Dear Colleagues, On behalf of my co-authors, I am pleased to announce that the following article has been published: Greta Dalle Luche, Ashley S. P. Boggs, John R. Kucklick, Jasmin Groß, Darryl W. Hawker & Susan Bengtson Nash Androstenedione and testosterone but not progesterone are potential biomarkers of pregnancy in Humpback Whales (Megaptera novaeangliae) approaching parturition ABSTRACT: The blubber steroid hormone profiles of 52 female humpback whales migrating along the east coast of Australia were investigated for seasonal endocrine changes associated with reproduction. Individuals were randomly sampled during two stages of the annual migration: before reaching the breeding grounds (northward migration; June/July), and after departing from the breeding grounds (southward migration; September/October). Assignment of reproductive status of the sampled individuals was based on season, single-hormone ranks and multi-variate analysis of the hormonal profiles. High concentrations of progesterone (>19 ng/g, wet weight), recognised as an indicator of pregnancy in this species, were only detected in one sample. However, the androgens, testosterone and androstenedione were measured in unusually high concentrations (1.6–12 and 7.8–40 ng/g wet weight, respectively) in 36% of the females approaching the breeding grounds. The absence of a strong accompanying progesterone signal in these animals raises the possibility of progesterone withdrawal prior to parturition. As seen with other cetacean species, testosterone and androstenedione could be markers of near-term pregnancy in humpback whales. Confirmation of these androgens as alternate biomarkers of near-term pregnancy would carry implications for improved monitoring of the annual fecundity of humpback whales via non-lethal and minimally invasive methods. The article is online (free access): www.nature.com/articles/<http://www.nature.com/articles/s41598-020-58933-4>s41598-020-58933-4<http://www.nature.com/articles/s41598-020-58933-4> Please, do not hesitate to contact me if you have any questions (dalleluche.greta@gmail.com<mailto:greta.dalleluche@griffithuni.edu.au>) Kind regards Greta - Greta Dalle Luche PhD Candidate Griffith University, Environmental Futures Research Institute (EFRI) SOPOPP | Southern Ocean Persistent Organic Pollutants Program Nathan Campus, 170 Kessels Road, QLD 4111 | Brisbane, Australia Mobile: +61/0 410 896069<tel:+61/0%20410%20896069> | E-mail: greta.dalleluche@griffithuni.edu.au<mailto:greta.dalleluche@griffithuni.edu.au>