Sök:

Sökresultat:

301 Uppsatser om Fish farming - Sida 18 av 21

Predicting spawning bed erosion and longevity : a case study in tributaries to river Vindelälven, northern Sweden

Timber floating operations in Scandinavia during the 19th and 20th centuries has contributed to severe negative impacts on riverine ecosystems. Increase in water velocity and lack of stream bed heterogeneity as a result of stream channelization lead to increased bed load transport. Since availability and recruitment of new suitable spawning substrate in Scandinavian watercourses is sparse, spawning habitats for salmonids has become a scarce commodity. Lately, increasingly more attention has been given to the recreation and improvement of brown trout (Salmo trutta) spawning habitats in restoration projects. While much of the research on spawning habitat has been focused on evaluation of the influence that the constructed spawning grounds have on fish populations, few studies have been conducted to evaluate the persistence of these constructions over time. I evaluate erosion of constructed spawning beds as an effect of sediment transport attributable to water discharge.

A big fish in a small pond -En studie av svenska företags samt EU-kommissionens perspektiv på konkurrens

Efter att en rad uppmärksammade nationella fusioner stoppats av EU-kommissionen har en debatt huruvida konkurrensreglerna ska tolkas och huruvida de är rättvisa utlösts. Utifrån denna bakgrund var uppsatsen syfte att skapa förståelse för olikheter i svenska företags respektive EU-kommissionens syn på konkurrenseffekter i fusionssammanhang. Författarna i denna studie hade för avsikt att beskriva de olika parternas syn på konkurrenseffekter samt analysera vad olikheternabaseras på. För att kunna besvara syftet genomfördes en kvalitativ studie med intervjuer som tillsammans med EU-kommissionens perspektiv i de olika fusionerna utgör grunderna i empirikapitlet. Teorikapitlet baseras på Porters branschstrukturanalys, PIMS och teori om olika marknadsstrukturer.

Dietary intake of zinc and iron within the female population of two farming villages in the Red River Delta, Vietnam

In many developing countries, among them Vietnam, contamination of agricultural land is a major issue that has public health implications. A fast growing population, rapid urbanization and industrialization have led to air and water emissions of potentially toxic elements (PTEs), such as cadmium (Cd). Earlier studies have shown that individuals with low iron (Fe) and zinc (Zn) status absorb larger quantities of Cd than those of adequate nutritional status. The purpose of this study was to investigate and compare the Fe and Zn intake from the foods consumed by women (15-45 years) in selected households in two agricultural villag-es in the Red River delta in Vietnam. In one of the villages the residents were involved in metal (mainly Fe) recycling activity, whereas in the other village the residents had agricul-tural production as main source of income. Interviews, followed by food intake calcula-tions, were performed.

Växtbäddar för stadsodling

Stadsodling finns redan i flera av våra städer och resultaten från projekten som idag drivs är goda och det är dags för nästa steg i utvecklingen mot ett grönare och mer hållbart stadsrum. Rapportens frågeställning är en teknisk vinkling av de mjukare värdena som normalt diskuteras när det gäller stadsodling: Går det att ta fram en generell typ av växtbädd för gemensamma fritidsmässiga odlingsytor i stadsmiljö för växtzon I? Hur skulle den i så fallvara uppbyggd? För att besvara frågeställningen gjordes ett urval av köksväxter man normalt kan hitta i trädgårdsodlingar. De krav urvalsväxterna hade på växtjord sammanställdes och sedan kontrollerades de mot de beskrivningar som normalt används som stöd vid anläggning idag, AB Svensk Byggtjänsts publikationer Anläggnings AMA 98 (1999a) och RA Anläggning 98 (1999b). Det visade sig att den sandiga siltjord som borde passa samtliga växter i urvalet utgjorde en av de standardjordar som anges i Anläggnings AMA 98. Även gällande växtbäddens uppbyggnad konsulterades AB Svensk Byggtjänsts två beskrivningar.

Godtagbara ändamål vid fastighetsbildningenligt 3:1 FBL : - en studie om ?udda? ändamål

The main objective with this study was to investigate so called odd purposes acceptable when registrating property along with how social development affects these purposes, furthermore to investigate how the cadastral surveyors estimates a foreseeable time. Tradition and praxis is used for several obvious purposes such as housing, farming, forests, offices and industry. Praxis is yet to be defined regarding more unique purposes. There is no mention in the law about which purposes are found acceptable to assure the demands on suitability are met. Cadastral authorities are responsible for making sure the division into property units is uniform and rule of law-accordingly.

Factors affecting crop insurance decision : a survey among Swedish farmers

Farmers are constantly facing changes, and the exposure to risk requires monitoring these changes. Financial risks, institutional risks, market risks and production risks are the different risk categories that the farmers face. Production risks stems from factors the farmer cannot affect or is beyond his control. The crop?s output is the basis for the primary income of agricultural operations, which is why it is important for farmer to manage their production risk. A tool to reduce the consequences of production risks is crop insurance.

Metodikstudie av trollingfisket i Vänern : Jämförelse av fångstrapportering mellan intervjuer och enkäter gjorda på trollingfiskare samt vädrets påverkan på ansträngning

There are five endemic populations of migratory Atlantic salmon (Salmo salar, Salmonidae) and brown trout (Salmo trutta, Salmonidae) remaining in Lake Vänern, whereof two are salmon and three are trout. There is one population of each species in Klarälven, also one of each in Gullspångsälven and there is a population of trout still remaining in Tidan River. Since the beginning of the 20th century endemic populations of salmon and trout have either vanished or declined dramatically due to the construction of hydropower in the rivers around the lake, and still today the future of the remaining populations remains uncertain. To manage salmonid fishes effectively more knowledge of their ecology throughout their different life-stages is needed. A large part of the Lake Vänern salmonoids lives are spent in the lake, where a mayor mortality factor is recreational fishing, especially angling.

Säker hantering av lösgående nötkreatur :

After I heard that two deadly accidents in farming 2003 were created by work with cattle, I got the idea of writing this degree project. So far there are not too many reports written about safety for the worker nor the animal. Therefore it will fit in with a report about safe handling of free stalled cattle. The Swedish Board of Agriculture would also like to do an information material about outside stalled cattle with this degree project as a background. The collecting of material was made by visiting farmers. The goal was to visit 15 ? 20 herds and when this is being written 19 herds have been visited.

Trädgård - en angelägen fråga : Carl Adam von Nolcken, Jordberga gods och trädgårdskulturens främjande i Skåne 1834-1857

Baron Carl Adam von Nolcken was born in 1811. In 1834 he took over Jordberga Estate in the South of Skåne from his father. The estate remained in his possession until his death in 1857. von Nolcken was interested in agriculture and horticulture from an early age and attended the newly started Institute of Agriculture, Degeberg in Västergötland in the early 1830:s. At Degeberg, von Nolcken learnt all about modern farming methods, which he put into practice on his own estate. von Nolcken was one of the persons who during the mid 19th century worked intensely to develop horticulture and the art of gardening in Skåne.

Illegal rovdjursjakt : en rättsekonomisk analys av rovdjursproblematiken i Sverige

In this essay a model of a potential illegal hunter?s decision-making is created and presented in order to provide an overview of important parts of the complexities associated with the current Swedish predator policy. A comparison is made between a livestock owner?s economic incentives, and the expected costs faced by the potentially caught lawbreaker. In accordance with economic theory the benefits and costs of illegal hunting are compared and thus the optimal choice is determined where marginal costs and benefits are equal.

Effekter av predationsrisk på sånglärkors (Alauda arvensis) habitatval på åkermark

Along with other European farmland birds, the skylark (Alauda arvensis) has declined rapidly since the 1970?s. Between 1975 and 2003, the Swedish population of skylarks declined with 64 %. In Britain, the decline is often explained by alterations in farming practices in general and the shift from spring-sown to winter-sown cereals in particular. The dense vegetation structure of winter cereals is limiting the number of breeding attempts possible, causing the entire population to decline.

Leaf area index in Vittelaria Paradoxa parklands in Burkina Faso estimated by light interception and leaf sampling

Burkina Faso as well as most sub-Saharan African countries struggle with providing food for a fast growing population. The dominating farming system is agroforestry parklands. Agroforestry parklands can broadly be defined as areas where scattered trees occur on farmlands as a result of selective clearing. The presence of trees in crop fields may in the long term have a positive effect on the production of annual crops. It is commonly discussed, but not proven, that the presence of trees leads to increased groundwater recharge due to higher infiltration capacity of the soil.

Är Lerbodaälven verkligen en problemälv? : undersökning av fosforhalter

Lerbodaälven is a river in the municipality of Kil which, due to high phosphorus content is not meeting the requirements for good ecological status according to the Water Framework Directive. The purpose of this report is to investigate the causes for the high content of phosphorus that has been measured in Lerbodaälven between 1995-2010. Four questions will be answered in this report. 1. Does the sewage treatment work affect the phosphorus level in Lerbodaälven? The result from the time series analysis shows that the sewage treatment works have a small impact on the phosphorus level in Lerbodaälven.

Metodik för resistenstest i renkavle : en studie om herbicidresistens; mekanismer, detektion och åtgärder

Herbicide resistance is the result of an evolutionary process where a population gradually changes from being susceptible to being resistant to an herbicide. The resistance mechanism is usually a change in the biochemistry of the weed, but in some cases changes in morphology or growth rhythm. The change is caused by random mutations. Two resistance mechanisms are found in black-grass; target site resistance and metabolic resistance.Black-grass is a tufty, winter annual grass weed, which is mainly found in milder climates. Black-grass is a big problem in Southern Europe.

Löslighet och metylering av kvicksilver i en förorenad sjö (Ala-Lombolo) i Kiruna kommun :

Transformation of inorganic mercury (Hg) to methyl mercury (MeHg) is a biotic process that is proposed to be conducted primarily by sulphate reducing bacteria (SRB). The formation of MeHg is of great interest because it is the mercury species that biomagnifies to the greatest extent in the aquatic food webs; about 90 % of all Hg in fish is MeHg. Our understanding of factors involved in the production of MeHg is very important for making a reliable risk assessment. The purposes of this study were to investigate the different factors that control the solubility of Hg and the production of MeHg in a contaminated lake sediment. The lake Ala-Lombolo, Kiruna municipality, is well-known to be contaminated by mercury from different sources. Sediment cores were sampled at three different locations (N, SW and SE) in the lake and divided in three different layers; 0-5, 5-10 and 10-15 cm.

<- Föregående sida 18 Nästa sida ->