Sökning: "Perch"
Visar resultat 6 - 10 av 76 avhandlingar innehållade ordet Perch.
6. Ecology and Evolution of Adaptive Morphological Variation in Fish Populations
Sammanfattning : The work in this thesis deals with the ecology and evolution of adaptive individual variation. Ecologists have long used niche theory to describe the ecology of a species as a whole, treating conspecific individuals as ecological equivalent. LÄS MER
7. Local adaptive pigmentation in Asellus aquaticus -effects of UV-radiation and predation regime
Sammanfattning : Pigmentation in the freshwater isopod Asellus aquaticus differed between two habitats. Asellus were lighter pigmented in stands of submerged stonewort vegetation, than in nearby reed stands. Moreover, Asellus pigmentation became lighter with time in recently established stonewort stands. LÄS MER
8. Development of GC-HRMS procedures for determination of naturally occuring polar compounds in various environmental applications
Sammanfattning : The overall objectives of this dissertation were to gain further understanding of the two following environmentally significant issues: (i) Determination of natural steroid hormones in blood plasma from perch (Perca fluviatilis) during a reproductive cycle and to evaluate the possibility of using the steroid composition as a biomarker for early signs of endocrine disruptive effects. (ii) Determination of dissolved free amino acids in size resolved airborne particles collected over the Arctic pack ice area (>80°N) in summer and to study their overall relationship with the ocean surface microlayer as a potential source. LÄS MER
9. Biological Diversity of Fish and Bacteria in Space and Time
Sammanfattning : Biological diversity is controlled by an array of factors and processes all active at different spatial and temporal scales. Regional factors control what species are available to occur locally, whereas the local factors determine what species are actually capable of colonizing the locality. LÄS MER
10. Does fish health matter? The Utility of Biomarkers in Fish for Environmental Assessment
Sammanfattning : Two common strategies to assess exposure to environmental toxicants are to measure chemical concentrations in the environment and to examine the presence of certain species that are known to be sensit... merive to pollution. LÄS MER