RV Investigator Voyage IN2019_V03 Cetaceans and seabirds along the Indian Ocean 110°E meridian (Second International Indian Ocean Expedition (IIOE-2) expedition)

The aim of this study, as part of a large number of related studies, was to examine the occurrence of cetaceans and seabirds along the 110◦E meridian from temperate to tropical waters (39.5–11.5◦S). Cetaceans and seabirds were actively scanned for across a four-week period spanning austral autumn to winter. Acoustic recordings of vocalising cetaceans weremade using directional and omnidirectional sonobuoys (n = 87 deployments). In total, seven cetacean sightings (six baleen whale, one toothed whale), 186 seabird sightings and 225 cetacean acoustic detections were recorded. A total of 22 seabird species were sighted, including, petrels, albatrosses, tropicbirds, terns, shearwaters, boobies, frigatebirds, gannets, gulls, skuas and prions.