Sökning: "Roach"

Visar resultat 1 - 5 av 20 avhandlingar innehållade ordet Roach.

1. 1. Population ecology of perch (Perca fluviatilis) in boreal lakes

   Författare :Arne Linløkken; Eva Bergman; Larry Greenberg; Anders Hargeby; Karlstads universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; perch; growth; size; mortality; temperature; acidification; density; roach; competition; Biology; Biologi; Biology; Biologi;

   Sammanfattning : I studied the effects of temperature, pH, competition and predation on Eurasian perch (Perca fluviatilis) in 30 lakes in Norway during 1981-2001. The study lakes were situated in two different areas in southern Norway; four lakes in Aust-Agder county in southernmost Norway were explored during 1981-1984 and 26 lakes in Hedmark county in south-eastern Norway were investigated during 1992-2001. LÄS MER

3. 2. Paleolimnological reconstructions of fish population changes in acidified lakes

   Författare :Fredrik Palm; Göteborgs universitet; []
   Nyckelord :Acidification; Chaoborus; C. flavicans; C. obscuripes; Cyprinids; Daphnia; Fish loss; Fish community composition; Ephippia; Fragmentation; Mandibles; Perch; Roach; Sediments; 210-Pb chronology;

   Sammanfattning : This thesis deals with the potential of using subfossil Chaoborus spp. and Daphnia spp. remains preserved in lake sediments to reveal past fish community alterations related to progressive acidification. LÄS MER

4. 3. Biodiversity in Swedish Cyprinid Fish: Insights Into Processes of Divergence

   Författare :Marnie H Demandt; Mats Björklund; Erik Petersson; Brent Emerson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; speciation; hybridization; bottleneck; genetic drift; phylogeny; speciation rates; common bream; white bream; roach; Swedish cyprinid fish; Cyprinidae; Biology; Biologi;

   Sammanfattning : Uncovering and understanding the processes that have led to the biological diversity we observe today are of fundamental interest in biology. Since direct observation of speciation is usually impossible, knowledge about the processes behind species formation can be gathered by studying mutations, natural/sexual selection, and genetic drift. LÄS MER

5. 4. Structural aspects of the hypothalamo-hypophysical complex of the roach, Leuciscus rutilus

   Författare :Bo Ekengren; Stockholms universitet; []
   Nyckelord :;

   Sammanfattning : .... LÄS MER

7. 5. The estrogen receptor in fish and effects of synthetic estrogens in the environment - Ecological and evolutionary perspectives and societal awareness

   Författare :Lina Nikoleris; Biodiversitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; the estrogen receptor; salmon evolution and ecology; contraceptives; information gaps; synthetic hormones; EE2; Atlantic salmon Salmo salar ; brown trout Salmo trutta ; roach Rutilus rutilus ;

   Sammanfattning : Synthetic hormones are a group of pharmaceuticals used for various human and animal treatments. However, consumption and disposal of these substances have also given rise to negative effects and environmental problems for organisms in the wild which is why these substances have been classified as estrogenic endocrine-disrupting chemicals (EDCs). LÄS MER