Streams and riparian zone are closely linked by reciprocal flows of energy and nutrients. A large part of the transportation from water to land is in form of emerged aquatic insects. Conversion of land from forest to agriculture can greatly affect aquatic ecosystems, and due to the close link, also affect the adjacent terrestral zone. Investigating how the presence of agriculture in the surrounding area affects amounts of emergent aquatic insects gives an indication on how agriculture, in turn, may affect the terrestral enviroment. The study was preformed alongside ten streams in northern Sweden; five in landscape transformed by agriculture and five in undisturbed forest areas.

It is hard to find streaming waters where humans haven?t affected the fish populations or the running water it self. In many streams the fish populations are over harvested and this results in a lack of older and larger fish. This is also the situation for many populations of Grayling (Thymallus spp.). To be able to develop management plans and to perform actions that improve the situation for the grayling, it is therefore crucial to know what natural, by humans unaffected populations look like.

Ett par av de trick som används i virtual reality för att få 3D-världen att verka mer levande är stereoskopi och ett dynamiskt perspektiv med head tracking. Tidigare undersökningar har visat att head tracking har större effekt på 3D-upplevelsen än stereo [1], i alla fall när bilderna visas på en vanlig datorskärm. Den här undersökningen har försökt att ta reda på om samma sak gäller då den virtuella världen projiceras på en horisontell bordsskiva. Intressant nog går resultaten från det genomförda experimentet tvärt emot all teori. Tyvärr kan inga konkreta slutsatser dras eftersom alltför många felkällor har uppmärksammats, men studien öppnar ändå upp för framtida forskning..

AbstractThe purpose of this study was to see if there is a connection between smolt length from Brattfors salmon cultivation and temperature. Climate changes are expected to give a higher temperature that could result in a longer growing season for the fish.Cultivated smolt is today bigger than it was before, it is also bigger than the wild salmon. The growth season of salmonids depend on the water temperature, salmonids need 6-80C to grow. Water temperature has been surveyd since the late 50´s in Brattfors. The result shows that it?s now considerable more days per year with higher temperature.

In Lake Vänern, Sweden, there is an endemic population of Atlantic salmon (Salmo salar L.) that lives its entire life in fresh water. The salmon is hindered from migrating to its natural spawning sites in the northern part of the River Klarälven by nine hydro-electric power plants. None of the hydro-electric power plants have fishways so that salmon migrating upstream or downstream may pass. In the current situation, the upward migrating salmon are caught in a Fish trap at the most downstream located power plant in Forshaga. From there, the salmon are driven in a truck, past eight power plants and released a few kilometers upstream of the eighth power plant at Edsforsen.

There are several thousands shallow bays along the Swedish east coast. Most of them are disturbed by different human activities, and undisturbed bays can be considered as quite unique. In the sheltered shallow bays water warms up more rapidly than adjacent water favoring the growth of vegetation, which in turns is beneficial to spring spawning fish species like perch and pike. It is nowadays more common that coastal habitats are inventoried to facilitate future preservation and planning. The aim of this study was to investigate the shallow bay Utanåfladen (59° 53`31.38 N 19°00`44.90 E) in the north Stockholm archipelago and evaluate its habitat value.

Benthic invertebrates play important roles as feeding resources for many organisms in different food webs. Shifts in predation of these organisms can generate cascading effects and potentially lead to the disappearance of one or more species from a site. Cascading effects can bring impacts to organisms who aren?t even directly involved, why studies in this field are important for understanding sudden changes in ecosystems. I examined the predation from fish and waterfowl on benthic invertebrates in the shallow and eutrophic Lake Tåkern in the plains of Östergötland County, southern Sweden.

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.

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.

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.

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.

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.

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).

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.

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.