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301 Uppsatser om Fish farming - Sida 4 av 21
Beteende inför lek hos odlad respektive vild lax (Salmo salar L.) i Klarälven
In many regulated rivers, authorities have stocked hatchery salmon to compensate for loss of wild populations. However, hatchery fish have not always behaved as wild fish do, and stocking them has not always fully compensated for the loss of wild fish. The purpose of this study was to compare swimming behaviour in the river before spawning, the choice of spawning areas and body size between wild and hatchery-reared salmon in the river Klarälven. Salmon behaviour in the river before spawning was analyzed using radio telemetry. The salmon were caught at Forshaga power plant, radio-tagged and returned to Klarälven at Ekshärad, 107 km from the river?s mouth.
Vattendragsrestaurering i teorin och fiskinventering i praktiken : en litteratur respektive metodstudie
Running water-pathways have played an important roll in Sweden and frequently been
manipulated. One profound change was made during the period of logging when
streams were cleared from obstacles as big boulders, sharp bends and side-streams.
Dams and different constructions gave control of the stream water and the streams
became channel-like with a homogen structure. This interference gave problems for
many fish populations and resulted in a shortage of feeding habitat, over-wintering
habitat, spawning habitat, unnatural flow regimes, sedimentation, unnatural
temperature fluctuations. Many of these historical changes of the watersheds are now
subjects for restoration, ie., bring back the streams to what we believed it was before the change. However, what once existed in terms of complexity is now gone and difficult toreplace.
Småskalig vattenkraft : Dagsläge och framtidsplaner
This study focuses on small scale hydropower in Sweden. This means plants with a capacity of up to 10 MW. The study has a special focus on plants with a capacity up to 2 MW. The study has three aims. It strives to describe the small-scale hydroelectric industry in Sweden.
Optimering av FISH- teknik för detektion av Laktobaciller
SammanfattningSyftet med den här studien var att utveckla och optimera FISH (Fluorescense In Situ Hybridisation) tekniken som en snabb och ganska billig metod för detektion av laktobaciller. Det vill säga att kunna på objektsglas använda FISH tekniken för att identifiera laktobaciller på artnivå med fluorescensmärkta prober mot 16S och 23S RNA. FISH är en allmän och användbar metod för att detektera och lokalisera mikroorganismer eller en specifik grupp av mikroorganismer i provet (1). Metoden detekterar DNA- eller RNA- sekvenser med hjälp av fluorescensmärkta prober som hybridiseras specifikt med komplementära målsekvenser i intakta celler (2). Detta innebär att man behåller cellmorfologin och tillför en lättdetekterad fluorescerande färg.
Poultry producers? perceptions of changing market conditions : a field study of the poultry production in Khartoum state of Sudan
Sudan has always showed great potential in the poultry industry, but it has not been until now that this potential has blossomed and is growing quickly. As large agribusinesses1are taking over the market shares within the urban areas, smallholders2 have been put out of business. They are not able to compete with mass production and lack financial assets to improve their production techniques. Contract farming is defined as initiatives from agro industrial companies to secure access to smallholder produce and has in developing countries become a way of allowing the poor to participate in a larger market (Farrington, 1999).
The aim with this study was to investigate the suitability of implementing the contract farming concept within the poultry industry in Sudan today. The study is a qualitative field study and the authors have conducted qualitative interviews with respondents involved in the poultry industry in Sudan.
Drank som proteinkälla till regnbågslax (Onchorhynchus mykiss) :
The objective of the present study was to evaluate distillers? dried grains with solubles (DDGS) as a protein source to rainbow trout (Oncorhynchus mykiss), by studying digestibility and growth measurements. One control diet, totally lacking DDGS, and three test diets were made containing 10 % (low), 31% (medium) and 51 % (high) DDGS respectively on dry matter (DM) basis. The control diet and the test diets were made to be as nutritionally equal as possible. Wheat bran was used to balance the fiber content of the diets.
Fisk- och fågelpredations påverkan på den bentiska makroevertebratfaunans sammansättning under tidig vår i Tåkern
Predation is one of many factors that form the structure of the macroinvertebrate community in lakes, wetlands and watercourses. Earlier studies lack an examination concerning how fish- and waterfowl predation affect macroinvertebrates during shorter periods in the spring. I performed an exclosure study in the shallow eutrophic Lake Tåkern which is located in the western part of Östergötland County, Sweden. The experiment was performed during a three week period (1-21 April 2012) when the water temperature was low and the density of migrating diving ducks was high. The experimental cages used included three out of four different treatments; general predation (open cages), bird exclusion (net with mesh size 90*45mm) and no predation (net with mesh size 1*1mm).
Influence of the habitat on the potential for cannibalism and population dynamics in stream-dwelling European grayling (Thymallus thymallus L.)
Cannibalism can have major influence on fish population dynamics. A prerequisite for cannibalism is that the cannibal and the potential victim meet, and besides density effects, the encounter rate between cannibals and their victims is therefore also largely dependent on habitat use and habitat heterogeneity. In this study I quantified and compared the potential for cannibalism in stream-dwelling European grayling populations in three rivers in Jämtland by means of habitat classifications. I also analyzed population dynamic consequences of varying the potential for cannibalism in terms of intensity, using a physiological structured population model. Findings based on habitat characteristics were that the potential for cannibalism is in general not favourable in these types of streams.
Finansiella instrument för svenska lantbruksföretag : riskhantering och finansiella instrument för lantbruksföretag i Sverige
The survey describes a number of risks that Swedish farming companies are exposed to. The risk areas covered by the survey are currency risks, price risks and financial risks. The survey further describes why these risks have a great impact on the future development of the farming companies. The survey highlights the interrelation between the risks and the measures which can be used to minimize the risks, so-called financial instruments.
The aim of the survey is to put focus on above mentioned risks and describe how these risks can be reduced to prevent the Swedish farming industry from stagnating in the future.
The survey is a secondary survey whereby existing knowledge about risks and risk management is applied to farming companies. The written information on price risks and hedging is primarily derived from foreign sources.
Organizing for value creation : a corporate perspective on urban farming
In the year 1800, about 5 % of the world population lived in cities (World Wide Fund for Nature, 2012, 3). Today that number is about 70 % in Europe and North America, and in 2050 it is expected to be 86 % in the developed world and 67 % in the developing world (www, UN, 2009). In addition, the global population is expected to increase with 2.2 billion people until 2050. As a result of the population increase more food has to be produced which requires more transport from the countryside to the cities. However, this flow of resources faces some difficulties.
Utveckling i Ammerån : att skapa ett hållbart fiske med hög kvalitet
Ammerån which is a small forest river in eastern Jämtland is a well-known river that has been a popular fishing river for a long time. The actual Ammerån begins downstream the lake Solbergsvattnet at Hammerdal and flows into the Indalsälven 10 km upstream Hammarstrand. The river environment switches between forests with wilderness feeling and open agricultural land. The entire Ammerån is today a nature reserve and protected from hydropower development. Fishing in Ammerån has mainly been focused on trout and grayling, and is so even today.
Markanvändningens förändring i vardagslandskapet : en analys av utvalda delar i Wessmantorp
During the last 100-200 years people have change their way of living and the condition and need for survival is no longer depending on the agricultural work. The forestry has replaced the farming and a lot of the natural pastural have been lost.
Wessmantorp in the north part of Skåne is an old place for forestry and farming where people have been living for several hundred years. Studies of selected parts of the everyday landscape, that earlier have been settlement with small crofter?s holding, show that the changes in the landscape mostly depends on the human factor and that a lot of the cultivable soil have been replaced with spruce. Some of the areas, which the earlier dwellings were placed, still contain some remains of old house foundations and stone fences and can regard as being of an historical value.
The studies provide the reader with a short background, the place as it is today and the changes of the land use in Wessmantorp.
Det obetydliga : om fiskhuvudformiga hängen, sociala praktiker och förändring, 600-1200 e. Kr.
Fish-head pendants are one of the characteristic Gotlandic Late Iron Age artefacts. This object has been rather neglected and mainly considered as an insignificant embellishment, normally worn as a neck-collar and seen as an artefact include in the typical Gotlandic set of female jewellery.The fact that the fish-head pendant has a very long life span, which stretches from grave-finds in the Early Vendel Age to hoards in Viking Age as well as secondary usage as brooches in the Early Middle Ages, makes the artefact an excellent starting point for discussions on social practices and change through material culture. It's shown in this study that, contrary to previous beliefs, the normal usages for fish-head pendants is as solitary pendants and not as neck-collars. Neck-collars is shown to have an intricate relation to inhumations for young individuals, whereas solitary pendants are found in cremation deposits for adult individuals, something that relates to a fixed social practice mainly in the period 700-900 AD and that develops from the cremation funeral practice. This particular social practice relates to aspects of attraction and protection and continues in to the 10th century outside of funeral structures, which is shown by the composition of hoard-finds from the 10th century, but is totally absent when the pendants is given a secondary usage as brooches in the end of the 11th and beginning of the 12th century.
Bestämning av utfallet av translokationen t(11;18)(q21;q21) hos patienter med MALT-lymfom genom FISH analys
Lymphoma is a group of malignant tumour diseases developing in the secondary lymphatic system. These diseases can develop in all organs as lymphocytes are ubiquitously in the body. In connection to mucus membranes we find mucosa-associated lymphoid tissue, MALT, in which lymphoma can spontaneously but slowly develop, mostly at chronic inflammation or at autoimmune diseases. Today these diseases are incureable with the exception of some cases caused by Helicobacter pylori-infection. Antibiotic treatment of these cases can induce remissions.MALT-lymphomas have characteristic histological and molecular properties.
Förekomst av kontaminanter i importerad fisk : en litteraturstudie
A literature review of contaminants; cadmium, methylmercury, dioxins, and PCB, for eleven different fish species (Greenland halibut, gilt headed bream, sea bass, wolffish, hoki, ocean perch, angler, Nile perch, pangasius, red snapper and tilapia) that were selected in concurrence with the National Food Administration. The result can be used by the National Food Administration to gain further knowledge about the different fish species to be able to continue to give advice to varied risk category and the public. The gilt headed bream and sea bass were the only fishes whose values for mercury exceeded the limit of 0,5 mg/kg (EU Reg. 1881/2006). In the angler, Nile perch and pangasius the mean value of mercury didn?t exceed the limit, however in some individuals the mercury content did exceed what is allowed.