Dear all, On-behalf of my co-authors, I am pleased to inform you our new publication in Polar Biology "Annual variation of oceanographic conditions changed migration timing of bowhead whales Balaena mysticetus in the southern Chukchi Sea". Tsujii, K., Otsuki, M., Akamatsu, T., Amakasu, K., Kitamura, M., Kikuchi, T., Fujiwara, A., Shirakawa, H., Miyashita, K. & Mitani, Y. (2021). Abstract The Chukchi Sea environment changes considerably in physical and biological conditions, driven by the expanding volume of warm Pacific summer water. These environmental changes can affect the migration timing of baleen whales in the southern Chukchi Sea. However, few studies have been conducted in this area to determine the migration timing of bowhead whales (Balaena mysticetus), the only baleen whale species endemic to the Arctic region. In this study, we conducted a fixed passive acoustic monitoring of bowhead whales in the southern Chukchi Sea from July 2012 to October 2015 and compared the occurrence patterns of vocalizations to physical and biological environmental factors. Bowhead whale calls were detected in fall/winter and spring during the ice-freezing and retreating periods, respectively. The fall migration timing of bowhead whales through the southern Chukchi Sea was delayed in the years when the timing of sea ice formation was late, and it formed increasingly later in the years 2013, 2014, and 2012, in that sequence. Moreover, the sea surface temperature decreased before freeze-up, which affected the timing of fall migration of bowhead whales. There was no clear relationship between the occurrence of bowhead whale calls and the abundance of prey, especially in spring, suggesting that most bowhead whales use the southern Chukchi Sea as a corridor during their spring northward migrations. However, the occurrence of bowhead whales and high abundance of zooplankton in October–November present the possibility that bowhead whales expand their feeding area in the southern Chukchi Sea. Here is the link to a view-only version of our paper: https://rdcu.be/cACsY If you have a request for a copy of the PDF, please email Koki Tsujii <kou1114t@gmail.com>, the first author. Thank you! Yoko -- -- 三谷曜子　Yoko Mitani 京都大学野生動物研究センター　海獣班 〒606-8203　京都市左京区田中関田町2-24 関田南研究棟 Email: mitani.yoko.3w@kyoto-u.ac.jp Yoko MITANI Ocean Mammal Team Wildlife Research Center, Kyoto University 2-24 Tanaka-Sekiden-cho, Sakyo, Kyoto, 606-8203, Japan E-mail: mitani.yoko.3w@kyoto-u.ac.jp