My coauthors and I are pleased to announce the publication of our 10-year study: 'Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups' in Scientific Reports. Open access at Scientific Reports: https://rdcu.be/dzF32 Abstract: Deep ocean foraging northern elephant seals (Mirounga angustirostris) consume fish and squid in remote depths of the North Pacific Ocean. Contaminants bioaccumulated from prey are subsequently transferred by adult females to pups during gestation and lactation, linking pups to mercury contamination in mesopelagic food webs (200-1000 m depths). Maternal transfer of mercury to developing seal pups was related to maternal mercury contamination and was strongly correlated with maternal foraging behavior (biotelemetry and isotopes). Mercury concentrations in lanugo (hair grown in utero) were among the highest observed worldwide for young pinnipeds (geometric mean 23.01 *g/g dw, range 8.03-63.09 *g/g dw; n=373); thus, some pups may be at an elevated risk of sub-lethal adverse health effects. Fetal mercury exposure was affected by maternal foraging geographic location and depth; mercury concentrations were highest in pups of the deepest diving, pelagic females. Moreover, pup lanugo mercury concentrations were strongly repeatable among successive pups of individual females, demonstrating relative consistency in pup mercury exposure based on maternal foraging strategies. Northern elephant seals are biosentinels of a remote deep-sea ecosystem. Our results suggest that mercury within North Pacific mesopelagic food webs may also pose an elevated risk to other mesopelagic-foraging predators and their offspring. Authors: Sarah H. Peterson, Michael G. Peterson, Joshua T. Ackerman, Cathy Debier, Chandra Goetsch, Rachel R. Holser, Luis A. Hückstädt, Jennifer C. Johnson, Theresa R. Keates, Birgitte I. McDonald, Elizabeth A. McHuron, and Daniel P. Costa Please reach out with any questions about this research or to request the pdf of this paper (sepeterson@usgs.gov). Best regards, Sarah Peterson ----------------------------------------------------------------------- Sarah H Peterson, PhD | she/her/hers Wildlife Biologist U.S. Geological Survey Western Ecological Research Center Dixon Field Station 800 Business Park Drive, Suite D Dixon, CA 95620 Email: sepeterson@usgs.gov<mailto:sepeterson@usgs.gov> Website: https://www.usgs.gov/staff-profiles/sarah-peterson ORCID: https://orcid.org/0000-0003-2773-3901