Dear MARMAM community, My co-authors and I are pleased to share our recent open-access publication in Animals reporting a successful rescue operation involving a juvenile humpback whale (Megaptera novaeangliae) trapped upstream of a tidal power station in Brittany, France. Olhasque, O., Carpentier, L., Duchemin, M., Jung, J.-L., Dars, C., Boucard, F., Labrut, S., & De Weerdt, J. (2025). Successful Rescue of a Juvenile Humpback Whale (Megaptera novaeangliae) Trapped Upstream of the Rance Tidal Power Station, Brittany, France. Animals, 15(23), 3503. https://doi.org/10.3390/ani15233503 The full article is available in open access at: https://www.mdpi.com/2076-2615/15/23/3503 ABSTRACT Rescue operations involving baleen whales trapped in dammed environments are difficult to perform successfully, yet increasingly relevant under growing coastal development. We report on a two-day (9–10 February 2023) rescue of a juvenile humpback whale trapped upstream of the Rance Tidal Power Station (TPS) in Brittany, France, providing rare peer-review evidence on response strategies in highly engineered estuaries. A collaborative, non-invasive strategy was implemented by adjusting water levels and creating artificial tidal currents to prevent the whale from stranding and to guide the individual back to open water. Approximately 100 people were mobilized as part of the rescue operation. This paper describes a detailed spatiotemporal account of the whale’s movements and a chronological record of the actions taken by the rescue team. After several attempts to guide it out, rescue efforts enabled its successful exit from the estuary on the second day of operations, and it was not subsequently reported stranded along the French coast. This case demonstrates the value of rapid multidisciplinary coordination between the French National Stranding Network (composed of marine scientists, veterinarians and local correspondents), local organizations, the local marine biology station, international marine mammal experts, national institutions, authorities and a tidal energy operator. Beyond documenting an unusual event, this paper provides operational lessons, highlighting (i) the adaptative management of a TPS as a guidance tool, (ii) the prioritization of animal welfare and responders’ safety, (iii) the effective public and media management and (iv) the involvement of trained volunteers during the rescue, promoting environmentally responsible behavior. These insights are transferable to other cases to inform future baleen whales rescue protocols in anthropogenic environments. All the best, Oihana Olhasque Scientific director - Association AL LARK PhD student at La Rochelle University/CNRS - Observatoire PELAGIS - UAR 3462 [cid:f00225e1-7c0e-4c15-ad58-d722a25fb87f][cid:cb5e0120-db97-4c16-82bd-93942fe4c10e] Association AL LARK Découverte du milieu marin, étude des cétacés et échouages en Ille et Vilaine. 50, rue Pierre et Marie Curie 35260 Cancale www.al-lark.org<http://www.al-lark.org/> contact@al-lark.org<mailto:contact@al-lark.org> 02.57.64.04.40 ou 06.78.71.41.09 Association loi 1901 reconnue d’intérêt général concourant à la défense de l’environnement naturel, Association éducative complémentaire de l’enseignement public agréée par l’académie de Rennes, Association agréée Jeunesse et Éducation populaire, Membre de France Nature Environnement Bretagne.