriptome, as evidenced by adaptations to different energy balances. Remarkably, this occurs in absence of major histological changes in the testis. Thus, fish are able to recover transcriptionally their testes if they are provided with enough food supply during sex

  1. THE GENETIC STRUCTURE OF DIFFERENT AGE GROUPS OF SILVER (HYPOPHTHALMICHTHYS MOLITRIX AND BIGHEAD (ARISTICHTHYS NOBILIS CARPS FROM FISH FARM LIMANSKE

    Directory of Open Access Journals (Sweden)

    Т. Nagorniuk

    2015-09-01

    Full Text Available Purpose. Studying the peculiarities of the genetic structure of different age groups of silver and bighead carps from fish farm Limanske with the use of genetic-biochemical markers. Methodology. The methods of vertical polyacrylamide and horizontal starch electrophoresis with our own modifications have been used for the study. Sampling of the biological material and histochemical staining of gel plates were carried out using the generally accepted methods. Statistical analysis of the obtained data were performed in "Biosys-I". Findings. We analyzed the genetic structure of age-1, age-1+ and age-2 of silver and bighead carps with the use of genetic-biochemical markers - Рralb, EST, MDH, МЕ, СА. We demonstrated the peculiarities of allele frequencies and genotypic composition of protein system loci. A high level of heterozygosity in the examined was detected loci for age-1 silver carp – 66.7-88.9% and age-1 bighead carp – 65.4-77.8%. A significantly higher level of the observed average heterozygosity compared to the expected heterozygosity of age-1 as silver carp (Ho = 75.9%, He = 49,6%, and bighead carp (Ho = 73,6%, He = 47,9% was observed. This fact indicated on the necessity for performing a stabilization of their genetic structure. The calculated Wright's F index in different age groups showed a predominance of the observed level of the average heterozygosity over the expected one for 22.7–53% in silver carp and 24.5-53.7% in bighead carp. A stabilization of the genetic structure in age-2 silver carp (Ho = 57.8%; He = 47.1% by the heterogeneity level was observed. Originality. For the first time we analyzed the genetic structure and the level of heterogeneity of the breeding groups of age-1, age-1+, age-2 silver and bighead carps from fish farm Limanske with the use of genetic-biochemical markers. Practical value. The results of the study can be used in selection and breeding works aimed at creating the breeding stocks of silver and

  2. Optimization Model for Mitigating Global Warming at the Farm Scale: An Application to Japanese Rice Farms

    Directory of Open Access Journals (Sweden)

    Kiyotaka Masuda

    2016-06-01

    Full Text Available In Japan, greenhouse gas emissions from rice production, especially CH4 emissions in rice paddy fields, are the primary contributors to global warming from agriculture. When prolonged midseason drainage for mitigating CH4 emissions from rice paddy fields is practiced with environmentally friendly rice production based on reduced use of synthetic pesticides and chemical fertilizers, Japanese rice farmers can receive an agri-environmental direct payment. This paper examines the economic and environmental effects of the agri-environmental direct payment on the adoption of a measure to mitigate global warming in Japanese rice farms using a combined application of linear programming and life cycle assessment at the farm scale. Eco-efficiency, which is defined as net farm income divided by global warming potential, is used as an integrated indicator for assessing the economic and environmental feasibilities. The results show that under the current direct payment level, the prolonged midseason drainage technique does not improve the eco-efficiency of Japanese rice farms because the practice of this technique in environmentally friendly rice production causes large economic disadvantages in exchange for small environmental advantages. The direct payment rates for agri-environmental measures should be determined based on the condition that environmentally friendly agricultural practices improve eco-efficiency compared with conventional agriculture.

  3. Otters and fish-farming: preliminary experiences of a WWF project in Austria

    Directory of Open Access Journals (Sweden)

    Michaela Bodner

    1995-12-01

    Full Text Available Abstract Simultaneously with a rise of the otter (Lutra lutra population in the Northern Waldviertel (Austria the number of complaints from pond owners (carp breeding about damage in their ponds is constantly increasing. In this study precautions (electric fences for keeping otters away from fish ponds are tested. Different fencing systems are used, data about the maintenance effort (cutting vegetation, recharging battery and the general effectiveness of the systems are sampled. Eight fences were installed in August 1992, so far (till November 1993 the otter was kept out of all eight ponds. Running the fences in winter is possible, although due to an increase in humidity the voltage in the fence decreases. In addition, it is tested if by offering an alternative food ("diversion ponds" the otter can be kept away from other close ponds. All damage reports of the past 9 years will be analysed to identify possible patterns (preferences for pond size, fish size, density of stocked fish; seasonal variations of damage. Thus, high risk ponds could be identified and protected selectively. Riassunto La lontra e gli allevamenti ittici: primi dati del progetto WWF in Austria - L'espansione della lontra (Lutra lutra nella parte settentrionale di Waldviertel (Austria ha coinciso con l'incremento dei danni procurati dalla specie agli allevamenti ittici (soprattutto di carpa in bacini artificiali. In questo studio, sono discussi alcuni interventi (recinzione elettrificata dei bacini per tenere lontana la lontra dagli allevamenti. Sono state valutate l'efficacia di differenti sistemi di recinzione e le condizioni più idonee per il loro regolare funzionamento (taglio della vegetazione che interferisce con la recinzione, ricarica delle batterie. Nell'agosto 1992 sono state installate 8 recinzioni, per mezzo delle quali la lontra finora (novembre 1993 è stata tenuta lontana dagli allevamenti. In

  4. PMCV and PRV occurrence in wild and farmed fish in Denmark

    DEFF Research Database (Denmark)

    Mikkelsen, Susie Sommer; Arnö, J.; Bruun, Morten Sichlau

    -virus in the family of Reoviridae, while Piscine myocarditis virus (PMCV) is a double-stranded RNA virus of the Totiviridae family. Wild and farmed salmon and trout have not been tested for PRV or PMCV in Denmark before, but both viruses are found in Norway, where they are suspected of causing Heart and Skeletal......Every year salmon are restocked in the 7 rivers Storå, Skjern Å, Varde Å, Sneum Å, Kongeå, Ribe Å and Gudenåen. Six-month-old and 1-year-old salmon for about 2 mio. Kr (€268000) are restocked every year. The salmon are restocked in both the main rivers as well as the larger inlets. 6-month......-old salmon are restocked in smaller rivers where the spawning and growth is ideal. They are released from a boat drifting downstream between September and October. 1-year-old smolt are restocked in a few places in the main rivers in April. They are restocked in large numbers to provide better protection...

  5. Physico-chemical qualities of water in high altitude rice fish farming system of Ziro valley, Arunachal Pradesh, India.

    Science.gov (United States)

    Saikia, Rajashree; Das, Tapati; Das, Debangshu Narayan

    2015-09-01

    Water in rice fields of mountain valley of Ziro, Arunachal Pradesh was investigated for physico-chemical characterization during rice fish farming season (Kharif) of 2013. Water temperature, dissolved oxygen, biological oxygen demand, free carbon dioxide, nitrate-nitrogen, phosphate-phosphorus, chloride, total hardness, calcium hardness, alkalinity, pH, total dissolved solids, specific conductivity and water depth were studied. This study revealed that the physical parameters of water in rice fields like water temperature, pH, total dissolved solids, specific conductivity and water depth were 23.5-31.3 degrees C, 5.9-6.9, 250.34-370.5 mgl(-1), 437.75-660.33 μScm(-1) and 3.72-16.9 cm respectively. The chemical features like dissolved oxygen, biological oxygen demand, free CO2, nitrate-nitrogen, phosphate-phosphorus, chloride, total hardness Ca hardness, alkalinity were 2.4-12.9 mgl(-1), 1.5-11.1 mgl(-1), 9.7-23.35 mgl(-1), 1.28-3.9 mgl(-1), 0.005-0.539 mgl(-1), 16.6-46.8 mgl(-1), 13.9-34.5 mgl(-1), 9.6-13.53 mgl(-1) and 23.16-43.34 mgl(-1) respectively. On the other hand, investigation on planktonic life forms indicated the presence of 13.5x10(3)-84.9x10(3) indl(-1)" and 1.23x10(3)-4.86x10(3) indl(-1) phytoplankton and zooplankton respectively during the Kharif season. The above physiochemical parameters were found to be conducive for raising fish as companion crop of rice due to occurrence of diversified planktonic life forms in underneath water.

  6. Effects of farm heterogeneity and methods for upscaling on modelled nitrogen losses in agricultural landscapes

    Energy Technology Data Exchange (ETDEWEB)

    Dalgaard, T., E-mail: tommy.dalgaard@agrsci.dk [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Hutchings, N. [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Dragosits, U. [CEH Edinburgh, Bush Estate, Penicuik, Midlothian EH26 0QB, Scotland (United Kingdom); Olesen, J.E.; Kjeldsen, C. [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Drouet, J.L.; Cellier, P. [INRA, UMR Environnement et Grandes Cultures, BP 01, 78850 Thiverval-Grignon (France)

    2011-11-15

    The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with around 20-30% difference compared to a scaling procedure not taking this non-linearity into account. A significant effect of farm type on soil N accumulation (p > 0.95) was also identified and needs to be included when modelling landscape level N-fluxes and greenhouse gas emissions. - Highlights: > Farm-N balances and the distribution on types of N-losses are modelled for 56 farms. > Farm type significantly affects N-losses and soil-N accumulation. > A non-linear relation between livestock density and ammonia loss is identified. > Approaches for upscaling from farm to landscape level are discussed. > Accounting farm heterogeneity is important when upscaling N-losses. - This study illustrates the importance of including non-linear effects of farm and landscape heterogeneity on the modelling and upscaling of farm nitrogen losses and greenhouse gas emissions in agricultural landscapes.

  7. The Making of a Second-generation Wind Farm Efficiency Model Complex

    DEFF Research Database (Denmark)

    Frandsen, Sten Tronæs; Ejsing Jørgensen, Hans; Barthelmie, Rebecca Jane

    2009-01-01

    kilometres down to the size of the individual wind turbine. Flow within wind farms is difficult to predict. The analytical and modified WAsP/park models show promise; however, these require further development/evaluation. For the flow downwind of the wind farm, several intermediate-scale models fit...

  8. Creating a model to detect dairy cattle farms with poor welfare using a national database.

    Science.gov (United States)

    Krug, C; Haskell, M J; Nunes, T; Stilwell, G

    2015-12-01

    The objective of this study was to determine whether dairy farms with poor cow welfare could be identified using a national database for bovine identification and registration that monitors cattle deaths and movements. The welfare of dairy cattle was assessed using the Welfare Quality(®) protocol (WQ) on 24 Portuguese dairy farms and on 1930 animals. Five farms were classified as having poor welfare and the other 19 were classified as having good welfare. Fourteen million records from the national cattle database were analysed to identify potential welfare indicators for dairy farms. Fifteen potential national welfare indicators were calculated based on that database, and the link between the results on the WQ evaluation and the national cattle database was made using the identification code of each farm. Within the potential national welfare indicators, only two were significantly different between farms with good welfare and poor welfare, 'proportion of on-farm deaths' (pwelfare indicators could be used to distinguish farms with good welfare from farms with poor welfare, we created a model using the classifier J48 of Waikato Environment for Knowledge Analysis. The model was a decision tree based on two variables, 'proportion of on-farm deaths' and 'calving-to-calving interval', and it was able to correctly identify 70% and 79% of the farms classified as having poor and good welfare, respectively. The national cattle database analysis could be useful in helping official veterinary services in detecting farms that have poor welfare and also in determining which welfare indicators are poor on each particular farm.

  9. Unraveling the molecular signatures of oxidative phosphorylation to cope with the nutritionally changing metabolic capabilities of liver and muscle tissues in farmed fish.

    Science.gov (United States)

    Bermejo-Nogales, Azucena; Calduch-Giner, Josep Alvar; Pérez-Sánchez, Jaume

    2015-01-01

    Mitochondrial oxidative phosphorylation provides over 90% of the energy produced by aerobic organisms, therefore the regulation of mitochondrial activity is a major issue for coping with the changing environment and energy needs. In fish, there is a large body of evidence of adaptive changes in enzymatic activities of the OXPHOS pathway, but less is known at the transcriptional level and the first aim of the present study was to define the molecular identity of the actively transcribed subunits of the mitochondrial respiratory chain of a livestock animal, using gilthead sea bream as a model of farmed fish with a high added value for European aquaculture. Extensive BLAST searches in our transcriptomic database (www.nutrigroup-iats.org/seabreamdb) yielded 97 new sequences with a high coverage of catalytic, regulatory and assembly factors of Complex I to V. This was the basis for the development of a PCR array for the simultaneous profiling of 88 selected genes. This new genomic resource allowed the differential gene expression of liver and muscle tissues in a model of 10 fasting days. A consistent down-regulated response involving 72 genes was made by the liver, whereas an up-regulated response with 29 and 10 differentially expressed genes was found in white skeletal muscle and heart, respectively. This differential regulation was mostly mediated by nuclear-encoded genes (skeletal muscle) or both mitochondrial- and nuclear-encoded genes (liver, heart), which is indicative of a complex and differential regulation of mitochondrial and nuclear genomes, according to the changes in the lipogenic activity of liver and the oxidative capacity of glycolytic and highly oxidative muscle tissues. These insights contribute to the identification of the most responsive elements of OXPHOS in each tissue, which is of relevance for the appropriate gene targeting of nutritional and/or environmental metabolic disturbances in livestock animals.

  10. Application of support vector machines to 1H NMR data of fish oils: methodology for the confirmation of wild and farmed salmon and their origins.

    Science.gov (United States)

    Masoum, Saeed; Malabat, Christophe; Jalali-Heravi, Mehdi; Guillou, Claude; Rezzi, Serge; Rutledge, Douglas Neil

    2007-02-01

    Support vector machines (SVMs) were used as a novel learning machine in the authentication of the origin of salmon. SVMs have the advantage of relying on a well-developed theory and have already proved to be successful in a number of practical applications. This paper provides a new and effective method for the discrimination between wild and farm salmon and eliminates the possibility of fraud through misrepresentation of the country of origin of salmon. The method requires a very simple sample preparation of the fish oils extracted from the white muscle of salmon samples. (1)H NMR spectroscopic analysis provides data that is very informative for analysing the fatty acid constituents of the fish oils. The SVM has been able to distinguish correctly between the wild and farmed salmon; however ca. 5% of the country of origins were misclassified.

  11. Bioenergetics modeling of percid fishes: Chapter 14

    Science.gov (United States)

    Madenjian, Charles P.; Kestemont, Patrick; Dabrowski, Konrad; Summerfelt, Robert C.

    2015-01-01

    A bioenergetics model for a percid fish represents a quantitative description of the fish’s energy budget. Bioenergetics modeling can be used to identify the important factors determining growth of percids in lakes, rivers, or seas. For example, bioenergetics modeling applied to yellow perch (Perca flavescens) in the western and central basins of Lake Erie revealed that the slower growth in the western basin was attributable to limitations in suitably sized prey in western Lake Erie, rather than differences in water temperature between the two basins. Bioenergetics modeling can also be applied to a percid population to estimate the amount of food being annually consumed by the percid population. For example, bioenergetics modeling applied to the walleye (Sander vitreus) population in Lake Erie has provided fishery managers valuable insights into changes in the population’s predatory demand over time. In addition, bioenergetics modeling has been used to quantify the effect of the difference in growth between the sexes on contaminant accumulation in walleye. Field and laboratory evaluations of percid bioenergetics model performance have documented a systematic bias, such that the models overestimate consumption at low feeding rates but underestimate consumption at high feeding rates. However, more recent studies have shown that this systematic bias was due, at least in part, to an error in the energy budget balancing algorithm used in the computer software. Future research work is needed to more thoroughly assess the field and laboratory performance of percid bioenergetics models and to quantify differences in activity and standard metabolic rate between the sexes of mature percids.

  12. Can multiple fish farms be integrated within a semi-enclosed bay without causing acute ecosystem degradation?

    Directory of Open Access Journals (Sweden)

    Kristian Puhr

    2017-07-01

    Full Text Available The current study explores the possibility that multiple fish farms (FFs containing sea bass (Dicentrarchus labrax and sea bream (Sparus aurata can be successfully integrated within a semi-enclosed bay in the Croatian Adriatic. The research focuses on determining principal environmental factors (EFs that control the integration and attempts to estimate their individual and synergic ability to influence deposition and removal of organic matter (OM and trace elements (TE from the system. The complexity of the designated tasks demanded a comprehensive number of various datasets and samples to be used in the analysis. The ADCP data revealed strong wind induced currents forming within the research domain resulting in high system flushing efficiency (3.5–6 days. The sediment samples from all stations contained relatively inert minerals which contributed to overall low OM and TE concentrations and very limited variability found across the entire bathymetric range. The thermal advection effect recorded at two stations was attributed to specific seabed topography and the hydrodynamic response formed during Maestral wind episodes. The results indicate that a successful integration of four FFs has taken place within the research site (semi enclosed bay, and that the key EFs responsible for its success are strong wind induced hydrodynamics, favorable seabed topography and sediment mineral composition. The synergy of the principal EFs that formed within the system was found to have an attenuating effect regarding FFs chemical influence (OM and TE and an amplifying one regarding spatial footprint which extended to ≈2000 m distance.

  13. Microsimulation Model Estimating Czech Farm Income from Farm Accountancy Data Network Database

    Directory of Open Access Journals (Sweden)

    Z. Hloušková

    2014-09-01

    Full Text Available Agricultural income is one of the most important measures of economic status of agricultural farms and the whole agricultural sector. This work is focused on finding the optimal method of estimating national agricultural income from micro-economic database managed by the Farm Accountancy Data Network (FADN. Use of FADN data base is relevant due to the representativeness of the results for the whole country and the opportunity to carry out micro-level analysis. The main motivation for this study was a first forecast of national agricultural income from FADN data undertaken 9 months before the final official FADN results were published. Our own method of estimating the income estimation and the simulation procedure were established and successfully tested on the whole database on data from two preceding years. Present paper also provides information on used method of agricultural income prediction and on tests of its suitability.

  14. Modeling a farm population to estimate on-farm compliance costs and environmental effects of a grassland extensification scheme at the regional scale

    DEFF Research Database (Denmark)

    Uthes, Sandra; Sattler, Claudia; Piorr, Annette

    2010-01-01

    production orientations and grassland types was modeled under the presence and absence of the grassland extensification scheme using the bio-economic model MODAM. Farms were based on available accountancy data and surveyed production data, while information on farm location within the district was derived...... and environmental effects were heterogeneous in space and farm types as a result of different agricultural production and site characteristics. On-farm costs ranged from zero up to almost 1500 Euro/ha. Such high costs occurred only in a very small part of the regional area, whereas the majority of the grassland had...

  15. Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru.

    Science.gov (United States)

    Langeland, Aubrey L; Hardin, Rebecca D; Neitzel, Richard L

    2017-03-14

    Artisanal and small-scale gold mining (ASGM) has been an important source of income for communities in the Madre de Dios River Basin in Peru for hundreds of years. However, in recent decades, the scale of ASGM activities in the region has increased dramatically, and exposures to a variety of occupational and environmental hazards related to ASGM, including mercury, are becoming more widespread. The aims of our study were to: (1) examine patterns in the total hair mercury level of human participants in several communities in the region and compare these results to the 2.2 µg/g total hair mercury level equivalent to the World Health Organization (WHO) Expert Committee of Food Additives (JECFA)'s Provisional Tolerable Weekly Intake (PTWI); and (2), to measure the mercury levels of paco (Piaractus brachypomus) fish raised in local aquaculture ponds, in order to compare these levels to the EPA Fish Tissue Residue Criterion of 0.3 µg Hg/g fish (wet weight). We collected hair samples from 80 participants in four communities (one control and three where ASGM activities occurred) in the region, and collected 111 samples from fish raised in 24 local aquaculture farms. We then analyzed the samples for total mercury. Total mercury levels in hair were statistically significantly higher in the mining communities than in the control community, and increased with increasing geodesic distance from the Madre de Dios headwaters, did not differ by sex, and frequently exceeded the reference level. Regression analyses indicated that higher hair mercury levels were associated with residence in ASGM communities. The analysis of paco fish samples found no samples that exceeded the EPA tissue residue criterion. Collectively, these results align with other recent studies showing that ASGM activities are associated with elevated human mercury exposure. The fish farmed through the relatively new process of aquaculture in ASGM areas appeared to have little potential to contribute to human

  16. Mercury Levels in Human Hair and Farmed Fish near Artisanal and Small-Scale Gold Mining Communities in the Madre de Dios River Basin, Peru

    Science.gov (United States)

    Langeland, Aubrey L.; Hardin, Rebecca D.; Neitzel, Richard L.

    2017-01-01

    Artisanal and small-scale gold mining (ASGM) has been an important source of income for communities in the Madre de Dios River Basin in Peru for hundreds of years. However, in recent decades, the scale of ASGM activities in the region has increased dramatically, and exposures to a variety of occupational and environmental hazards related to ASGM, including mercury, are becoming more widespread. The aims of our study were to: (1) examine patterns in the total hair mercury level of human participants in several communities in the region and compare these results to the 2.2 µg/g total hair mercury level equivalent to the World Health Organization (WHO) Expert Committee of Food Additives (JECFA)’s Provisional Tolerable Weekly Intake (PTWI); and (2), to measure the mercury levels of paco (Piaractus brachypomus) fish raised in local aquaculture ponds, in order to compare these levels to the EPA Fish Tissue Residue Criterion of 0.3 µg Hg/g fish (wet weight). We collected hair samples from 80 participants in four communities (one control and three where ASGM activities occurred) in the region, and collected 111 samples from fish raised in 24 local aquaculture farms. We then analyzed the samples for total mercury. Total mercury levels in hair were statistically significantly higher in the mining communities than in the control community, and increased with increasing geodesic distance from the Madre de Dios headwaters, did not differ by sex, and frequently exceeded the reference level. Regression analyses indicated that higher hair mercury levels were associated with residence in ASGM communities. The analysis of paco fish samples found no samples that exceeded the EPA tissue residue criterion. Collectively, these results align with other recent studies showing that ASGM activities are associated with elevated human mercury exposure. The fish farmed through the relatively new process of aquaculture in ASGM areas appeared to have little potential to contribute to human

  17. Model for Predicting Passage of Invasive Fish Species Through Culverts

    Science.gov (United States)

    Neary, V.

    2010-12-01

    Conservation efforts to promote or inhibit fish passage include the application of simple fish passage models to determine whether an open channel flow allows passage of a given fish species. Derivations of simple fish passage models for uniform and nonuniform flow conditions are presented. For uniform flow conditions, a model equation is developed that predicts the mean-current velocity threshold in a fishway, or velocity barrier, which causes exhaustion at a given maximum distance of ascent. The derivation of a simple expression for this exhaustion-threshold (ET) passage model is presented using kinematic principles coupled with fatigue curves for threatened and endangered fish species. Mean current velocities at or above the threshold predict failure to pass. Mean current velocities below the threshold predict successful passage. The model is therefore intuitive and easily applied to predict passage or exclusion. The ET model’s simplicity comes with limitations, however, including its application only to uniform flow, which is rarely found in the field. This limitation is addressed by deriving a model that accounts for nonuniform conditions, including backwater profiles and drawdown curves. Comparison of these models with experimental data from volitional swimming studies of fish indicates reasonable performance, but limitations are still present due to the difficulty in predicting fish behavior and passage strategies that can vary among individuals and different fish species.

  18. DISPLACE: a dynamic, individual-based model for spatial fishing planning and effort displacement: Integrating underlying fish population models

    DEFF Research Database (Denmark)

    Bastardie, Francois; Nielsen, J. Rasmus; Miethe, Tanja

    We previously developed a spatially explicit, individual-based model (IBM) evaluating the bio-economic efficiency of fishing vessel movements between regions according to the catching and targeting of different species based on the most recent high resolution spatial fishery data. The main purpose...... version couples the vessel model to selected size-based population models and considers the underlying resource dynamics in the distribution and density patterns of the targeted stocks for the cases of Danish and German vessels harvesting the North Sea and Baltic fish stocks. The stochastic fishing...... by vessels on the fish stocks, with resulting fishing mortality, and the vessels’ economic consequences are evaluated on high spatial and seasonal disaggregation levels by simulating different individual choices of vessel speed, fishing grounds and ports. All tested scenarios led to increased overall energy...

  19. O&M Modeling of Offshore Wind Farms - State of the Art and Future Developments

    DEFF Research Database (Denmark)

    Asgarpour, Masoud; Sørensen, John Dalsgaard

    2016-01-01

    In this paper the state of the art in O&M models for O&M cost estimation of offshore wind farms is discussed and then, a case study for O&M cost estimation of an 800 MW reference offshore wind farm is given. Moreover, a framework for an ideal O&M strategy optimizer to achieve the maximum possible O...

  20. Wind deficit model in a wind farm using finite volume method

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2010-01-01

    A wind deficit model for wind farms is developed in this work using finite volume method. The main question addressed here is to calculate approximately the wind speed in the vicinity of each wind turbine of a farm. The procedure followed is to solve the governing equations of flow for the whole ...

  1. Bio-economic farm modelling to analyse agricultural land productivity in Rwanda

    NARCIS (Netherlands)

    Bidogeza, J.C.

    2011-01-01

    Keywords: Rwanda; farm household typology; sustainable technology adoption; multivariate analysis;
    land degradation; food security; bioeconomic model; crop simulation models; organic fertiliser; inorganic fertiliser; policy incentives In Rwanda, land degradation contributes to the low and

  2. Development of Solar Drying Model for Selected Cambodian Fish Species

    Directory of Open Access Journals (Sweden)

    Anna Hubackova

    2014-01-01

    Full Text Available A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6°C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg·h−1. Based on coefficient of determination (R2, chi-square (χ2 test, and root-mean-square error (RMSE, the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing.

  3. Development of solar drying model for selected Cambodian fish species.

    Science.gov (United States)

    Hubackova, Anna; Kucerova, Iva; Chrun, Rithy; Chaloupkova, Petra; Banout, Jan

    2014-01-01

    A solar drying was investigated as one of perspective techniques for fish processing in Cambodia. The solar drying was compared to conventional drying in electric oven. Five typical Cambodian fish species were selected for this study. Mean solar drying temperature and drying air relative humidity were 55.6 °C and 19.9%, respectively. The overall solar dryer efficiency was 12.37%, which is typical for natural convection solar dryers. An average evaporative capacity of solar dryer was 0.049 kg · h(-1). Based on coefficient of determination (R(2)), chi-square (χ(2)) test, and root-mean-square error (RMSE), the most suitable models describing natural convection solar drying kinetics were Logarithmic model, Diffusion approximate model, and Two-term model for climbing perch and Nile tilapia, swamp eel and walking catfish and Channa fish, respectively. In case of electric oven drying, the Modified Page 1 model shows the best results for all investigated fish species except Channa fish where the two-term model is the best one. Sensory evaluation shows that most preferable fish is climbing perch, followed by Nile tilapia and walking catfish. This study brings new knowledge about drying kinetics of fresh water fish species in Cambodia and confirms the solar drying as acceptable technology for fish processing.

  4. Fish parasites

    DEFF Research Database (Denmark)

    This book contains 22 chapters on some of the most important parasitic diseases in wild and farmed fish. International experts give updated reviews and provide solutions to the problems......This book contains 22 chapters on some of the most important parasitic diseases in wild and farmed fish. International experts give updated reviews and provide solutions to the problems...

  5. Modeling large offshore wind farms under different atmospheric stability regimes with the Park wake model

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Réthoré, Pierre-Elouan; Rathmann, Ole

    2014-01-01

    We evaluate a modified version of the Park wake model against power data from a west-east row in the middle of the Horns Rev I offshore wind farm. The evaluation is performed on data classified in four different atmospheric stability conditions, for a narrow wind speed range, and a wide range of ...... are different. The ensemble average of the simulations does not approach the limits of the infinite wind farm under any stability condition as such averages account for directions misaligned with the row....

  6. Offshore wind farms as productive sites or ecological traps for gadoid fishes?--impact on growth, condition index and diet composition.

    Science.gov (United States)

    Reubens, Jan T; Vandendriessche, Sofie; Zenner, Annemie N; Degraer, Steven; Vincx, Magda

    2013-09-01

    With the construction of wind farms all across the North Sea, numerous artificial reefs are created. These windmill artificial reefs (WARs) harbour high abundances of fish species which can be attracted from elsewhere or can be the result of extra production induced by these wind farms. To resolve the attraction-production debate in suddenly altered ecosystems (cf. wind farms), the possible consequences of attraction should be assessed; thereby bearing in mind that ecological traps may arise. In this paper we investigated whether the wind farms in the Belgian part of the North Sea act as ecological traps for pouting and Atlantic cod. Length-at-age, condition and diet composition of fish present at the windmill artificial reefs was compared to local and regional sandy areas. Fish data from the period 2009-2012 were evaluated. Mainly I- and II-group Atlantic cod were present around the WARs; while the 0- and I-group dominated for pouting. For Atlantic cod, no differences in length were observed between sites, indicating that fitness was comparable at the WARs and in sandy areas. No significant differences in condition index were observed for pouting. At the WARs, they were slightly larger and stomach fullness was enhanced compared to the surrounding sandy areas. Also diet differed considerably among the sites. The outcome of the proxies indicate that fitness of pouting was slightly enhanced compared to the surrounding sandy areas. No evidence was obtained supporting the hypothesis that the WARs act as an ecological trap for Atlantic cod and pouting.

  7. Modeling and investigation of Gulf El-Zayt wind farm for stability studying during extreme

    Directory of Open Access Journals (Sweden)

    Omar Noureldeen

    2014-03-01

    Full Text Available This paper investigates the impact of extreme gust wind as a case of wind speed variation on a wind farm interconnected electrical grid. The impact of extreme gust wind speed variation on active and reactive power of the wind farms is studied for variable speed wind farm equipped with Doubly Fed Induction Generators (DFIGs. A simulation model of the under implementation 120 MW wind farm at Gulf El-Zayt region, Red Sea, Egypt, is simulated as a case study. A detailed model of extreme gust wind speed variation is implemented and simulated, using MATLAB/Simulink toolbox, based on International Electrotechnical Commission IEC 61400-1 and climate characteristic of Gulf El-Zayt site. The simulation results show the influence of different extreme gust wind speed variations on the fluctuation of active power and reactive power at the Point of Common Coupling (PCC of the studied wind farm.

  8. Water and Soil Analyses of Balongis Fish Cage and Oster (Talaba Farms in Concepcion River, Kabasalan, Zamboanga Sibugay Province, Philippines

    Directory of Open Access Journals (Sweden)

    Victoria L. Lim

    2017-02-01

    Full Text Available The decline of the talaba (saccosrea malabonensis production in Barangay Concepcion, Kabasalan, Zamboanga Sibugay motivated the fisher folks to determine the cause of the phenomenon through the Social Action Ministry (SAM – Diocese of Ipil, Ipil, Zamboanga Sibugay,Philippines who arranged for the conduct of the study. The research was hypothesized to be caused by climate change. Data collection began on January 28 until February 8, 2012 on site. Twelve (12 sampling sites were installed in Concepcion River barangay Balongis, Buayan Zamboanga Sibugay where the barangay’s fish cage and oyster (Talaba farms are Global Positioning System (GPS gadget was used for the identification/markings of sampling stations (07⁰ 46.00 N and 122⁰47.116E to 07⁰45.778 N and 122⁰47.151 E Water and soil/sediment samples were taken and analyzed once a week for three consecutive weeks – January 28 to February 18, 2012. Physical water parameters were taken in situ (pH, Temperature, salinity and TSS. Water temperature raging 24⁰C-31.5⁰C, water pH 7.0-8.24, water salinity 18 -27.6 ppt. Total Suspended Solids (TSS ranged 0.104 g/L to 0.672 g/L – classified turbid water for all sampling sites. Sediment analysis: for mercury containment – qualitative analysis is negative, Soil Classification using the Textual triangle – soil classified as Loamy Sand (Sites 7-10 and Sandy Loam for all other sites. Meiofauna component using the Nematoma, turbellaria, Ciliophora, Ostracoda, Gastrotricha, Tardigrada, Sarcomastigaphora, Sincarida, Copepoda and some other unidentified fauna. Sedimentation rate averaged from 1410-6469 g/m2 per week. The high sediment rate could have caused the decline in oyster production but not by mercury contamination as suspected.

  9. Wind farms providing secondary frequency regulation: Evaluating the performance of model-based receding horizon control

    Science.gov (United States)

    Shapiro, Carl R.; Meyers, Johan; Meneveau, Charles; Gayme, Dennice F.

    2016-09-01

    We investigate the use of wind farms to provide secondary frequency regulation for a power grid. Our approach uses model-based receding horizon control of a wind farm that is tested using a large eddy simulation (LES) framework. In order to enable real-time implementation, the control actions are computed based on a time-varying one-dimensional wake model. This model describes wake advection and interactions, both of which play an important role in wind farm power production. This controller is implemented in an LES model of an 84-turbine wind farm represented by actuator disk turbine models. Differences between the velocities at each turbine predicted by the wake model and measured in LES are used for closed-loop feedback. The controller is tested on two types of regulation signals, “RegA” and “RegD”, obtained from PJM, an independent system operator in the eastern United States. Composite performance scores, which are used by PJM to qualify plants for regulation, are used to evaluate the performance of the controlled wind farm. Our results demonstrate that the controlled wind farm consistently performs well, passing the qualification threshold for all fastacting RegD signals. For the RegA signal, which changes over slower time scales, the controlled wind farm's average performance surpasses the threshold, but further work is needed to enable the controlled system to achieve qualifying performance all of the time.

  10. Modeling Commercial Freshwater Turtle Production on US Farms for Pet and Meat Markets.

    Directory of Open Access Journals (Sweden)

    Ivana Mali

    Full Text Available Freshwater turtles are being exploited for meat, eggs, traditional medicine, and pet trade. As a response, turtle farming became a booming aquaculture industry in the past two decades, specifically in the southeastern states of the United States of America (US and across Southeast Asia. However, US turtle farms are currently producing turtles only for the pet trade while commercial trappers remain focused on catching the largest individuals from the wild. In our analyses we have created a biological and economic model that describes farming operations on a representative turtle farm in Louisiana. We first modeled current production of hatchling and yearling red-eared slider turtles (Trachemys scripta elegans (i.e., traditional farming for foreign and domestic pet markets, respectively. We tested the possibility of harvesting adult turtles from the breeding stock for sale to meat markets to enable alternative markets for the farmers, while decreasing the continued pressures on wild populations (i.e., non-traditional farming. Our economic model required current profit requirements of ~$13/turtle or ~$20.31/kg of meat from non-traditional farming in order to acquire the same profit as traditional farming, a value which currently exceeds market values of red-eared sliders. However, increasing competition with Asian turtle farms and decreasing hatchling prices may force the shift in the US toward producing turtles for meat markets. In addition, our model can be modified and applied to more desirable species on the meat market once more knowledge is acquired about species life histories and space requirements under farmed conditions.

  11. Modeling Commercial Freshwater Turtle Production on US Farms for Pet and Meat Markets

    Science.gov (United States)

    Mali, Ivana; Wang, Hsiao-Hsuan; Grant, William E.; Feldman, Mark; Forstner, Michael R. J.

    2015-01-01

    Freshwater turtles are being exploited for meat, eggs, traditional medicine, and pet trade. As a response, turtle farming became a booming aquaculture industry in the past two decades, specifically in the southeastern states of the United States of America (US) and across Southeast Asia. However, US turtle farms are currently producing turtles only for the pet trade while commercial trappers remain focused on catching the largest individuals from the wild. In our analyses we have created a biological and economic model that describes farming operations on a representative turtle farm in Louisiana. We first modeled current production of hatchling and yearling red-eared slider turtles (Trachemys scripta elegans) (i.e., traditional farming) for foreign and domestic pet markets, respectively. We tested the possibility of harvesting adult turtles from the breeding stock for sale to meat markets to enable alternative markets for the farmers, while decreasing the continued pressures on wild populations (i.e., non-traditional farming). Our economic model required current profit requirements of ~$13/turtle or ~$20.31/kg of meat from non-traditional farming in order to acquire the same profit as traditional farming, a value which currently exceeds market values of red-eared sliders. However, increasing competition with Asian turtle farms and decreasing hatchling prices may force the shift in the US toward producing turtles for meat markets. In addition, our model can be modified and applied to more desirable species on the meat market once more knowledge is acquired about species life histories and space requirements under farmed conditions. PMID:26407157

  12. Modeling Commercial Freshwater Turtle Production on US Farms for Pet and Meat Markets.

    Science.gov (United States)

    Mali, Ivana; Wang, Hsiao-Hsuan; Grant, William E; Feldman, Mark; Forstner, Michael R J

    2015-01-01

    Freshwater turtles are being exploited for meat, eggs, traditional medicine, and pet trade. As a response, turtle farming became a booming aquaculture industry in the past two decades, specifically in the southeastern states of the United States of America (US) and across Southeast Asia. However, US turtle farms are currently producing turtles only for the pet trade while commercial trappers remain focused on catching the largest individuals from the wild. In our analyses we have created a biological and economic model that describes farming operations on a representative turtle farm in Louisiana. We first modeled current production of hatchling and yearling red-eared slider turtles (Trachemys scripta elegans) (i.e., traditional farming) for foreign and domestic pet markets, respectively. We tested the possibility of harvesting adult turtles from the breeding stock for sale to meat markets to enable alternative markets for the farmers, while decreasing the continued pressures on wild populations (i.e., non-traditional farming). Our economic model required current profit requirements of ~$13/turtle or ~$20.31/kg of meat from non-traditional farming in order to acquire the same profit as traditional farming, a value which currently exceeds market values of red-eared sliders. However, increasing competition with Asian turtle farms and decreasing hatchling prices may force the shift in the US toward producing turtles for meat markets. In addition, our model can be modified and applied to more desirable species on the meat market once more knowledge is acquired about species life histories and space requirements under farmed conditions.

  13. Modelling studies of fish production in integrated agriculture - aquaculture systems

    NARCIS (Netherlands)

    Dam, van A.A.

    1995-01-01


    The general objective of this thesis is to formulate a general model for fish production in integrated ponds and ricefields as a means of obtaining a better understanding of these production systems. Integrated culture systems produce fish without large industrial energy inputs and have

  14. A socio-hydrologic model of coupled water-agriculture dynamics with emphasis on farm size.

    Science.gov (United States)

    Brugger, D. R.; Maneta, M. P.

    2015-12-01

    Agricultural land cover dynamics in the U.S. are dominated by two trends: 1) total agricultural land is decreasing and 2) average farm size is increasing. These trends have important implications for the future of water resources because 1) growing more food on less land is due in large part to increased groundwater withdrawal and 2) larger farms can better afford both more efficient irrigation and more groundwater access. However, these large-scale trends are due to individual farm operators responding to many factors including climate, economics, and policy. It is therefore difficult to incorporate the trends into watershed-scale hydrologic models. Traditional scenario-based approaches are valuable for many applications, but there is typically no feedback between the hydrologic model and the agricultural dynamics and so limited insight is gained into the how agriculture co-evolves with water resources. We present a socio-hydrologic model that couples simplified hydrologic and agricultural economic dynamics, accounting for many factors that depend on farm size such as irrigation efficiency and returns to scale. We introduce an "economic memory" (EM) state variable that is driven by agricultural revenue and affects whether farms are sold when land market values exceed expected returns from agriculture. The model uses a Generalized Mixture Model of Gaussians to approximate the distribution of farm sizes in a study area, effectively lumping farms into "small," "medium," and "large" groups that have independent parameterizations. We apply the model in a semi-arid watershed in the upper Columbia River Basin, calibrating to data on streamflow, total agricultural land cover, and farm size distribution. The model is used to investigate the sensitivity of the coupled system to various hydrologic and economic scenarios such as increasing market value of land, reduced surface water availability, and increased irrigation efficiency in small farms.

  15. Modelling the interactions between regional farming structure, nitrogen losses and environmental regulation

    DEFF Research Database (Denmark)

    Happe, Kathrin; Hutchings, Nick; Dalgaard, Tommy;

    2011-01-01

    Changes in the structure of agriculture are known to affect emissions of environmental pollutants from agriculture. Such changes are often driven by structural changes in agricultural production, so structural changes are likely to have indirect effects on emissions. In a pilot study, we consider...... how linking two complementary simulation models might be used to explore these effects. The agent-based AgriPoliS model was used to simulate the structural dynamics of agricultural production. The results from AgriPoliS were passed via a number of intermediate models to the Farm-N model, which...... was used to estimate the nitrogen surplus and losses from each farm for each year. The modelling complex was exercised by simulating the effects of two plausible policy scenarios for each of 14 years. The initial sizes and types of farms were based on statistics from a region in Denmark and the farms were...

  16. Sustainable agriculture: how to make it work? : a modeling approach to support management of a mixed ecological farm

    NARCIS (Netherlands)

    Wolfert, S.

    2002-01-01

    Keywords: sustainable agriculture; organic farming; whole farm management; decision support; farming systems research; designing; modeling; beta-gamma integration

    The objective of the research described in this thesis was to develop a model that helps

  17. Identification and functional expression of a glutamate- and avermectin-gated chloride channel from Caligus rogercresseyi, a southern Hemisphere sea louse affecting farmed fish.

    Directory of Open Access Journals (Sweden)

    Isabel Cornejo

    2014-09-01

    Full Text Available Parasitic sea lice represent a major sanitary threat to marine salmonid aquaculture, an industry accounting for 7% of world fish production. Caligus rogercresseyi is the principal sea louse species infesting farmed salmon and trout in the southern hemisphere. Most effective control of Caligus has been obtained with macrocyclic lactones (MLs ivermectin and emamectin. These drugs target glutamate-gated chloride channels (GluCl and act as irreversible non-competitive agonists causing neuronal inhibition, paralysis and death of the parasite. Here we report the cloning of a full-length CrGluClα receptor from Caligus rogercresseyi. Expression in Xenopus oocytes and electrophysiological assays show that CrGluClα is activated by glutamate and mediates chloride currents blocked by the ligand-gated anion channel inhibitor picrotoxin. Both ivermectin and emamectin activate CrGluClα in the absence of glutamate. The effects are irreversible and occur with an EC(50 value of around 200 nM, being cooperative (n(H = 2 for ivermectin but not for emamectin. Using the three-dimensional structure of a GluClα from Caenorabditis elegans, the only available for any eukaryotic ligand-gated anion channel, we have constructed a homology model for CrGluClα. Docking and molecular dynamics calculations reveal the way in which ivermectin and emamectin interact with CrGluClα. Both drugs intercalate between transmembrane domains M1 and M3 of neighbouring subunits of a pentameric structure. The structure displays three H-bonds involved in this interaction, but despite similarity in structure only of two these are conserved from the C. elegans crystal binding site. Our data strongly suggest that CrGluClα is an important target for avermectins used in the treatment of sea louse infestation in farmed salmonids and open the way for ascertaining a possible mechanism of increasing resistance to MLs in aquaculture industry. Molecular modeling could help in the design of new

  18. Using a whole farm model to determine the impacts of mating management on the profitability of pasture-based dairy farms.

    Science.gov (United States)

    Beukes, P C; Burke, C R; Levy, G; Tiddy, R M

    2010-08-01

    An approach to assessing likely impacts of altering reproductive performance on productivity and profitability in pasture-based dairy farms is described. The basis is the development of a whole farm model (WFM) that simulates the entire farm system and holistically links multiple physical performance factors to profitability. The WFM consists of a framework that links a mechanistic cow model, a pasture model, a crop model, management policies and climate. It simulates individual cows and paddocks, and runs on a day time-step. The WFM was upgraded to include reproductive modeling capability using reference tables and empirical equations describing published relationships between cow factors, physiology and mating management. It predicts reproductive status at any time point for individual cows within a modeled herd. The performance of six commercial pasture-based dairy farms was simulated for the period of 12 months beginning 1 June 2005 (05/06 year) to evaluate the accuracy of the model by comparison with actual outcomes. The model predicted most key performance indicators within an acceptable range of error (residualfarms to estimate the profitability of changes in farm "set-up" (farm conditions at the start of the farming year on 1 June) and mating management from 05/06 to 06/07 year. Among the six farms simulated, the 4-week calving rate emerged as an important set-up factor influencing profitability, while reproductive performance during natural bull mating was identified as an area with the greatest opportunity for improvement. The WFM presents utility to explore alternative management strategies to predict likely outcomes to proposed changes to a pasture-based farm system. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  19. Integrating Water Flow, Solute Transport and Crop Production Models At The Farm-scale

    Science.gov (United States)

    Assinck, F. B. T.; de Vos, J. A.

    Minimising nitrate pollution of ground and surface water and optimising agricultural yields are problems which have to be addressed at the farm-scale. However, simulation models usually operate at the field-scale. We coupled the subsurface hydrology model SWAP with other existing deterministic (sub)models for solute transport, organic mat- ter dynamics, crop growth, and dairy farm management at the farm-scale, resulting in the model WATERPAS. The (sub)models are coupled in a Framework environment obeying the principles of object oriented modelling. Based on daily weather data, groundwater regimes, soil and farm characteristics WATERPAS is able to simulate the water and nutrient balances, grass production, economical benefits, nitrate leaching and greenhouse gas emissions at a farm. Problems of coupling, such as data-transfer, quality checks, over-parameterisation, complexity and sensitivity of the systems are discussed. Application of deducted simpler models and expert judgement can be use- ful for practical use. However, we believe that integrated models are a powerful tool to understand the complex relationships between the different processes. It also gives opportunities to perform scenario analysis for future boundary conditions, i.e. due to changing farm management, (sea) water levels and climate change.

  20. A REGIONAL ANALYSIS OF THE USE OF TRACTORS ON MODEL FARMS PRODUCING ENERGY CROPS

    Directory of Open Access Journals (Sweden)

    Benedykt Pepliński

    2015-06-01

    Full Text Available The potential area of energy crops in Poland is estimated at 1.0–4.5 million ha. The decrease in the prices of energy reduces the high pressure to cut the costs of biomass production. The aim of this study is an analysis of the use of tractors on model farms producing energy crops, which have different areas, intensity of production and quality of soils from different regions of Poland. The use of tractors increased along with the farm area, the soil quality and production intensity. The use of tractors on the smallest farms is low, so they should buy old tractors. A large share of crops for biogas leads to the situation where it takes 20–30 years of work for tractors to achieve full wear of 12,000 hours on farms with 130 ha of farmland, whereas it takes only 8–14 years on farms with 600 and 1500 ha of farmland. Regional differences in the use of tractors increased along with the farm area from 4.7–5.7% on the smallest farms to 10.1–14.8% on the largest farms.

  1. Beyond the zebrafish: diverse fish species for modeling human disease

    Directory of Open Access Journals (Sweden)

    Manfred Schartl

    2014-02-01

    Full Text Available In recent years, zebrafish, and to a lesser extent medaka, have become widely used small animal models for human diseases. These organisms have convincingly demonstrated the usefulness of fish for improving our understanding of the molecular and cellular mechanisms leading to pathological conditions, and for the development of new diagnostic and therapeutic tools. Despite the usefulness of zebrafish and medaka in the investigation of a wide spectrum of traits, there is evidence to suggest that other fish species could be better suited for more targeted questions. With the emergence of new, improved sequencing technologies that enable genomic resources to be generated with increasing efficiency and speed, the potential of non-mainstream fish species as disease models can now be explored. A key feature of these fish species is that the pathological condition that they model is often related to specific evolutionary adaptations. By exploring these adaptations, new disease-causing and disease-modifier genes might be identified; thus, diverse fish species could be exploited to better understand the complexity of disease processes. In addition, non-mainstream fish models could allow us to study the impact of environmental factors, as well as genetic variation, on complex disease phenotypes. This Review will discuss the opportunities that such fish models offer for current and future biomedical research.

  2. Wind Farm Reliability Modelling Using Bayesian Networks and Semi-Markov Processes

    Directory of Open Access Journals (Sweden)

    Robert Adam Sobolewski

    2015-09-01

    Full Text Available Technical reliability plays an important role among factors affecting the power output of a wind farm. The reliability is determined by an internal collection grid topology and reliability of its electrical components, e.g. generators, transformers, cables, switch breakers, protective relays, and busbars. A wind farm reliability’s quantitative measure can be the probability distribution of combinations of operating and failed states of the farm’s wind turbines. The operating state of a wind turbine is its ability to generate power and to transfer it to an external power grid, which means the availability of the wind turbine and other equipment necessary for the power transfer to the external grid. This measure can be used for quantitative analysis of the impact of various wind farm topologies and the reliability of individual farm components on the farm reliability, and for determining the expected farm output power with consideration of the reliability. This knowledge may be useful in an analysis of power generation reliability in power systems. The paper presents probabilistic models that quantify the wind farm reliability taking into account the above-mentioned technical factors. To formulate the reliability models Bayesian networks and semi-Markov processes were used. Using Bayesian networks the wind farm structural reliability was mapped, as well as quantitative characteristics describing equipment reliability. To determine the characteristics semi-Markov processes were used. The paper presents an example calculation of: (i probability distribution of the combination of both operating and failed states of four wind turbines included in the wind farm, and (ii expected wind farm output power with consideration of its reliability.

  3. Farm Process (FMP) Parameters used in the Central Valley Hydrologic Model (CVHM)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital dataset defines the farm-process parameters used in the transient hydrologic model of the Central Valley flow system. The Central Valley encompasses an...

  4. The role of a fish pond in optimizing nutrient flows in integrated agriculture-aquaculture farming systems

    NARCIS (Netherlands)

    Nhan, D.K.

    2007-01-01

      In the Mekong delta, the Vietnamese government promoted integrated agriculture-aquaculture (IAA) farming systems as an example of sustainable agriculture. An important advantage of IAA-farming is the nutrient linkage between the pond and terrestrial components within a f

  5. The role of a fish pond in optimizing nutrient flows in integrated agriculture-aquaculture farming systems

    NARCIS (Netherlands)

    Nhan, D.K.

    2007-01-01

      In the Mekong delta, the Vietnamese government promoted integrated agriculture-aquaculture (IAA) farming systems as an example of sustainable agriculture. An important advantage of IAA-farming is the nutrient linkage between the pond and terrestrial components within a

  6. The role of a fish pond in optimizing nutrient flows in integrated agriculture-aquaculture farming systems

    NARCIS (Netherlands)

    Nhan, D.K.

    2007-01-01

      In the Mekong delta, the Vietnamese government promoted integrated agriculture-aquaculture (IAA) farming systems as an example of sustainable agriculture. An important advantage of IAA-farming is the nutrient linkage between the pond and terrestrial components within a f

  7. Modelization of a large wind farm, considering the modification of the atmospheric boundary layer

    Energy Technology Data Exchange (ETDEWEB)

    Crespo, A.; Gomez-Elvira, R. [Univ. Politecnica de Madrid, Mecanica de Fluidos, E.T.S.I. Industriales, Madrid (Spain); Frandsen, S.; Larsen, S.E. [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    A method is presented to adapt existing models of wind farms to very large ones that may affect the whole planetary boundary layer. An internal boundary layer is considered that starts developing at the leading edge of the farm until it reaches, sufficiently far downstream, the top of the planetary boundary layer, and a new equilibrium region is reached. The wind farm is simulated by an artificial roughness that is function of the turbine spacing, drag and height. From this model the flow conditions are calculated at a certain reference height and then are used as boundary conditions for a numerical code used to model a wind farm. Three-dimensional effects are considered by applying appropriate conditions at the sides of the farm. Calculations are carried out to estimate the energy production in large wind farms, and it is found that additional losses due to modification of the planetary boundary layer may be of importance for wind farms of size larger than about 100 km. (au)

  8. Analytical Modeling of Wind Farms: A New Approach for Power Prediction

    Directory of Open Access Journals (Sweden)

    Amin Niayifar

    2016-09-01

    Full Text Available Wind farm power production is known to be strongly affected by turbine wake effects. The purpose of this study is to develop and test a new analytical model for the prediction of wind turbine wakes and the associated power losses in wind farms. The new model is an extension of the one recently proposed by Bastankhah and Porté-Agel for the wake of stand-alone wind turbines. It satisfies the conservation of mass and momentum and assumes a self-similar Gaussian shape of the velocity deficit. The local wake growth rate is estimated based on the local streamwise turbulence intensity. Superposition of velocity deficits is used to model the interaction of the multiple wakes. Furthermore, the power production from the wind turbines is calculated using the power curve. The performance of the new analytical wind farm model is validated against power measurements and large-eddy simulation (LES data from the Horns Rev wind farm for a wide range of wind directions, corresponding to a variety of full-wake and partial-wake conditions. A reasonable agreement is found between the proposed analytical model, LES data, and power measurements. Compared with a commonly used wind farm wake model, the new model shows a significant improvement in the prediction of wind farm power.

  9. Silagem de peixe em ração artesanal para tilápia-do-nilo Fish silage in farm-made feed for Nile tilapia

    Directory of Open Access Journals (Sweden)

    Eduardo Gianini Abimorad

    2009-05-01

    Full Text Available O objetivo deste trabalho foi avaliar o emprego de ração artesanal à base de silagem de resíduo da filetagem de pescado na criação de tilápia-do-nilo (Oreochromis niloticus. Dois mil e setenta juvenis de tilápia revertidos (83,1 g foram distribuídos em seis viveiros escavados com 230 m² cada um, na densidade de estocagem de 1,5 peixe por metro quadrado, em delineamento inteiramente casualizado com dois tratamentos (ração artesanal e ração comercial e três repetições. Foram analisados os parâmetros de desempenho produtivo (sobrevivência, ganho em peso, conversão alimentar aparente, taxa de crescimento específico e coeficiente de variação do peso final, as variáveis de qualidade da água (oxigênio dissolvido, transparência e fósforo e nitrogênio total, o custo de arraçoamento e a composição corporal. Não houve diferença significativa entre as rações para os parâmetros de desempenho produtivo. Verificou-se maior eutrofização da água dos viveiros onde os peixes receberam ração artesanal. O custo por quilograma de peixe produzido com ração artesanal (R$ 1,07 foi aproximadamente 42% menor que o de peixe produzido com ração comercial (R$ 1,86. Os peixes alimentados com ração artesanal tiveram teor de lipídios significativamente menor na carcaça.The objective of this work was to evaluate the use of a farm-made feed based on silage of fish filleting residues for Nile tilapia (Oreochromis niloticus farming. Two thousand and seventy masculinized tilapia juveniles (83.1 g were distributed into six ponds (230 m², at a stocking density of 1.5 fish per square meter. The experimental design was a completely randomized with two treatments (farm-made and commercial feeds and three replicates. The performance parameters analyzed were survival, weight gain, apparent feed conversion, specific growth rate, and final weight coefficient of variation. The water quality variables analyzed were dissolved oxygen

  10. Damped trophic cascades driven by fishing in model marine ecosystems

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Pedersen, Martin

    2010-01-01

    that fishing does not change the overall slope of the size spectrum, but depletes the largest individuals and induces trophic cascades. A trophic cascade can propagate both up and down in trophic levels driven by a combination of changes in predation mortality and food limitation. The cascade is damped...... cascade triggered by the removal of top predators. Here we use a novel size- and trait-based model to explore how marine ecosystems might react to perturbations from different types of fishing pressure. The model explicitly resolves the whole life history of fish, from larvae to adults. The results show...

  11. Modelling of offshore wind turbine wakes with the wind farm program FLaP

    DEFF Research Database (Denmark)

    Lange, B.; Waldl, H.P.; Guerrero, A.G.

    2003-01-01

    The wind farm layout program FLaP estimates the wind speed at any point in a wind farm and the power output of the turbines. The ambient flow conditions and the properties of the turbines and the farm are used as input. The core of the program is an axisymmetric wake model describing the wake...... been extended to improve the description of wake development in offshore conditions, especially the low ambient turbulence and the effect of atmospheric stability. Model results are compared with measurements from the Danish offshore wind farm Vindeby. Vertical wake profiles and mean turbulence...... intensities in the wake are compared for single-, double- and quintuple-wake cases with different mean wind speed, turbulence intensity and atmospheric stability. It is found that within the measurement uncertainties the results of the wake model compare well with the measurements for the most important...

  12. Production and economic results of intensive carp (Cyprinus Carpio farming in Serbia

    Directory of Open Access Journals (Sweden)

    Rajić Zoran

    2016-01-01

    Full Text Available Carp production in Serbia is traditionally conducted in large area fish farms under a semi-intensive farming system. Total area under fish farms in Serbia amounts to approximately 11 thousand hectares, with 8.5 thousand hectares being under exploitation each year. In 2004, a significant intensification of production began at fish farms in Serbia which have traditionally organized their production under a classic semi-intensive farming system. Intensification of production was undertaken with partial or complete feeding with pelleted complete feeds. That way carp production per area unit (kg/ha was increased by over 50%. Apart from intensification by means of using the complete extruded feeds, construction of specialized fish farms for intensive carp production started in 2003. At this moment (2016 their area amounts to several hundred hectares. Data from intensive carp fish farms indicate that production of one- and two-year fish has been approximately 3t/ha in the period from 2003 until today, with a mild increase during the last couple of years. With the purpose of determining the cost effectiveness of investments in fish ponds for intensive carp production two organization-economic models have been analyzed in the study. The models have been formed based on in line with the specific features of the Serbian carp farming, which has been analyzed both on the basis of data obtained from the scientific and specialist literature but also from the production practice. Models of intensive carp production in technical and production sense have been defined in the study and production plans have been prepared. Therefore, based on such defined models, dynamic methods have been prepared for assessment of economic effects of the investments. The results of the analysis have demonstrated that investment in intensive carp production on 10ha fish farm is not, and on 50ha fish farm is barely economically justifiable, as well as methods for improvement of

  13. The tetracycline resistance determinant Tet 39 and the sulphonamide resistance gene sulII are common among resistant Acinetobacter spp. isolated from integrated fish farms in Thailand

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Petersen, Andreas

    2007-01-01

    Objectives: To determine the genetic basis for tetracycline and sulphonamide resistance and the prevalence of class I and II integrons in oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Methods: A total of 222 isolates were screened for tetracycline resistance...... genes [tet(A), tet(B), tet(H), tet(M) and tet(39)] and class II integrons by PCR. One hundred and thirty-four of these isolates were also sulphonamide resistant and these isolates were screened for sulphonamide resistance genes (sulII and sulIII) as well as class I integrons. Plasmid extraction...

  14. Whole-farm models to quantify greenhouse gas emissions and their potential use for linking climate change mitigation and adaptation in temperate grassland ruminant-based farming systems.

    Science.gov (United States)

    Del Prado, A; Crosson, P; Olesen, J E; Rotz, C A

    2013-06-01

    The farm level is the most appropriate scale for evaluating options for mitigating greenhouse gas (GHG) emissions, because the farm represents the unit at which management decisions in livestock production are made. To date, a number of whole farm modelling approaches have been developed to quantify GHG emissions and explore climate change mitigation strategies for livestock systems. This paper analyses the limitations and strengths of the different existing approaches for modelling GHG mitigation by considering basic model structures, approaches for simulating GHG emissions from various farm components and the sensitivity of GHG outputs and mitigation measures to different approaches. Potential challenges for linking existing models with the simulation of impacts and adaptation measures under climate change are explored along with a brief discussion of the effects on other ecosystem services.

  15. LES of wind farm response to transient scenarios using a high fidelity actuator disk model

    Science.gov (United States)

    Moens, M.; Duponcheel, M.; Winckelmans, G.; Chatelain, P.

    2016-09-01

    Large eddy simulations coupled to Actuator Disks are used to investigate wake effects in wind farms. An effort is made on the wind turbine model: it uses the prevailing velocities at each point of the disk to estimate the aerodynamic loads and is improved using a tip-loss correction and realistic control schemes. This accurate and efficient tool is used to study the wind farm response in terms of flow and power production during an unsteady scenario: this work focuses on an emergency shutdown of one rotor inside a wind farm.

  16. Local Knowledge of Pond Fish-Farming Ecosystem Services: Management Implications of Stakeholders’ Perceptions in Three Different Contexts (Brazil, France and Indonesia

    Directory of Open Access Journals (Sweden)

    Syndhia Mathé

    2015-06-01

    Full Text Available This article addresses ecosystem service perceptions in the case of pond fish-farming systems in Brazil, France and Indonesia. The Millennium Ecosystem Assessment vision suggests a more integrated reflection on environmental policies with greater adaptability to local knowledge and the development of social learning processes, which tend to promote more sustainable changes in behavior and practice than do sanctions. This study considers a part of the identification of ecosystem services. It shows that perceptions differ with the context, and found few differences depending on the type of stakeholders (fish farmers and other stakeholders. From a methodological viewpoint, this paper opens up new prospects for valuing ecosystem services through a perception study.

  17. FAST Real Time PCR for control of intra-species recycling in aquaculture feed, focused to the most relevant fish species farmed in Europe.

    Science.gov (United States)

    Espiñeira, Montserrat; Vieites, Juan M

    2016-08-01

    Recent regulations in animal feed composition prohibit intra-species recycling, the recycling of one given animal species to the same species, in order to avoid potential safety risks to human and animal health. These regulations have generated the need of their control in aquaculture by effective and specific analytical techniques. To date, most studies of species identification and detection in feedstuffs are focused on land species, but few studies are focused on species composition in fish feed. The present work describes five methodologies based in Real Time PCR for detection of the most relevant fish species farmed in Europe: gilthead sea bream (Sparus aurata); sea bass (Dicentrarchus labrax); turbot (Scophthalmus maximus); rainbow trout (Onchorynchus mykiss); and salmon (Salmo salar), in order to guarantee the intra-species recycling regulation in aquaculture feedstuffs.

  18. Harmonic models of a back-to-back converter in large offshore wind farms compared with measurement data

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2009-01-01

    The offshore wind farm with installed back-to-back power converter in wind turbines is studied. As an example the Burbo Bank offshore wind farm with Siemens Wind Power wind turbines is taken into consideration. The wind farm is simulated in DIgSILENT Power Factory software in order to determine...... results are compared with measurement data from the Burbo Bank offshore wind farm. The delimitations of both power converter models with referent to harmonic analysis are shown in this paper....

  19. Building a stakeholder's vision of an offshore wind-farm project: A group modeling approach.

    Science.gov (United States)

    Château, Pierre-Alexandre; Chang, Yang-Chi; Chen, Hsin; Ko, Tsung-Ting

    2012-03-15

    This paper describes a Group Model Building (GMB) initiative that was designed to discuss the various potential effects that an offshore wind-farm may have on its local ecology and socioeconomic development. The representatives of various organizations in the study area, Lu-Kang, Taiwan, have held several meetings, and structured debates have been organized to promote the emergence of a consensual view on the main issues and their implications. A System Dynamics (SD) model has been built and corrected iteratively with the participants through the GMB process. The diverse interests within the group led the process toward the design of multifunctional wind-farms with different modalities. The scenario analyses, using the SD model under various policies, including no wind-farm policy, objectively articulates the vision of the local stakeholders. The results of the SD simulations show that the multifunctional wind-farms may have superior economic effects and the larger wind-farms with bird corridors could reduce ecological impact. However, the participants of the modeling process did not appreciate any type of offshore wind-farm development when considering all of the identified key factors of social acceptance. The insight gained from the study can provide valuable information to actualize feasible strategies for the green energy technique to meet local expectations.

  20. The k-ε-fP model applied to wind farms

    DEFF Research Database (Denmark)

    Laan, van der, Paul Maarten; Sørensen, Niels N.; Réthoré, Pierre-Elouan;

    2015-01-01

    The recently developed k-ε-fP eddy-viscosity model is applied to one on-shore and two off-shore wind farms. The results are compared with power measurements and results of the standard k-ε eddy-viscosity model. In addition, the wind direction uncertainty of the measurements is used to correct...... by the turbulence models becomes smaller for wind turbines that are located further downstream. Moreover, the difference between the capability of the turbulence models to estimate the wind farm efficiency reduces with increasing wind farm size and wind turbine spacing. Copyright © 2014 John Wiley & Sons, Ltd....... the model results with a Gaussian filter. The standard k-ε eddy-viscosity model underpredicts the power deficit of the first downstream wind turbines, whereas the k-ε-fP eddy-viscosity model shows a good agreement with the measurements. However, the difference in the power deficit predicted...

  1. Fast simulation approaches for power fluctuation model of wind farm based on frequency domain

    DEFF Research Database (Denmark)

    Lin, Jin; Gao, Wen-zhong; Sun, Yuan-zhang

    2012-01-01

    This paper discusses one model developed by Riso, DTU, which is capable of simulating the power fluctuation of large wind farms in frequency domain. In the original design, the “frequency-time” transformations are time-consuming and might limit the computation speed for a wind farm of large size....... is more than 300 times if all these approaches are adopted, in any low, medium and high wind speed test scenarios....

  2. Impacts of Wake Effect and Time Delay on the Dynamic Analysis of Wind Farms Models

    Science.gov (United States)

    El-Fouly, Tarek H. M.; El-Saadany, Ehab F.; Salama, Magdy M. A.

    2008-01-01

    This article investigates the impacts of proper modeling of the wake effects and wind speed delays, between different wind turbines' rows, on the dynamic performance accuracy of the wind farms models. Three different modeling scenarios were compared to highlight the impacts of wake effects and wind speed time-delay models. In the first scenario,…

  3. Distributed Model Predictive Control of A Wind Farm for Optimal Active Power Control

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Guo, Qinglai;

    2015-01-01

    This paper presents a dynamic discrete-time Piece- Wise Affine (PWA) model of a wind turbine for the optimal active power control of a wind farm. The control objectives include both the power reference tracking from the system operator and the wind turbine mechanical load minimization. Instead......, which combines the clustering, linear identification and pattern recognition techniques. The developed model, consisting of 47 affine dynamics, is verified by the comparison with a widely-used nonlinear wind turbine model. It can be used as a predictive model for the Model Predictive Control (MPC......) or other advanced optimal control applications of a wind farm....

  4. Effects of marine wind farms on the distribution of fish, shellfish and marine mammals in the Horns Rev area

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, E.; Astrup, J.; Larsen, Finn; Munch-Petersen, S.

    2000-05-15

    The purpose of the report is: 1) to give a quantitative description of the abundance of the fish and shellfish in the area surrounding the windmill area and to evaluate the effects of the physically presence of the windmills on the abundance of fish and shellfish in the area; 2) to evaluate the artificial reef effect in the windmill area; 3) to evaluate the effects of noise and electromagnetic fields on the abundance of fish and marine mammals. (au)

  5. Statistical meandering wake model and its application to yaw-angle optimisation of wind farms

    Science.gov (United States)

    Thøgersen, E.; Tranberg, B.; Herp, J.; Greiner, M.

    2017-05-01

    The wake produced by a wind turbine is dynamically meandering and of rather narrow nature. Only when looking at large time averages, the wake appears to be static and rather broad, and is then well described by simple engineering models like the Jensen wake model (JWM). We generalise the latter deterministic models to a statistical meandering wake model (SMWM), where a random directional deflection is assigned to a narrow wake in such a way that on average it resembles a broad Jensen wake. In a second step, the model is further generalised to wind-farm level, where the deflections of the multiple wakes are treated as independently and identically distributed random variables. When carefully calibrated to the Nysted wind farm, the ensemble average of the statistical model produces the same wind-direction dependence of the power efficiency as obtained from the standard Jensen model. Upon using the JWM to perform a yaw-angle optimisation of wind-farm power output, we find an optimisation gain of 6.7% for the Nysted wind farm when compared to zero yaw angles and averaged over all wind directions. When applying the obtained JWM-based optimised yaw angles to the SMWM, the ensemble-averaged gain is calculated to be 7.5%. This outcome indicates the possible operational robustness of an optimised yaw control for real-life wind farms.

  6. Fish farming in «Baetica». The «piscine» of the halieutic site at Trafalgar Cape (Cádiz

    Directory of Open Access Journals (Sweden)

    Darío BERNAL CASASOLA

    2011-10-01

    Full Text Available The present paper presents a structure of Roman date, cut into bedrock, and possibly used for fish farming purposes. So far, this sort of evidence, which is well attested in Italian villae maritimae dating to the Late Republic and the Early Empire, had only been found in the Iberian Peninsula in the southern Tarraconense (coast of Alicante. The above mentioned structure is, therefore, the first of its kind found in the Baetica. Interpretation must combine archaeological evidence for Roman fish farming in Andalusia (ostrearum vivaria at Traducta, current Algeciras and geoarchaeological features; the structure is located in the intertidal zone and enjoys fresh water supply from the nearby halieutic site of Trafalgar Cape (Barbate, Cádiz. This paper aims at the re-interpretation of this coastal site, previously interpreted as a salted products factory, or cetaria, but the topographical and architectural features of which (vats with inner steps, cisterns, terraced structures, etc. are rather suggestive of a villa maritima or a complex centre for the exploitation of marine resources.

  7. Combined Active and Reactive Power Control of Wind Farms based on Model Predictive Control

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Wang, Jianhui;

    2017-01-01

    This paper proposes a combined wind farm controller based on Model Predictive Control (MPC). Compared with the conventional decoupled active and reactive power control, the proposed control scheme considers the significant impact of active power on voltage variations due to the low X=R ratio...... of wind farm collector systems. The voltage control is improved. Besides, by coordination of active and reactive power, the Var capacity is optimized to prevent potential failures due to Var shortage, especially when the wind farm operates close to its full load. An analytical method is used to calculate...... the sensitivity coefficients to improve the computation efficiency and overcome the convergence problem. Two control modes are designed for both normal and emergency conditions. A wind farm with 20 wind turbines was used to verify the proposed combined control scheme....

  8. Coordinated Voltage Control of a Wind Farm based on Model Predictive Control

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Guo, Qinglai

    2016-01-01

    This paper presents an autonomous wind farm voltage controller based on Model Predictive Control (MPC). The reactive power compensation and voltage regulation devices of the wind farm include Static Var Compensators (SVCs), Static Var Generators (SVGs), Wind Turbine Generators (WTGs) and On......-Load Tap Changing (OLTC) Transformer, and they are coordinated to keep the voltages of all the buses within the feasible range. Moreover, the reactive power distribution is optimized throughout the wind farm in order to maximize the dynamic reactive power reserve. The sensitivity coefficients...... are calculated based on an analytical method to improve the computation efficiency and overcome the convergence problem. Two control modes are designed for both voltage violated and normal operation conditions. A wind farm with 20 wind turbines was used to conduct case studies to verify the proposed coordinated...

  9. Small Signal Model for VSC-HVDC Connected DFIG-Based Offshore Wind Farms

    Directory of Open Access Journals (Sweden)

    Kai Liao

    2014-01-01

    Full Text Available Large-scale offshore wind farms are integrated with onshore ac grids through the voltage source converter based high voltage direct current (VSC-HVDC transmission system. The impact on the stability of the ac grids will be significant. The small signal model of a wind farm connected with voltage source converter based dc transmission system is studied in this paper. A suitable model for small signal stability analysis is presented. The control system of wind generator and the HVDC system has also been modeled in this model for small signal stability analysis. The impact of the control parameters on the network stability is investigated.

  10. Aggregated Modelling for Wind Farms for Power System Transient Stability Studies

    DEFF Research Database (Denmark)

    Liu, Hongzhi; Chen, Zhe

    2012-01-01

    Wind energy is consistently attracting great research effort and actively developed in many countries. As a result, the penetration level of wind power in the power grid is increasing as well as the size of wind farms. A large-scale wind farm may consist of hundreds of wind turbines and its total...... on a wind farm with permanent magnet synchronous generator (PMSG) wind turbines. Simulation results of the aggregated models and the detailed model are compared and analyzed respectively to prove the effectiveness of the aggregating techniques....... installed capacity could be at a level of 1000MW or even more. Consequently, the large-scale wind farm could seriously impact the operation and control of the grid. To represent a large-scale wind farm, aggregated modelling takes advantage of fast computation and simplified implementation compared...... to detailed modelling that models every wind turbines individually and the interconnections among them. In this paper, three aggregated modelling techniques, namely, multi-machine equivalent aggregation, full aggregation and semi-aggregation are presented for power system transient stability studies based...

  11. Enhanced Kalman Filtering for a 2D CFD NS Wind Farm Flow Model

    Science.gov (United States)

    Doekemeijer, B. M.; van Wingerden, J. W.; Boersma, S.; Pao, L. Y.

    2016-09-01

    Wind turbines are often grouped together for financial reasons, but due to wake development this usually results in decreased turbine lifetimes and power capture, and thereby an increased levelized cost of energy (LCOE). Wind farm control aims to minimize this cost by operating turbines at their optimal control settings. Most state-of-the-art control algorithms are open-loop and rely on low fidelity, static flow models. Closed-loop control relying on a dynamic model and state observer has real potential to further decrease wind's LCOE, but is often too computationally expensive for practical use. In this paper two time-efficient Kalman filter (KF) variants are outlined incorporating the medium fidelity, dynamic flow model “WindFarmSimulator” (WFSim). This model relies on a discretized set of Navier-Stokes equations in two dimensions to predict the flow in wind farms at low computational cost. The filters implemented are an Ensemble KF and an Approximate KF. Simulations in which a high fidelity simulation model represents the true wind farm show that these filters are 101 —102 times faster than a regular KF with comparable or better performance, correcting for wake dynamics that are not modeled in WFSim (noticeably, wake meandering and turbine hub effects). This is a first big step towards real-time closed-loop control for wind farms.

  12. Wind farm related mortality among avian migrants - a remote sensing study and model analysis

    Energy Technology Data Exchange (ETDEWEB)

    Desholm, M.

    2006-11-15

    This thesis is the result of a PhD study on bird-wind farm collisions and consists of a synopsis, five published papers, one submitted manuscript and another ready for submission. The papers describe the findings from pre- and post-construction visual, radar and thermal imaging studies (1999-2006) of migrating birds at the Nysted offshore wind farm in the Baltic Sea, Denmark. This thesis poses and answers the following questions: a) what hazard factors do offshore wind farming pose to wild birds, b) how should one choose the key focal species to study, c) how can remote sensing techniques be applied to the study of bird wind farm interactions, and d) specifically, how do water birds react when approaching an offshore wind farm? The main aim of the study was the development of a predictive bird-wind farm collision model that incorporates the avoidance rate of birds at multiple scales. Out of 235,136 migrating sea ducks only 47 individuals were predicted to collide with the wind turbine rotor-blades, equivalent to an overall mean collision risk of c. 0.02%. This thesis shows the added value of modelling in supplementing sound empirical studies in accessing the effects of major human development pressures on migratory bird populations. (au)

  13. Stackelberg Game Model of Wind Farm and Electric Vehicle Battery Switch Station

    Science.gov (United States)

    Jiang, Zhe; Li, Zhimin; Li, Wenbo; Wang, Mingqiang; Wang, Mengxia

    2017-05-01

    In this paper, a cooperation method between wind farm and Electric vehicle battery switch station (EVBSS) was proposed. In the pursuit of maximizing their own benefits, the cooperation between wind farm and EVBSS was formulated as a Stackelberg game model by treating them as decision makers in different status. As the leader, wind farm will determine the charging/discharging price to induce the charging and discharging behavior of EVBSS reasonably. Through peak load shifting, wind farm could increase its profits by selling more wind power to the power grid during time interval with a higher purchase price. As the follower, EVBSS will charge or discharge according to the price determined by wind farm. Through optimizing the charging /discharging strategy, EVBSS will try to charge with a lower price and discharge with a higher price in order to increase its profits. Since the possible charging /discharging strategy of EVBSS is known, the wind farm will take the strategy into consideration while deciding the charging /discharging price, and will adjust the price accordingly to increase its profits. The case study proved that the proposed cooperation method and model were feasible and effective.

  14. Stable isotopes as a useful tool for revealing the environmental fate and trophic effect of open-sea-cage fish farm wastes on marine benthic organisms with different feeding guilds.

    Science.gov (United States)

    Wai, Tak-Cheung; Leung, Kenneth M Y; Wu, Rudolf S S; Shin, Paul K S; Cheung, S G; Li, X Y; Lee, Joseph H W

    2011-01-01

    Environmental fate of fish farm wastes (FFW) released from an open-sea-cage farm at Kat O, Hong Kong was examined by measuring carbon and nitrogen stable isotope (SI) ratios in selected benthic organisms collected along a 2000 m transect from the farm. Our results showed that FFW significantly influenced the energy utilization profile of consumers near the fish farm. Although nitrogen enrichment effect on δ15N was anticipated in biota near the farm, the predicted patterns did not consistently occur in all feeding guilds. Two species of suspension-feeders, which relied on naturally δ15N-depleted sources, were δ15N-enriched near the fish farm. In contrast, both species of benthic grazer and deposit-feeder, which relied on naturally δ15N-enriched algal sources, were δ15N-depleted under the influence of FFW. The SI signatures of biota can, therefore, serve as feasible biomarkers for FFW discharges only when the trophic structure of the receiving environment is fully elucidated.

  15. The influence of cage farming on infection of the corvine fish Plagioscion squamosissimus (Perciformes: Sciaenidae) with metacercariae of Austrodiplostomum compactum (Digenea: Diplostomidae) from the Chavantes reservoir, São Paulo State, Brazil.

    Science.gov (United States)

    Ramos, I P; Franceschini, L; Zica, É O P; Carvalho, E D; Silva, R J

    2014-09-01

    The development of cage fish farms has been associated with an increase in parasitic diseases. Organic matter resulting from feed waste and faeces attracts animals such as birds and invertebrates that can act as hosts for parasites. The aim of this study was to evaluate the influence of cage farming on Austrodiplostomum compactum metacercariae infections of Plagioscion squamosissimus collected close to a cage farm in the Chavantes reservoir (Paranapanema River). Thirty-seven fish were collected in an area close to cages (CF), and 28 in an area not influenced by cages (CT). All specimens were weighed, measured and the eyes removed for morphological analyses of metacercariae. The prevalence, mean intensity of infection, mean abundance and condition factor were calculated. The prevalence (CF = 86.4%, CT = 57.1%), mean infection intensity (CF = 20.31 ± 1.13, CT = 4.29 ± 7.14) and mean abundance (CF = 17.70 ± 6.27, CT = 2.35 ± 0.77) were higher in the CF (P 0.05) between the mean abundance and standard length or the total weight and condition factor in either group (P> 0.05). Fish farms may interfere with the life cycle of A. compactum, leading to more infections with P. squamosissimus. This could be due to an increase in the number of host animals that are attracted by the availability of food resources derived from fish farms.

  16. Caracterização da piscicultura na região do Vale do Ribeira - SP Characterization of fish farming in the Ribeira Valley region - SP

    Directory of Open Access Journals (Sweden)

    Daniela Castellani

    2005-02-01

    Full Text Available Este trabalho buscou caracterizar a piscicultura na Região do Vale do Ribeira quanto aos sistemas de manejo. Estudaram-se quarenta e duas pisciculturas sendo que, destas, 36 praticam o sistema semi-intensivo e seis o sistema intensivo, com os seguintes objetivos: engorda de peixes, produção de alevinos e pesque-pagues. Foram listadas 41 espécies de peixes cultivadas. Apenas 6 espécies são nativas da Bacia do Rio Ribeira de Iguape: lambari (Astyanax sp Linneaus, 1758, traíra (Hoplias malabaricus Bloch, 1794, robalo (Centropomus ssp Cuvier e Valenciennes, 1928, jundiá (Rhamdia quelen Quoy e Gaimard, 1824, cascudo (Hypostomus sp Marschall, 1873 e cará (Geophagus brasiliensis Quoy e Gaimard, 1824. Em 95% das pisciculturas foram verificadas fugas de peixes exóticos e alóctones dos cultivos. A tilápia nilótica (Oreochromis niloticus Linneaus, 1758 foi a espécie mais freqüente em escapes, e também é a segunda mais cultivada pelos piscicultores, perdendo somente para o pacu (Piaractus mesopotamicus Halmberg, 1887. Foi possível verificar mediante o cálculo da conversão alimentar, que há um desperdício anual de cerca de 32% da ração utilizada nos cultivos pesquisados. A piscicultura encontra-se em plena expansão nesta região, e já representa a atividade agropecuária mais importante após a bananicultura.The aim of this work was to characterize the fish farming in the Ribeira de Iguape Basin, southern São Paulo State (Brazil, in relation to the management systems. Forty two farms were studied. A semi-intensive system is used by 36 farmers, while an intensive system is used only by 6 studied farmers. Their objectives were raising fish, juvenile fish production and sportive fishery. Forty one fish species were found to be cultivated, but only six were native species from Ribeira Valley: lambari (Astyanax sp Linneaus, 1758, traíra (Hoplias malabaricus Bloch, 1794, robalo (Centropomus ssp Cuvier and Valenciennes, 1928, jundi

  17. A process-based emission model of volatile organic compounds from silage sources on farms

    Science.gov (United States)

    Bonifacio, H. F.; Rotz, C. A.; Hafner, S. D.; Montes, F.; Cohen, M.; Mitloehner, F. M.

    2017-03-01

    Silage on dairy farms can emit large amounts of volatile organic compounds (VOCs), a precursor in the formation of tropospheric ozone. Because of the challenges associated with direct measurements, process-based modeling is another approach for estimating emissions of air pollutants from sources such as those from dairy farms. A process-based model for predicting VOC emissions from silage was developed and incorporated into the Integrated Farm System Model (IFSM, v. 4.3), a whole-farm simulation of crop, dairy, and beef production systems. The performance of the IFSM silage VOC emission model was evaluated using ethanol and methanol emissions measured from conventional silage piles (CSP), silage bags (SB), total mixed rations (TMR), and loose corn silage (LCS) at a commercial dairy farm in central California. With transport coefficients for ethanol refined using experimental data from our previous studies, the model performed well in simulating ethanol emission from CSP, TMR, and LCS; its lower performance for SB could be attributed to possible changes in face conditions of SB after silage removal that are not represented in the current model. For methanol emission, lack of experimental data for refinement likely caused the underprediction for CSP and SB whereas the overprediction observed for TMR can be explained as uncertainty in measurements. Despite these limitations, the model is a valuable tool for comparing silage management options and evaluating their relative effects on the overall performance, economics, and environmental impacts of farm production. As a component of IFSM, the silage VOC emission model was used to simulate a representative dairy farm in central California. The simulation showed most silage VOC emissions were from feed lying in feed lanes and not from the exposed face of silage storages. This suggests that mitigation efforts, particularly in areas prone to ozone non-attainment status, should focus on reducing emissions during feeding. For

  18. Fish under exercise.

    Science.gov (United States)

    Palstra, Arjan P; Planas, Josep V

    2011-06-01

    Improved knowledge on the swimming physiology of fish and its application to fisheries science and aquaculture (i.e., farming a fitter fish) is currently needed in the face of global environmental changes, high fishing pressures, increased aquaculture production as well as increased concern on fish well-being. Here, we review existing data on teleost fish that indicate that sustained exercise at optimal speeds enhances muscle growth and has consequences for flesh quality. Potential added benefits of sustained exercise may be delay of ovarian development and stimulation of immune status. Exercise could represent a natural, noninvasive, and economical approach to improve growth, flesh quality as well as welfare of aquacultured fish: a FitFish for a healthy consumer. All these issues are important for setting directions for policy decisions and future studies in this area. For this purpose, the FitFish workshop on the Swimming Physiology of Fish ( http://www.ub.edu/fitfish2010 ) was organized to bring together a multidisciplinary group of scientists using exercise models, industrial partners, and policy makers. Sixteen international experts from Europe, North America, and Japan were invited to present their work and view on migration of fishes in their natural environment, beneficial effects of exercise, and applications for sustainable aquaculture. Eighty-eight participants from 19 different countries contributed through a poster session and round table discussion. Eight papers from invited speakers at the workshop have been contributed to this special issue on The Swimming Physiology of Fish.

  19. Space-time modelling of the spread of pancreas disease (PD) within and between Norwegian marine salmonid farms.

    Science.gov (United States)

    Aldrin, M; Huseby, R B; Jansen, P A

    2015-09-01

    Infectious diseases are a constant threat to industrialised farming, which is characterised by high densities of farms and farm animals. Several mathematical and statistical models on spatio-temporal dynamics of infectious diseases in various farmed host populations have been developed during the last decades. Here we present a spatio-temporal stochastic model for the spread of a disease between and within aquaculture farms. The spread between farms is divided into several transmission pathways, including (i) distance related spread and (ii) other types of contagious contacts. The within-farm infection dynamics is modelled by a susceptible-infected-recovered (SIR) model. We apply this framework to model the spread of pancreas disease (PD) in salmon farming, using data covering all farms producing salmonids over 9 years in Norway. The motivation for the study was partly to unravel the spatio-temporal dynamics of PD in salmon farming and partly to use the model for scenario simulation of PD control strategies. We find, for example, that within-farm infection dynamics vary with season and we provide estimates of the timing from unobserved infection events to disease outbreaks on farms are detected. The simulations suggest that if a strategy involving culling of infectious cohorts is implemented, the number of detected disease outbreaks per year may be reduced by 57% after the full effect has been reached. We argue that the high detail and coverage of data on salmonid production and disease occurrence should encourage the use of simulation modelling as a means of testing effects of extensive control measures before they are implemented in the salmon farming industry.

  20. Binary fish passage models for uniform and nonuniform flows

    Energy Technology Data Exchange (ETDEWEB)

    Neary, Vincent S [ORNL

    2011-01-01

    Binary fish passage models are considered by many fisheries managers to be the best 21 available practice for culvert inventory assessments and for fishway and barrier design. 22 Misunderstandings between different binary passage modeling approaches often arise, 23 however, due to differences in terminology, application and presentation. In this paper 24 one-dimensional binary fish passage models are reviewed and refined to clarify their 25 origins and applications. For uniform flow, a simple exhaustion-threshold (ET) model 26 equation is derived that predicts the flow speed threshold in a fishway or velocity barrier 27 that causes exhaustion at a given maximum distance of ascent. Flow speeds at or above 28 the threshold predict failure to pass (exclusion). Flow speeds below the threshold predict 29 passage. The binary ET model is therefore intuitive and easily applied to predict passage 30 or exclusion. It is also shown to be consistent with the distance-maximizing model. The 31 ET model s limitation to uniform flow is addressed by deriving a passage model that 32 accounts for nonuniform flow conditions more commonly found in the field, including 33 backwater profiles and drawdown curves. Comparison of these models with 34 experimental observations of volitional passage for Gambusia affinis in uniform and 35 nonuniform flows indicates reasonable prediction of binary outcomes (passage or 36 exclusion) if the flow speed is not near the threshold flow velocity. More research is 37 needed on fish behavior, passage strategies under nonuniform flow regimes and 38 stochastic methods that account for individual differences in swimming performance at or 39 near the threshold flow speed. Future experiments should track and measure ground 40 speeds of ascending fish to test nonuniform flow passage strategies and to improve model 41 predictions. Stochastic models, such as Monte-Carlo techniques, that account for 42 different passage performance among individuals and allow

  1. Marine Model Trout Farms: developments in marine RAS

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg

    2011-01-01

    , nitrogen is removed in a full-scale experimental set-up where sludge from the drum filter is hydrolysed and the VFAs generated used as energy-source for the denitrification process in separate tanks/filters. Final polishing follows in a constructed wetland. For the first 2 years of operation production...... temperature the pumps can be individually turned on/off primarily in relation to oxygen need and consumption in the fish tank. In a 1 year batch production some 20 t of fish will be introduced in April and some 80 t are supposed to be harvested in December. End-of-pipe treatment is a two-step process. First...

  2. An Integrated Multi-Criteria Decision Making Model for Evaluating Wind Farm Performance

    Directory of Open Access Journals (Sweden)

    Mei-Sung Kang

    2011-11-01

    Full Text Available The demands for alternative energy resources have been increasing exponentially in the 21st century due to continuous industrial development, depletion of fossil fuels and emerging environmental consciousness. Renewable energy sources, including wind energy, hydropower energy, geothermal energy, solar energy, biomass energy and ocean power, have received increasing attention as alternative means of meeting global energy demands. After Japan's Fukushima nuclear plant disaster in March 2011, more and more countries are having doubt about the safety of nuclear plants. As a result, safe and renewable energy sources are attracting even more attention these days. Wind energy production, with its relatively safer and positive environmental characteristics, has evolved in the past few decades from a marginal activity into a multi-billion dollar industry. In this research, a comprehensive evaluation model is constructed to select a suitable location for developing a wind farm. The model incorporates interpretive structural modeling (ISM, benefits, opportunities, costs and risks (BOCR and fuzzy analytic network process (FANP. Experts in the field are invited to contribute their expertise in evaluating the importance of the factors and various aspects of the wind farm evaluation problem, and the most suitable wind farm can finally be generated from the model. A case study is carried out in Taiwan in evaluating the expected performance of several potential wind farms, and a recommendation is provided for selecting the most appropriate wind farm for construction.

  3. Physiology-based modelling approaches to characterize fish habitat suitability

    NARCIS (Netherlands)

    Teal, L.R.; Marras, Stefano; Peck, M.A.; Domenici, Paolo

    2015-01-01

    Models are useful tools for predicting the impact of global change on species distribution and abundance. As ectotherms, fish are being challenged to adapt or track changes in their environment, either in time through a phenological shift or in space by a biogeographic shift. Past modelling efforts

  4. Monitoring, modeling and mitigating impacts of wind farms on local meteorology

    Science.gov (United States)

    Baidya Roy, Somnath; Traiteur, Justin; Kelley, Neil

    2010-05-01

    Wind power is one of the fastest growing sources of energy. Most of the growth is in the industrial sector comprising of large utility-scale wind farms. Recent modeling studies have suggested that such wind farms can significantly affect local and regional weather and climate. In this work, we present observational evidence of the impact of wind farms on near-surface air temperatures. Data from perhaps the only meteorological field campaign in an operational wind farm shows that downwind temperatures are lower during the daytime and higher at night compared to the upwind environment. Corresponding radiosonde profiles at the nearby Edwards Air Force Base WMO meteorological station show that the diurnal environment is unstable while the nocturnal environment is stable during the field campaign. This behavior is consistent with the hypothesis proposed by Baidya Roy et al. (JGR 2004) that states that turbulence generated in the wake of rotors enhance vertical mixing leading to a warming/cooling under positive/negative potential temperature lapse rates. We conducted a set of 306 simulations with the Regional Atmospheric Modeling System (RAMS) to test if regional climate models can capture the thermal effects of wind farms. We represented wind turbines with a subgrid parameterization that assumes rotors to be sinks of momentum and sources of turbulence. The simulated wind farms consistently generated a localized warming/cooling under positive/negative lapse rates as hypothesized. We found that these impacts are inversely correlated with background atmospheric boundary layer turbulence. Thus, if the background turbulence is high due to natural processes, the effects of additional turbulence generated by wind turbine rotors are likely to be small. We propose the following strategies to minimize impacts of wind farms: • Engineering solution: design rotors that generate less turbulence in their wakes. Sensitivity simulations show that these turbines also increase the

  5. Linking Fish Habitat Modelling and Sediment Transport in Running Waters

    Institute of Scientific and Technical Information of China (English)

    Andreas; EISNER; Silke; WIEPRECHT; Matthias; SCHNEIDER

    2005-01-01

    The assessment of ecological status for running waters is one of the major issues within an integrated river basin management and plays a key role with respect to the implementation of the European Water Frame- work Directive (WFD).One of the tools supporting the development of sustainable river management is physi- cal habitat modeling,e.g.,for fish,because fish population are one of the most important indicators for the e- colngical integrity of rivers.Within physical habitat models hydromorphological ...

  6. A Generic Bio-Economic Farm Model for Environmental and Economic Assessment of Agricultural Systems

    NARCIS (Netherlands)

    Janssen, S.J.C.; Louhichi, K.; Kanellopoulos, A.; Zander, P.; Flichman, G.; Hengsdijk, H.; Meuter, E.C.; Andersen, E.; Belhouchette, H.; Blanco, M.; Borkowski, N.; Heckelei, T.; Hecker, M.; Li, Hongtao; Oude Lansink, A.G.J.M.; Stokstad, G.; Thorne, P.; Keulen, van H.; Ittersum, van M.K.

    2010-01-01

    Bio-economic farm models are tools to evaluate ex-post or to assess ex-ante the impact of policy and technology change on agriculture, economics and environment. Recently, various BEFMs have been developed, often for one purpose or location, but hardly any of these models are re-used later for other

  7. Actuator disk model of wind farms based on the rotor average wind speed

    DEFF Research Database (Denmark)

    Han, Xing Xing; Xu, Chang; Liu, De You;

    2016-01-01

    Due to difficulty of estimating the reference wind speed for wake modeling in wind farm, this paper proposes a new method to calculate the momentum source based on the rotor average wind speed. The proposed model applies volume correction factor to reduce the influence of the mesh recognition...

  8. Geographical Information Systems (GIS) as a Simple Tool to Aid Modelling of Particulate Waste Distribution at Marine Fish Cage Sites

    Science.gov (United States)

    Pérez, O. M.; Telfer, T. C.; Beveridge, M. C. M.; Ross, L. G.

    2002-04-01

    Deposition of particulate organic waste from marine fish farm cages on to sea-bed sediments can cause major changes to the benthic ecosystem. Validated spatial models are considered as the most cost-effective tools for predicting environmental impacts. An improved version of an existing predictive particulate waste distribution model for farmed Atlantic salmon ( Salmo salar L.) is presented, which uses Geographic Information Systems (GIS) combined with a spreadsheet. The model presented uses existing distribution algorithms but also incorporates functions to calculate feed loading for all the cages within a pontoon independently, spreads the input load over the whole cage area and simulates post-depositional distribution of the carbon. The model uses approximate estimates of feed and faecal waste derived from dietary considerations (mass balance model) and separate, unique settling velocities for waste feed and faecal particles. The model incorporates values of current speed and direction recorded over spring and neap tides. Output from the model is in the form of a contour plot of organic carbon (g C m -2), showing distribution of the particulate organic carbon material as deposited on the sea-bed. During this study using hydrographic data collected from near a fish farm, the model predicted a smooth gradient of sediment carbon concentrations which decreased with distance from the cages. Model performance was validated using measured levels of sediment carbon, and showed a significant correlation between predicted and actual sediment loading (R=0·7; P <0·01). The differences between predicted and measured quantities of carbon found at some sampling stations are likely to be due to processes not included in the model, such as small differences in bathymetry, differences in bottom type which may have increased or decreased the carbon distribution through saltation, or natural variation in the sediment composition.

  9. Statistical modeling of the power grid from a wind farm standpoint

    DEFF Research Database (Denmark)

    Farajzadehbibalan, Saber; Ramezani, Mohammad H.; Nielsen, Peter

    2017-01-01

    to a wind farm, we propose an algorithm that optimally combines the principal components and scores. The principal components are estimated by the optimization of a cost function based on the modeling error while the scores are selected corresponding to the worst case scenario among the wind turbine...... generators. Our results show that the optimized principal components result in the modeling error less than 5% and the selected scores cover the variance of the data with probability higher than 95% among all generators in the wind farm....

  10. Fishing

    Institute of Scientific and Technical Information of China (English)

    姜群山

    2002-01-01

    @@ Last Saturday my cousin (表兄) came to my home. We were very happy to see each other. We decided that the next day we went to fish. We got up very early that day. When we left home,the moon could still be seen in the sky.

  11. A survey of modelling methods for high-fidelity wind farm simulations using large eddy simulation.

    Science.gov (United States)

    Breton, S-P; Sumner, J; Sørensen, J N; Hansen, K S; Sarmast, S; Ivanell, S

    2017-04-13

    Large eddy simulations (LES) of wind farms have the capability to provide valuable and detailed information about the dynamics of wind turbine wakes. For this reason, their use within the wind energy research community is on the rise, spurring the development of new models and methods. This review surveys the most common schemes available to model the rotor, atmospheric conditions and terrain effects within current state-of-the-art LES codes, of which an overview is provided. A summary of the experimental research data available for validation of LES codes within the context of single and multiple wake situations is also supplied. Some typical results for wind turbine and wind farm flows are presented to illustrate best practices for carrying out high-fidelity LES of wind farms under various atmospheric and terrain conditions.This article is part of the themed issue 'Wind energy in complex terrains'.

  12. Wind flow conditions in offshore wind farms. Validation and application of a CFD wake model

    Energy Technology Data Exchange (ETDEWEB)

    Westerhellweg, Annette; Canadillas, Beatriz; Kinder, Friederike; Neumann, Thomas [Deutsches Windenergie-Institut GmbH (DEWI), Wilhelmshaven (Germany)

    2013-04-01

    Since August 2009, the first German offshore wind farm 'alpha ventus' is operating close to the wind measurement platform FINO1. Within the research project RAVE-OWEA the wind flow conditions in 'alpha ventus' were assessed in detail, simulated with a CFD wake model and compared with the measurements. Wind data measured at FINO1 have been evaluated for wind speed reduction and turbulence increase in the wake. Additionally operational data were evaluated for the farm efficiency. The atmospheric stability has been evaluated by temperature measurements of air and water and the impact of atmospheric stability on the wind conditions in the wake has been assessed. As an application of CFD models the generation of power matrices is introduced. Power matrices can be used for the continual monitoring of the single wind turbines in the wind farm. A power matrix based on CFD simulations has been created for 'alpha ventus' and tested against the measured data. (orig.)

  13. Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2015-01-01

    Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distribu......Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint...... quite well in terms of the coefficient of determination R-2. Then, the best of these joint distributions is used in the layout optimization of the Horns Rev 1 wind farm and the choice of bin sizes for wind speed and wind direction is also investigated. It is found that the choice of bin size for wind...... direction is especially critical for layout optimization and the recommended choice of bin sizes for wind speed and wind direction is finally presented....

  14. Fast Modeling of Large Wave Energy Farms Using Interaction Distance Cut-Off

    Directory of Open Access Journals (Sweden)

    Malin Göteman

    2015-12-01

    Full Text Available In many wave energy concepts, power output in the MW range requires the simultaneous operation of many wave energy converters. In particular, this is true for small point-absorbers, where a wave energy farm may contain several hundred devices. The total performance of the farm is affected by the hydrodynamic interactions between the individual devices, and reliable tools that can model full farms are needed to study power output and find optimal design parameters. This paper presents a novel method to model the hydrodynamic interactions and power output of very large wave energy farms. The method is based on analytical multiple scattering theory and uses time series of irregular wave amplitudes to compute the instantaneous power of each device. An interaction distance cut-off is introduced to improve the computational cost with acceptable accuracy. As an application of the method, wave energy farms with over 100 devices are studied in the MW range using one month of wave data measured at an off-shore site.

  15. Fish welfare assurance system: initial steps to set up an effective tool to safeguard and monitor farmed fish welfare at a company level

    NARCIS (Netherlands)

    Vis, van de J.W.; Poelman, M.; Lambooij, E.; Bégout, M.L.; Pilarczyk, M.

    2012-01-01

    The objective was to take a first step in the development of a process-oriented quality assurance (QA) system for monitoring and safeguarding of fish welfare at a company level. A process-oriented approach is focused on preventing hazards and involves establishment of critical steps in a process tha

  16. Net cages in fish farming: a scientometric analysis Tanques rede em piscicultura: uma análise cienciométrica

    Directory of Open Access Journals (Sweden)

    Juliana Déo Dias

    2012-03-01

    Full Text Available AIM: This study presents a scientometric analysis of studies on net cages in order to determine whether these studies are considering environmental issues or only seeking an increase in food production; METHODS: The survey of articles was accomplished using the Thomson Reuters Database (ISI Web of Knowledge, with "cage culture" and "net cage" as keywords. We selected 238 articles that were published between 1990 and 2009; RESULTS: There was a temporal increase in the number of articles published. These articles focused mainly on fish production and environmental impacts; CONCLUSION: The studies of net cages in fish farming mainly investigated fish production, although environmental issues relating to this recent human activity were also important. Policy makers should consider both sides of the coin (i.e., both the benefits and environmental impacts of fish production in regulation of this activity.OBJETIVO: O presente estudo teve como objetivo apresentar uma análise cienciométrica sobre os estudos de tanques rede, a fim de responder se estes estudos estão considerando as questões ambientais ou, apenas, buscam um aumento na produção de alimentos; MÉTODOS: O levantamento dos artigos foi realizado na base Thomson Reuters (ISI Web of Knowledge, sendo utilizadas "cage culture" e "net cage" como palavras-chave. Foram selecionados 238 artigos durante o período de 1990 a 2009; RESULTADOS: Houve um incremento temporal no número de artigos publicados. Esses artigos enfocaram, principalmente, na produção pesqueira e impactos ambientais; CONCLUSÃO: Os estudos de tanques rede abordaram, principalmente, produção pesqueira, entretanto, as questões ambientais também foram importantes nesta recente atividade humana. Os decisores políticos devem considerar ambos os lados da moeda, ou seja, benefícios e impactos ambientais da produção pesqueira, antes de regular esta atividade.

  17. PECULIARITIES OF THE GENETIC STRUCTURE OF RAINBOW TROUT (ONCORHYNCHUS MYKISS GROUPS AT THE FISH FARM “SLOBODA BANILOV”, CHERNIVTSI REGION

    Directory of Open Access Journals (Sweden)

    Р. Mendrishora

    2016-06-01

    Full Text Available Purpose. Study of the peculiarities of the genetic structure based on genetic-biochemical markers in age-1+ and 2+ rainbow trout of the fish farm “Sloboda Banilov”, Chernivtsi region Methodology. We used the methods of vertical polyacrylamide and horizontal starch electrophoresis with own modification. Sampling of biological material and histochemical and staining of gel plates were performed according to generally accepted methods. The frequency of allele and genotypic variants were calculated, actual and expected level of heterozygosis for each individual locus and the level of mean heterozygosis per locus were determined, Wright F fixation index was calculated. Statistical processing of experimental data was performed with the use "Biosys-1" software. Findings. We performed an analysis of the genetic structure of rainbow trout (Oncorhynchus mykiss groups with the use of genetic-biochemical markers — esterase loci (EST, EC 3.1.1.1, carboanhydrase (CA, EC 4.2.1.1, isocitrate dehydrohenase (IDH, EC1.1.1.41, superoxide dismutase (SОD, EC 1.15.1.1. We showed the peculiarities of the distribution of allele variants of the studied loci of rainbow trout. The genotypic composition of biochemical system loci supposed the surplus of fish with heterozygous genotypes by SOD locus in age-1+ fish (Go=26; Ge=15.3, χ2=15.4, Р<0.001, as well as by EST loci (Go=22; Ge=14.6, χ2=7.9, Р<0.01 Originality. For the first time we performed an assessment of the genetic structure based on genetic-biochemical markers and calculated the level of heterozygosis in age-1+ and 2+ rainbow trout reared at the fish farm “Sloboda Banyliv” of Chernivtsi region. Practical value. Results of the study can be used for solving various tasks of group and individual identification of populations when forming the stocks for optimizing their genetic structure. Experimental data of the frequency of allele and genotype distribution will be used for studying the effect of

  18. The influence of fish age, salt level, and Mtgase addition on the quality of gels prepared from unwashed mince of farmed meagre (Argyrosomus regius).

    Science.gov (United States)

    Cardoso, Carlos; Ribeiro, Bernardo; Mendes, Rogério

    2014-06-01

    The potential of using the unwashed mince of farmed meagre as raw material for the preparation of heat-induced gel products was assessed taking into account the effect of age (small size 2kg meagre), lower salt levels (1.0%, w/w, vs 2.5%, w/w), and microbial transglutaminase (MTGase) incorporation (0.0%, w/w, vs 0.5%, w/w). Heat-induced gel products from > 2 kg fish were of superior quality. Salt reduction from 2.5% to 1.0% (w/w) was detrimental for textural quality, particularly, of gels prepared from >2 kg meagre mince. MTGase addition improved texture. Moreover, MTGase incorporation led to a greater importance of non-covalent hydrophobic bonding.

  19. Application of Google Earth in Standardized Fish Farming Ponds Information Management System%Google Earth在标准化渔业养殖池塘信息管理系统中的应用

    Institute of Scientific and Technical Information of China (English)

    甘付兵; 殷杰; 尤尔茂; 黄呈炜

    2012-01-01

    通过阐述Google Earth的二次开发和KML文件生成等关键技术及其实例应用,实现了基于Google Earth 的标准化渔业养殖池塘管理信息系统的构建.该方法简单、直观,可快速、准确地对标准化渔业养殖池塘信息进行浏览、查询、统计分析和辅助规划,是对标准化渔业养殖池塘信息管理新方法的一种尝试,对数字化渔业管理具有较高的研究价值和广阔的应用前景.%Elaborating on the key technique and the application thereof of secondary development of Google Earth and KML file generation , this paper realizes the construction of standardized fish farming pond management information system based on Google Earth, which is simple and illustrative and can be used to browse, query, analyze and plan standardized fish farming pond information accurately. The method is a new way of applying information management to standardized fish farming pond, and it is high in research value of digitized fish farming and has a wide application prospect.

  20. Linking effort and fishing mortality in a mixed fisheries model

    DEFF Research Database (Denmark)

    Thøgersen, Thomas Talund; Hoff, Ayoe; Frost, Hans Staby

    2012-01-01

    in fish stocks has led to overcapacity in many fisheries, leading to incentives for overfishing. Recent research has shown that the allocation of effort among fleets can play an important role in mitigating overfishing when the targeting covers a range of species (multi-species—i.e., so-called mixed...... fisheries), while simultaneously optimising the overall economic performance of the fleets. The so-called FcubEcon model, in particular, has elucidated both the biologically and economically optimal method for allocating catches—and thus effort—between fishing fleets, while ensuring that the quotas...

  1. Atmospheric stability-dependent infinite wind-farm models and the wake-decay coefficient

    DEFF Research Database (Denmark)

    Peña, Alfredo; Rathmann, Ole

    2014-01-01

    We extend the infinite wind-farm boundary-layer (IWFBL) model of Frandsen to take into account atmospheric static stability effects. This extended model is compared with the IWFBL model of Emeis and to the Park wake model used inWind Atlas Analysis and Application Program (WAsP), which is computed...... for an infinite wind farm. The models show similar behavior for the wind-speed reduction when accounting for a number of surface roughness lengths, turbine to turbine separations and wind speeds under neutral conditions. For a wide range of atmospheric stability and surface roughness length values, the extended...... IWFBL model of Frandsen shows a much higher wind-speed reduction dependency on atmospheric stability than on roughness length (roughness has been generally thought to have a major effect on the wind-speed reduction). We further adjust the wake-decay coefficient of the Park wake model for an infinite...

  2. New species for the biomitigation of a super-intensive marine fish farm effluent: Combined use of polychaete-assisted sand filters and halophyte aquaponics.

    Science.gov (United States)

    Marques, Bruna; Calado, Ricardo; Lillebø, Ana I

    2017-12-01

    The main objective of this study was to test an innovative biomitigation approach, where polychaete-assisted (Hediste diversicolor) sand filters were combined with the production of Halimione portulacoides in aquaponics, to remediate an organic-rich effluent generated by a super intensive fish farm operating a land-based RAS (Recirculating aquaculture system). The set up included four different experimental combinations that were periodically monitored for 5months. After this period, polychaete-assisted sand filters reduced in 70% the percentage of OM and the average densities increased from ≈400ind.m(-2) to 7000ind.m(-2). H. portulacoides in aquaponics contributed to an average DIN (Dissolved inorganic Nitrogen) decrease of 65%, which increased to 67% when preceded by filter tanks stocked with polychaetes. From May until October (5months) halophytes biomass increased from 1.4kgm(-2)±0.7 (initial wet weight) to 18.6kgm(-2)±4.0. Bearing in mind that the uptake of carbon is mostly via photosynthesis and not though the uptake of dissolved inorganic carbon, this represents an approximate incorporation of ≈1.3kgm(-2) carbon (C), ≈15gm(-2) nitrogen (N) and ≈8gm(-2) phosphorus (P) in the aerial part (76% of total biomass), and an approximate incorporation of ≈0.5kgm(-2) carbon (C), ≈3gm(-2) nitrogen (N) and ≈2gm(-2) phosphorus (P) in the roots (24% of total biomass). In the present study, the potential of the two extractive species for biomitigation of a super-intensive marine fish farm effluent could be clearly demonstrated, contributing in this way to potentiate the implementation of more sustainable practices. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Investigations in associated protozoa-bacterial infections of cyprinids from a fish farm situated on the Jijia river in N-E of Romania

    Directory of Open Access Journals (Sweden)

    M. Laz?r

    2014-06-01

    Full Text Available In autumn 2011 in cyprinid farms located in Iasi on the Jijia river, several infections with bacterial strains and macroscopical external cysts on the skin were diagnosedwhich developed as a result of the stress induced by biotic and abiotic factors. On the examination of the cyst contents the presence of numerous spores was observed, mostly of the Dermocystidium sp genusThe samples were taken from the common carp (Cyprinus carpio and crucian carp (Carassius auratus gibelio species from the fish farm as well as from the Jijia River. 35 fish were examined, all of them showing cysts, fragmentation of their dorsal fin and congestion of the gills. Histological examination of the skin showed a field of multiple dermal cysts with round light eosinophilic formations (14-16µm containing a central refractable body similar to that reported for Dermocystidium sp. Gills samples were taken from the affected areas for the SEM examination with the purpose of evaluating not only aspects of normal morphology, but also aspects of some modifications of the affected areas as well as the presence of the etiologically incriminated bacteria Pseudomonas fluorescens. The isolates were identified through phenotypic methods. All the strains that showed mobility and oxidase-positivity were tested using API 20 NE strip. Consequently, they were taxonomically grouped into the species Pseudomonas fluorescens. The scanning electron microscope (SEM was used for the first time in the characterization of the bacterial lesions produced by Pseudomonas strains on Cyprinus carpio and Carassius auratus gibelio gills. The diagnosis of septicemia with conditional pathogen species of Pseudomonas fluorescens was correlated with the results of the physico-chemical investigations of water and the data concerning the breeding conditions of the investigated livestock.

  4. Comparison of Farm Structures, Success Factors, Obstacles, Clients’ Expectations and Policy Wishes of Urban Farming’s Main Business Models in North Rhine-Westphalia, Germany

    OpenAIRE

    Bernd Pölling

    2016-01-01

    Low-cost specialization, differentiation, and diversification are common business models of urban farms in developed countries. Similarities and differences between them as well as detailed insights into specific farm characteristics are widely absent in scientific discourses. This paper compares farm structures, success factors, obstacles, clients’ expectations, and policy wishes between specialized, differentiated, and diversified farms as well as diversifiers into agriculture. A standardiz...

  5. Genetic considerations on the introduction of farmed fish in marine protected areas: The case of study of white seabream restocking in the Gulf of Castellammare (Southern Tyrrhenian Sea)

    Science.gov (United States)

    González-Wangüemert, Mercedes; Fernández, Tomás Vega; Pérez-Ruzafa, Angel; Giacalone, Maximiliano; D'Anna, Giovanni; Badalamenti, Fabio

    2012-02-01

    Human exploitation has drastically reduced the abundance and distribution of several marine fish and invertebrate populations through overfishing and habitat destruction. Restocking can potentially mitigate these impacts and help to reconstitute depleted stocks but genetic repercussions must be considered. In the present study, the degree of genetic similarity between white seabream (Diplodus sargus Linnaeus 1758) individuals reared for restocking purposes and the receiving population in the Gulf of Castellammare fishery reserve (Sicily, Italy) was assessed using microsatellites. We also inferred the spatial pattern of the genetic structure of D. sargus and connectivity along Sicilian coasts. The farmed population showed significant heterozygosity deficiency in 6 loci and an important reduction in the number of alleles, which could indicate an incipient inbreeding. Both the farmed population and the target one for restocking (Castellammare fishery reserve), showed high and significant values of genetic differentiation due to different allele frequencies, number of privative alleles and total number of alleles. These findings indicate a low degree of genetic similarity between both populations, therefore this restocking initiative is not advisable. The genetic connectivity pattern, highly consistent with oceanographic currents, identified two distinct metapopulations of white seabream around Sicily. Thus it is recommended to utilize broods from the same metapopulation for restocking purposes to provide a better genetic match to the wild populations.

  6. PBDE and PCB levels correlated in wild caught and farm-raised fish fillets in the USA

    Energy Technology Data Exchange (ETDEWEB)

    Hayward, D.; Wong, J.; Krynitsky, A. [US Food and Drug Administration, College Park (United States)

    2004-09-15

    Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are two classes of industrial chemicals that have been widely used in the manufacture of many materials found commonly in highly industrial societies. PCBs used as an electrical insulator and in plastics have been banned in the US since 1977. PCB levels have steadily declined in foods. PBDEs are currently used as effective flame retardant in electronics, automobiles, home furnishings, textiles and in building materials. Environmental levels have not reached equilibrium. Both classes are ubiquitous contaminants with a strong tendency for bioaccumulation. The detection of PBDEs in human and some animal fats and fish/shellfish has been reported1. Recent reports of PBDEs in the US population have reported PBDE levels higher than most other industrialized countries. The pathway of these exposures is not precisely known, but one likely pathway is food. US FDA is planning to monitor some PBDE congeners beginning 2005. Data collection will begin with fish and shellfish and most likely be expanded to other foods. Fish/shellfish are already being monitored for PCDD/F and some PCB content. Several different instrumental approaches have been used successfully to measure PBDEs in human tissues and in environmental media including HRGC/HRMS, ECNI-LRMS, EI-LRMS and tandem mass spectrometry. The focus of this study is to determine PBDE levels in fish that are already known to have higher levels of PCBs relative to other fish or other foods. EI-LRMS was selected for initial testing with PBDE measurements in fish for its simplicity and availability in every FDA field laboratory.

  7. Generalized coupled wake boundary layer model: applications and comparisons with field and LES data for two wind farms

    NARCIS (Netherlands)

    Stevens, Richard J.A.M.; Gayme, Dennice F.; Meneveau, Charles

    2016-01-01

    We describe a generalization of the coupled wake boundary layer (CWBL) model for wind farms that can be used to evaluate the performance of wind farms under arbitrary wind inflow directions, whereas the original CWBL model (Stevens et al., J. Renewable and Sustainable Energy 7, 023115 (2015)) focuse

  8. Wind farm related mortality among avian migrants - a remote sensing study and model analysis

    DEFF Research Database (Denmark)

    Desholm, M.

    ,136 migrating sea ducks only 47 individuals were predicted to collide with the wind turbine rotor-blades, equivalent to an overall mean collision risk of c. 0.02%. This thesis shows the added value of modelling in supplementing sound empirical studies in accessing the effects of major human development......-2006) of migrating birds at the Nysted offshore wind farm in the Baltic Sea, Denmark. This thesis poses and answers the following questions: a) what hazard factors do offshore wind farming pose to wild birds, b) how should one choose the key focal species to study, c) how can remote sensing techniques be applied...

  9. Simulation of a 7.7 MW onshore wind farm with the Actuator Line Model

    Science.gov (United States)

    Guggeri, A.; Draper, M.; Usera, G.

    2017-05-01

    Recently, the Actuator Line Model (ALM) has been evaluated with coarser resolution and larger time steps than what is generally recommended, taking into account an atmospheric sheared and turbulent inflow condition. The aim of the present paper is to continue these studies, assessing the capability of the ALM to represent the wind turbines’ interactions in an onshore wind farm. The ‘Libertad’ wind farm, which consists of four 1.9MW Vestas V100 wind turbines, was simulated considering different wind directions, and the results were compared with the wind farm SCADA data, finding good agreement between them. A sensitivity analysis was performed to evaluate the influence of the spatial resolution, finding acceptable agreement, although some differences were found. It is believed that these differences are due to the characteristics of the different Atmospheric Boundary Layer (ABL) simulations taken as inflow condition (precursor simulations).

  10. Wind Speed Estimation and Wake model Re-calibration for Downregulated Offshore Wind Farms

    Science.gov (United States)

    Göçmen Bozkurt, Tuhfe; Giebel, Gregor; Kjølstad Poulsen, Niels; Réthoré, Pierre-Elouan; Mirzaei, Mahmood

    2014-05-01

    In recent years, the wind farm sizes have increased tremendously and with increasing installed capacity, the wind farms are requested to downregulate from their maximum possible power more frequently, especially in the offshore environment. Determination of the possible (or available) power is crucial not only because the reserve power has considerable market value but also for wind farm developers to be properly compensated for the loss during downregulation. While the available power calculation is straightforward for a single turbine, it gets rather complicated for the whole wind farm due to the change in the wake characteristics. In fact, the wake losses generated by the upstream turbine(s) decrease during downregulation and the downstream turbines therefore see more wind compared to the normal operation case. Currently, the Transmission System Operators (TSOs) have no real way to determine exactly the available power of a whole wind farm which is downregulated. Therefore, the PossPOW project aims to develop a verified and internationally accepted way to determine the possible power of a down-regulated offshore wind farm. The first phase of the project is to estimate the rotor effective wind speed. Since the nacelle anemometers are not readily available and are known to have reliability issues, the proposed method is to use power, pitch angle and rotational speed as inputs and combine it with a generic Cp model to estimate the wind speed. The performance of the model has been evaluated for both normal operation and downregulation periods using two different case studies: Horns Rev-I wind farm and NREL 5MW single turbine. During downregulation, the wake losses are not as severe and the velocity deficits at the downstream turbines are smaller as if also the wake is "downregulated". On the other hand, in order to calculate the available power, the wakes that would have been produced normally (if the turbines were not curtailed) are of importance, not the

  11. Teaching Diversified Organic Crop Production Using the Community Supported Agriculture Farming System Model

    Science.gov (United States)

    Falk, Constance L.; Pao, Pauline; Cramer, Christopher S.

    2005-01-01

    An organic garden operated as a community supported agriculture (CSA) venture on the New Mexico State University (NMSU) main campus was begun in January 2002. Students enroll in an organic vegetable production class during spring and fall semesters to help manage and work on the project. The CSA model of farming involves the sale of shares to…

  12. On-farm evaluation of the Salmon Welfare Index Model (SWIM 1.0)

    NARCIS (Netherlands)

    Folkedal, O.; Pettersen, J.M.; Bracke, M.B.; Stien, L.H.; Nilsson, J.; Martins, C.; Breck, O.; Midtlyng, P.J.; Kristiansen, T.

    2016-01-01

    The present study investigated the operational feasibility of the recently developed Salmon Welfare Index Model (SWIM 1.0) designed for Atlantic salmon (Salmo salar L) in production cages. Ten salmon farms containing spring smolts were visited twice, first between May and June the first year in s

  13. Evaluating nitrogen taxation scenarios using the dynamic whole farm simulation model FASSET

    DEFF Research Database (Denmark)

    Berntsen, J.; Petersen, B.M.; Jacobsen, Brian H.

    2003-01-01

    The whole farm model FASSET ver. 1.0 was used for evaluation of the environmental and economic consequences of implementing different nitrogen taxes. The taxation policies analysed were a tax on nitrogen in mineral fertiliser, a tax on nitrogen in mineral fertiliser and imported animal feedstuff...

  14. Teaching Diversified Organic Crop Production Using the Community Supported Agriculture Farming System Model

    Science.gov (United States)

    Falk, Constance L.; Pao, Pauline; Cramer, Christopher S.

    2005-01-01

    An organic garden operated as a community supported agriculture (CSA) venture on the New Mexico State University (NMSU) main campus was begun in January 2002. Students enroll in an organic vegetable production class during spring and fall semesters to help manage and work on the project. The CSA model of farming involves the sale of shares to…

  15. Integrated Organic Farm; a model aimed at contributing to food security for indigenous communities in Talamanca

    Directory of Open Access Journals (Sweden)

    Ricardo Salazar-Díaz

    2015-06-01

    Traditional farming in Talamanca comes from the continuous and balanced relationship between humans and their natural environment; however, there is evidence of deterioration in this relationship. As a result of this initiative, this proposal intends to be a model to be replicated in neighboring communities and so contribute to sustainable human development in the region of Talamanca.

  16. Harmonic models of a back-to-back converter in large offshore wind farms compared with measurement data

    OpenAIRE

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2009-01-01

    The offshore wind farm with installed back-to-back power converter in wind turbines is studied. As an example the Burbo Bank offshore wind farm with Siemens Wind Power wind turbines is taken into consideration. The wind farm is simulated in DIgSILENT Power Factory software in order to determine and assess harmonic emission in the point of common coupling. Different modelling methods of power electronic devices installed in wind turbines are presented. Harmonic load flow analysis and impedance...

  17. Integrative modeling and novel particle swarm-based optimal design of wind farms

    Science.gov (United States)

    Chowdhury, Souma

    To meet the energy needs of the future, while seeking to decrease our carbon footprint, a greater penetration of sustainable energy resources such as wind energy is necessary. However, a consistent growth of wind energy (especially in the wake of unfortunate policy changes and reported under-performance of existing projects) calls for a paradigm shift in wind power generation technologies. This dissertation develops a comprehensive methodology to explore, analyze and define the interactions between the key elements of wind farm development, and establish the foundation for designing high-performing wind farms. The primary contribution of this research is the effective quantification of the complex combined influence of wind turbine features, turbine placement, farm-land configuration, nameplate capacity, and wind resource variations on the energy output of the wind farm. A new Particle Swarm Optimization (PSO) algorithm, uniquely capable of preserving population diversity while addressing discrete variables, is also developed to provide powerful solutions towards optimizing wind farm configurations. In conventional wind farm design, the major elements that influence the farm performance are often addressed individually. The failure to fully capture the critical interactions among these factors introduces important inaccuracies in the projected farm performance and leads to suboptimal wind farm planning. In this dissertation, we develop the Unrestricted Wind Farm Layout Optimization (UWFLO) methodology to model and optimize the performance of wind farms. The UWFLO method obviates traditional assumptions regarding (i) turbine placement, (ii) turbine-wind flow interactions, (iii) variation of wind conditions, and (iv) types of turbines (single/multiple) to be installed. The allowance of multiple turbines, which demands complex modeling, is rare in the existing literature. The UWFLO method also significantly advances the state of the art in wind farm optimization by

  18. Factors influencing adoption of farm management practices in three agrobiodiversity hotspots in India: an analysis using the Count Data Model

    Directory of Open Access Journals (Sweden)

    Prabhakaran T. Raghu

    2014-07-01

    Full Text Available Sustainable agricultural practices require, among other factors, adoption of improved nutrient management techniques, pest mitigation technology and soil conservation measures. Such improved management practices can be tools for enhancing crop productivity. Data on micro-level farm management practices from developing countries is either scarce or unavailable, despite the importance of their policy implications with regard to resource allocation. The present study investigates adoption of some farm management practices and factors influencing the adoption behavior of farm households in three agrobiodiversity hotspots in India: Kundra block in the Koraput district of Odisha, Meenangadi panchayat in the Wayanad district of Kerala and Kolli Hills in the Namakkal district of Tamil Nadu. Information on farm management practices was collected from November 2011 to February 2012 from 3845 households, of which the data from 2726 farm households was used for analysis. The three most popular farm management practices adopted by farmers include: application of chemical fertilizers, farm yard manure and green manure for managing nutrients; application of chemical pesticides, inter-cropping and mixed cropping for mitigating pests; and contour bunds, grass bunds and trenches for soil conservation. A Negative Binomial count data regression model was used to estimate factors influencing decision-making by farmers on farm management practices. The regression results indicate that farmers who received information from agricultural extension are statistically significant and positively related to the adoption of farm management practices. Another key finding shows the negative relationship between cultivation of local varieties and adoption of farm management practices.

  19. The shadow effect of large wind farms: measurements, data analysis and modelling. Summary report[Final summary report

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, Steen; Barthelmie, R.; Rathmann, O.; Joergensen, Hans E.; Badger, J.; Hansen, Kurt; Ott, S.; Rethore, P.-E.; Larsen, Soeren E.; Jensen, Leo E.

    2007-07-15

    It was the goal of the project by means of data from the demonstration wind farms Horns Rev and Nysted, analyses of these data and modelling to facilitate prediction of the power losses from a wind farm should a new wind farm be built upwind relative to the prevailing wind direction. Or conversely, predict with adequate accuracy the production of a new wind farm built downwind of an existing wind farm. The project should be seen in the perspective of the two existing demonstration wind farms that extend 5-10 km in each direction. In order to e.g. use the existing electrical infrastructure it may be appropriate to build new wind farms rather close to the existing wind farms. A relevant question is therefore how far away new wind farms must be placed to avoid too large power losses. Measurements have been carried out for several years at the two sites, and databases have been prepared. The databases one for each site include production and operational statistics for the wind turbines and statistics for the meteorological measurements carries out in the vicinity of the wind farms. Several different modelling activities were carried out, which intentionally to some extent are redundant. Thus, if different modelling efforts results in comparable results, the quality of the models will be tested outside the physical range where data are available. All project participants find that the project has been immensely successful. The main achievements of the project are: 1) Measurements were carried out at the Nysted and Horns Rev demonstration wind farms for several years. Doing so included design, installation and operation of the measurement system 2) A data base was built from the incoming data. The data have been organized to facilitate verification of the models developed as part of the project 3) 6-7 different models have been developed and compared. 4) Approximately 20 journal and conference papers have resulted directly from the project (au)

  20. A mechanistic model for electricity consumption on dairy farms: definition, validation, and demonstration.

    Science.gov (United States)

    Upton, J; Murphy, M; Shalloo, L; Groot Koerkamp, P W G; De Boer, I J M

    2014-01-01

    Our objective was to define and demonstrate a mechanistic model that enables dairy farmers to explore the impact of a technical or managerial innovation on electricity consumption, associated CO2 emissions, and electricity costs. We, therefore, (1) defined a model for electricity consumption on dairy farms (MECD) capable of simulating total electricity consumption along with related CO2 emissions and electricity costs on dairy farms on a monthly basis; (2) validated the MECD using empirical data of 1yr on commercial spring calving, grass-based dairy farms with 45, 88, and 195 milking cows; and (3) demonstrated the functionality of the model by applying 2 electricity tariffs to the electricity consumption data and examining the effect on total dairy farm electricity costs. The MECD was developed using a mechanistic modeling approach and required the key inputs of milk production, cow number, and details relating to the milk-cooling system, milking machine system, water-heating system, lighting systems, water pump systems, and the winter housing facilities as well as details relating to the management of the farm (e.g., season of calving). Model validation showed an overall relative prediction error (RPE) of less than 10% for total electricity consumption. More than 87% of the mean square prediction error of total electricity consumption was accounted for by random variation. The RPE values of the milk-cooling systems, water-heating systems, and milking machine systems were less than 20%. The RPE values for automatic scraper systems, lighting systems, and water pump systems varied from 18 to 113%, indicating a poor prediction for these metrics. However, automatic scrapers, lighting, and water pumps made up only 14% of total electricity consumption across all farms, reducing the overall impact of these poor predictions. Demonstration of the model showed that total farm electricity costs increased by between 29 and 38% by moving from a day and night tariff to a flat

  1. Modelling farm vulnerability to flooding: A step toward vulnerability mitigation policies appraisal

    Science.gov (United States)

    Brémond, P.; Abrami, G.; Blanc, C.; Grelot, F.

    2009-04-01

    flood. In the case of farm activities, vulnerability mitigation consists in implementing measures which can be: physical (equipment or electric power system elevation), organizational (emergency or recovery plan) or financial (insurance). These measures aim at decreasing the total damage incurred by farmers in case of flooding. For instance, if equipment is elevated, it will not suffer direct damage such as degradation. As a consequence, equipment will be available to continue production or recovery tasks, thus, avoiding indirect damage such as delays, indebtedness… The effects of these policies on farms, in particular vulnerability mitigation cannot be appraised using current methodologies mainly because they do not consider farm as a whole and focus on direct damage at the land plot scale (loss of yield). Moreover, since vulnerability mitigation policies are quite recent, few examples of implementation exist and no feedback experience can be processed. Meanwhile, decision makers and financial actors require more justification of the efficiency of public fund by economic appraisal of the projects. On the Rhône River, decision makers asked for an economic evaluation of the program of farm vulnerability mitigation they plan to implement. This implies to identify the effects of the measures to mitigate farm vulnerability, and to classify them by comparing their efficacy (avoided damage) and their cost of implementation. In this presentation, we propose and discuss a conceptual model of vulnerability at the farm scale. The modelling, in Unified Modelling Language, enabled to represent the ties between spatial, organizational and temporal dimensions, which are central to understanding of farm vulnerability and resilience to flooding. Through this modelling, we encompass three goals: To improve the comprehension of farm vulnerability and create a framework that allow discussion with experts of different disciplines as well as with local farmers; To identify data which

  2. The theoretical foundations for size spectrum models of fish communities

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Jacobsen, Nis Sand; Farnsworth, K.D.

    2016-01-01

    assessment of fisheries. We describe the fundamental concepts in size-based models about food encounter and the bioenergetics budget of individuals. Within the general framework three model types have emerged that differs in their degree of complexity: the food-web, the trait-based and the community model....... We demonstrate the differences between the models through examples of their response to fishing and their dynamic behavior. We review implementations of size spectrum models and describe important variations concerning the functional response, whether growth is food-dependent or fixed...

  3. The emerging farmed fish species meagre (Argyrosomus regius): how culinary treatment affects nutrients and contaminants concentration and associated benefit-risk balance.

    Science.gov (United States)

    Costa, Sara; Afonso, Cláudia; Bandarra, Narcisa Maria; Gueifão, Sandra; Castanheira, Isabel; Carvalho, Maria Luísa; Cardoso, Carlos; Nunes, Maria Leonor

    2013-10-01

    The effect of cooking methods (boiling, grilling, and roasting) on the proximate and mineral composition, contaminants concentration and fatty acids profile was evaluated aiming to understand the benefits and risks associated to the consumption of the emerging farmed fish meagre (Argyrosomus regius). All the treatments led to lower moisture content. After grilling and roasting, the SFA, MUFA and PUFA contents increased. There was no degradation of EPA and DHA during the culinary processes. Significant retention of minerals in grilled and roasted meagre samples was registered. For Pb and Cd there were no concentration differences between culinary treatments and regarding raw fish. Whereas As level was higher in grilled meagre, total Hg and Me-Hg values were augmented in grilled and roasted meagre. The consumption of meagre is advisable due to the low and healthy fat, high selenium and protein content. Grilling would be the best culinary treatment due to the retention of protein, EPA, DHA and minerals. But as the risk of ingestion of Me-Hg content also increases, based on the risk assessment, intake should not exceed two weekly meals, provided that no other important Me-Hg food source is present in the diet. Otherwise, even this maximum threshold should be lower. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Applicability of Perinereis aibuhitensis Grube for fish waste removal from fish cages in Sanggou Bay, P. R. China

    Science.gov (United States)

    Fang, Jinghui; Jiang, Zengjie; Jansen, Henrice M.; Hu, Fawen; Fang, Jianguang; Liu, Yi; Gao, Yaping; Du, Meirong

    2017-04-01

    The present study investigated the applicability of integrated polychaete-fish culture for fish waste removal to offset negative impact induced by organic benthic enrichment. A field study demonstrated that deposition rate was significantly higher underneath the fish farm than that in control area. The material settling under the farm was characterized by a high amount of fish feces (45%) and uneaten feed (27%). Both feeding rate (FR) and apparent digestibility rate (ADR) increased with decreasing body weight, as was indicated by significantly a higher rate observed for the groups containing smaller individuals in a lab study. The nutrient in fresh deposited material (De) was higher than that in sediments collected under the farm (Se), resulting in lower feces production but higher apparent digestibility rate for the De group as feeding rate was similar. Consequently, higher nutrient removal efficiency was observed in the De group. A mass balance approach indicated that approximately 400-500 individuals m-2 is required for removing all waste materials deposited underneath the fish farm, whereas abundance can be lower (about 300-350 individuals m-2) when only the fish waste needs to be removed. The results showed that a significant amount of waste had been accumulated in the fish cages in Sanggou Bay. The integration of fish with P. aibuhitensis seems promising for preventing organic pollution in the sediment and therefore is an effective strategy for mitigating negative effect of fish farms. Thus such integration can become a new IMTA (integrated multi-trophic aquaculture) model in Sanggou Bay.

  5. Applicability of Perinereis aibuhitensis Grube for fish waste removal from fish cages in Sanggou Bay, P. R. China

    Science.gov (United States)

    Fang, Jinghui; Jiang, Zengjie; Jansen, Henrice M.; Hu, Fawen; Fang, Jianguang; Liu, Yi; Gao, Yaping; Du, Meirong

    2016-11-01

    The present study investigated the applicability of integrated polychaete-fish culture for fish waste removal to offset negative impact induced by organic benthic enrichment. A field study demonstrated that deposition rate was significantly higher underneath the fish farm than that in control area. The material settling under the farm was characterized by a high amount of fish feces (45%) and uneaten feed (27%). Both feeding rate (FR) and apparent digestibility rate (ADR) increased with decreasing body weight, as was indicated by significantly a higher rate observed for the groups containing smaller individuals in a lab study. The nutrient in fresh deposited material (De) was higher than that in sediments collected under the farm (Se), resulting in lower feces production but higher apparent digestibility rate for the De group as feeding rate was similar. Consequently, higher nutrient removal efficiency was observed in the De group. A mass balance approach indicated that approximately 400-500 individuals m-2 is required for removing all waste materials deposited underneath the fish farm, whereas abundance can be lower (about 300-350 individuals m-2) when only the fish waste needs to be removed. The results showed that a significant amount of waste had been accumulated in the fish cages in Sanggou Bay. The integration of fish with P. aibuhitensis seems promising for preventing organic pollution in the sediment and therefore is an effective strategy for mitigating negative effect of fish farms. Thus such integration can become a new IMTA (integrated multi-trophic aquaculture) model in Sanggou Bay.

  6. Wind Farm Flow Modeling using an Input-Output Reduced-Order Model

    Energy Technology Data Exchange (ETDEWEB)

    Annoni, Jennifer; Gebraad, Pieter; Seiler, Peter

    2016-08-01

    Wind turbines in a wind farm operate individually to maximize their own power regardless of the impact of aerodynamic interactions on neighboring turbines. There is the potential to increase power and reduce overall structural loads by properly coordinating turbines. To perform control design and analysis, a model needs to be of low computational cost, but retains the necessary dynamics seen in high-fidelity models. The objective of this work is to obtain a reduced-order model that represents the full-order flow computed using a high-fidelity model. A variety of methods, including proper orthogonal decomposition and dynamic mode decomposition, can be used to extract the dominant flow structures and obtain a reduced-order model. In this paper, we combine proper orthogonal decomposition with a system identification technique to produce an input-output reduced-order model. This technique is used to construct a reduced-order model of the flow within a two-turbine array computed using a large-eddy simulation.

  7. Effective turbulence models and fatigue reliability in wind farms

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Frandsen, Sten Tronæs; Tarp-Johansen, N.J.

    2008-01-01

    intensity in wakes behind wind turbines can imply a significant reduction in the fatigue lifetime of wind turbines placed in wakes. Ill this paper the design code model ill the wind turbine code [IEC 61400-1, Wind turbine generator systems - Part 1: Safety requirements. 2005] is evaluated from...... a probabilistic point of view, including the importance of modeling the SN-curve by a bi-linear model. Fatigue models relevant for welded, cast steel and fiber reinforced details are considered. Further, the influence on the fatigue reliability is investigated from modeling the fatigue response by a stochastic...

  8. Change in Farm Production Structure Within Different CAP Schemes – an LP Modelling Approach

    Directory of Open Access Journals (Sweden)

    Jaka ŽGAJNAR

    2008-01-01

    Full Text Available After accession to European Union in 2004 direct payments became veryimportant income source also for farmers in Slovenia. But agricultural policy inplace at accession changed significantly in year 2007 as result of CAP reformimplementation. The objective of this study was to evaluate decision makingimpacts of direct payments scheme implemented with the reform: regional or morelikely hybrid scheme. The change in farm production structure was simulated withmodel, applying gross margin maximisation, based on static linear programmingapproach. The model has been developed in a spreadsheet framework in MS Excelplatform. A hypothetical farm has been chosen to analyse different scenarios andspecializations. Focus of the analysis was on cattle sector, since it is expected thatdecoupling is going to have significant influence on its optimal productionstructure. The reason is high level of direct payments that could in pre-reformscheme rise up to 70 % of total gross margin. Model results confirm that the reformshould have unfavourable impacts on cattle farms with intensive productionpractice. The results show that hybrid scheme has minor negative impacts in allcattle specializations, while regional scheme would be better option for sheepspecialized farm. Analysis has also shown growing importance of CAP pillar IIpayments, among them particularly agri-environmental measures. In all threeschemes budgetary payments enable farmers to improve financial results and inboth reform schemes they alleviate economic impacts of the CAP reform.

  9. Modeling and simulation of offshore wind farm O&M processes

    Energy Technology Data Exchange (ETDEWEB)

    Joschko, Philip, E-mail: joschko@informatik.uni-hamburg.de [University of Hamburg, Dept. of Informatics, Vogt-Kölln-Straße 30, 22527 Hamburg (Germany); Widok, Andi H., E-mail: a.widok@htw-berlin.de [University of Hamburg, Dept. of Informatics, Vogt-Kölln-Straße 30, 22527 Hamburg (Germany); Appel, Susanne, E-mail: susanne.appel@hs-bremen.de [HSB Bremen, Institute for Environment and Biotechnology, Neustadtswall 30, 28199 Bremen (Germany); Greiner, Saskia, E-mail: saskia.greiner@hs-bremen.de [HSB Bremen, Institute for Environment and Biotechnology, Neustadtswall 30, 28199 Bremen (Germany); Albers, Henning, E-mail: henning.albers@hs-bremen.de [HSB Bremen, Institute for Environment and Biotechnology, Neustadtswall 30, 28199 Bremen (Germany); Page, Bernd, E-mail: page@informatik.uni-hamburg.de [University of Hamburg, Dept. of Informatics, Vogt-Kölln-Straße 30, 22527 Hamburg (Germany)

    2015-04-15

    This paper describes a holistic approach to operation and maintenance (O&M) processes in the domain of offshore wind farm power generation. The acquisition and process visualization is followed by a risk analysis of all relevant processes. Hereafter, a tool was designed, which is able to model the defined processes in a BPMN 2.0 notation, as well as connect and simulate them. Furthermore, the notation was enriched with new elements, representing other relevant factors that were, to date, only displayable with much higher effort. In that regard a variety of more complex situations were integrated, such as for example new process interactions depending on different weather influences, in which case a stochastic weather generator was combined with the business simulation or other wind farm aspects important to the smooth running of the offshore wind farms. In addition, the choices for different methodologies, such as the simulation framework or the business process notation will be presented and elaborated depending on the impact they had on the development of the approach and the software solution. - Highlights: • Analysis of operation and maintenance processes of offshore wind farms • Process modeling with BPMN 2.0 • Domain-specific simulation tool.

  10. A Bayesian network approach to knowledge integration and representation of farm irrigation: 1. Model development

    Science.gov (United States)

    Wang, Q. J.; Robertson, D. E.; Haines, C. L.

    2009-02-01

    Irrigation is important to many agricultural businesses but also has implications for catchment health. A considerable body of knowledge exists on how irrigation management affects farm business and catchment health. However, this knowledge is fragmentary; is available in many forms such as qualitative and quantitative; is dispersed in scientific literature, technical reports, and the minds of individuals; and is of varying degrees of certainty. Bayesian networks allow the integration of dispersed knowledge into quantitative systems models. This study describes the development, validation, and application of a Bayesian network model of farm irrigation in the Shepparton Irrigation Region of northern Victoria, Australia. In this first paper we describe the process used to integrate a range of sources of knowledge to develop a model of farm irrigation. We describe the principal model components and summarize the reaction to the model and its development process by local stakeholders. Subsequent papers in this series describe model validation and the application of the model to assess the regional impact of historical and future management intervention.

  11. High-resolution computational algorithms for simulating offshore wind turbines and farms: Model development and validation

    Energy Technology Data Exchange (ETDEWEB)

    Calderer, Antoni [Univ. of Minnesota, Minneapolis, MN (United States); Yang, Xiaolei [Stony Brook Univ., NY (United States); Angelidis, Dionysios [Univ. of Minnesota, Minneapolis, MN (United States); Feist, Chris [Univ. of Minnesota, Minneapolis, MN (United States); Guala, Michele [Univ. of Minnesota, Minneapolis, MN (United States); Ruehl, Kelley [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Guo, Xin [Univ. of Minnesota, Minneapolis, MN (United States); Boomsma, Aaron [Univ. of Minnesota, Minneapolis, MN (United States); Shen, Lian [Univ. of Minnesota, Minneapolis, MN (United States); Sotiropoulos, Fotis [Stony Brook Univ., NY (United States)

    2015-10-30

    The present project involves the development of modeling and analysis design tools for assessing offshore wind turbine technologies. The computational tools developed herein are able to resolve the effects of the coupled interaction of atmospheric turbulence and ocean waves on aerodynamic performance and structural stability and reliability of offshore wind turbines and farms. Laboratory scale experiments have been carried out to derive data sets for validating the computational models.

  12. Modelling scenarios on feed-to-fillet transfer of dioxins and dioxin-like PCBs in future feeds to farmed Atlantic salmon (Salmo salar).

    Science.gov (United States)

    Berntssen, Marc H G; Sanden, Monica; Hove, Helge; Lie, Øyvind

    2016-11-01

    The salmon feed composition has changed the last decade with a replacement of traditionally use of fish oil and fishmeal diets with vegetable ingredients and the use decontaminated fish oils, causing reduced concentrations of dioxins and dioxin-like PCBs in farmed Norwegian Atlantic salmon. The development of novel salmon feeds has prompted the need for prediction on dioxins and dl-PCB concentrations in future farmed salmon. Prediction on fillet dioxins and dl-PCB concentrations from different feed composition scenarios are made using a simple one-compartmental transfer model based on earlier established dioxin and dl-PCB congener specific uptake and elimination kinetics rates. The model is validated with two independent feeding trials, with a significant linear correlation (r(2) = 0.96, y = 1.0x, p dioxin and dl-PCB concentrations from 1999 (1.05 ng WHO2005-TEQs kg(-1)ww) and 2013 (0.57 ng WHO2005-TEQs kg(-1)ww) are in line with the data observed in national surveillance programs of those years (1.1 and 0.52 ng WHO2005-TEQs kg(-1)ww, respectively). Future use of high replacement and decontaminated oils feeds gave predicted fillet concentrations of 0.27 ng WHO2005-TEQs kg(-1)ww, which is near the limit of quantification. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Cooperative Fish and Wildlife Research Units - A model partnership program

    Science.gov (United States)

    Dennerline, Donald E.; Childs, Dawn E.

    2017-04-20

    The U.S. Geological Survey (USGS) Cooperative Fish and Wildlife Research Units (CRU) program is a unique model of cooperative partnership among the USGS, other U.S. Department of the Interior and Federal agencies, universities, State fish and wildlife agencies, and the Wildlife Management Institute. These partnerships are maintained as one of the USGS’s strongest links to Federal and State land and natural resource management agencies.Established in 1935 to meet the need for trained professionals in the growing field of wildlife management, the program currently consists of 40 Cooperative Fish and Wildlife Research Units located on university campuses in 38 States and supports 119 research scientist positions when fully funded. The threefold mission of the CRU program is to (1) conduct scientific research for the management of fish, wildlife, and other natural resources; (2) provide technical assistance to natural resource managers in the application of scientific information to natural resource policy and management; and (3) train future natural resource professionals.

  14. A capture-recapture model of amphidromous fish dispersal

    Science.gov (United States)

    Smith, W.; Kwak, Thomas J.

    2014-01-01

    Adult movement scale was quantified for two tropical Caribbean diadromous fishes, bigmouth sleeper Gobiomorus dormitor and mountain mullet Agonostomus monticola, using passive integrated transponders (PITs) and radio-telemetry. Large numbers of fishes were tagged in Rio Mameyes, Puerto Rico, U.S.A., with PITs and monitored at three fixed locations over a 2-5 year period to estimate transition probabilities between upper and lower elevations and survival probabilities with a multistate Cormack-Jolly-Seber model. A sub-set of fishes were tagged with radio-transmitters and tracked at weekly intervals to estimate fine-scale dispersal. Changes in spatial and temporal distributions of tagged fishes indicated that neither G. dormitor nor A. monticola moved into the lowest, estuarine reaches of Rio Mameyes during two consecutive reproductive periods, thus demonstrating that both species follow an amphidromous, rather than catadromous, migratory strategy. Further, both species were relatively sedentary, with restricted linear ranges. While substantial dispersal of these species occurs at the larval stage during recruitment to fresh water, the results indicate minimal dispersal in spawning adults. Successful conservation of diadromous fauna on tropical islands requires management at both broad basin and localized spatial scales.

  15. Mathematical modeling of fish burger baking using fractional calculus

    Directory of Open Access Journals (Sweden)

    Bainy Eduarda M.

    2017-01-01

    Full Text Available Tilapia (Oreochromis sp. is the most important and abundant fish species in Brazil due to its adaptability to different environments. The development of tilapia-based products could be an alternative in order to aggregate value and increase fish meat consumption. However, there is little information available on fishburger freezing and cooking in the literature. In this work, the mathematical modeling of the fish burger baking was studied. Previously to the baking process, the fishburgers were assembled in cylindrical shape of height equal to 8mm and diameter 100mm and then baked in an electrical oven with forced heat convection at 150ºC. A T-type thermocouple was inserted in the burger to obtain its temperature profile at the central position. In order to describe the temperature of the burger during the baking process, lumped-parameter models of integer and fractional order and also a nonlinear model due to heat capacity temperature dependence were considered. The burger physical properties were obtained from the literature. After proper parameter estimation tasks and statistical validation, the fractional order model could better describe the experimental temperature behavior, a value of 0.91±0.02 was obtained for the fractional order of the system with correlation coefficient of 0.99. Therefore, with the better temperature prediction, process control and economic optimization studies of the baking process can be conducted.

  16. Fatigue Reliability and Effective Turbulence Models in Wind Farms

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Frandsen, S.; Tarp-Johansen, N.J.

    2007-01-01

    behind wind turbines can imply a significant reduction in the fatigue lifetime of wind turbines placed in wakes. In this paper the design code model in the wind turbine code IEC 61400-1 (2005) is evaluated from a probabilistic point of view, including the importance of modeling the SN-curve by linear...

  17. Modelling heavy metal and phosphorus balances for farming systems

    NARCIS (Netherlands)

    Keller, A.N.; Schulin, R.

    2003-01-01

    Accounting for agricultural activities such as P fertilization in regional models of heavy metal accumulation provides suitable sustainable management strategies to reduce nutrient surpluses and metal inputs in agricultural soils. Using the balance model PROTERRA-S, we assessed the phosphorus ( P),

  18. Stochastic von Bertalanffy models, with applications to fish recruitment.

    Science.gov (United States)

    Lv, Qiming; Pitchford, Jonathan W

    2007-02-21

    We consider three individual-based models describing growth in stochastic environments. Stochastic differential equations (SDEs) with identical von Bertalanffy deterministic parts are formulated, with a stochastic term which decreases, remains constant, or increases with organism size, respectively. Probability density functions for hitting times are evaluated in the context of fish growth and mortality. Solving the hitting time problem analytically or numerically shows that stochasticity can have a large positive impact on fish recruitment probability. It is also demonstrated that the observed mean growth rate of surviving individuals always exceeds the mean population growth rate, which itself exceeds the growth rate of the equivalent deterministic model. The consequences of these results in more general biological situations are discussed.

  19. A Hidden Markov Model Representing the Spatial and Temporal Correlation of Multiple Wind Farms

    DEFF Research Database (Denmark)

    Fang, Jiakun; Su, Chi; Hu, Weihao

    2015-01-01

    To accommodate the increasing wind energy with stochastic nature becomes a major issue on power system reliability. This paper proposes a methodology to characterize the spatiotemporal correlation of multiple wind farms. First, a hierarchical clustering method based on self-organizing maps...... is adopted to categorize the similar output patterns of several wind farms into joint states. Then the hidden Markov model (HMM) is then designed to describe the temporal correlations among these joint states. Unlike the conventional Markov chain model, the accumulated wind power is taken into consideration....... The proposed statistical modeling framework is compatible with the sequential power system reliability analysis. A case study on optimal sizing and location of fast-response regulation sources is presented....

  20. Labour Quality Model for Organic Farming Food Chains

    OpenAIRE

    Gassner, B.; Freyer, B.; Leitner, H.

    2008-01-01

    The debate on labour quality in science is controversial as well as in the organic agriculture community. Therefore, we reviewed literature on different labour quality models and definitions, and had key informant interviews on labour quality issues with stakeholders in a regional oriented organic agriculture bread food chain. We developed a labour quality model with nine quality categories and discussed linkages to labour satisfaction, ethical values and IFOAM principles.

  1. Gis-Based Wind Farm Site Selection Model Offshore Abu Dhabi Emirate, Uae

    Science.gov (United States)

    Saleous, N.; Issa, S.; Mazrouei, J. Al

    2016-06-01

    The United Arab Emirates (UAE) government has declared the increased use of alternative energy a strategic goal and has invested in identifying and developing various sources of such energy. This study aimed at assessing the viability of establishing wind farms offshore the Emirate of Abu Dhabi, UAE and to identify favourable sites for such farms using Geographic Information Systems (GIS) procedures and algorithms. Based on previous studies and on local requirements, a set of suitability criteria was developed including ocean currents, reserved areas, seabed topography, and wind speed. GIS layers were created and a weighted overlay GIS model based on the above mentioned criteria was built to identify suitable sites for hosting a new offshore wind energy farm. Results showed that most of Abu Dhabi offshore areas were unsuitable, largely due to the presence of restricted zones (marine protected areas, oil extraction platforms and oil pipelines in particular). However, some suitable sites could be identified, especially around Delma Island and North of Jabal Barakah in the Western Region. The environmental impact of potential wind farm locations and associated cables on the marine ecology was examined to ensure minimal disturbance to marine life. Further research is needed to specify wind mills characteristics that suit the study area especially with the presence of heavy traffic due to many oil production and shipping activities in the Arabian Gulf most of the year.

  2. Generalized fish life-cycle poplulation model and computer program

    Energy Technology Data Exchange (ETDEWEB)

    DeAngelis, D. L.; Van Winkle, W.; Christensen, S. W.; Blum, S. R.; Kirk, B. L.; Rust, B. W.; Ross, C.

    1978-03-01

    A generalized fish life-cycle population model and computer program have been prepared to evaluate the long-term effect of changes in mortality in age class 0. The general question concerns what happens to a fishery when density-independent sources of mortality are introduced that act on age class 0, particularly entrainment and impingement at power plants. This paper discusses the model formulation and computer program, including sample results. The population model consists of a system of difference equations involving age-dependent fecundity and survival. The fecundity for each age class is assumed to be a function of both the fraction of females sexually mature and the weight of females as they enter each age class. Natural mortality for age classes 1 and older is assumed to be independent of population size. Fishing mortality is assumed to vary with the number and weight of fish available to the fishery. Age class 0 is divided into six life stages. The probability of survival for age class 0 is estimated considering both density-independent mortality (natural and power plant) and density-dependent mortality for each life stage. Two types of density-dependent mortality are included. These are cannibalism of each life stage by older age classes and intra-life-stage competition.

  3. Model to evaluate welfare in dairy cow farms

    Directory of Open Access Journals (Sweden)

    Luigi Calamari

    2010-01-01

    Full Text Available The assessment of herd welfare is a scientific discipline that is rapidly developing. The scientific community plays an important role in delivering appropriate, repeatable, valid and feasible models for this assessment. Unfortunately, there are different feelings regarding the welfare of animals and it is imperative for its assessment that certain agreement on the meaning of animal welfare is accepted. Then it is necessary to look at the goals of the models of welfare assessment because different goals require a different combination of welfare indicators. The different models for welfare assessment can be categorized broadly into research, legislative requirements, certification systems, and advisory/management tools. These models may have various goals: quantification of welfare, provision of welfare assurance or welfare management. However, it is widely accepted that welfare is best assessed with multiple different measures; therefore, a welfare assessment model for a livestock herd can include two types of measure: a description of the housing system and management (indirect indicators and data recording on how the animals react to the system (direct indicators. The first type provides information on risk factors for welfare problems. Direct measures on the animals provide information on their response to the environment and are more direct measures of welfare than their counterparts, but direct welfare indicators alone do not point out the causes of impaired welfare. Because welfare is a complex construct, different approaches for the aggregation of the different aspects of welfare have been proposed, although the aggregation in an overall welfare value is not sufficient. The thresholds between acceptable and unacceptable welfare levels have to be included in the model of welfare assessment but it seems useful to set certain minimum standards for each single welfare aspect. Afterward, judging the validity of a common welfare assessment

  4. Coupling dairy manure storage with injection to improve nitrogen management: whole-farm simulation using the integrated farm system Model

    Science.gov (United States)

    Application of livestock manure to farm soils represents a priority nutrient management concern in the Chesapeake Bay Watershed. Historically strong emphasis has been placed on adding manure storage to dairy operations, and, there has been recognition that manure application methods can be improved....

  5. A model for the optimal risk management of (farm) firms

    DEFF Research Database (Denmark)

    Rasmussen, Svend

    Current methods of risk management focus on efficiency and do not provide operational answers to the basic question of how to optimise and balance the two objectives, maximisation of expected income and minimisation of risk. This paper uses the Capital Asset Pricing Model (CAPM) to derive...

  6. A model for the optimal risk management of (farm) firms

    DEFF Research Database (Denmark)

    Rasmussen, Svend

    Current methods of risk management focus on efficiency and do not provide operational answers to the basic question of how to optimise and balance the two objectives, maximisation of expected income and minimisation of risk. This paper uses the Capital Asset Pricing Model (CAPM) to derive...

  7. Disease spread models to estimate highly uncertain emerging diseases losses for animal agriculture insurance policies: an application to the U.S. farm-raised catfish industry.

    Science.gov (United States)

    Zagmutt, Francisco J; Sempier, Stephen H; Hanson, Terril R

    2013-10-01

    Emerging diseases (ED) can have devastating effects on agriculture. Consequently, agricultural insurance for ED can develop if basic insurability criteria are met, including the capability to estimate the severity of ED outbreaks with associated uncertainty. The U.S. farm-raised channel catfish (Ictalurus punctatus) industry was used to evaluate the feasibility of using a disease spread simulation modeling framework to estimate the potential losses from new ED for agricultural insurance purposes. Two stochastic models were used to simulate the spread of ED between and within channel catfish ponds in Mississippi (MS) under high, medium, and low disease impact scenarios. The mean (95% prediction interval (PI)) proportion of ponds infected within disease-impacted farms was 7.6% (3.8%, 22.8%), 24.5% (3.8%, 72.0%), and 45.6% (4.0%, 92.3%), and the mean (95% PI) proportion of fish mortalities in ponds affected by the disease was 9.8% (1.4%, 26.7%), 49.2% (4.7%, 60.7%), and 88.3% (85.9%, 90.5%) for the low, medium, and high impact scenarios, respectively. The farm-level mortality losses from an ED were up to 40.3% of the total farm inventory and can be used for insurance premium rate development. Disease spread modeling provides a systematic way to organize the current knowledge on the ED perils and, ultimately, use this information to help develop actuarially sound agricultural insurance policies and premiums. However, the estimates obtained will include a large amount of uncertainty driven by the stochastic nature of disease outbreaks, by the uncertainty in the frequency of future ED occurrences, and by the often sparse data available from past outbreaks.

  8. Wind resource modelling for micro-siting - Validation at a 60-MW wind farm site

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, J.C.; Gylling Mortensen, N. [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark); Said, U.S. [New and Renewable Energy Authority, Cairo (Egypt)

    1999-03-01

    This paper investigates and validates the applicability of the WAsP-model for layout optimization and micro-siting of wind turbines at a given site for a 60-MW wind farm at Zafarana at the Gulf of Suez in Egypt. Previous investigations show large gradients in the wind climate within the area. For the design and optimization of the wind farm it was found necessary to verify the WAsP extrapolation of wind atlas results from 2 existing meteorological masts located 5 and 10 km, respectively, from the wind farm site. On-site measurements at the 3.5 x 3.5 km{sup 2} wind farm site in combination with 7 years of near-site wind atlas measurements offer significant amounts of data for verification of wind conditions for micro-siting. Wind speeds, wind directions, turbulence intensities and guests in 47.5 m a.g.l. have been measured at 9 locations across the site. Additionally, one of the site masts is equipped as a reference mast, measuring both vertical profiles of wind speed and temperature as well as air pressure and temperature. The exercise is further facilitated by the fact that winds are highly uni-directional; the north direction accounting for 80-90% of the wind resource. The paper presents comparisons of 5 months of on-site measurements and modeled predictions from 2 existing meteorological masts located at distances of 5 and 10 km, respectively, from the wind farm site. Predictions based on terrain descriptions of the Wind Atlas for the Gulf of Suez 1991-95 showed over-predictions of wind speeds of 4-10%. With calibrated terrain descriptions, made based on measured data and a re-visit to critical parts of the terrain, the average prediction error of wind speeds was reduced to about 1%. These deviations are smaller than generally expected for such wind resource modeling, clearly documenting the validity of using WAsP modeling for micro-siting and layout optimization of the wind farm. (au)

  9. A hierarchical community occurrence model for North Carolina stream fish

    Science.gov (United States)

    Midway, S.R.; Wagner, Tyler; Tracy, B.H.

    2016-01-01

    The southeastern USA is home to one of the richest—and most imperiled and threatened—freshwater fish assemblages in North America. For many of these rare and threatened species, conservation efforts are often limited by a lack of data. Drawing on a unique and extensive data set spanning over 20 years, we modeled occurrence probabilities of 126 stream fish species sampled throughout North Carolina, many of which occur more broadly in the southeastern USA. Specifically, we developed species-specific occurrence probabilities from hierarchical Bayesian multispecies models that were based on common land use and land cover covariates. We also used index of biotic integrity tolerance classifications as a second level in the model hierarchy; we identify this level as informative for our work, but it is flexible for future model applications. Based on the partial-pooling property of the models, we were able to generate occurrence probabilities for many imperiled and data-poor species in addition to highlighting a considerable amount of occurrence heterogeneity that supports species-specific investigations whenever possible. Our results provide critical species-level information on many threatened and imperiled species as well as information that may assist with re-evaluation of existing management strategies, such as the use of surrogate species. Finally, we highlight the use of a relatively simple hierarchical model that can easily be generalized for similar situations in which conventional models fail to provide reliable estimates for data-poor groups.

  10. Dynamic modelling of VSC-HVDC for connection of offshore wind farms

    DEFF Research Database (Denmark)

    Rios, Bardo; Garcia-Valle, Rodrigo

    2011-01-01

    A VSC-HVDC (Voltage Source Converter – High Voltage Direct Current) dynamic model with a set of control strategies is developed in DIgSILENT Power-Factory with the objective of analyzing the converter’s operating capability for grid support during grid faults. The investigation is carried out based...... on a 165 MW offshore wind farm with induction generators and a Low Voltage Ride-Through solution of the offshore wind turbines and Static Voltage Compensator units in the point of connection with a grid represented by a reduced four-generator power grid model. VSC-HVDC promises to be a reliable alternative...... solution for interconnection with off-shore wind farms as they become larger, with a higher installed power capacity, increased number of wind turbines, and geographically situated at larger distances from suitable connection points in the transmission grids....

  11. Transient Model Validation of Fixed-Speed Induction Generator Using Wind Farm Measurements

    DEFF Research Database (Denmark)

    Rogdakis, Georgios; Garcia-Valle, Rodrigo; Arana Aristi, Iván

    2012-01-01

    In this paper, an electromagnetic transient model for fixed-speed wind turbines equipped with induction generators is developed and implemented in PSCAD/EMTDC. The model is comprised by: an induction generator, aerodynamic rotor, and a two-mass representation of the shaft system. Model validation...... is conducted by measurement comparison using recordings obtained from switching operations performed at the Nysted OffshoreWind Farm in Denmark. A sensitivity analysis is performed to determine the impact of different model parameters on the simulated response as compared with measurements. This validated...

  12. A linear model for the dynamics of fish larvae

    Directory of Open Access Journals (Sweden)

    Noureddine Ghouali

    2004-11-01

    Full Text Available We consider a linear model for the growth and the dispersion of fish larvae of certain species. Dispersion is modeled as entailed by the combination of transport and vertical diffusion. We generalize the work of Boushaba, Arino and Boussouar [5,6] in the sense that horizontal velocities are uniform throughout the water column; but we deal with vertical component velocity and vertical diffusion depending on the space variables and on time, which was not the case in [5,6]. This new vision leads us to non-autonomous problems, the aim of this work is to show the existence, uniqueness, and positivity of solutions.

  13. A bio-economic farm household model to assess cropping systems in the Rift valley of Ethiopia : towards climate smart agriculture: do food security and mitigration goals match?

    NARCIS (Netherlands)

    Hengsdijk, H.; Verhagen, A.

    2012-01-01

    Modelling approach for rain fed farm household systems in the Central Rif Valley of Ethiopia to assess the possible effects of intensification of cereal-based cropping systems to farm income, mitigation of GHG emissions and other household indicators

  14. Modelling the cost-effectiveness of mitigation methods for multiple pollutants at farm scale.

    Science.gov (United States)

    Gooday, R D; Anthony, S G; Chadwick, D R; Newell-Price, P; Harris, D; Duethmann, D; Fish, R; Collins, A L; Winter, M

    2014-01-15

    Reductions in agricultural pollution are essential for meeting nationally and internationally agreed policy targets for losses to both air and water. Numerous studies quantify the impact of relevant mitigation methods by field experimentation or computer modelling. The majority of these studies have addressed individual methods and frequently also individual pollutants. This paper presents a conceptual model for the synthesis of the evidence base to calculate the impact of multiple methods addressing multiple pollutants in order to identify least cost solutions for multiple policy objectives. The model is implemented as a farm scale decision support tool that quantifies baseline pollutant losses for identifiable sources, areas and pathways and incorporates a genetic algorithm based multi-objective procedure for determining optimal suites of mitigation methods. The tool is generic as baseline losses can be replaced with measured data and the default library of mitigation methods can be edited and expanded. The tool is demonstrated through application to two contrasting farm systems, using survey data on agricultural practices typical of England and Wales. These examples show how the tool could be used to help target the adoption of mitigation options for the control of diffuse pollution from agriculture. The feedback from workshops where Farmscoper was demonstrated is included to highlight the potential role of Farmscoper as part of the farm advisory process.

  15. Dynamic modelling and analysis of multi-machine power systems including wind farms

    Science.gov (United States)

    Tabesh, Ahmadreza

    2005-11-01

    This thesis introduces a small-signal dynamic model, based on a frequency response approach, for the analysis of a multi-machine power system with special focus on an induction machine based wind farm. The proposed approach is an alternative method to the conventional eigenvalue analysis method which is widely employed for small-signal dynamic analyses of power systems. The proposed modelling approach is successfully applied and evaluated for a power system that (i) includes multiple synchronous generators, and (ii) a wind farm based on either fixed-speed, variable-speed, or doubly-fed induction machine based wind energy conversion units. The salient features of the proposed method, as compared with the conventional eigenvalue analysis method, are: (i) computational efficiency since the proposed method utilizes the open-loop transfer-function matrix of the system, (ii) performance indices that are obtainable based on frequency response data and quantitatively describe the dynamic behavior of the system, and (iii) capability to formulate various wind energy conversion unit, within a wind farm, in a modular form. The developed small-signal dynamic model is applied to a set of multi-machine study systems and the results are validated based on comparison (i) with digital time-domain simulation results obtained from PSCAD/EMTDC software tool, and (ii) where applicable with eigenvalue analysis results.

  16. Rural Credit and Farms Efficiency: Modelling Farmers Credit Allocation Decisions, Evidences from Benin

    Directory of Open Access Journals (Sweden)

    Comlan Hervé Sossou

    2014-01-01

    Full Text Available This paper analyses farmers’ credit allocation behaviors and their effects on technical efficiency. Data were collected from 476 farmers using the multistage sampling procedure. The stochastic frontier truncated-normal with conditional mean model is used to assess allocation schemes effects on technical efficiency. Tobit model reveals the impact of farmers’ sociodemographic characteristics on efficiency scores. Results reveal that farm revenue (about 2,262,566 Fcfa on average is positively correlated with land acreage, quantity of labour, and costs of fertilizers and insecticides. Farmers’ behaviors respond to six schemes which are categorized in two allocations contexts: out-farm and in-farm allocations. The model shows that only scheme (e positively impacts technical efficiency. This scheme refers to the decision to invest credit to purchase better quality of pesticides, herbicides, fertilizers, and so forth. The positive effect of the scheme (c may be significant under conditions of farmers’ education level improvement. Then, scheme (e is a better investment for all farmers, but effect of credit allocation to buy agricultural materials is positive only for educated farmers. Efficiency scores are reduced by household size and gender of the household head. Therefore a household with more than 10 members and a woman as head is likely to not be technically efficient.

  17. Leininger's model for discoveries at The Farm and midwifery services to the Amish.

    Science.gov (United States)

    Finn, J

    1995-01-01

    This paper is a descriptive report and analysis of a transcultural nurse's experiences immersed in a hippie subculture at The Farm near Summertown, Tennessee. This subcultural group initially was established over 20 years ago as a community with a unique worldview which included pacifistic, vegetarian, and collective values and beliefs. This community prefers health care provided by their own community members who serve as generic care providers and also as folk midwives for home births. Leininger's (1991) Theory of Culture Care Diversity and Universality and her Sunrise Model provided the framework for discovering and understanding this unique subcultural group. The major components of Leininger's Sunrise Model including worldview, cultural values, and lifeways were used in the analysis. The important social structure factors discovered included environmental context, technological factors, religious and philosophical factors, political and legal factors, economic factors, and educational factors. The Farm community's culture care expressions, patterns and practices for health and well being were discovered including generic and folk systems of care. The farm midwives provide primary care and home birthing care to a nearby Old Order Amish community. The Amish culture and health care seeking patterns are discussed including their selective use of generic, folk, and professional care systems. The discoveries that resulted from the application of Leininger's Sunrise Model are presented including implications for transcultural nurse caregiving.

  18. Heavy metals content and microbiological quality of carp (Cyprinus carpio, L.) muscle from two Southwestern Slovak fish farms.

    Science.gov (United States)

    Andreji, Jaroslav; Stranai, Ivan; Kacániová, Miroslava; Massányi, Peter; Valent, Miroslav

    2006-01-01

    The purpose of this study was to assess concentration and correlation of selected heavy metals and level of some microbiological indicators (total bacteria count-TBC, mesophilic anaerobic sporulating bacteria-MASB) in the muscle of common carp (Cyprinus carpio). Fish were collected by seine net within the frame of pondfishing, in October (pond Horné Obdokovce--pond A) and December (pond Budmerice--pond B) 2003. Concentrations of selected metals were measured using an atomic absorption spectrophotometer Pye Unicam SP9. The concentrations of metals (mg/kg wet weight basis) ranged as follows: Fe 3.47-15.15; Mn 0.14-0.42; Zn 3.47-9.52; Cu 0.24-1.32; Co 0.05-0.17; Ni 0.07-0.42; Cr 0.08-0.19; Pb 0.11-0.30; and Cd 0.01-0.05. The count of MASB and TCB (in CFU/g) varied as follow: 1.12-7.76 x 10(3) and 0.03-7.59 x 10(6), respectively. Significant differences (P MASB between ponds were recorded. An opposite trend of bioaccumulation was found in only 12 of 36 cases. Positive correlations between counts of MASB and accumulated heavy metals, except Ni and negative correlations between TBC and accumulated heavy metals, except Cr, were recorded, (P MASB count exceeded the maximum allowed concentration in 100% by both ponds. On average, the order of metal concentrations in the fish muscle was: (Pond-A) Fe > Zn > Cu > Mn > Pb > Cr > Ni > Co > Cd; (Pond-B) Fe > Zn > Cu > Mn > Pb > Ni > Cr > Co > Cd.

  19. Modeling and simulation of fish swimming with active muscles.

    Science.gov (United States)

    Curatolo, Michele; Teresi, Luciano

    2016-11-21

    Our goal is to reproduce the key features of carangiform swimming by modeling muscle functioning using the notion of active distortions, thus emphasizing the kinematical role of muscle, the generation of movement, rather than the dynamical one, the production of force. This approach, already proposed to model the action of muscles in different contexts, is here tested again for the problem of developing an effective and reliable framework to model and simulate swimming. A proper undulatory movement of a fish-like body is reproduced by defining a pattern of distortions, tuned in both space and time, meant to model the muscles activation which produce the flexural motion of body fish; eventually, interactions with the surrounding water yields the desired thrust. Carangiform swimmers have a relatively inflexible anterior body section and a generally flat, flexible posterior section. Because of this configuration, undulations sent rearward along the body attain a significant amplitude only in the posterior section. We compare the performances of different swimming gaits, and we are able to find some important relations between key parameters such as frequencies, wavelength, tail amplitude, and the achieved swim velocity, or the generated thrust, which summarize the swimming performance. In particular, an interesting relation is found between the Strouhal number and the wavelength of muscles activation. We highlight the muscle function during fish locomotion describing the activation of muscles and the relation between the force production and the shortening-lengthening cycle of muscle. We found a great accordance between results and empirical relations, giving an implicit validation of our models. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Contribution to a dynamic wind turbine model validation from a wind farm islanding experiment

    DEFF Research Database (Denmark)

    Pedersen, Jørgen Kaas; Pedersen, Knud Ole Helgesen; Poulsen, Niels Kjølstad;

    2003-01-01

    and possible discrepancies are explained. The work with the wind turbine model validation relates to the dynamic stability investigations on incorporation of large amount of wind power in the Danish power grid, where the dynamic wind turbine model is applied.......Measurements from an islanding experiment on the Rejsby Hede wind farm, Denmark, are used for the validation of the dynamic model of grid-connected, stall-controlled wind turbines equipped with induction generators. The simulated results are found to be in good agreement with the measurements...

  1. Characterization of a multiresistant mosaic plasmid from a fish farm Sediment Exiguobacterium sp. isolate reveals aggregation of functional clinic-associated antibiotic resistance genes.

    Science.gov (United States)

    Yang, Jing; Wang, Chao; Wu, Jinyu; Liu, Li; Zhang, Gang; Feng, Jie

    2014-02-01

    The genus Exiguobacterium can adapt readily to, and survive in, diverse environments. Our study demonstrated that Exiguobacterium sp. strain S3-2, isolated from marine sediment, is resistant to five antibiotics. The plasmid pMC1 in this strain carries seven putative resistance genes. We functionally characterized these resistance genes in Escherichia coli, and genes encoding dihydrofolate reductase and macrolide phosphotransferase were considered novel resistance genes based on their low similarities to known resistance genes. The plasmid G+C content distribution was highly heterogeneous. Only the G+C content of one block, which shared significant similarity with a plasmid from Exiguobacterium arabatum, fit well with the mean G+C content of the host. The remainder of the plasmid was composed of mobile elements with a markedly lower G+C ratio than the host. Interestingly, five mobile elements located on pMC1 showed significant similarities to sequences found in pathogens. Our data provided an example of the link between resistance genes in strains from the environment and the clinic and revealed the aggregation of antibiotic resistance genes in bacteria isolated from fish farms.

  2. Wake interaction and power production of variable height model wind farms

    DEFF Research Database (Denmark)

    Vested, Malene Hovgaard; Hamilton, N.; Sørensen, Jens Nørkær;

    2014-01-01

    of comparison. It was found that downstream of the exit row wind turbine, the power was increased by 25% in the case of a staggered height configuration. This is partly due to the fact that the taller turbines reach into a flow area with a softened velocity gradient. Another aspect is that the wake downstream......Understanding wake dynamics is an ongoing research topic in wind energy, since wakes have considerable effects on the power production when wind turbines are placed in a wind farm. Wind tunnel experiments have been conducted to study the wake to wake interaction in a model wind farm in tandem...... with measurements of the extracted power. The aim is to investigate how alternating mast height influences the interaction of the wakes and the power production. Via the use of stereo-particle image velocimetry, the flow field was obtained in the first and last rows of the wind turbine array as a basis...

  3. SYSTEM APPROACH TO THE MODELLING OF THE PROCESS OF EGG PRODUCTION ON THE FARM

    Directory of Open Access Journals (Sweden)

    Tomislav Guć

    2010-12-01

    Full Text Available This document presents a dynamics model of producing eggs on a farm using the system approach and methodology of system dynamics. We used system approach because it was about a continuous dynamic process. Our aim was to describe dynamic process of egg production and how production, numbers of hens and eggs stocks are changing after the modification of variables, demand and number of orders. The first part generally describes the process and the direction in which it will be developed. After that the subjects of the process and their role have been pointed out. The next thing was to describe how the process of the production functions in details with all its elements, objects and connections. In the second part we have presented the system flow chart diagram. The information has been obtained from the interview with people who were included in the work on that farm as well as from the observation.

  4. Forecasting wind power production from a wind farm using the RAMS model

    DEFF Research Database (Denmark)

    Tiriolo, L.; Torcasio, R. C.; Montesanti, S.;

    2015-01-01

    The importance of wind power forecast is commonly recognized because it represents a useful tool for grid integration and facilitates the energy trading. This work considers an example of power forecast for a wind farm in the Apennines in Central Italy. The orography around the site is complex...... and the horizontal resolution of the wind forecast has an important role. To explore this point we compared the performance of two 48 h wind power forecasts using the winds predicted by the Regional Atmospheric Modeling System (RAMS) for the year 2011. The two forecasts differ only for the horizontal resolution...... of the ECMWF Integrated Forecasting System (IFS), whose horizontal resolution over Central Italy is about 25 km at the time considered in this paper. Because wind observations were not available for the site, the power curve for the whole wind farm was derived from the ECMWF wind operational analyses available...

  5. A model for environmental sex reversal in fish.

    Science.gov (United States)

    Hurley, M A; Matthiessen, P; Pickering, A D

    2004-03-21

    A mathematical model is presented which combines genetic XX-female/XY-male sex determination with environmental pressure for phenotypic sex reversal. This may occur when fishes are exposed to endocrine disrupters, specifically masculinization by exposure to androgens and feminization by exposure to estrogens. A generic model is derived for the sex ratio in successive generations and three special cases, with chronic and constant pressure to sex reverse, are discussed in detail. These show that, with extreme environmental pressure to masculinize, the male genotype is at risk of dying out but with less extreme pressure, masculinization will not be detectable since the proportion of phenotypic males becomes one-half. With feminization at any pressure to sex reverse, the male and female genotypes will be maintained in a stable sex ratio in which the proportion of genotypic males exceeds one-half and is close to one-half if YY offspring (eggs) are not viable. In converse, the model is also applicable to the genetic ZZ-male/ZW-female system of sex determination in fish. At present suitable data are not available with which to validate the model, but proposals are made for relevant experimental studies.

  6. Diffusion of a Sustainable Farming Technique in Sri Lanka: An Agent-Based Modeling Approach

    Science.gov (United States)

    Jacobi, J. H.; Gilligan, J. M.; Carrico, A. R.; Truelove, H. B.; Hornberger, G.

    2012-12-01

    We live in a changing world - anthropogenic climate change is disrupting historic climate patterns and social structures are shifting as large scale population growth and massive migrations place unprecedented strain on natural and social resources. Agriculture in many countries is affected by these changes in the social and natural environments. In Sri Lanka, rice farmers in the Mahaweli River watershed have seen increases in temperature and decreases in precipitation. In addition, a government led resettlement project has altered the demographics and social practices in villages throughout the watershed. These changes have the potential to impact rice yields in a country where self-sufficiency in rice production is a point of national pride. Studies of the climate can elucidate physical effects on rice production, while research on social behaviors can illuminate the influence of community dynamics on agricultural practices. Only an integrated approach, however, can capture the combined and interactive impacts of these global changes on Sri Lankan agricultural. As part of an interdisciplinary team, we present an agent-based modeling (ABM) approach to studying the effects of physical and social changes on farmers in Sri Lanka. In our research, the diffusion of a sustainable farming technique, the system of rice intensification (SRI), throughout a farming community is modeled to identify factors that either inhibit or promote the spread of a more sustainable approach to rice farming. Inputs into the ABM are both physical and social and include temperature, precipitation, the Palmer Drought Severity Index (PDSI), community trust, and social networks. Outputs from the ABM demonstrate the importance of meteorology and social structure on the diffusion of SRI throughout a farming community.

  7. Effect of inter-annual variability in pasture growth and irrigation response on farm productivity and profitability based on biophysical and farm systems modelling.

    Science.gov (United States)

    Vogeler, Iris; Mackay, Alec; Vibart, Ronaldo; Rendel, John; Beautrais, Josef; Dennis, Samuel

    2016-09-15

    Farm system and nutrient budget models are increasingly being used in analysis to inform on farm decision making and evaluate land use policy options at regional scales. These analyses are generally based on the use of average annual pasture yields. In New Zealand (NZ), like in many countries, there is considerable inter-annual variation in pasture growth rates, due to climate. In this study a modelling approach was used to (i) include inter-annual variability as an integral part of the analysis and (ii) test the approach in an economic analysis of irrigation in a case study within the Hawkes Bay Region of New Zealand. The Agricultural Production Systems Simulator (APSIM) was used to generate pasture dry matter yields (DMY) for 20 different years and under both dryland and irrigation. The generated DMY were linked to outputs from farm-scale modelling for both Sheep and Beef Systems (Farmaxx Pro) and Dairy Systems (Farmax® Dairy Pro) to calculate farm production over 20 different years. Variation in DMY and associated livestock production due to inter-annual variation in climate was large, with a coefficient of variations up to 20%. Irrigation decreased this inter-annual variation. On average irrigation, with unlimited available water, increased income by $831 to 1195/ha, but when irrigation was limited to 250mm/ha/year income only increased by $525 to 883/ha. Using pasture responses in individual years to capturing the inter-annual variation, rather than the pasture response averaged over 20years resulted in lower financial benefits. In the case study income from irrigation based on an average year were 10 to >20% higher compared with those obtained from individual years.

  8. Offshore Wind Turbine Foundation Model Validation with Wind Farm Measurements and Uncertainty Quantification

    DEFF Research Database (Denmark)

    Koukoura, Christina; Natarajan, Anand; Krogh, Thomas

    2013-01-01

    The variation in simulated monopile substructure loads is quantified by validating an aero-hydro-servo-elastic design tool with offshore foundation load measurements. A three bladed 3.6MW pitch controlled variable speed wind turbine for offshore monopile foundations is modeled in the HAWC2...... simulation code. A flexible soil model is included in the analysis. Fatigue loads analysis is performed for both the dynamic simulations and on-site foundation strain measurements. The wind farm wake effects on the monopile fatigue loads is also examined and compared with load measurements. Potential...

  9. A survey of modelling methods for high-fidelity wind farm simulations using large eddy simulation

    DEFF Research Database (Denmark)

    Breton, Simon-Philippe; Sumner, J.; Sørensen, Jens Nørkær

    2017-01-01

    Large eddy simulations (LES) of wind farms have the capability to provide valuable and detailed information about the dynamics of wind turbine wakes. For this reason, their use within the wind energy research community is on the rise, spurring the development of new models and methods. This review...... surveys the most common schemes available to model the rotor, atmospheric conditions and terrain effects within current state-of-the-art LES codes, of which an overview is provided. A summary of the experimental research data available for validation of LES codes within the context of single and multiple...

  10. Investigation of sonar transponders for offshore wind farms: modeling approach, experimental setup, and results.

    Science.gov (United States)

    Fricke, Moritz B; Rolfes, Raimund

    2013-11-01

    The installation of offshore wind farms in the German Exclusive Economic Zone requires the deployment of sonar transponders to prevent collisions with submarines. The general requirements for these systems have been previously worked out by the Research Department for Underwater Acoustics and Marine Geophysics of the Bundeswehr. In this article, the major results of the research project "Investigation of Sonar Transponders for Offshore Wind Farms" are presented. For theoretical investigations a hybrid approach was implemented using the boundary element method to calculate the source directivity and a three-dimensional ray-tracing algorithm to estimate the transmission loss. The angle-dependence of the sound field as well as the weather-dependence of the transmission loss are compared to experimental results gathered at the offshore wind farm alpha ventus, located 45 km north of the island Borkum. While theoretical and experimental results are in general agreement, the implemented model slightly underestimates scattering at the rough sea surface. It is found that the source level of 200 dB re 1 μPa at 1 m is adequate to satisfy the detectability of the warning sequence at distances up to 2 NM (≈3.7 km) within a horizontal sector of ±60° if realistic assumptions about signal-processing and noise are made. An arrangement to enlarge the angular coverage is discussed.

  11. Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

    Directory of Open Access Journals (Sweden)

    Ju Feng

    2015-04-01

    Full Text Available Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distributions of wind speed and wind direction, which is based on the parameters of sector-wise Weibull distributions and interpolations between direction sectors. It is applied to the wind measurement data at Horns Rev and three different joint distributions are obtained, which all fit the measurement data quite well in terms of the coefficient of determination . Then, the best of these joint distributions is used in the layout optimization of the Horns Rev 1 wind farm and the choice of bin sizes for wind speed and wind direction is also investigated. It is found that the choice of bin size for wind direction is especially critical for layout optimization and the recommended choice of bin sizes for wind speed and wind direction is finally presented.

  12. Regional climate model simulations indicate limited climatic impacts by operational and planned European wind farms.

    Science.gov (United States)

    Vautard, Robert; Thais, Françoise; Tobin, Isabelle; Bréon, François-Marie; Devezeaux de Lavergne, Jean-Guy; Colette, Augustin; Yiou, Pascal; Ruti, Paolo Michele

    2014-01-01

    The rapid development of wind energy has raised concerns about environmental impacts. Temperature changes are found in the vicinity of wind farms and previous simulations have suggested that large-scale wind farms could alter regional climate. However, assessments of the effects of realistic wind power development scenarios at the scale of a continent are missing. Here we simulate the impacts of current and near-future wind energy production according to European Union energy and climate policies. We use a regional climate model describing the interactions between turbines and the atmosphere, and find limited impacts. A statistically significant signal is only found in winter, with changes within ±0.3 °C and within 0-5% for precipitation. It results from the combination of local wind farm effects and changes due to a weak, but robust, anticyclonic-induced circulation over Europe. However, the impacts remain much weaker than the natural climate interannual variability and changes expected from greenhouse gas emissions.

  13. Energy Self-sufficiency from an Emergy Perspective Exemplified by a Model System of a Danish Farm Cooperative

    DEFF Research Database (Denmark)

    Østergård, Hanne; Markussen, Mads Ville

    2010-01-01

    Danish organic farm cooperative with a small biogas plant shared between five farms. We model the energy, matter and emergy flows in a crop rotation scenario developed by the Danish organic farmers association including grass-clover lays, cereals, oilseed rape and legumes; also we consider the emergy...... of the biodiesel and a little electricity and heat are used on the farms; the remaining products are supplied to the society. Different emergy indices for resource use efficiency are evaluated and compared to results from other bioenergy studies. The roles of nutrient balances and green manure are discussed....

  14. STUDY ON RESIDUES OF 14C-FENITROTHION IN MODEL RICE-FISH ECOSYSTEM AND FIELD RICE-FISH ECOSYSTEM

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    Residues of 14C-fenitrothion in a model rice-fish ecosystem and field rice-fish ecosystem were studied.When equal amounts of the pesticide were applied.the extractable residues in brown rice (equivalent to 34.3±1.9ug/kg fenitrothion) and rice stems and leaves(20.9±1.5ug/kg) of the model rice-fish ecosystem were 10-15times higher than that of the field rice-fish ecosystem(4.48±0.13ug/kg and 1.27±0.34ug/kg respectively).Residues in upper part of the soil (6.50±0.1-8.10±0.2ug/kg)and lower part of the soil(1.30±0.1-1.50±0.1ug/kg)of the model rice-fish ecosystem were 10-40 times higher than that of the field rice-fish ecosystem (0.17±0.01ug/kg).The extractable residues in paddy water of the model ecosystem (0.30±0.01ug/kg)were similar to that of the field ecosystem(0.20±0.02ug/kg),When the fenitrothion was sprayed on the rice plants.residues in brown rice,fish body.soil and paddy water were lower than those when the pesticide was sprayed on the surface of the soil.

  15. Environmental management of marine fish culture in Hong Kong.

    Science.gov (United States)

    Lee, J H W; Choi, K W; Arega, F

    2003-01-01

    Marine fish farming is an important commercial practice in Hong Kong. Marine fish farms located in eutrophic coastal waters often face the threat of severe dissolved oxygen depletion associated with algal blooms and red tides. On the other hand, mariculture activities also contribute to pollution. The sustainable management of mariculture requires proper siting of the fish farms and stocking density control. Both of these are related to the carrying capacity of the water body concerned, which is mainly governed by its flushing characteristics. A simple method to determine the carrying capacity of a fish farm has been developed by using three-dimensional (3D) hydrodynamic modelling and its effective coupling with a diagenetic water quality model. A systematic methodology using numerical tracer experiments has been developed to compute the tidal flushing in a fish farm. The flushing time is determined from the results of a numerical tracer experiment using robust 3D hydrodynamic and mass transport models. A unit tracer concentration is initially prescribed inside the region of interest and zero elsewhere; the subsequent mass transport and the mass removal process are then tracked. The fish farms are usually situated in well-sheltered shallow embayments and may not connect directly to the open water. It is found that it is necessary to define both "local" and "system-wide" flushing times to represent the effectiveness of the mass exchange with the surrounding water body and the open sea respectively. A diagenetic water quality model simulating the sediment-water-pollutant interaction is employed to address the response of the water column and the benthic layer to pollution discharges. With the flushing rate reliably computed, the carrying capacity of the fish farm can be determined in terms of key water quality parameters: chlorophyll-a, dissolved oxygen, organic nitrogen and potential lowest dissolved oxygen level on a day of negligible photosynthetic production. The

  16. Modelling and Measuring Flow and Wind Turbine Wakes in Large Wind Farms Offshore

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Hansen, Kurt Schaldemose; Frandsen, Sten Tronæs

    2009-01-01

    power losses due to wakes and loads. The research presented is part of the EC-funded UpWind project, which aims to radically improve wind turbine and wind farm models in order to continue to improve the costs of wind energy. Reducing wake losses, or even reduce uncertainties in predicting power losses...... of models from computational fluid dynamics (CFD) to wind form models in terms of how accurately they represent wake losses when compared with measurements from offshore wind forms. The ultimate objective is to improve modelling of flow for large wind forms in order to optimize wind form layouts to reduce...... from wakes, contributes to the overall goal of reduced costs. Here, we assess the state of the art in wake and flow modelling for offshore wind forms, the focus so for has been cases at the Horns Rev wind form, which indicate that wind form models require modification to reduce under-prediction of wake...

  17. Contract Farming Preferences of Smallholder Rice Producers in Benin: A Stated Choice Model Using Mixed Logit Erodibility

    Directory of Open Access Journals (Sweden)

    Arouna, A.

    2017-01-01

    Full Text Available In developing countries, smallholder farmers face many constraints including lack of information, and lack of access to credit and markets. To overcome these constraints, smallholder farmers can engage in contract farming. However, contract farming needs to meet farmers' preferences in order to be sustainable. This study aimed to analyze rice farmers' preferences for contract farming in Benin. Stated choice data were collected from 574 rice farmers. To account for heterogeneity, data were analyzed using a mixed logit model. Producers preferred contracts with seven major attributes: short term, payment on delivery, collective selling, agreement on quantity, no provision of credit, application of the market price, and no control by the partner. However, there was heterogeneity in the contract preferences of rice farmers. The study suggests that these differences and the preferred attributes are important in the design of best-fit contract farming models by agribusiness firms and policy-makers.

  18. Modelling deforestation caused by the expansion of subsistence farming in the Philippines

    Energy Technology Data Exchange (ETDEWEB)

    Uitamo, E. [Joensuu Univ. (Finland). Faculty of Forestry

    1999-04-01

    The forest area of the Philippines declined in twenty years, during 1970 - 1990, from about one third to about one fifth of the total land area, i. e. from 10 to 6 million hectares. The relative significance of the various direct and indirect causes of deforestation obviously have changed over the course of time. It has been suggested that during the last decades, the expansion of subsistence or small-scale cultivators into the previously forested upland areas has been the major human activity leading to deforestation. The indirect causes of deforestation include economic, political, demographic, and environmental factors. In this paper, it is hypothesised that the indirect causes increasing the expansion of agriculture into the uplands include factors like population density, conditions on farms in the lowlands, as well as poverty and lack of non-farm employment opportunities. The aim is by no means to present a comprehensive causal model but rather to analyse and understand one part of the complexity related to deforestation. Deforestation or forest cover changes in the Philippines are analysed using multiple regression with pooled data from 55-64 provinces and from two years, 1969 and 1990. In the empirical models, the dependent variable is the logit-transformation of the forest cover of each province, and the independent variables include population density, the share of small farms, and the tenancy rate of each province. First, a model with pooled data and a common intercept is analysed using the ordinary least squares (OLS) method. In addition, the data are analysed using the so-called fixed effects (FEM) and random effects models (REM). According to these estimated models, forest cover is negatively related to all of the three independent variables used, i.e. the bigger the population density and the larger the shares of small and tenant farms, the smaller the forest cover in each province. Unfortunately, omitting some theoretically relevant variables due to

  19. Assessing manure management strategies through small-plot research and whole-farm modeling

    Science.gov (United States)

    Garcia, A.M.; Veith, T.L.; Kleinman, P.J.A.; Rotz, C.A.; Saporito, L.S.

    2008-01-01

    Plot-scale experimentation can provide valuable insight into the effects of manure management practices on phosphorus (P) runoff, but whole-farm evaluation is needed for complete assessment of potential trade offs. Artificially-applied rainfall experimentation on small field plots and event-based and long-term simulation modeling were used to compare P loss in runoff related to two dairy manure application methods (surface application with and without incorporation by tillage) on contrasting Pennsylvania soils previously under no-till management. Results of single-event rainfall experiments indicated that average dissolved reactive P losses in runoff from manured plots decreased by up to 90% with manure incorporation while total P losses did not change significantly. Longer-term whole farm simulation modeling indicated that average dissolved reactive P losses would decrease by 8% with manure incorporation while total P losses would increase by 77% due to greater erosion from fields previously under no-till. Differences in the two methods of inference point to the need for caution in extrapolating research findings. Single-event rainfall experiments conducted shortly after manure application simulate incidental transfers of dissolved P in manure to runoff, resulting in greater losses of dissolved reactive P. However, the transfer of dissolved P in applied manure diminishes with time. Over the annual time frame simulated by whole farm modeling, erosion processes become more important to runoff P losses. Results of this study highlight the need to consider the potential for increased erosion and total P losses caused by soil disturbance during incorporation. This study emphasizes the ability of modeling to estimate management practice effectiveness at the larger scales when experimental data is not available.

  20. Modeling Tribal Exposures to Methyl Mercury from Fish Consumption

    Data.gov (United States)

    U.S. Environmental Protection Agency — data is from NHANES study and EPA fish intake and HG concentration in fish tissue. This dataset is associated with the following publication: Xue , J., V. Zartarian...

  1. Wind Power Curve Modeling Using Statistical Models: An Investigation of Atmospheric Input Variables at a Flat and Complex Terrain Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bulaevskaya, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Irons, Z. [Enel Green Power North America, Andover, MA (United States); Qualley, G. [Infigen Energy, Dallas, TX (United States); Newman, J. F. [Univ. of Oklahoma, Norman, OK (United States); Miller, W. O. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-28

    The goal of our FY15 project was to explore the use of statistical models and high-resolution atmospheric input data to develop more accurate prediction models for turbine power generation. We modeled power for two operational wind farms in two regions of the country. The first site is a 235 MW wind farm in Northern Oklahoma with 140 GE 1.68 turbines. Our second site is a 38 MW wind farm in the Altamont Pass Region of Northern California with 38 Mitsubishi 1 MW turbines. The farms are very different in topography, climatology, and turbine technology; however, both occupy high wind resource areas in the U.S. and are representative of typical wind farms found in their respective areas.

  2. Drinks like a fish: zebra fish (Danio rerio) as a behavior genetic model to study alcohol effects.

    Science.gov (United States)

    Gerlai, R; Lahav, M; Guo, S; Rosenthal, A

    2000-12-01

    Zebra fish may be an ideal vertebrate model system for numerous human diseases with which the genetics and biological mechanisms of the disease may be studied. Zebra fish has been successfully used in developmental genetics, and recently, neurobiologists have also started to study this species. A potentially interesting target disease amenable for analysis with zebra fish is drug addiction, e.g. alcoholism. Although genetic tools to manipulate the genome of zebra fish are available, appropriate phenotypical testing methods are often lacking. In this paper, we describe basic behavioral tests to investigate the acute effects of alcohol on zebra fish. These behavioral paradigms will be useful for the genetic and biological analysis of acute and chronic drug effects as well as addiction. In addition to presenting findings for the acute effects of alcohol, we briefly describe our strategy for generating and screening mutants. We hope that our pilot work will facilitate the future development of behavioral tests and the use of zebra fish in the genetic analysis of the biological effects of drugs of abuse.

  3. Using data from an encounter sampler to model fish dispersal

    Science.gov (United States)

    Obaza, A.; DeAngelis, D.L.; Trexler, J.C.

    2011-01-01

    A method to estimate speed of free-ranging fishes using a passive sampling device is described and illustrated with data from the Everglades, U.S.A. Catch per unit effort (CPUE) from minnow traps embedded in drift fences was treated as an encounter rate and used to estimate speed, when combined with an independent estimate of density obtained by use of throw traps that enclose 1 m2 of marsh habitat. Underwater video was used to evaluate capture efficiency and species-specific bias of minnow traps and two sampling studies were used to estimate trap saturation and diel-movement patterns; these results were used to optimize sampling and derive correction factors to adjust species-specific encounter rates for bias and capture efficiency. Sailfin mollies Poecilia latipinna displayed a high frequency of escape from traps, whereas eastern mosquitofish Gambusia holbrooki were most likely to avoid a trap once they encountered it; dollar sunfish Lepomis marginatus were least likely to avoid the trap once they encountered it or to escape once they were captured. Length of sampling and time of day affected CPUE; fishes generally had a very low retention rate over a 24 h sample time and only the Everglades pygmy sunfish Elassoma evergladei were commonly captured at night. Dispersal speed of fishes in the Florida Everglades, U.S.A., was shown to vary seasonally and among species, ranging from 0.05 to 0.15 m s-1 for small poeciliids and fundulids to 0.1 to 1.8 m s-1 for L. marginatus. Speed was generally highest late in the wet season and lowest in the dry season, possibly tied to dispersal behaviours linked to finding and remaining in dry-season refuges. These speed estimates can be used to estimate the diffusive movement rate, which is commonly employed in spatial ecological models.

  4. Spatial modeling and habitat quantification for two diadromous fish in New Zealand streams: a GIS-based approach with application for conservation management.

    Science.gov (United States)

    Eikaas, Hans S; Kliskey, Andrew D; McIntosh, Angus R

    2005-11-01

    We developed logistic regression models from data on biotic and abiotic variables for 172 sites on Banks Peninsula, New Zealand, to predict the probability of occurrence of two diadromous fish, banded kokopu (Galaxias fasciatus) and koaro (G. brevipinnis). Banded kokopu occurrence was positively associated with small streams and low-intensity land uses (e.g., sheep grazing or forested), whereas intensive land uses (e.g., mixed sheep and cattle farming) and lack of riparian forest cover impacted negatively on occurrence at sampled sites. Also, if forests were positioned predominantly in lowland areas, banded kokopu occurrence declined with increasing distance to stream mouth. Koaro occurrence was positively influenced by catchment forest cover, high stream altitudes, and areas of no farming activity or mixed land uses. Intensive land uses, distance to stream mouth, and presence of banded kokopu negatively influenced koaro occupancy of stream reaches. Banded kokopu and koaro presence was predicted in 86.0% and 83.7% agreement, respectively, with field observations. We used the models to quantify the amount of stream reaches that would be of good, moderate, and poor quality, based on the probability of occurrences of the fish being greater than 0.75, between 0.75 and 0.5, or less than 0.5, respectively. Hindcasting using historical data on vegetation cover undertaken for one catchment, Pigeon Bay, showed they would have occupied most of the waterway before anthropogenic modification. We also modeled potential future scenarios to project potential fish distribution.

  5. Multi-factor Analysis Model for Improving Profit Management Using Excel in Shellfish Farming Projects

    Institute of Scientific and Technical Information of China (English)

    Zhuming; ZHAO; Changlin; LIU; Xiujuan; SHAN; Jin; YU

    2013-01-01

    By using a farm’s data in Yantai City and the theory of Cost-Volume-Profit analysis and the financial management methods,this paper construct a multi-factor analysis model for improving profit management using Excel 2007 in Shellfish farming projects and describes the procedures to construct a multi-factor analysis model.The model can quickly calculate the profit,improve the level of profit management,find out the breakeven point and enhance the decision-making efficiency of businesses etc.It is also a thought of the application to offer suggestions for government decisions and economic decisions for corporations as a simple analysis tool.While effort has been exerted to construct a four-variable model,some equally important variables may not be discussed sufficiently due to limitation of the paper’s space and the authors’knowledge.All variables can be listed in EXCEL 2007 and can be associated in a logical way to manage the profit of shellfish farming projects more efficiently and more practically.

  6. COMPUTER MODEL USED TO CALCULATE PROFITABILITY AND ECONOMIC RISK ON FARMS

    Directory of Open Access Journals (Sweden)

    Rozi BEREVOIANU

    2013-12-01

    Full Text Available Economic information is an essential element of progress, being present in all fields. With the development of market economy must grow and economic information in order to reflect as accurately as patrimonial situation and results of financial and economic activity of enterprises. The main source of economic information is the accounting, which is the main instrument of knowledge, management and control of assets and results of any enterprise. In this paper we present a computer model to analyze economic information on the profitability and economic risk, available both in the vegetable farms and for the livestock sector.

  7. A Simulation Model of Combined Biogas, Bioethanol and Protein Fodder Co-Production in Organic Farming

    DEFF Research Database (Denmark)

    Oleskowicz-Popiel, Piotr; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2009-01-01

    from the BioConcens project (http://www.bioconcens.elr.dk). Different design approaches were evaluated in order to establish the most suitable configuration. Rye grains, clover grass silage, maize silage, whey and cattle manure were selected as raw materials for co-production of fuels, feed......, respectively). Results from batch and lab-scale fermentation trials provided basic input for the model. To cover the direct energy requirements on the farm, it was calculated that it requires approximately 16.2 ha of rye and 14 milking cows or 5.7 ha of clover grass, 2.5 ha of maize and 13 cows to supply a 100...

  8. Benthic community structure and biomarker responses of the clam Scrobicularia plana in a shallow tidal creek affected by fish farm effluents (Rio San Pedro, SW Spain).

    Science.gov (United States)

    Silva, Claudio; Mattioli, Mattia; Fabbri, Elena; Yáñez, Eleuterio; Delvalls, T Angel; Martín-Díaz, M Laura

    2012-10-15

    The effects of solid organic wastes from a marine fish farm on sediments were tested using benthic community as ecological indicators and biomarkers in native clam (Scrobicularia plana) as biochemical indicators. The benthic fauna and clam samples were collected in the intertidal sediment in October 2010 from five sites of the Rio San Pedro (RSP) creek, following a gradient of contamination from the aquaculture effluent to the control site. Numbers of species, abundance, richness and Shannon diversity were the biodiversity indicators measured in benthic fauna. Morphological and reproduction status of clams were assessed using the condition factor and gonado-somatic index, respectively. Phase I and Phase II detoxification enzymatic activities (ethoxyresorufin O-deethylase (EROD), glutathione S-transferase (GST)), antioxidant enzymatic activities (glutathione peroxidase (GPX), glutathione reductase (GR)) and oxidative stress parameters (Lipid Peroxidation (LPO) and DNA strand breaks) were measured in clams' digestive gland tissues. In parallel, temperature and salinity in the adjacent water, redox potential, pH and organic matter in sediment, and dissolved oxygen in the interstitial water were measured. The results suggested that RSP showed a spatial gradient characterised by hypoxia/anoxia, reduced potential, acidic conditions and high organic enrichment in sediments at the most contaminated sites. Significant (pbiodiversity indicators were observed in the areas impacted by the aquaculture discharges. Biomarkers did not show a clear pattern and of all biochemical responses tested, GPX, DNA damage and LPO were the most sensitive ones and showed significant (ppolluted sites. Benthic biodiversity indicators were significantly (pchanges of the benthic population structure and health status of the exposed organisms.

  9. River water temperature and fish growth forecasting models

    Science.gov (United States)

    Danner, E.; Pike, A.; Lindley, S.; Mendelssohn, R.; Dewitt, L.; Melton, F. S.; Nemani, R. R.; Hashimoto, H.

    2010-12-01

    Water is a valuable, limited, and highly regulated resource throughout the United States. When making decisions about water allocations, state and federal water project managers must consider the short-term and long-term needs of agriculture, urban users, hydroelectric production, flood control, and the ecosystems downstream. In the Central Valley of California, river water temperature is a critical indicator of habitat quality for endangered salmonid species and affects re-licensing of major water projects and dam operations worth billions of dollars. There is consequently strong interest in modeling water temperature dynamics and the subsequent impacts on fish growth in such regulated rivers. However, the accuracy of current stream temperature models is limited by the lack of spatially detailed meteorological forecasts. To address these issues, we developed a high-resolution deterministic 1-dimensional stream temperature model (sub-hourly time step, sub-kilometer spatial resolution) in a state-space framework, and applied this model to Upper Sacramento River. We then adapted salmon bioenergetics models to incorporate the temperature data at sub-hourly time steps to provide more realistic estimates of salmon growth. The temperature model uses physically-based heat budgets to calculate the rate of heat transfer to/from the river. We use variables provided by the TOPS-WRF (Terrestrial Observation and Prediction System - Weather Research and Forecasting) model—a high-resolution assimilation of satellite-derived meteorological observations and numerical weather simulations—as inputs. The TOPS-WRF framework allows us to improve the spatial and temporal resolution of stream temperature predictions. The salmon growth models are adapted from the Wisconsin bioenergetics model. We have made the output from both models available on an interactive website so that water and fisheries managers can determine the past, current and three day forecasted water temperatures at

  10. Quantifying Fish Backscattering using SONAR Instrument and Kirchhoff Ray Mode (KRM) Model

    Science.gov (United States)

    Manik, Henry M.

    2016-08-01

    Sonar instrument was used to study backscattering from tuna fish. Extraction of target strength, incidence angle, and frequency dependence of the backscattered signal for individual scatterer was important for biological information. For this purpose, acoustic measurement of fish backscatter was conducted in the laboratory. Characteristics and general trends of the target strength of fish with special reference to tuna fish were investigated by using a Kirchhoff Ray Mode (KRM) model. Backscattering strength were calculated for the KRM having typical morphological and physical parameters of actual fish. Those backscattering amplitudes were shown as frequency, body length, backscattering patterns, the density and sound speed dependences, and orientation dependence. These results were compared with experimentally measured target strength data and good agreement was found. Measurement and model showed the target strength from the fish are depend on the presence of swimbladder. Target Strength increase with increasing the frequency and fish length.

  11. Optimal Active Power Control of A Wind Farm Equipped with Energy Storage System based on Distributed Model Predictive Control

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Guo, Qinglai

    2016-01-01

    This paper presents the Distributed Model Predictive Control (D-MPC) of a wind farm equipped with fast and short-term Energy Storage System (ESS) for optimal active power control using the fast gradient method via dual decomposition. The primary objective of the D-MPC control of the wind farm...... is power reference tracking from system operators. Besides, by optimal distribution of the power references to individual wind turbines and the ESS unit, the wind turbine mechanical loads are alleviated. With the fast gradient method, the convergence rate of the DMPC is significantly improved which leads...... is independent from the wind farm size and is suitable for the real-time control of the wind farm with ESS....

  12. Regional scale hydrodynamic modelling of offshore wind farm development areas off the east coast of Scotland

    Science.gov (United States)

    O'Hara Murray, Rory; Gallego, Alejandro

    2013-04-01

    There is considerable interest in Scotland, supported by the Scottish Government, in the expansion of renewable energy production. In particular, significant offshore wind energy developments are already planned in coastal waters to the east of the Forth and Tay estuaries. It is important to understand the local and cumulative environmental impact of such developments within this region, to aid licensing decisions but also to inform marine spatial planning in general. Substantial wind farm developments may affect physical processes within the region, such as tidal-, wind-, and wave-driven circulation, as well as coastal sediment transport and more complex estuarine dynamics. Such physical impacts could have ecological and, ultimately, socio-economic consequences. The Firth of Forth and Tay areas both exhibit complex estuarine characteristics due to fresh water input, complex bathymetry and coastline, and tidal mixing. Our goal is to construct an unstructured grid hydrodynamic model of the wider Firth of Forth and Tay region using the Finite-Volume Coastal Ocean Model (FVCOM), resolving the complex estuarine hydrography of the area and representing offshore wind developments. Hydrodynamic modelling will provide an accurate baseline of the hydrography in this region but also allow the assessment of the effect on the physical environment of multiple wind farm development scenarios.

  13. Stochastic bio-economic modeling of mastitis in Ethiopian dairy farms.

    Science.gov (United States)

    Getaneh, Abraham Mekibeb; Mekonnen, Sefinew Alemu; Hogeveen, Henk

    2017-03-01

    Mastitis is an inflammation of the mammary gland that is considered to be one of the most frequent and costly diseases in the dairy industry. Also in Ethiopia, bovine mastitis is one of the most frequently encountered diseases of dairy cows. However, there was no study, so far, regarding the costs of clinical mastitis and only two studies were reported on costs of subclinical mastitis. Presenting an appropriate and complete study of the costs of mastitis will help farmers in making management decisions for mastitis control. The objective of this study was to estimate the economic effects of mastitis on Ethiopian market-oriented dairy farms. Market-oriented dairy farming is driven by making profits through selling milk in the market on a regular basis. A dynamic stochastic Monte-Carlo simulation model (bio-economic model) was developed taking into account both clinical and subclinical mastitis. Production losses, culling, veterinarian costs, treatment, discarded milk, and labour were the main cost factors which were modeled in this study. The annual incidence of clinical mastitis varied from 0 to 50% with a mean annual incidence of 21.6%, whereas the mean annual incidence of subclinical mastitis was 36.2% which varied between 0 and 75%. The total costs due to mastitis for a default farm size of 8 lactating cows were 6,709 ETB per year (838 ETB per cow per year). The costs varied considerably, with 5th and 95th percentiles of 109 ETB and 22,009 ETB, respectively. The factor most contributing to the total annual cost of mastitis was culling. On average a clinical case costs 3,631 ETB, varying from 0 to 12,401, whereas a sub clinical case costs 147 ETB, varying from 0 to 412. The sensitivity analysis showed that the total costs at the farm level were most sensitive for variation in the probability of occurrence of clinical mastitis and the probability of culling. This study helps farmers to raise awareness about the actual costs of mastitis and motivate them to timely

  14. A simple rule based model for scheduling farm management operations in SWAT

    Science.gov (United States)

    Schürz, Christoph; Mehdi, Bano; Schulz, Karsten

    2016-04-01

    For many interdisciplinary questions at the watershed scale, the Soil and Water Assessment Tool (SWAT; Arnold et al., 1998) has become an accepted and widely used tool. Despite its flexibility, the model is highly demanding when it comes to input data. At SWAT's core the water balance and the modeled nutrient cycles are plant growth driven (implemented with the EPIC crop growth model). Therefore, land use and crop data with high spatial and thematic resolution, as well as detailed information on cultivation and farm management practices are required. For many applications of the model however, these data are unavailable. In order to meet these requirements, SWAT offers the option to trigger scheduled farm management operations by applying the Potential Heat Unit (PHU) concept. The PHU concept solely takes into account the accumulation of daily mean temperature for management scheduling. Hence, it contradicts several farming strategies that take place in reality; such as: i) Planting and harvesting dates are set much too early or too late, as the PHU concept is strongly sensitivity to inter-annual temperature fluctuations; ii) The timing of fertilizer application, in SWAT this often occurs simultaneously on the same date in in each field; iii) and can also coincide with precipitation events. Particularly, the latter two can lead to strong peaks in modeled nutrient loads. To cope with these shortcomings we propose a simple rule based model (RBM) to schedule management operations according to realistic farmer management practices in SWAT. The RBM involves simple strategies requiring only data that are input into the SWAT model initially, such as temperature and precipitation data. The user provides boundaries of time periods for operation schedules to take place for all crops in the model. These data are readily available from the literature or from crop variety trials. The RBM applies the dates by complying with the following rules: i) Operations scheduled in the

  15. Replacing fish meal by food waste to produce lower trophic level fish containing acceptable levels of polycyclic aromatic hydrocarbons: Health risk assessments.

    Science.gov (United States)

    Cheng, Zhang; Mo, Wing-Yin; Lam, Cheung-Lung; Choi, Wai-Ming; Wong, Ming-Hung

    2015-08-01

    This study aimed at using different types of food wastes (mainly containing cereal [food waste A] and meat meal [food waste B]) as major sources of protein to replace the fish meal used in fish feeds to produce quality fish. The traditional fish farming model used to culture low trophic level fish included: bighead, (Hypophthalmichthys nobilis), grass carp, (Ctenopharyngodon idellus), and mud carp, (Cirrhinus molitorella) of omnivorous chain. The results indicated that grass carp and bighead carp fed with food waste feeds were relatively free of PAHs. The results of health risk assessment showed that the fish fed with food waste feeds were safe for consumption from the PAHs perspective.

  16. Assessing the forecasting performance of a generic Bio-Economic farm model calibrated with two different PMP variants

    NARCIS (Netherlands)

    Kanellopoulos, A.; Berentsen, Paul; Heckelei, T.; Ittersum, van M.K.; Oude Lansink, A.G.J.M.

    2010-01-01

    Using linear programming in bio-economic farm modelling often results in overspecialised model solutions. The positive mathematical programming (PMP) approach guarantees exact calibration to base year data but the forecasting capacity of the model is affected by necessary but arbitrary assumptions

  17. Assessing the forecasting performance of a generic Bio-Economic farm model calibrated with two different PMP variants

    NARCIS (Netherlands)

    Kanellopoulos, A.; Berentsen, Paul; Heckelei, T.; Ittersum, van M.K.; Oude Lansink, A.G.J.M.

    2010-01-01

    Using linear programming in bio-economic farm modelling often results in overspecialised model solutions. The positive mathematical programming (PMP) approach guarantees exact calibration to base year data but the forecasting capacity of the model is affected by necessary but arbitrary assumptions i

  18. Implementation of cable models for studies of compatibility of electric components in wind farms

    DEFF Research Database (Denmark)

    Holdyk, Andrzej; Holbøll, Joachim; Jensen, Asger

    2011-01-01

    that problem in a sufficiently general way, trying to take into consideration different layouts of farms and different wind farm electric environments at the same time. This paper introduces a first step towards the concept of compatibility of electric components in wind farms by relating different cable...

  19. Changes in the Welfare of an Injured Working Farm Dog Assessed Using the Five Domains Model

    Directory of Open Access Journals (Sweden)

    Katherine E. Littlewood

    2016-09-01

    Full Text Available The present structured, systematic and comprehensive welfare evaluation of an injured working farm dog using the Five Domains Model is of interest in its own right. It is also an example for others wanting to apply the Model to welfare evaluations in different species and contexts. Six stages of a fictitious scenario involving the dog are considered: (1 its on-farm circumstances before one hind leg is injured; (2 its entanglement in barbed wire, cutting it free and transporting it to a veterinary clinic; (3 the initial veterinary examination and overnight stay; (4 amputation of the limb and immediate post-operative recovery; (5 its first four weeks after rehoming to a lifestyle block; and (6 its subsequent life as an amputee and pet. Not all features of the scenario represent average-to-good practice; indeed, some have been selected to indicate poor practice. It is shown how the Model can draw attention to areas of animal welfare concern and, importantly, to how welfare enhancement may be impeded or facilitated. Also illustrated is how the welfare implications of a sequence of events can be traced and evaluated, and, in relation to specific situations, how the degrees of welfare compromise and enhancement may be graded. In addition, the choice of a companion animal, contrasting its welfare status as a working dog and pet, and considering its treatment in a veterinary clinical setting, help to highlight various welfare impacts of some practices. By focussing attention on welfare problems, the Model can guide the implementation of remedies, including ways of promoting positive welfare states. Finally, wider applications of the Five Domains Model are noted: by enabling both negative and positive welfare-relevant experiences to be graded, the Model can be applied to quality of life assessments and end-of-life decisions and, with particular regard to negative experiences, the Model can also help to strengthen expert witness testimony during

  20. A multi-state model for wind farms considering operational outage probability

    DEFF Research Database (Denmark)

    Cheng, Lin; Liu, Manjun; Sun, Yuanzhang;

    2013-01-01

    power penetration levels. Therefore, a more comprehensive analysis toward WECS as well as an appropriate reliability assessment model are essential for maintaining the reliable operation of power systems. In this paper, the impact of wind turbine outage probability on system reliability is firstly......As one of the most important renewable energy resources, wind power has drawn much attention in recent years. The stochastic characteristics of wind speed lead to generation output uncertainties of wind energy conversion system (WECS) and affect power system reliability, especially at high wind...... developed by considering the following factors: running time, operating environment, operating conditions, and wind speed fluctuations. A multi-state model for wind farms is also established. Numerical results illustrate that the proposed model can be well applied to power system reliability assessment...