Demography of an ice-obligate mysticete in a region of rapid environmental change

• Published in: Royal Society Open Science
• Main Authors: Pallin, L., Bierlich, K. C., Durban, J., Fearnbach, H., Savenko, O., Baker, C. S., Bell, E., Double, M. C., de la Mare, W., Goldbogen, J., Johnston, D., Kellar, N., Nichols, R., Nowacek, D., Read, A. J., Steel, D., Friedlaender, A.
• Other Authors: Office of Polar Programs, the Dr. Earl H. Myers & Ethel M. Myers Oceanographic & Marine Biology Trust, World Wildlife Fund, The International Whaling Commission's Southern Ocean Research Partnership, OneOcean Expeditions, Hurtigruten cruises, Ministry of Education and Science of Ukraine's State Institution National Antarctic Scientific Center Special-Purpose Research Program in Antarctica, NSF LTER, State of the State Institution National Antarctic Scientific Center, National Science Foundation Graduate Research Fellowship Program, UC Santa Cruz's Graduate Division and department of Ecology and Evolutionary Biology, Lindblad Expeditions-National Geographic Conservation Fund, Dr. Anita North
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2022
• Subjects: Multidisciplinary; Antarc*; Antarctic; Antarctic Peninsula; Balaenoptera bonaerensis
• Online Access: http://dx.doi.org/10.1098/rsos.220724; https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.220724; https://royalsocietypublishing.org/doi/full-xml/10.1098/rsos.220724

Antarctic minke whales ( Balaenoptera bonaerensis , AMW) are an abundant, ice-dependent species susceptible to rapid climatic changes occurring in parts of the Antarctic. Here, we used remote biopsy samples and estimates of length derived from unoccupied aircraft system (UAS) to characterize for the first time the sex ratio, maturity, and pregnancy rates of AMWs around the Western Antarctic Peninsula (WAP). DNA profiling of 82 biopsy samples (2013–2020) identified 29 individual males and 40 individual females. Blubber progesterone levels indicated 59% of all sampled females were pregnant, irrespective of maturity. When corrected for sexual maturity, the median pregnancy rate was 92.3%, indicating that most mature females become pregnant each year. We measured 68 individuals by UAS (mean = 8.04 m) and estimated that 66.5% of females were mature. This study provides the first data on the demography of AMWs along the WAP and represents the first use of non-lethal approaches to studying this species. Furthermore, these results provide baselines against which future changes in population status can be assessed in this rapidly changing marine ecosystem.