Dear colleagues, We are pleased to announce the publication of our review of hearing in two focal cetacean species exposed to Ocean Economy developments in the Indian Ocean: Plön, S. and N. Roussouw. 2022. Focussing on the receiver- hearing in two focal cetaceans exposed to Ocean Economy developments. *Applied Acoustics 196:108890.* Abstract: Plans for large-scale economic developments in the Indian Ocean, including increased shipping, oil and gas exploration and offshore mining, have resulted in concerns about potential impacts on cetaceans. Two species of particular interest are the resident, coastal Indian Ocean humpback dolphin *Sousa plumbea* and the migratory humpback whale *Megaptera novaeangliae*. As the two species belong to different hearing groups (high-frequency odontocetes vs low-frequency mysticetes), we review the available literature on their differing hearing mechanisms (physiology), specialities and sensitivities here as there is a lack of data available for these two species in the Indian Ocean region. The reviewed information included audiogram data, species-specific frequencies and sensitivity ranges, ear morphology and adaptations for hearing in their respective groups where available. For odontocetes, most information stems from animals under human care, while for mysticetes bioacoustic measurements, like audiograms, are more difficult to access, resulting in a lack of data on hearing for *M. novaeangliae*. Our review highlights an absence of baselines upon which to measure future impacts from anthropogenic developments in the Indian Ocean and we suggest future work to address this. Our work is not only timely in view of the planned anthropogenic developments in the Indian Ocean, but also has wider implications in the global context as cumulative impacts on cetaceans grow due to increased international demand for resources and associated Ocean Economy developments. You can access the pdf for free at the following link for the next 50 days: https://authors.elsevier.com/a/1fIeS_,YInY-8 Alternatively, please e-mail me for a pdf copy or any queries. Kind regards, Stephanie Assoc. Prof. Stephanie Plön Medical Virology Department of Pathology Stellenbosch University and Bayworld Centre for Research and Education (BCRE) Port Elizabeth South Africa Cell: +27-76-3791067 https://www.researchgate.net/profile/Stephanie_Ploen *https://iucn-csg.org/stephanie-plon-phd/ <https://iucn-csg.org/stephanie-plon-phd/>*