Dear MARMAM community, We are pleased to share our new publication on the long-term stability of Southern Hemisphere fin whale high-frequency components: Wöhle, S., Parker, L., Burkhardt, E., Van Opzeeland, I., & Schall, E. (2025). Shifts in Acoustic Signature of Southern Hemisphere Fin Whales: Declining Peak Frequency of High-Frequency Components. JASA Express Letters.https://doi.org/10.1121/10.0039500 Abstract Population-specific acoustic features are vital for using passive acoustic monitoring to study marine mammal populations in remote regions. Southern Hemisphere fin whale (Balaenoptera physalus) songs include region-specific high-frequency components, with the 86- and 99-Hz high-frequency components present in the Atlantic Sector of the Southern Ocean. Using long-term passive acoustic monitoring data, we show that, despite gradual interannual and intra-annual variabilities, these features remain distinct and recognizable across regions and years. Our findings support their use as reliable acoustic markers for monitoring fin whale populations, providing valuable insights into distribution and population structure. Please feel free to reach out with any questions or comments. Best wishes, Svenja Wöhle (on behalf of all co-authors) ____________________ Svenja Wöhle | PhD student (she/her) Ocean Acoustics Group, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research Klußmannstr. 3d, 27570 Bremerhaven Tel.: 0471-4831-2212 Email: svenja.woehle@awi.de