The proposed Marine Protected Areas could make a difference for baleen whales in Antarctica

etacean studies in Antarctic marine ecosystems face climatic/logistical obstacles, increasing the knowledge gap on population dynamics and spatiotemporal distributions. Using multitemporal data obtained onboard cruises of opportunity, we applied Kernel Density Estimation function to answer: 1) What are the distribution areas and overlap of Balaenoptera physalus, Megaptera novaeangliae, Balaenoptera musculus, and Balaenoptera bonaerensis over the last decade? 2) To what extent do the occurrence records of the species overlap with current and proposed Marine Protected Areas (MPAs)?. Results show a latitudinal gradient with regional overlaps (between parallels 60° and 65°S) and species segregations. M. novaeangliae shows a wide latitudinal distribution (55°- 70°S); in contrast, B. physalus shows distribution areas associated primarily with northern latitudes (55°S - 65°S). B. musculus occurs predominantly south of the Antarctic Circle (55° - 77°S), and B. bonaerensis, with the broadest range (60°–70°S), is also linked to areas south of the Circle. Although the South Orkney Islands Southern Shelf MPA (SOISS MPA) provides partial protection (B. physalus 0.8%, M. novaeangliae 7.5%, B. musculus 0%, B. bonaerensis 0.1%), overlap increases substantially when considering the proposed Antarctic Peninsula and Southern Scotia Arc MPA (D1MPA) and Weddell Sea MPA (WSMPA) Phase 1: B. physalus 49.7%, M. novaeangliae 62.7%, B. musculus 39.3%, and B. bonaerensis 59.3%. Updating knowledge on cetacean distributions and conservation area coverage can help reduce knowledge gaps and improve the ability of international organizations to adapt mitigation and conservation actions.