Linking foraging behavior and diet in a diving seabird

SABRINA HARRIS; FLAVIO QUINTANA; JAVIER CIANCIO; LUCIANA RICCIALDELLI; ANDREA RAYA REY

MARINE ECOLOGY-PUBBLICAZIONI DELLA STAZIONE ZOOLOGICA DI NAPOLI I

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015

0173-9565

Foraging behavior and diet of breeding seabirds may be analyzedsimultaneously with the combined use of remote sensing devices and stableisotope analysis. Imperial shags Phalacrocorax atriceps breeding atPunta León colony, Argentina, were equipped with GPS loggers to record foragingtrips and blood samples were taken after removal of devices in order to analyzetheir nitrogen and carbon stable isotope composition in whole blood and plasma.Whole blood was correlated to plasma isotopic composition for each individual(n = 35), linking diet in the short and medium term, and sexes did not differin isotopic signatures. Maximum distance reached and total dives individualsmade on two consecutive foraging trips were correlated to their plasma nitrogenisotopic signature, as individuals that went further from the colony and divedfewer times presented more positive signatures, indicative of benthic preyconsumption (e.g. Raneya brasiliensis). Diet was predominantly benthicwith some individuals incorporating pelagic prey (Engraulis anchoita)and even cephalopods (Octopus tehuelchus). Within breeding pairs (n =9), different combinations of foraging and prey preferences were observed.Estimated trophic levels of these individuals were similar to those of the samespecies in other colonies further south along the Patagonian coast.