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

• Published in: Royal Society Open Science
• Main Authors: L. Pallin, K. C. Bierlich, J. Durban, H. Fearnbach, O. Savenko, C. S. Baker, E. Bell, M. C. Double, W. de la Mare, J. Goldbogen, D. Johnston, N. Kellar, R. Nichols, D. Nowacek, A. J. Read, D. Steel, A. Friedlaender
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2022
• Subjects: antarctic minke whale; progesterone; demography; pregnancy; climate change; photogrammetry; Science; Q; Antarctic; Antarctic Peninsula; The Antarctic; Antarc*; Antarctic Minke whale; Balaenoptera bonaerensis; minke whale
• Online Access: https://doi.org/10.1098/rsos.220724; https://doaj.org/article/df1f2a88eeab4e0f9a1ccce5b3ea6e90

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.