Dear colleague, We are glad to announce the launch of the BioDCASE 2025 challenge<https://biodcase.github.io/>, where we have designed task 2<https://biodcase.github.io/challenge2025/task2> dedicated to the detection of large baleen whales from Antarctica based on Passive Acoustic Monitoring. For the colleagues who want to develop/use AI models (to put it one word..), we kindly invite you to participate in the challenge by developing any kind of models that answer the task specifications. As in any data challenge, this is an opportunity for our community to compare models in a FAIR way and thus contribute to build altogether a genuine state of the art in marine bioacoustics. All modalities are described on the task page presentation. For the colleagues who don't want to develop/use any AI model (especially within the tight time period we can understand..), you can also take part in the challenge through the most popular analysis method of any bioacoustician.. manual annotation ! Indeed, in addition to the classical data challenge, we will organize a "challenge" on comparing the results of different annotators .. our multi-annotator campaign has already started, you can join it whenever you want! The amount of data to annotate is totally adjustable on your availability.. especially if you are a marine bioacoustician, annotating even only a few spectrograms would already be very precious for this study.. More globally, if you are interested in this kind of collaborative research initiative but you don't have time to participate this time, please don't hesitate to contact us to see how you could be involved in this project in the near future! It is our very first edition, everything is just starting.. All the best, Dorian Cazau on behalf of the Organization team of BioDCASE - Task 2 Associate professor in Ocean data science * ENSTA<https://www.ensta-bretagne.fr/fr> | Institut Polytechnique de Paris<https://www.ip-paris.fr/> * Lab-STICC, UMR CNRS 6285<https://labsticc.fr/en/departments/ia-ocean> * OSmOSE<https://osmose.ifremer.fr/>