Dear MARMAM community, We are working on an international collaborative paper documenting harbor porpoise mating patterns globally. If you or your colleagues have photos, videos or other data on harbor porpoise aerial behavior or mating, please reach out us. Our goal is to document whether the conspicuous behavior that we described from San Francisco Bay in our 2018 paper (the male's rapid approach to the female's left side that often ends with the male becoming aerial) occurs in all harbor porpoise populations. Our results have shown that porpoise aerial behavior may be a sign of mating activity, and such observations could factor into decisions affecting potential breeding hotspots and the designation of marine protected areas. Our open access paper in Aquatic Mammals (https://doi.org/10.1578/AM.44.6.2018.620) is available here: 44_6_keener<https://www.aquaticmammalsjournal.org/index.php?option=com_hikashop&ctrl=product&task=download&file_id=915>. At the World Marine Mammal Conference in Barcelona, we presented a poster inviting collaborators, available here: https://www.marinemammalcenter.org/assets/pdfs/vetsci-stranding/scientific-c... All the best, Bill Keener (The Marine Mammal Center; keenerb@tmmc.org) Marc Webber (The Marine Mammal Center; webberm@tmmc.org) Dara Orbach (Texas A&M University - Corpus Christi; dara.orbach@tamucc.edu) Bill Keener Research Associate Cetacean Field Research Program KeenerB@tmmc.org<http://www.marinemammalcenter.org/> | C: 415.297.6139 | MarineMammalCenter.org<http://www.marinemammalcenter.org/> The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965