Hello MARMAM Members, On behalf of my colleagues and myself, I am pleased to share with you all our new research article “Stress-related and reproductive hormones in hair from three north Pacific otariid species: Steller sea lions, California sea lions and northern fur seals”, now available in Conservation Physiology. The article is Open Access and can be found here<https://bit.ly/2Yie6Sf>. Keogh MJ, Gastaldi A, Charapata P, Melin S, Fadely BS (2020) Stress-related and reproductive hormones in hair from three north Pacific otariid species: Steller sea lions, California sea lions and northern fur seals. ConservPhysiol 00(00): coaa069; doi:10.1093/conphys/coaa069.<https://bit.ly/2Yie6Sf> Abstract Assessing the physiological impact of stressors in pinnipeds is logistically challenging, and many hormones are altered by capture and handling, limiting the utility of metabolically active tissues. Hair is increasingly being used to investigate stress- related and reproductive hormones in wildlife populations due to less-invasive collection methods, being metabolically inert once grown and containing multiple biomarkers of ecological interest. We validated enzyme immunoassays for measuring aldosterone, cortisol, corticosterone, and testosterone in lanugo (natal hair grown in utero) samples collected from Steller sea lions (Eumetopias jubatus), California sea lions (Zalophus californianus), and northern fur seals (Callorhinus ursinus). We applied laboratory validation methods including recovery of added mass, parallelism and dilution linearity. We found no effects due to differences in alcohol- versus detergent-based cleaning methods. Further, there were no significant differences in hormone concentrations in hair samples collected immediately after the molt and the subsequent samples collected over 1 year, indicating steroid hormones are stable once deposited into pinniped hair. We found no sex differences in any hormone concentrations, likely due to the lanugo being grown in utero and influenced by maternal hormone concentrations. For Steller sea lion and California sea lion pups, we found hormone concentrations significantly differed between rookeries, which warrants future research. Hair provides a novel tissue to explore the intrinsic or extrinsic drivers behind hormone measurements in otariids, which can be paired with multiple health-related metrics to further investigate possible drivers of physiological stress. Please email lead and corresponding author (Mandy Keogh, mandyjkeogh@gmail.com<mailto:mandyjkeogh@gmail.com>) if you have any questions or are interested in the manuscript. If for any reason you do not have access to the article through the links, I would be happy to provide a PDF of the manuscript upon request (Patrick_charapata1@baylor.edu<mailto:Patrick_charapata1@baylor.edu>). Cheers, Patrick Charapata PhD Candidate, Baylor University Patrick_charapata1@baylor.edu<mailto:Patrick_charapata1@baylor.edu>