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1383 Uppsatser om Nature-like fish passage - Sida 1 av 93

Passage efficiency and migration behavior for adult Atlantic salmon at a Half-Ice Harbor fish ladder

Due to exploitation of the world?s rivers, the upstream migration of anadromous species is frequently delayed or even prevented. To mitigate these problems and allow fish to migrate past obstacles, structures such as fish ladders have been developed. However, recent studies show that many of the present fish passage facilities are deficient. Monitoring and evaluation of passage facilities is therefore crucial to enable necessary adjustments.

Migration losses of Atlantic salmon (Salmo salar L.) smolts at a hydropower station area in River Åbyälven, Northern Sweden : passage fates at a reservoir, a power house and a bypass structure

A large number of rivers in northern Sweden have hydropower developments that cause negative effects on both up- and downstream migrations of anadromous species like Atlantic salmon. So far, most attention has focused on the hindrances of adult fish during their upstream spawning migration. However, since turbines in power stations cause losses on downstream passing fish, the focus on negative effects on smolts has increased. The aim of this study was to compare three different causes of losses of salmon smolts passing downstream through a power station area in the flow-controlled River Åbyälven in northern Sweden.A total of 61 wild salmon smolts were caught and radio-tagged in the River Åbyälven during their downstream migration in June 2009. The salmon smolts were released at three locations, 1.1 km upstream from the power station, in the turbine intake and in the upper part of a fishway, acting both for up- and downstream fish passage.

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.

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.

Möjligheter för naturturism i Borgsjö

Increased interest in nature tourism may be what saves small and dying villages, like Borgsjo? in the county of Va?sterbotten in northern Sweden, from disappearing. The nearly untouched nature in these areas is in many cases an unused resource, since true wildlife experiences are sought by many travelers. The purpose with this report is to investigate if Borgsjo? has the potential and abilities to become a destination for nature tourists, and how this should be done to avoid negative effects on nature, wildlife and culture.

Beteende hos lekvandrande lax i Klarälven ? utvärdering av en fiskfälla

During the migration season in 2013 a study on spawning migrating salmon and the effect of water flow on the behavior was conducted of the salmon at the Forshaga hydropower station in the River Klarälven. The River Klarälven with its nine hydropower plants on the Swedish side, constituting migration obstacles for the migrating salmon. Fortum Generation AB has together with the County Administrative Board restored a salmon trap at the lowermost hydropower station in Forshaga, aiming at making it possible for the salmon to swim into the trap, and thereafter be transported by truck past the power plants and then continue their journey to the spawning grounds on their own. Unfortunately, it is believed that the trap does not work as well as it should. In this study, I focused on salmon position in relation to water flow and if the number of salmon that swam into the fish trap differed between salmon with previous experience of the trap (experienced) and salmon without experience (unexperienced).

Där jag aldrig varit

The sites I visit turned into routines a long time ago. Everywhere someone has decided what should be there and what will not fit. I retreat into my daydreams, away from everyday life. A longing for something different, something wonderful. I decided to go where I've never been, searching for something unknown.

Aquaculture : animal welfare, the environment, and ethical implications

The aim of this review is to assess the ethical implications of aquaculture, regarding fish welfare and environmental aspects. The aquaculture industry has grown substantially the last decades, both as a result of the over-fishing of wild fish populations, and because of the increasing consumer demand for fish meat. As the industry is growing, a significant amount of research on the subject is being conducted, monitoring the effects of aquaculture on the environment and on animal welfare. The areas of concern when it comes to animal welfare have here been divided into four different stages: breeding period; growth period; capturing and handling; and slaughter. Besides these stages, this report includes a chapter on the current evidence of fish sentience, since this issue is still being debated among biologists.

Livscykelanalys av sex olika fiskodlingssystem : Fiskens miljöpåverkan för konsumtion i Stockholm

This thesis evaluates the environmental performance of six different fish farming systems. The thesis is part of the network group ?Hållbar fiskförsörjning I Stockholms län? (HFFS) which tries to increase the domestic and regional production of fish in Stockholm and move to a more sustainable supply in the Stockholm county. Two of the chosen systems; pangasius from Vietnam and salmon from Norway are delivering a substantial part of the fish consumed in Stockholm today, although they are very different when it comes to system characteristics. One system, arctic char with conventional feed, is produced in a fairly small scale in the north of Sweden, while the three remaining systems are viewed upon as possible options to supply Stockholm with fish in the future.

36 nyanser av torsk : en osteologisk analys av fiskben från Hemmor i Dalbo i När sn på Gotland

The purpose of this paper was to analyze fishbones from the Pitted Ware Culture settlement named Hemmor. in Dalbo, När parish on Gotland. The fishbones are unburnt and derive from one specific culture layer (c:6) in trench one VI:7, and radiocarbon dated to 2600-2300 BC cal.In this paper I wanted to answer these following questions:1. What kind of fish species did they eat in Hemmor?2.

Utvärdering av strömmätningar vid Höga Kusten : Strömmars betydelse för lokalisering av odlingslokaler och utformning av kontrollprogram i kustområden

A study was made to evaluate how current measurementscould help to determine how particles from fish farms are dispersed. During sixweeks of the summer 2012, two different current measurements were conducted.One of them consisted of measurements each fifth minute at 5 m and 15 m atthree locations for 14-16 days each. The other consisted of profilemeasurements at each location at four times during the period of six weeks. Forthe current measurements two instruments (model RCM 9) were used. A two weekmeasurement can give enough data to make an evaluation of how the currents at alocation will transport litter from a fish farm.

Fri passage och tomtplatsavgränsning : En studie av två länsstyrelsers överprövningsärenden av kommunala strandskyddsdispenser

Strandskyddet i Sverige är en del av allemansrätten som innebär att var och en har rätt att under ansvar färdas fritt i den svenska naturen, den rätten skyddas av strandskyddslagstiftning i miljöbalken. Dispens från förbuden i strandskyddslagstiftningen kan medges av kommunen. Strandskyddslagstiftningen har sedan 2009 fått nytt innehåll, bland annat att Länsstyrelsen är den myndighet som efter att kommunen medgett strandskyddsdispens granskar och i vissa fall överprövar dessa ärenden. En ny regel som ska säkerställa att fri passage ges vid tomtplatsbestämning infördes även 2009.Ett antal överprövningsärenden har studerats för att kunna analysera tillämpningen av bestämmelserna av tomtplats och fri passage. En litteraturstudie är tänkt att svara på om krav på fri passage förekommer i andra länder.

En studie av Fish-Bird?s navigeringssystem

Fish-Bird är ett pågående vetenskapligt/konstnärligt projekt som genomförs i samarbetemellan konstnären Mari Veloni och Australien Center for Field Robotics. I korthet bestårprojekt av två robotar i form av rullstolar som interagerar med varandra och sinomgivning. Robotarna heter Fish respektive Bird och därav projektnamnet Fish-Bird.Detta examensarbete utvärderar Fish-Birds navigeringssystem. Bakgrunden tillutvärderingen är en oklarhet i huruvida navigeringssystem är ofullständigt eller felaktigt.Navigeringssystemet har visat bristande funktionalitet vid upprepade tillfällen. En stordel av problematiken förekommer oftast när hinder befinner sig nära varandra.Studien är gjord genom en detaljerad analys av Fish-Birds navigeringssystem.

Passage Retrieval en studie av index

The aim with this thesis came out of a strong interest for Passage Retrieval. Our intention has not been to evaluate an IR-system. Instead our goal has been to analyze the result of indexing documents and their passages. We have been studying the weights of the different terms in the different indices, in comparison with other parameters like frequency, normalized frequency and the inversed document frequency. Further more we have been looking at how the weights are spread using for instance the standard deviation.

KULTURLÅDAN.SE - En etnologisk studie om ett digitalt nostalgotek

Nature and culture are often described as opposites, but at the same time nature is often de-scribed as culture and past. This essay examines how nature and the past are culture. I study how 51 people make shifting distinctions between nature and the past in relation to culture, the present and the future. By using the concept of Orientation of Sarah Ahmed I analyze how the informants direct themselves against nature, past and culture through a questionnaire, ob-servations and walk-alongs. I discuss how their ideas about nature and the past differ with their different starting points and are shaped through their physical meetings with them.

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