Sök:

Sökresultat:

153 Uppsatser om Fish ladder - Sida 1 av 11

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.

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.

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).

Småskalig vattenkraft vid Olofsfors bruksmuseum : Med faunapassage

In Sweden there are 1894 small-scale hydropower plants in operation, which together generate 4.3 TWh of electricity per year according to Swedish hydropower compound (SVKF, 2011). This corresponds to the annual consumption of about 860,000 Swedish households (based on an annual consumption of 5000 kWh). In the mid-1950s there were around 4000 small-scale hydropower plants in operation in Sweden before cheap fossil fuels and uranium competed with them, in the current situation only 1,894 of these are in use. If slumbering small hydropower plants once again would be taken into use and some new ones are built, we would be able to extract about 7 TWh of renewable electricity from these annually in Sweden, representing about 1.4 million households.The thesis intends to calculate and construct a hydroelectric power plant at the existing dam in Olofsfors and give suggestions on how the power station should run during the time that fish migration is greatest in Leduån.The turbine and generator to the station in Leduån at Olofsfors is designed by the height of the fall and the water flow through the dam. The turbine selected for the station is a CK-1000RM turbine with a 4-pole 250 kW generator from Cargo & power turbine Sweden AB, which is expected to deliver 1.2 GWh per year.

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.

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.

Smärtlindring i samband med vaccination av fisk :

Vaccination of fish can be assumed to cause pain. This study was designed to see if we can minimize the suffering of fish following vaccination. Fishes are cold-blooded animals and thus more primitive than warm-blooded animals. Despite this, many organs, e.g. the nervous system, have the same basic structure as that of other vertebrates. The fibre system for conducting pain is more diffuse than in humans.

Nursing technique and growth environment of Rabbit fish (Siganus guttatus) in the area of Tam Giang lagoon, Thua Thien Hue

SummaryIn the area to the east of Hue city, in Vietnam, lays Tam Giang lagoon, one of Asia's largest lagoons, with an area of 22,000 hectares. This lagoon is suitable for aquaculture. One reason for this is because the salinity differs from sweet to salty in different parts of the lagoon. The Vietnamese Government advocates an increase in environmentally-friendly aquaculture and the fish Siganus guttatus (Rabbit fish) is a candidate for this. This fish eats mainly algae and can be cultivated in a polyculture.

Konstruktion av steghållare till brandbilar

High demands are set on all equipment used in emergency service work, where small margins can be the distinguishing factor between life and death during a rescue operation. It is important that tools such as ladders quickly and easily can be dismounted from a vehicle and still satisfy the regulatory requirements for securing loads during transport. The existing solution for getting ladders down from the roof of a fire engine requires a large manual effort from the user in an ergonomically unsound posture.In this degree project a new ladder holder is developed with focus on the user to solve the ergonomic problems and at the same time create a more compact design that can be adapted to several different types of ladders. After an initial pre-study with user-interviews and measurement of forces and distances a set of requirements was formulated that came to govern the project's direction. Creative methods were used to generate concepts that improved the function and through design solutions, calculations and testing in CAD a base for manufacturing of a new product was created.The result is a completely new type of ladder holder that minimizes the user's manual effort and simplifies the securing of ladders in the holder.

Fisksamhället i Spexhultasjön, Nässjö

The lake Spexhultasjön is a moderate humic mesotrophic lake that is not acidified. The fish fauna was investigated by using a standard method for sampling freshwater fish with multi mesh gill nets. The fish fauna was diverse with perch, pike, tench, common whitefish, and roach. Perch and roach dominated. There were few pikes.

Fiskevård och delning av fiske vid lantmäteriförrättningar : Studie av FBL 3 kap 8 §

AbstractThis bachelor thesis was performed at the Royal Institute of Technology in Stockholm on behalf of the Land Survey Authority. The thesis is about fish conservation and division of fishing water at official duty. It is the Land Survey Authority that examines division of fisheries, but before a case can be implemented, certain requirements must be achieved such as FBL 3:8, which prevent divisions that are deleterious for fish conservation. The purpose of this thesis is: to obtain a clearer view how FBL 3:8 should be applied in practice, how the application differs between the offices in central Sweden, and how fish care is regulated at both international and national levels.At an international level, in EU the commercial fishery is regulated through the common fisheries policy (CFP). The fisheries policy consists of a reform that will last for 10 years.

Störs laxens lekvandring i en kraftverkspåverkad älvsträcka? :

The upstream spawning migration of Atlantic salmon (Salmo salar) at the confluence area between the power-station outlet and the bypass-channel in river Umeälven (flow 430 m3s-1) was compared in 2004 and 2005, two years with different experimental flow-regimes. In 2004 the water flow in the bypass-channel was altered during the day with increased flows during the nights while the water flow in 2005 mainly was altered between the weekdays and weekends. Salmon showed altered migratory behaviour in this confluence area, assessed with telemetry (n=116) and echo-sounding, with up- or downstream responses depending on flow-changes in both the bypass and the power station outlet. Increased turbine flow through the power-station generally attracted salmon into the tunnel outlet area while increased spill-flows facilitated salmon to enter the bypass. Echo-sounding in the confluence area showed an increased swimming activity up- and downstream due to time in the day and flow-rates through the tunnel outlet. No changes in activity could be detected due to increasing or decreasing flow through the hydro-power facility.

1 Nästa sida ->