Cetacean occurrence near the South Shetland Islands based on long-term passive acoustic monitoring

Passive acoustic monitoring is an effective tool to investigate cetacean ecology, particularly in remote locations and over long time periods. Several baleen and toothed whale species occur in Antarctic waters, but knowledge of their year-round relative abundance, distribution, and seasonality is relatively sparse. Long-term, broadband recordings were collected near the South Shetland Islands between 2014 and 2016, and spatio-temporal patterns in cetacean acoustic occurrence were investigated at three different locations within this shelf break area. Cetaceans detected included blue (Balaenoptera musculus), fin (B. physalus), humpback (Megaptera novaeangliae), sperm (Physeter macrocephalus), and killer whales (Orcinus orca), as well as several unidentified species of beaked whales and dolphins. Overall detection rates of these species varied across the recording sites, and also showed strong seasonal trends. Sea ice dynamics will be explored as a possible driver for the shifts in seasonal relative abundance of cetaceans in this region of the Southern Ocean, and proximity to the Southern Antarctic Circumpolar Current Front (SACCF) will also be examined to evaluate differences in habitat use across the sites.