Dear MARMAM community, On behalf of my coauthors, I am pleased to share our recent article published in JASA Express Letters. Simone Antichi, Maia Austin, Laura J. May-Collado, Jorge Urbán R, Sergio Martínez-Aguilar, Lorena Viloria-Gómora; Differences in the whistles of two ecotypes of bottlenose dolphins from the Gulf of California. JASA Express Lett 1 May 2023; 3 (5): 051201. Abstract Intraspecific whistle variation in dolphins has been explained in the context of geographical isolation, soundscape, and social structure. Whistles of two ecotypes of bottlenose dolphins from La Paz Bay, Gulf of California, were analyzed. Both ecotypes showed similar whistle contours. However, they could be identified by contour maximum frequency which was predominantly above 15 kHz for oceanic dolphins and below 15 kHz for coastal dolphins. The different whistle frequencies of the two ecotypes could result from differences in group size and acoustic characteristics of their respective habitats, suggesting potential future passive acoustic monitoring applications. The paper and can be downloaded at: https://doi.org/10.1121/10.0019502 If you have any questions regarding our work please contact me at: santichi_20@alu.uabcs.mx Best regards, Simone Antichi -- PhD candidate Departamento de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, La Paz, Baja California Sur, Mexico. email: santichi_20@alu.uabcs.mx cell: +52 612 228 5196