Sökning: "Halichoerus grypus"

Visar resultat 1 - 5 av 6 uppsatser innehållade orden Halichoerus grypus.

  1. 1. Impact of Great cormorant (Phalacrocorax carbo sinensis) on post-smolt survival of hatchery reared salmon (Salmo salar) and sea trout (Salmo trutta)

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

    Författare :Carolina Gavell; [2018]
    Nyckelord :great cormorant; salmon; sea trout; sea trout; grey seal; post-smolt survival;

    Sammanfattning : To compensate for the losses due to altered stream habitat large amounts of hatchery-reared Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) are released into the Baltic Sea each year. During the last decades there have been an overall declining trend in the post-smolt survival of both hatchery reared and wild salmon in the Baltic Sea. LÄS MER

  2. 2. Analysing the seal-fishery conflict in the Baltic Sea and exploring new ways of looking at marine mammal movement data

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

    Författare :Ornella Jogi; [2017]
    Nyckelord :Halichoerus grypus; Phoca hispida botnica; seal-fishery conflict; human-wildlife conflict; integrated step selection analysis;

    Sammanfattning : A comprehensive analysis of the available data reveals that there is currently not enough information for making informed management decisions regarding the seal-fishery conflict in the Baltic Sea. Knowledge of hidden and visual damages is limited, which means that the actual cost to the fishing industry from damages is not known. LÄS MER

  3. 3. Attack behavior and presence of grey seals around pots : a search for seal-safe cod-pots in the Baltic sea

    Master-uppsats, SLU/Dept. Of Aquatic Resources

    Författare :Jasmine Stavenow; [2016]
    Nyckelord :grey seal; Halichoerus grypus; seal behavior; seal attacks; seal presence; sealsafe; seals-fishery conflict; seals and fishery; fishing gear; cod-pots; sustainable fishing; Baltic sea; coastal fishery;

    Sammanfattning : The seals and the fishery are forced to share the role as top-predators in the Baltic waters since they both depend on the same fish stocks, which leads to an unavoidable competition. Seals are raiding traps, leading not only to costly damaged fishing gears and loss in fish catch but also to the seals themselves getting caught and drowned in the gears as by-catch. LÄS MER

  4. 4. Hälsotillståndet hos sälar i Östersjön

    Kandidat-uppsats, SLU/Dept. of Biomedical Sciences and Veterinary Public Health

    Författare :Hanna Lundén; [2012]
    Nyckelord :gråsäl; Halichoerus grypus; vikare; Phoca hispida botnica; Östersjön; patologi; marina miljöföroreningar;

    Sammanfattning : Sälpopulationerna i Östersjön består av tre arter: gråsäl, vikare och knubbsäl. Sälarna befinner sig som rovdjur högst upp i näringskedjan och livnär sig till största delen på fisk. Detta gör att de i hög grad utsätts för de miljögifter som finns både i vattnet och i fisken. LÄS MER

  5. 5. Födosammansättning hos gråsäl (Halichoerus grypus) samt test av flotte för insamling av sälfekalier.

    Magister-uppsats, Högskolan i Kalmar/Naturvetenskapliga institutionen

    Författare :Christian Lagström; [2008]
    Nyckelord :grey seal; food preferences; ecosystem; Baltic Sea; otoliths; floating platform; scats; cormorants;

    Sammanfattning : During the 1960´s and 1970´s the number of grey seals in the Baltic Sea was decreasing rapidly, mostly due to hunting and toxic substances like DDT and PCB. When hunting became less intense and toxic substances decreased in the environment the grey seal population started to increase. LÄS MER