| Summary: | Dissertação de Mestrado em Ecologia apresentada à Faculdade de Ciências e Tecnologia Antarctic region, which includes the Southern Ocean, is one of the most affected areas of the planet by climate change. The effects in marine organisms are already visible especially in the Scotia Sea, including at South Georgia, across various species but only at a small temporal scale.For Antarctic cephalopods, little is known of their general ecology and on how they are coping with these past and– ongoing environmental changes in the pelagic waters they live. Indeed, for Antarctic cephalopods, there are practically no long-term studies addressing their adaptation or change in habitat and trophic ecology to ongoing environmental changes, as well the state of their abundance and importance to top predators. To fulfill these gaps, the main objective of this thesis is assessing inter-decadal variation in the habitat and trophic ecology of the most important Antarctic squid in the diet of wandering albatrosses (a well-known cephalopod predator) breeding at South Georgia and related them with the oceanographic conditions (i.e. Southern Annular Mode, Southern Oscillation Index and Sea-ice), over the past decades. In addition, the inter-decadal variations of the cephalopods in the diet of wandering albatrosses and possible relationships with environmental conditions were also assessed. The cephalopod beaks were obtained from boluses from wandering albatross chicks, prior to fledging, at South Georgia, spanning over 5 decades (1976, 1984, 1995, 2006 and 2016).The habitat and trophic ecology, through a stable isotopic analysis of δ13C and δ15N of the main Antarctic squid (Kondakovia longimana, Taonius sp. B (Voss), G. antarcticus, G. glacialis, Histioteuthis atlantica and Histioteuthis eltaninae) were analysed using lower beaks of each species. A total of 46 different species were recorded in wandering albatross’ diet. The squid Kondakovia longimana was the most consumed cephalopod by frequency and by mass through the decades, ...
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