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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Early Holocene Seal Hunting on the Island of Gotland / Mesolitisk säljakt på Gotland

Sjöstrand, Alexander January 2011 (has links)
Denna studie inkluderar resultat från osteologiska analyser från tre stenålderslokaler på Gotland: Visborgs Kungsladugård, Strå samt Gisslause. Dessa tre lokaler är daterade till Mesolitikum, dvs. bland de tidigaste faserna på Gotland. En majoritet av de identifierade benen har varit från säl och därför har uppsatsen kommit att handla om den säljakt som utövats på dessa tre platser. Utifrån de fynd som analyserats har skillnader kunnat uttolkas vad det gäller både åldersfördelning och fördelning av olika sälarter mellan vissa av lokalerna. Visborgs Kungsladugård visar på en majoritet av yngre gråsälar till skillnad från Strå och Gisslause där det existerar en jämn fördelning mellan gråsäl och vikare, likaså en jämn fördelning mellan åldrarna. Tolkningen av detta pekar på en delvis säsongsjakt där populationerna har jagat på olika sätt på olika delar av Gotland. I uppsatsen har även en diskussion angående den marina anpassningen tagits upp. Denna anpassning har setts i tre stadier, lakustrin, littorin och marin. Den mesolitiska populationen på Gotland passar in på det littorina stadiet där en full marin kultur inte ännu varit helt utvecklad. Då det främst jagats säl på och nära stranden samt att ett visst insjöfiske utövats påvisar resultaten att ett fullt utnyttjande av havet ännu inte bedrivits.
22

The ecology of Arctic cod (Boreogadus saida) and interactions with seabirds, seals, and whales in the Canadian Arctic

Matley, Jordan January 2012 (has links)
This thesis investigates the foraging of Arctic cod (Boreogadus saida) and its predators during the summer in the Canadian Arctic. Findings included the identification of Arctic cod, ringed seal (Pusa hispida), beluga (Delphinapterus leucas), and narwhal (Monodon monoceros) diet shifts in response to seasonal prey availability; calculation of isotopic diet-tissue discrimination factors for Arctic cod, ringed seals, and whales based on local tissue and stomach content sampling; and determination of predatory cues to optimize foraging, such as the presence of schools. Additionally, I quantified seabird feeding and interspecific interactions such kleptoparasitism and found that black-legged kittiwakes (Rissa tridactyla) and northern fulmars (Fulmarus glacialis) captured cod directly but lost many to parasitic jaegers (Stercorarius parasiticus) and glaucous gulls (Larus hyperboreus). Finally, I determined that schools of cod were important prey sources for northern fulmars, glaucous gulls, and whales however non-schooling cod were a significant source for black-legged kittiwakes and ringed seals.
23

The ecology of Arctic cod (Boreogadus saida) and interactions with seabirds, seals, and whales in the Canadian Arctic

Matley, Jordan January 2012 (has links)
This thesis investigates the foraging of Arctic cod (Boreogadus saida) and its predators during the summer in the Canadian Arctic. Findings included the identification of Arctic cod, ringed seal (Pusa hispida), beluga (Delphinapterus leucas), and narwhal (Monodon monoceros) diet shifts in response to seasonal prey availability; calculation of isotopic diet-tissue discrimination factors for Arctic cod, ringed seals, and whales based on local tissue and stomach content sampling; and determination of predatory cues to optimize foraging, such as the presence of schools. Additionally, I quantified seabird feeding and interspecific interactions such kleptoparasitism and found that black-legged kittiwakes (Rissa tridactyla) and northern fulmars (Fulmarus glacialis) captured cod directly but lost many to parasitic jaegers (Stercorarius parasiticus) and glaucous gulls (Larus hyperboreus). Finally, I determined that schools of cod were important prey sources for northern fulmars, glaucous gulls, and whales however non-schooling cod were a significant source for black-legged kittiwakes and ringed seals.

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