01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0024 |
| Title of Abstract | Occurrence of cetaceans and seabirds along the Indian Ocean 110E meridian from temperate to tropical waters |
| Authors | Curt Jenner, Alicia Sutton*, Micheline Jenner |
| Organisation | Centre for Whale Research (Western Australia) |
| Address | Unit 1 23 Ocean Drive North Coogee, Western Australia, Australia Pincode: 6162 E-mail: curt@cwr.org.au |
| Country | Australia |
| Presentation | Oral |
| Abstract | 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 110E meridian from temperate to tropical waters (39.5⿿11.5S). Cetaceans and seabirds were actively scanned for across a four-week period spanning austral autumn to winter. Acoustic recordings of vocalising cetaceans were made using directional and omnidirectional sonobuoys (n = 87 deployments). In total, seven cetacean sightings, 186 seabird sightings and 225 cetacean acoustic detections were recorded. Pygmy blue whales were detected across Subantarctic to Tropical Surface Waters, and were the most commonly detected cetacean. There was some delineation in other cetaceans: the spot call was detected in Subantarctic and Subtropical Surface Water (south of 23S); fin whales in Subtropical Surface Water (between 23 and 30.5S); and Antarctic minke whales in Tropical Surface Water (between 14 and 23S). Data were not collected on cetaceans during IIOE-1, so data here represent baseline occurrence along 110E for future studies. A total of 22 seabird species were sighted, including, petrels, albatrosses, tropicbirds, terns, shearwaters, boobies, frigatebirds, gannets, gulls, skuas and prions. Soft-plumaged petrels (Pterodroma mollis) were observed across all water masses and were the most commonly sighted seabird. There was some delineation of seabird species; albatrosses were sighted south of the Subtropical Front (south of 32S); flesh-footed shearwaters (Ardenna carneipes) in Subantarctic and Subtropical Surface Waters (south of 27S); and tropicbirds in Tropical Surface Water (north of 20S). The occurrence of highly mobile species is particularly important to investigate as the waters in the eastern Indian Ocean have been warming faster than in the Pacific and Atlantic Oceans. |
| Are you part of IIOE-2 endorsed project | yes |
| Endorsed Project Number | IIOE2-IN2019_V03 |
| Keywords | Whales, seabirds, Indian Ocean, acoustic detection |
| For Awards | no |