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Cephalopods play a key role in marine environments as food resources for top predators such as marine mammals and seabirds. However, detailed information on their trophic relationships with Antarctic seals is scarce. The aim of the present study was to examine the cephalopod portion of the diet of adult and subadult Weddell seals, Leptonychotes weddellii, at Hope Bay, Antarctic Peninsula, through the analysis of scats collected during three consecutive summers (2003, 2004 and 2005). Cephalopods occurred in almost 45% of the 217 samples collected during the whole period of study. A total of 662 beaks (358 upper and 304 lower) were removed from scats containing cephalopod remains (n = 93). Octopods were largely dominant in comparison with teuthoids constituting in numerical abundance over 95% of the cephalopod prey. The octopod Pareledone turqueti was the most frequent and dominant prey species representing, respectively, 57.9 and 71.1% in numbers and biomass of cephalopods consumed. Species belonging to the group of papillated Pareledone were second in importance. The results were compared with information from previous dietary studies of L. weddellii at other localities of Antarctica. Based on the examination of the cephalopod prey taxa identiWed in this study, it is suggested that during the study period Weddell seal individuals foraged mainly on benthic prey resources close to the coast, in inshore waters where octopods were dominant in comparison with pelagic squid.

International audienceWeddell seals, Leptonychotes weddellii, areimportant apex predators in the food web of the Antarcticmarine ecosystem. However, detailed information on theirtrophic relationships with cephalopods is scarce. Moreover,cephalopods play a key role in the marine environment, butknowledge of their feeding habits is limited by lack of data.Here, we have combined the use of this seal as a biologicalsampler together with measurements of the stable isotopicsignature of the beaks of their cephalopod prey. Thus, theaims of the present study were: (1) to examine in detail thecephalopod portion of the diet of Weddell seals by meansof scat analysis and (2) to assess the habitat use and trophiclevel of the different cephalopod prey taxa identified. FromJanuary to February 2009, a total of 48 faecal droppingswere collected at Hope Bay, Antarctic Peninsula. Cephalopodswere mainly represented by beaks (n = 83) whichwere identified to the lowest possible taxonomic level.Furthermore, subsamples of beaks were separated for furtherisotopic analysis. Relative abundance of stable isotopesof carbon (d13C) and nitrogen (d15N) was determined by continuous-flow isotope-ratio mass spectrometry.Cephalopods were represented uniquely by octopods of thesubfamily Eledoninae. Pareledone turqueti was the dominantprey species followed by the papillated Pareledonespecies group and Adelieledone polymorpha. We concludethat Weddell seals preyed primarily on benthic preyresources. Furthermore, the relatively similar d13C andd15N values in beaks of the three octopod prey taxa suggestthat these share the same type of habitat and occupy similartrophic level positions

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