Frozen verses: Antarctic minke whales ( Balaenoptera bonaerensis) call predominantly during austral winter

• Published in: Royal Society Open Science
• Main Authors: Filun, Diego, Thomisch, Karolin, Boebel, Olaf, Brey, Thomas, Širović, Ana, Spiesecke, Stefanie, Van Opzeeland, Ilse
• Other Authors: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Scholarship Asociacion Nacional de Investigacion y Desarrollo de Chile (ANID)- Deutscher Akademischer Austauschdienst
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2020
• Subjects: Antarctic; Austral; Southern Ocean; Weddell; Weddell Sea; Antarc*; Antarctic Minke whale; Balaenoptera bonaerensis; minke whale; ice covered areas
• Online Access: http://dx.doi.org/10.1098/rsos.192112; https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.192112; https://royalsocietypublishing.org/doi/full-xml/10.1098/rsos.192112

The recent identification of the bio-duck call as Antarctic minke whale (AMW) vocalization allows the use of passive acoustic monitoring to retrospectively investigate year-round spatial-temporal patterns in minke whale occurrence in ice-covered areas. Here, we present an analysis of AMW occurrence patterns based on a 9-year passive acoustic dataset (2008–2016) from 21 locations throughout the Atlantic sector of the Southern Ocean (Weddell Sea). AMWs were detected acoustically at all mooring locations from May to December, with the highest presence between August and November (bio-duck calls present at more than 80% of days). At the southernmost recording locations, the bio-duck call was present up to 10 months of the year. Substantial inter-annual variation in the seasonality of vocal activity correlated to variation in local ice concentration. Our analysis indicates that part of the AMW population stays in the Weddell Sea during austral winter. The period with the highest acoustic presence in the Weddell Sea (September–October) coincides with the timing of the breeding season of AMW in lower latitudes. The bio-duck call could therefore play a role in mating, although other behavioural functions of the call cannot be excluded to date.