Foraging area rather than trophic level explains mercury concentration in Patagonian rockhopper penguin colonies

LOIS, NICOLÁS A.; BALZA, ULISES; DODINO, SAMANTA; POLITO, MICHAEL J.; PÜTZ, KLEMENS; BRASSO, REBECKA L.; RAYA REY, ANDREA

Virtual

Congreso; 3rd World Seabird Conference; 2021

Outlying high mercury (Hg) concentrations have been detected in southern South American penguins. In order to provide further insights into the variation of mercury prevalence in relation to foraging habitat at a regional scale, we measured mercury (Hg) concentrations and Carbon and Nitrogen stable isotopes in feathers from six southern rockhopper penguins (Eudyptes chrysocome) colonies in the Patagonian Shelf. We found that mercury exposure is explained by site, which is most probably driven by differences in baseline Hg concentration in the specific foraging areas used by each colony. In this sense, the lack of correlation between mercury prevalence and trophic position in this system, expected due to bioaccumulation, is screened by local differences in Hg prevalence. The Hg hotspot location is restricted around the southern tip of South America and further environmental studies should be targeted to this area to elucidate its driving processes. Intraspecific foraging variability and plasticity in the studied species and many other seabirds in the region highlight the relevance of regional and colony-based seabird conservation planning