Dear MARMAM community, We are pleased to announce the publication of Iceland’s first matrilineal catalogue for killer whales. A total of 38 matrilines could be established from 737 encounters of the most-sighted individuals in West Iceland between 2014 and 2023, using identification images as far back as 2006. Only matrilines of the most-documented individuals (≥15 encounters) spotted over several years (≥6 years; at least one encounter per year) and between 2014 and 2023 in West Iceland were included in the analysis. Both alive and deceased individuals were included in the study, and details were compiled on the year of birth (and year of death, if applicable), sex, and, if possible, maternal ancestry. The matrilineal catalogue is a joint project by Orca Guardians Iceland and the West Iceland Nature Research Centre (Náttúrustofa Vesturlands), with the great support of Láki Tours whale watching and contributions from whale watching guides, researchers, and members of the public. It is an addition to the regularly updated, full photo-identification catalogue maintained by Orca Guardians Iceland and the West Iceland Nature Research Centre. You can access the matrilineal catalogue here: https://orcaguardians.org/wp-content/uploads/2023/04/Matrilineal-catalogue-o... You can also find our previous catalogues here: http://orcaguardians.org/orca-id-catalogues/ For further enquiries please e-mail: info@orcaguardians.org Best, Marie Mrusczok