Dear Colleagues, On behalf of myself and my co-authors, we are excited to share the following paper: *First characterization of vocalizations and passive acoustic monitoring of the vulnerable African manatee (Trichechus senegalensis)* Athena M. Rycyk, Clinton Factheu, Eric A. Ramos, Beth A. Brady, Mumi Kikuchi, Hannah F. Nations, Karianne Kapfer, Cecilia M. Hampton, Emily R. Garcia, and Aristide Takoukam Kamla *Abstract* Even among the understudied sirenians, African manatees (*Trichechus senegalensis*) are a poorly understood, elusive, and vulnerable species that is difficult to detect. We used passive acoustic monitoring in the first effort to acoustically detect African manatees and provide the first characterization of their vocalizations. Within two 3-day periods at Lake Ossa, Cameroon, at least 3367 individual African manatee vocalizations were detected such that most vocalizations were detected in the middle of the night and at dusk. Call characteristics such as fundamental frequency, duration, harmonics, subharmonics, and emphasized band were characterized for 289 high-quality tonal vocalizations with a minimum signal-to-noise ratio of 4.5 dB. African manatee vocalizations have a fundamental frequency of 4.65 ± 0.700 kHz (mean ± SD), duration of 0.181 ± 0.069 s, 97% contained harmonics, 21% contained subharmonics, and 27% had an emphasized band other than the fundamental frequency. Altogether, the structure of African manatee vocalizations is similar to other manatee species. We suggest utilizing passive acoustic monitoring to fill in the gaps in understanding the distribution and biology of African manatees. The Journal of the Acoustical Society of America 150, 3028 (2021) https://doi.org/10.1121/10.0006734 Please feel free to contact me with any questions! Best regards, Athena Rycyk arycyk@ncf.edu -- *Athena Rycyk, Ph.D. *(she/her) New College of Florida Assistant Professor of Biology & Marine Science 5800 Bay Shore Rd. Sarasota, FL 34243-2109