A team of Australian scientists has successfully interpreted how the Burrunan dolphin, a critically endangered dolphin species, communicates using unique vocal patterns and sounds.
The discovery provides crucial data to help protect and monitor the species more effectively to support broader conservation efforts, according to a statement from Curtin University and the Marine Mammal Foundation published on the Science Media Exchange website on Wednesday (July 16).
The Burrunan dolphin, officially recognized as a separate species in 2011, is found only in two small populations resident in Port Phillip Bay and the Gippsland Lakes, both in Victoria, Australia, with fewer than 250 remaining, researchers said.
This species is critically endangered due to habitat loss, pollution, ship traffic, and low genetic diversity.
Marine scientists have completed their first in-depth analysis of Burrunan dolphin communication.
They interpreted 21 hours of underwater sound recordings from 2016 to 2023, and identified more than 12,900 unique vocalizations, including 3,400 whistles and 9,500 burst-pulse sounds.
Researchers identified six types of Burrunan dolphin whistles, with the "upsweep" and "convex" types being the most frequently used.
Of the four categories of burst-pulse sounds, the "bark" type dominates, while "squeak", "creak", and "moan" are also used in their vocal repertoire.
Both populations have similar calls, but environmental factors cause Burrunan dolphins in Port Phillip Bay to have a more uniform vocal repertoire than Burrunan dolphins in the Gippsland Lakes, the study said.
Studying Burrunan dolphin calls is crucial for monitoring and protecting this ecosystem indicator, as passive acoustic data allows for continuous monitoring when visual surveys are limited, the study said.
