Dear all, On the behalf of my co-authors, I would like to announce our new publication on grey seal pup saliva use for steroid analysis: V. Survilienė, O. Rukšėnas, P.P. Pomeroy, S.E.W. Moss and K.A. Bennett. 2022. Evaluating suitability of saliva to measure steroid concentrations in grey seal pups. General and Comparative Endocrinology, Volume 326, 114070, https://doi.org/10.1016/j.ygcen.2022.114070. You can find this article using a 50-day free access link: https://authors.elsevier.com/a/1fD0u3oGhS0K%7E If you miss a cut-off date for free access, please feel free to contact me by email (vaida.surviliene@gmail.com), twitter (@SurvilieneVaida) or a researchgate. Abstract Measurement of steroids in wild pinnipeds can facilitate assessment of breeding, nutritional and stress status, and is useful in understanding behavioral responses. Even in young animals, sex steroids may be important in behavioral interactions and immune modulation. Use of saliva can avoid the large fluctuations seen in some steroids in plasma, and can negate the need for venipuncture, making it a potentially useful matrix in the wildlife. However, its utility in estimating steroid levels in wild young pinnipeds has not been evaluated. Here, we investigated the suitability of saliva for steroid hormone analysis in wild grey seal pups during their suckling and post-weaning fast periods. We collected saliva (n = 38) and plasma (n = 71) samples during the breeding season on the Isle of May, Scotland, 2012. We investigated the success of sample collection, ease of preparation, accuracy and precision of analysis, and, where possible, comparability of measurements (n = 27) from saliva and plasma. Plasma sampling was rapid, whereas sampling saliva took up to five times longer. Analytical performance criteria (parallelism, accuracy, and precision (intra and inter assay coefficient of variation (% CV)) of commercial ELISA kits to measure estradiol, testosterone and cortisol in both matrices were assessed. Estradiol and cortisol assays performed well and can be used in plasma and saliva. However, we could not confidently validate testosterone for either matrix. Saliva estradiol correlated with levels in plasma. Saliva sample preparation was faster and simpler than plasma preparation because it did not require extraction. However, given the additional time taken to obtain saliva in the wild, the possibility of blood contamination from oral damage and the lower success rate in obtaining sufficient sample for analysis, we recommend that this matrix only be used as an alternative to plasma sampling measurement in pinnipeds when animals are anaesthetized, tolerate mouth swabbing, or have been trained to accept saliva sampling in captivity. All the best, Vaida Pagarbiai/ Regards, Vaida Survilienė Mob.: + 370 66211047 PhD Student/Junior research fellow Institute of Biosciences Life Sciences Center Vilnius University