Dear MARMAM readers, My colleagues and I are organizing a workshop within the European Cetacean Society conference 2022, entitled Long Term Ecological Data Series in cetaceans: essential but challenging! In recent years, Long Term Ecological Research have become increasingly important to understand ecosystem complexity, identify natural variability, and allow detection of rare events or disturbances caused by anthropogenic or natural changes. Ecological systems usually operate at large temporal scales, so their impact might be overlooked when analysing short periods of data, which usually provide a good understanding of the time window considered, but a weak and often misunderstood general context. Collecting long-term wildlife occurrence data is challenging, but opportunistic platforms often provide a cost-effective method to obtain information over long periods and defined areas, and can effectively complement data collected in standardized and/or dedicated surveys. Nevertheless, as it is well known, maintaining and keeping LTER is a challenging process, due to many potential inconveniences such as lack of funding to maintain the initiatives. We want to encourage researchers to share their experience and outputs of LTE programs for cetaceans, especially those based on citizen science. We aim to showcase some of the different initiatives that exist nowadays, and share experiences, challenges and solutions to keep these initiatives alive. Looking forward to a friendly environment where we all can learn from each other 😊 Date: 4th April, 9-13h CET Where? ONLINE via Zoom. Registration open (free of charge!) More info, including registration and preliminary program: https://sites.google.com/view/lter-workshop-ecs2022/ Looking forward to see you there! Laura González García, PhD. Universidade dos Açores