Le Croizier Gael auteur aut IRD Point David auteur aut IRD Renedo M. auteur aut IRD Munaron Jean-Marie auteur aut IRD Espinoza P. auteur aut IRD Amezcua-Martinez F. auteur aut IRD Bertrand S. L. auteur aut IRD Lorrain Anne auteur aut IRD text journalArticle eng text/pdf born digital access Assessing mercury (Hg) biomagnification requires the description of prey-predator relationships, for each species and ecosystem, usually based on carbon and nitrogen isotope analyses. Here, we analyzed two seabirds from the Humboldt Current ecosystem, the Guanay cormorant (Phalacrocorax bougainvillii) and the Peruvian booby (Sula variegata), as well as their main prey, the Peruvian anchovy (Engraulis ringens). We reported Hg concentrations, Hg biomagnification (BMF) and isotopic discrimination factors (delta C-13 and delta N-15) in seabird whole blood. BMFs and delta C-13 in our study (on wild birds where diet was not controlled) were similar to other piscivorous seabirds previously studied in captive settings, but delta N-15 were lower than most captive experiments. We observed lower Hg concentrations in Humboldt seabirds compared to other oligotrophic ecosystems, possibly due to Hg biodilution in the high biomass of the first trophic levels. This work calls for a better characterization of Hg trophic dynamics in productive upwelling ecosystems. specialized Trophic discrimination factors Carbon and nitrogen stable isotopes Cormorant Booby Anchovy Upwelling PACIFIQUE PEROU 034 036 038 177 113481 [7 ] 2022 0025-326X https://www.documentation.ird.fr/hor/fdi:010084633 10.1016/j.marpolbul.2022.113481 0025-326X [F B010084633] https://www.documentation.ird.fr/hor/fdi:010084633 https://www.documentation.ird.fr/intranet/publi/2022-05/010084633.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2022-05-04 2025-02-24 fdi:010084633 fre