Sökning: "otoliths"

Visar resultat 6 - 10 av 14 uppsatser innehållade ordet otoliths.

  1. 6. A diet study of post-breeding Great cormorants (Phalacrocorax carbo sinensis) on Gotland

    Master-uppsats, SLU/Dept. of Wildlife, Fish and Environmental Studies

    Författare :Anton Larsson; [2017]
    Nyckelord :Baltic sea; regurgitated pellets; otoliths; prey species composition; sea birds;

    Sammanfattning : The Swedish population of great cormorant (Phalacrocorax carbo sinensis) has rapidly increased to over 40 000 breeding couples since the EU-protection 1980. Since the cormorant are high efficient predators living in large colonies, they are accused for reducing fish populations and competing with fishery. LÄS MER

  3. 7. Northern pike Esox lucius growth rates in sub populations of freshwater and sea water origins in the Baltic Sea : Otolith method approach

    Master-uppsats, Linnéuniversitetet/Institutionen för biologi och miljö (BOM)

    Författare :Nelson Mbawala; [2016]
    Nyckelord :Esox lucius; otolith; polishing; staining; core; annuli; growth rate and age;

    Sammanfattning : Northern pike or pike Esox lucius is total piscivorous fish species found in the brackish and freshwater ecosystems of the Northern hemisphere. It is a top predator and keystone species that causes cascading effects in these ecosystems. Otoliths have been used to estimate age and growth rates in most fishes. LÄS MER

  4. 8. Life history trade-offs in Anadromous Burbot Lota lota (Linnaeus 1758) from Rickleån and Sävarån, Northern Sweden

    Master-uppsats, SLU/Dept. of Wildlife, Fish and Environmental Studies

    Författare :Mikael Sandberg; [2015]
    Nyckelord :life history trade-offs; anadromous burbots; Bothnian Bay; Rickleån; Sävarån; otoliths;

    Sammanfattning : Anadromous burbots Lota lota (Linnaeus 1758) from two similar rivers in the Gulf of Bothnia area, Sävarån and Rickleån, Northern Sweden, were compared. The aim was to test for and explain differences in ecology. Spawning burbots in Sävarån were smaller, younger, grew slower and were more densely populated. LÄS MER

  5. 9. Assessing the importance of freshwater tributary systems for the recruitment of Eurasian Perch (Perca fluviatilis) in Baltic Sea Coastal Ecosystems

    Master-uppsats, SLU/Dept. Of Aquatic Resources

    Författare :Joe Wastie; [2014]
    Nyckelord :Perch; Freshwater systems; Coastal areas; Coastal ecosystems;

    Sammanfattning : Populations of one of the most important predatory fish species within Baltic Sea coastal ecosystems, the Eurasian Perch (Perca fluviatilis), have declined in some coastal areas during recent decades. This has caused negative effects on an ecological, commercial, and cultural scale, and protection and restoration of recruitment areas (perch spawning grounds) are believed to be an important player in supporting future stocks. LÄS MER

  7. 10. Utvärdering av rörelsemönster hos öring (Salmo trutta) utifrån otolitmikrokemi

    Magister-uppsats, Karlstads universitet/Fakulteten för hälsa, natur- och teknikvetenskap (from 2013)

    Författare :Magdalena Andersson; [2014]
    Nyckelord :öring; otolit; migration; mikrokemi;

    Sammanfattning : The classic view of trout (Salmo trutta) life history is that trout begins its life in freshwater, migrates to the ocean after about 1-4 years and then returns to freshwater to spawn. As trout fry have been caught at the mouth of the River Emån, near the Baltic Sea, researchers have speculated that some trout emigrate during their first year of life. LÄS MER