| Summary: | Dissertação de mestrado em Biologia, apresentada ao Departamento Ciências da vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra. White-chinned petrels, Procellaria aequinoctialis, are one of the most abundant pelagic seabirds in the Southern Ocean and have the highest incidental mortality rate by long-line fisheries in the region. Tracking results on this population have shown that their foraging areas cover the waters around South Georgia, Scotia Sea and sub-Antarctic waters to the Patagonian shelf. However, much information on their diet and activity patterns is needed to better understand their foraging ecology in relation to fisheries and thus provide valuable information for the conservation of this species. The diet has been broadly characterized previously using breeding birds caught at the colonies, however, no diet information is available from white-chinned petrels caught out at sea, caught accidently by fishing vessels, including the cephalopod part of the diet. As cephalopods are poorly known in the Southern Ocean, and they have no Antarctic fisheries targeting them, understanding their importance in the diet of these seabirds can contribute to our understanding of how white-chinned petrels catch prey (in this case cephalopods) naturally. The diving and activity patterns of white-chinned petrels, related to their feeding ecology, are, also, poorly understood. This species possibly feed by seizing live prey from the surface, by surface plunging and they are also excellent divers. As they are also scavengers, potentially feeding on bait and discards from longline fishing vessels, they may become vulnerable species due to possible attraction to fishing vessels and are known to being caught accidently by longline hooks. The objectives of this study will be to characterize the diet of white-chinned petrels caught in South Georgian waters onboard of longline fishing vessels, in two different years (2002 and 2004), assess diving patterns of white-chinned petrels, from colonies on Bird ...
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