Sök:

Sökresultat:

162 Uppsatser om Fish trap - Sida 2 av 11

Something fishy in Christians : Dietrekonstruktioner genom analys av stabila isotoper på tidigmedeltida skelett från Rambodal, Styrstad Sn, Östergötland

Dietary patterns has varied throughout history, both due to resource and cultural limitations. In this thesis, a study was conducted to establish the dietary patterns of eight individuals from an early Midieaval gravesite in Rambodal, Östergötland, in order to explain why they were buried there. This was done through stable isotope analysis on collagen extracted from bone and tooth on the buried individuals. The analysis showed that these indviduals had a diet that was mainly based on freshwater fish. This suggests that these people may have been christians, due to the fact that fish was not regarded as meat and therefore you did not have to abstain from it during periods of fasting.

Pre-spawning habitat selection of subarctic brown trout (Salmo trutta L.) in the river Vindelälven, Sweden

Habitat selection of migratory brown trout at the upper reaches of River Vindelälven, wasstudied in September during the pre-spawning period. The fish migrate from down- orupriver lakes for spawning in the river and data was collected by habitat mapping andradio-telemetry. Habitat selection of fish was analysed with preference curves andstatistical modelling, using the physical variables; depth, stream velocity and streambedsubstrate. Preference curves were derived by comparing fish habitat use with their nearbyavailable environment while the statistical modelling aimed to answer three main questions.1) Do the trout have a specific preference of depth, water velocity and streambed substrate?2) Is there any difference in habitat selection between sexes? 3) Is there a shift in habitatselection over time? The preference curves indicated that trout favored water depths of 1-2m, velocity compositions characterized as glides (c.

Vandring av vårlekande fisk och jämförelse av fångst mellan ryssja och strömöversiktsnät i Hammerstaån, Stockholms län

During the last two hundred years many wetlands and streams in Sweden have been lowered to provide land for agriculture and forestry. Some of the coastal wetlands and streams probably served as spawning sites for certain species of fish in the Baltic Sea, but the present situation is not well known. As standardized methods to monitor fish in running waters are carried out during late summer or autumn, there is a need for methods to sample spring-spawning fish in these streams.The aim of this study was to survey the lower kilometer stretch of Hammerstaån in Stockholm, to investigate the extent to which the stream is used by spring-spawning fish. Furthermore, the study aims to evaluate a new type of survey fishing gill net called strömöversiktsnät (SÖN). This was done by comparing the catch of fish by SÖN with that of fyke nets.

Konsumentbeteende vid köp av färsk fisk : en kvalitativ studie för utveckling av ett produktkoncept hos ICA

Health and convenience trends dominate the food industry and retailing business of today. The health consciousness is spreading while appealing product attributes concerning taste and packaging also are increasingly important. At the same time, the competition is growing fierce in the Swedish market with hard discount formats and niche concepts who also are trying to provide the market with perishables. Therefore, the pressure to lower prices is increasing making economies of scale and rationalization progressively more important. In 2004, ICA launched private label meat packaged in a modified atmosphere. Consequently, many stores went from in-store cutting-up and packaging to selling centrally packaged and distributed meat. ICA is now developing a concept with fresh fish in modified atmosphere packages and needs to increase the knowledge about the market and the consumer.

Förluster av nedströmsvandrande fisk vid turbinpassage : En fallstudie för att främja den småskaliga, såsom storskaliga vattenkraften

The expansion of the Swedish hydro power has contributed positively to the reduction of the environmental impacts from the fossil fueled power production. In the same time the extensive expansion has been proved to cause negative ecological and local environment impacts of a stream. This, in turn, has been affecting the biodiversity and fish stock negatively, which has been reduced. One of the underlying problems is the lack of possibility for the fish to pass the plants, but it is also directly correlated to the mortality rate of the fish passing through the turbine, which this study is investigating.The mortality rate has been computed for three different locations in Sweden, Untra, Tännfallet and a third one whose location is confidential, and is denoted as Case 1, 2 and 3. The model used to calculate the mortality rate in this investigation is based by existing blade strike models and knowledge and are investigating the death due to mechanical injuries from collision with a runner blade in the turbine.

What factors correlates with the use of game meat, wild fish, berries and mushroom in Swedish households : urban vs. rural areas

This study was made to see too what extent Swedes uses consumptive resources such as berries and mushrooms, game meat and meat from fish in their household on a yearly basis. I have also looked into the difference between rural and urban areas in Sweden. Further aim was to determine what factors that correlates with the participation in berry and mushroom picking and the use of game and fish meat within the household. The study was conducted in form of a mail survey that was sent to randomly chosen persons in every municipality in the six northern most counties in Sweden and in the county of Stockholm. In addition a sample was sent to randomly chosen persons on a national level.The results showed there is a difference in use between rural and urban areas in Sweden in all 4 investigated consumptive resources.

Hållbar vattenkraft i Nissan : En förstudie och konsekvensutredning över förutsättningarna för ökade vandringsmöjligheter med nya fiskvägar.

The hydropower from Nissan River is of national interest and produces annually 230 GWh from the twelve power stations in the main flow. For modified waters a consideration between the power production and the biological values has to be made. This reports serves as a pre-study for Nissans Vattenråd. It tries to evaluate some of the biological values in the Nissan basin and map the power production in the area. And the size and value of lost power production from new fishways for the twelve stations in the main flow.The investment of new fishways is calculated using simplified templates with values from the business.

Vandring av vårlekande fisk och jämförelse av fångst mellan ryssja och strömöversiktsnät i Hammerstaån, Stockholms län

During the last two hundred years many wetlands and streams in Sweden have been lowered to provide land for agriculture and forestry. Some of the coastal wetlands and streams probably served as spawning sites for certain species of fish in the Baltic Sea, but the present situation is not well known. As standardized methods to monitor fish in running waters are carried out during late summer or autumn, there is a need for methods to sample spring-spawning fish in these streams.The aim of this study was to survey the lower kilometer stretch of Hammerstaån in Stockholm, to investigate the extent to which the stream is used by spring-spawning fish. Furthermore, the study aims to evaluate a new type of survey fishing gill net calledströmöversiktsnät (SÖN). This was done by comparing the catch of fish by SÖN with that of fyke nets.

Utvärdering av rörelsemönster hos öring (Salmo trutta) utifrån otolitmikrokemi

The classic view of trout (Salmo trutta) life history is that trout begins its life in freshwater, migrates to the ocean after about 1-4 years and then returns to freshwater to spawn. As trout fry have been caught at the mouth of the River Emån, near the Baltic Sea, researchers have speculated that some trout emigrate during their first year of life. The purpose of this study was to describe the variation in the length of time trout reside in freshwater before they migrate to the ocean for the first time. Another purpose was to investigate whether it was possible to discern where and how long the fish spent in freshwater and saltwater during different parts of their lives. Between 2007 and 2009, 23 adult trout were captured in the River Emån in southeastern Sweden.

Gäddan & fisket i Ringsjöholm : en osteologisk metodstudie i säsong & bevarande

This paper presents the results from an osteological method study of the Ringsjöholm fishbone material. Ringsjöholm is located in Scania, southern Sweden and is 14C dated to 5960-5200 B.P. The aim of this paper is to critically analyse methods used on fish bone material in estimations of season. Three different approaches were used to estimate the fishing season at the Ringsjöholm settlement; 1) identified species, 2) size estimations of the pike based on Enghoffs (1994-95) regression formulae of os dentale, and 3) growth rings of the pike vertebrae.The identified species and the size estimations of the pike points to the fishing being active both during spring and summer. Growth rings analysis of the pike vertebrae didn?t give any quantitative results because of fragmentation.

Vermicompost for reduction of vegetable waste - and a possible means to produce fish feed in aquaponic systems?

Aquaponics is a food production system consisting of a consecutive cultivation of plants and aquatic animals, fish or shellfish, in recirculating water. The plants feed on the nutritious effluents from the fish tank and bacteria converts ammonia from the fish tank into nitrate that is absorbed by the plants. The plants receive nutrition and the fish gain purified water. The environmental impact of the production of fish meal and fish oil used in conventional fish feed includes a large consumption of fossil fuels with subsequent carbon dioxide emission. The aquaponic system can be made environmentally sustainable and self-supporting if supplemented with a vermicompost/vermiculture for the production of worm protein as a fish feed. Vegetable waste from the hydroponic part of the system can be reused as worm feed in the compost and the protein rich worms can be harvested, dried and grinded and brought back to the aquaculture as fish feed. As a first step in this direction, I have investigated the effect of recycling of vegetable waste in vermicomposts on the growth and number of earthworms (this was evaluated after harvesting). The hypotheses were that earthworms can be cultivated in the vegetable waste and that by adding manure to the vermicompost it is possible to obtain a nutrient content adequate to support a continuous worm harvest, in other words create a vermiculture. Eisenia fetida and Dendrobaena veneta were grown in 20 L bins containing peat mixed with either poultry or cattle manure. The proportions were 70% peat and 30 % manure. Discarded plant parts from lettuce cultivation was added to the vermicomposts (35 g per week) and water was supplied with 0.8 L per week.

Listeria monocytogenes i vakuumförpackad lax :

Listeriosis, which is caused by Listeria monocytogenes, is a rare food borne disease that primarily affects people whose immune system is weakened. These may be elderly people, pregnant women, new-born infants and individuals on immunosuppressive medication. The most common symptoms are meningitis, septikemia and abortion. The mortality is high, on average 20-30 %. In recent years the number of cases in Sweden has increased.

I domstolens fälla? Den Liberala Intergovernmentalismen från Utstationeringsdirektivet till Lavaldomen

This thesis aim to advance the Liberal Integrovernmentalism (LIG) developed byAndrew Moravcsik in order to order to explain how the European Court of Justice (ECJ) can make de facto EU policies diverge from what was originally intended by the Member States. More specifically it describes how the Posting of Workers Directive, Directive 96/71/EC, originally was created to shield certain Member States and their respective systems of regulating the labour market from pressure arising from the posting of workers form low-wage countries inside the EU. However, through a series of cases in the ECJ the de facto policy of the directive has changed and it is now in itself a potential threat against these systems. The Member States now find themselves caught in a ?Joint-Decision Trap?, unable to rectify the situation even though their original agreement has been turned on its head.

Hälsostatus hos abborre (Perca fluviatilis) i Gumpfjärden, Bottenhavet :

Perch (Perca fluviatilis) is a very popular fish in Sweden and it is common in Swedish waters. In some areas along the Swedish coast the perch population has decreased. It is therefore important to get a view at the health status of perch. During April, July and August of 2008, a total of 346 perches were caught in the Gump Bay in the Botnian Sea. The fish were mainly caught by net but also by rod.

Full Circle: upstream and downstream migration of Atlantic salmon (Salmo salar) in the northern Swedish river Vindelälven

The life cycle of the anadromous Atlantic salmon (Salmo salar) can span large geographic, political, and socio-economic boundaries. Management strategies and regulations that only concentrate on small spatial scales often overlook larger basin-wide problems, especially relating to post-spawn seaward migration. In this master thesis one entire migration cycle of wild adult Atlantic salmon in the unregulated northern Swedish river Vindelälven was monitored by radio-telemetry tracking during upstream spawning migration and downstream seaward migration back to the Baltic Sea. The effect of ladder passage variables (time to pass, total time in the ladder, passage day over the ladder) at a fish ladder downstream in the river Umeälven, as well as fish size, were evaluated to determine if differences in upstream migration distance in the river Vindelälven could be observed. Ladder passage variables did not affect migration distance, but size exhibited a negative relationship to migration distance.

<- Föregående sida 2 Nästa sida ->