Sökning: "Perch"

Visar resultat 21 - 25 av 76 avhandlingar innehållade ordet Perch.

1. 21. Assessment of organochlorine contamination in the aquatic environment of Latvia with perch and heron as biomarkers

   Författare :Karlis Valters; Derek Muir; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Environmental Chemistry; miljökemi;

   Sammanfattning : Polychlorinated biphenyls (PCBs), DDT, DDT transformation products, and several other organochlorine substances (OCS) have been analysed in numerous species and matrices from different parts of the world including Arctic environments. However, knowledge on levels and distribution of OCS is still lacking for many regions world-wide including the Eastern Europe in general. LÄS MER

3. 22. Nutrition of Arctic charr (Salvelinus alpinus) and Eurasian perch (Perca fluviatilis) and evaluation of alternative protein sources

   Författare :Markus Langeland; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

   Sammanfattning : The aim of this thesis was to estimate the dietary lysine requirement of Eurasian perch (Perca fluviatilis), to study the digestive enzyme activity in perch and Arctic charr (Salvelinus alpinus) and the utilization of meals of microbial and mussel meals. Juvenile Eurasian perch were fed semi-purified diets containing graded levels of lysine (12. LÄS MER

4. 23. Habitat selection and indirect interactions in fish communities : mechanisms to explain spatial distribution of perch, roach, and vendace

   Författare :Ulrika Beier; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
   Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : To increase the understanding of freshwater lake ecosystems, I have studied the habitat selection of perch (Perca fluviatilis L.), roach (Rutilus rutilus (L.)), and vendace (Coregonus albula (L.)). LÄS MER

5. 24. Environmental influence on Hg and 137Cs levels in perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) from circumneutral lakes

   Författare :Lars Sonesten; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; Hg; 137Cs; fish; PLS; land use; cations; humic substances; circumneutral; Biologi; Biology; Biologi; limnologi; Limnology;

   Sammanfattning : Mercury and radioactive caesium have received immense attention in Sweden during the past decades, as common contaminants in fish. This thesis examines how the Hg and 137Cs levels in fish from 79 circumneutral lakes are affected by various environmental factors. LÄS MER

7. 25. The fate and effect of pharmaceuticals in boreal surface waters

   Författare :Johan Fahlman; Jonatan Klaminder; Jan Karlsson; Fredrik Jutfelt; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Aquatic ecosystems; behavioural effects; ecotoxicology; acoustic telemetry; field verification; social network; ekotoxikologi; Ecotoxicology; environmental science; miljövetenskap;

   Sammanfattning : Traces of pharmaceuticals are often found in streams, rivers, and lakes as the result of effluent water discharge. This dissertation aims to create a better understanding of the fate of drugs in aquatic ecosystems and how oxazepam, an anxiolytic pharmaceutical commonly detected in surface waters, affects the behavior of perch (Perca fluviatilis). LÄS MER