Cephalopods in the diet of nonbreeding black-browed and grey-headed albatrosses from South Georgia

• Published in: Polar Biology
• Main Authors: Alvito, Pedro M., Rosa, Rui, Phillips, Richard A., Cherel, Yves, Ceia, Filipe, Guerreiro, Miguel, Seco, Jose, Baeta, Alexandra, Vieira, Rui P., Xavier, Jose C
• Other Authors: Marine and environmental research centre - IMAR-CMA (Coimbra, Portugal), University of Coimbra Portugal (UC), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: Antarctica; Albatrosses; Cephalopods; Thalassarche melanophris; Thalassarche chrysostoma; [SDE]Environmental Sciences; Antarc*; Polar Biology
• Online Access: https://hal.archives-ouvertes.fr/hal-01274103; https://doi.org/10.1007/s00300-014-1626-3

International audience The food and feeding ecology of albatrossesduring the nonbreeding season is still poorly known, particularlywith regard to the cephalopod component. Thiswas studied in black-browed Thalassarche melanophrisand grey-headed T. chrysostoma albatrosses by analysingboluses collected shortly after adults returned to colonies atBird Island, South Georgia (54S, 38W), in 2009. Basedon stable isotopic analyses of the lower beaks, we determinedthe habitat and trophic level (from d13C and d15N,respectively) of the most important cephalopods andassessed the relative importance of scavenging in terms ofthe albatrosses’ feeding regimes. Based on lower rostrallengths (LRLs), the main cephalopod species in the diets ofboth albatrosses was Kondakovia longimana, by frequencyof occurrence (F[90 %), number (N[40 %) and mass(M[80 %). The large estimated mass of many squid,including K. longimana, suggests that a high proportion([80 % by mass) was scavenged, and that scavenging ismuch more important during the nonbreeding season thanwould be expected from breeding-season diets. Thediversity of cephalopods consumed by nonbreeding birds inour study was similar to that recorded during previousbreeding seasons, but included two new species [Moroteuthissp. B (Imber) and ?Mastigoteuthis A (Clarke)].Based on similarities in LRL, d13C and d15N, the squidconsumed may have been from the same oceanic populationsor region, with the exception of Taonius sp. B (Voss)and K. longimana, which, based on significant differencesin d15N values, suggest that they may have originated fromdifferent stocks, indicating differences in the albatrosses’feeding regimes.