SYDNEY, July 16 (Xinhua) -- Australian scientists have uncovered how the critically endangered Burrunan dolphin communicates, revealing unique sounds and vocal patterns.
The discovery provides essential data to help protect and monitor the species more effectively, supporting broader conservation efforts, said a statement from Curtin University and the Marine Mammal Foundation published on the Science Media Exchange website on Wednesday.
The Burrunan dolphin, formally recognized as a distinct species in 2011, is found only in two small resident populations in Port Phillip Bay and the Gippsland Lakes, both in Victoria, Australia, where fewer than 250 individuals remain, said researchers.
The species is critically threatened by habitat loss, pollution, vessel traffic and low genetic diversity.
Marine scientists completed the first in-depth analysis of Burrunan dolphin communication, decoding 21 hours of underwater recordings from 2016 to 2023, and identified over 12,900 unique vocalizations, including 3,400 whistles and 9,500 burst-pulse sounds.
Researchers identified six whistle types in Burrunan dolphins, with "upsweep" and "convex" being the most frequent. Of four burst-pulse sound categories, "barks" dominate, while squeaks, creaks, and moans are also used in their vocal repertoire.
Both populations share similar calls, but environmental factors lead Port Phillip Bay dolphins to have a more uniform vocal repertoire than those in Gippsland Lakes, the study showed.
Studying Burrunan dolphin calls is key for monitoring and protecting this ecosystem indicator, as passive acoustic data enables ongoing tracking when visual surveys are limited, it said. ■
