Sökning: "Esox lucius"

Visar resultat 11 - 15 av 19 avhandlingar innehållade orden Esox lucius.

  1. 11. Influence of cyanobacterial blooms on coastal fish recruitment

    Författare :Karl-Johan Persson; Catherine Legrand; Markku Viitasalo; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cyanobacteria; coastal fish recruitment; Akvatisk ekologi; Aquatic Ecology;

    Sammanfattning : Cyanobacteria are the oldest oxygen-producing organisms on Earth and can be found in almost every terrestrial and aquatic habitat. Their long evolutionary history has enabled them to develop diverse adaptations in order to increase their survival in environments subjected to natural and anthropogenic changes. LÄS MER

  3. 12. Foraging behaviour in piscivorous fish: mechanisms and patterns

    Författare :Håkan Turesson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; marine biology; Hydrobiology; piscivory; consumption rate; confusion effect; capture success; predation; encounter rate; prey choice;

    Sammanfattning : Mechanistic understanding of piscivore foraging at the individual level is important in order to understand and make predictions of piscivore effects at population and community levels. To understand the mechanisms affecting selection and consumption rates each step in the foraging cycle (search, encounter, active choice, attack, capture, ingestion, digestion) should be studied. LÄS MER

  4. 13. Ecological and evolutionary effects of predation in environmental gradients

    Författare :Gunnar Öhlund; Göran Englund; Skuli Skulason; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Understanding species interactions and how they affect densities and distributions of organisms is a central theme in ecological research. Studying such interactions in an ecosystem context is challenging as they often depend on species-specific characteristics and rates that not only change during the ontogeny of an organism, but also are affected by the surrounding environment. LÄS MER

  5. 14. Improved Assessment in Environmental Monitoring of POPs : Using monitoring data from the aquatic ecosystem and human milk

    Författare :Elisabeth Nyberg; Anders Bignert; Jochen Mueller; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Environmental monitoring; temporal trends; power analysis; sampling strategy; PCBs; DDTs; HCHs; HCB; PCDD Fs; fish; bird eggs; blue mussels; human milk; miljökemi; Environmental Chemistry;

    Sammanfattning : The thesis deals with several aspects of monitoring of persistent organic contaminants (POPs) in biological matrices, for example choice of sample, sampling design, and statistical treatment of data both for temporal and spatial trends and for compliance towards a set target value. The efficiency has been evaluated through statistical power analyses. LÄS MER

  7. 15. Invasion of top and intermediate consumers in a size structured fish community

    Författare :Per Ask; Lennart Persson; Daniel E Schindler; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Invasion; intraguild predation; size-structure; cannibalism; climate; temperature; Arctic char; ninespine stickleback; Freshwater ecology; Limnisk ekologi; biology; biologi;

    Sammanfattning : In this thesis I have investigated the effects of invading top and intermediate consumers in a size-structured fish community, using a combination of field studies, a lake invasion experiment and smaller scale pond and aquaria experiments. The lake invasion experiment was based on introductions of an intermediate consumer, ninespine stickleback (Pungitius pungitius L. LÄS MER