Avancerad sökning

Visar resultat 16 - 20 av 20 avhandlingar som matchar ovanstående sökkriterier.

  1. 16. Migration in anadromous brown trout

    Författare :David Aldvén; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Downstream migration; Temperature; Discharge; Genetics; Growth rate; Climate change; Salmo trutta; Salmo salar; Sea trout; Salmon; Biology; Ecology;

    Sammanfattning : This thesis investigates the anadromous migration of brown trout (Salmo trutta) with the overall aim to improve stock management within the region. Several field studies were conducted in different streams and coastal areas on the west coast of Sweden specifically aimed to evaluate environmental triggers for migration (Paper I), migration pathways and strategies (Paper III and IV) as well as the genetic differentiation of anadromous populations of brown trout (Paper V). LÄS MER

  3. 17. Piscivore-prey fish interactions - consequences of changing optical environment

    Författare :Lynn Ranåker; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; behaviour; brownification; freshwater ecosystems; growth; piscivore-prey fish interactions; selectivity; turbidity;

    Sammanfattning : Predator-prey interactions are a primary structuring force in aquatic systems. A change in the predator-prey interactions may cause a change in the strength of trophic cascades and even resulting in ecosystem shifts. LÄS MER

  4. 18. Biology of Borrelia garinii Spirochetes

    Författare :Pär Comstedt; Sven Bergström; Wolfram R. Zückert; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Borrelia garinii; Lyme borreliosis; birds; migration; reservoir host; complement; Ixodes ricinus; Europe; Asia; infection cycle; Molecular biology; Molekylärbiologi;

    Sammanfattning : Lyme borreliosis is a tick-transmitted infectious disease. The causative agents are spiral-shaped bacteria and the most common sign of infection is a skin rash at the site of the tick bite. LÄS MER

  5. 19. Fish on drugs : behaviour modifying contaminants in aquatic ecosystems

    Författare :Annelie Lagesson; Jonatan Klaminder; Tomas Brodin; Kathryn Arnold; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Aquatic ecosystems; Behavioural effects; Ecotoxicology; Endocrine disruptors; Pharmaceuticals; Interaction effects; ekotoxikologi; Ecotoxicology;

    Sammanfattning : Contamination of surface waters is a worldwide problem. One group of emerging contaminants that reach aquatic ecosystems via sewage treatment plant effluents and agricultural run-offs is pharmaceuticals. LÄS MER

  7. 20. Stress in chickens : Effects of domestication and early experience on behaviour and welfare

    Författare :Maria Ericsson; Per Jensen; Linda Keeling; Bjarne Braastad; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The domestication is the process where animals have adapted to human conditions. A prerequisite for domestication is tame behaviour towards humans and subsequently, selection for other desirable traits took place which led to changes in several behavioural and physiological parameters. LÄS MER