Sökning: "fiskar"

Visar resultat 16 - 20 av 54 avhandlingar innehållade ordet fiskar.

  1. 16. Foraging behaviour in benthivorous fish

    Författare :Marika Stenberg; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Marinbiologi; resource assessment; giving-up densities; predation risk; foraging behaviour; limnology; marine biology; Ekologi; akvatisk ekologi; limnologi; group foraging; benthivorous fish; aquatic ecology; Hydrobiology; Ecology;

    Sammanfattning : The foraging ability of an organism is essential since it affects various traits, e.g. growth, reproduction effort, social status and, ultimately, fitness. LÄS MER

  3. 17. Evolution of Vertebrate Eyes: a study on lens suspension and optical proterties

    Författare :Ola Gustafsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; evolution; eye; fish; crystalline lens; lens suspension; multifocal optical systems; Agnatha; Actinopterygii; Chondrichthyes; Vertebrate; Sarcopterygii;

    Sammanfattning : Many fishes have well-developed visual systems with color vision capabilities. The crystalline lens is the major refractive element in a fish eye since the cornea is optically inactive underwater. A typical fish eye has a large pupil and a lens of short focal length, features that increase light gathering ability. LÄS MER

  4. 18. Salmonid behaviour under winter conditions

    Författare :Johan Watz; Larry Greenberg; Eva Bergman; John Piccolo; Richard Cunjak; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; climate change; drift; energy budget; foraging; grayling; ice cover; lotic; metabolic rate; predation; salmon; stream; stress; temperature; trout; Biology; Biologi;

    Sammanfattning : Winter conditions are believed to play an important role in the population dynamics of northern temperate stream fish, challenging the ability of fish to physiologically and behaviourally adapt. Climate change is predicted to increase both mean temperature and temperature fluctuations, especially during winter, leading to dynamic environmental conditions in terms of river ice production and flow. LÄS MER

  5. 19. Aquatic organisms on the pill - effects on different organizational levels

    Författare :Per Hallgren; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; EDC; EE2; 17α-ethinylestradiol; fish; zooplankton; gastropods; population growth rates; direct and indirect effects; somatic growth; invertebrates;

    Sammanfattning : Communities are composed of organisms that interact with each other and with the non-biological environment. There are also anthropogenic pollutants in the environment that also interact with the organisms. LÄS MER

  7. 20. 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