Ratsimbazafindranahaka, M. N., Huetz, C., Saloma, A., Andrianarimisa, A., Charrier, I., and Adam, O. (2025). A Descriptive Breakdown of Pre- and Post-Nursing Behavioral Sequences in Humpback Whale Mother-Calf Pairs on a Calving Ground, Marine Mammal Science, 42, no. 1: e70084

Ratsimbazafindranahaka, M. N., Adam, O., Huetz, C., Reidenberg, J. S., Saloma, A., Andrianarimisa, A., and Charrier, I. (2025). Behavioral data suggest adaptive buoyancy control during shallow dives in humpback whales, Journal of Experimental Biology

Dubus, G., Torterotot, M., Béesau, J., Dupont, M., Gros-Martial, A., Michel, M., Morin, E., Nguyen Hong Duc, P., Raumer, P.-Y., Adam, O., Samaran, F., and Cazau, D. (2025). APLOSE: A web-based annotation platform for underwater passive acoustic monitoring. SoftwareX, vol. 29, 102055

Doh, Y., Cazau, D., Lamaj, G., Mercado, E., Reidenberg, J. S., Jacobsen, J. K., Perazio, C. E., Ecalle, B., and Adam, O. (2025). Study of non-linearities in humpback whale song units, J. Mar. Sci. Eng. 2025, 13, 215

Dubus, G., Cazau, D., Torterotot, M., Gros-Martial, A., Nguyen Hong Duc, P., and Adam, O. (2024). From citizen science to AI models: Advancing cetacean vocalization automatic detection through multi-annotator campaigns, Ecological Informatics, vol 81, 102642

Underwater acoustic soundscapes are composed of sounds originating from human activities (anthrophony), geophysical processes (geophony), and biological sources (biophony). The latter category includes, for example, sounds produced by shrimp, certain fish species, and marine mammals. It is these biological sounds that I have been studying as part of my research in bioacoustics since the early 2000s. My goal is to better understand cetacean culture—including their social interactions, behaviors, and learning processes—as well as their habitats, through the study of vocal communication, the effects of acoustic propagation in the marine environment, and the contribution of human-generated noise to underwater soundscapes.

I have studied several cetacean species. In particular, I have led multiple research projects on humpback whales, including the analysis of their songs and social sounds, detailed investigations of their habitats, long-term monitoring programs in the Caribbean and the Indian Ocean, and studies revealing the interactions between mothers and calves.

For sperm whales, I have investigated their clicks for detection and localization purposes. More recently, my work has focused on codas—temporal sequences of clicks—to identify social clans and track their movements using passive acoustic monitoring and linguistic-inspired analytical approaches.

To conduct this research, I use a variety of tools, including hydrophones, aerial drones, and Argos satellite tags. Since 2015, we have also deployed multi-sensor tags directly on cetaceans. These devices are equipped with a waterproof camera, hydrophone, inertial measurement unit, and temperature sensor, enabling the simultaneous collection of behavioral, acoustic, and environmental data.

To monitor groups of cetaceans, we developed *Cétoscope*, an innovative observation platform featuring a tetrahedral structure with a 720-degree camera at its center and hydrophones positioned at its vertices. More recently, I have also conducted playback experiments, broadcasting sounds to cetaceans in order to better understand their responses to anthropogenic noise, particularly noise generated by maritime traffic.

I have developed algorithms to estimate underwater acoustic propagation losses and to automatically detect and localize cetaceans using passive acoustic monitoring. I have also characterized and classified cetacean vocalizations and other underwater acoustic events using advanced signal-processing techniques, including spectral correlation, wavelet transforms, Hilbert–Huang transforms, and, more recently, deep-learning approaches.

Artificial intelligence methods hold great promise for bioacoustic research but require large, annotated datasets. To address this challenge, we developed an online platform in collaboration with ENSTA Brest, enabling citizen scientists to label acoustic recordings as part of participatory science projects.