Researchers from the University of the Sunshine Coast have become the first to publish acoustic data that confirms the presence of the elusive dwarf minke whale in the southern Great Barrier Reef.
Lead author and UniSC marine biologist Isabel Taylor says the findings are surprising, as the species is typically found further north, so the information provides crucial baseline data for a region where traditional surveys are difficult.
"By listening instead of looking, we were able to detect species that might otherwise go unnoticed, including the first confirmed acoustic presence of dwarf minke whales in this region."
"The southern Great Barrier Reef is a migration highway, yet we've had very limited long-term monitoring to understand which species are there and when," Ms Taylor said.
"By listening instead of looking, we were able to detect species that might otherwise go unnoticed, including the first confirmed acoustic presence of dwarf minke whales in this region."
Over two years, scientists deployed underwater listening devices near Lady Elliot Island - the southernmost reef in the Great Barrier Reef Marine Park - to continuously monitor marine mammal activity without the need for boats or clear weather.
During the study, published in Marine Mammal Science, the devices recorded more than 1,600 hours of underwater sound and detected humpback whales, dwarf minke whales and several dolphin species, each using the area in different seasons and times of day.
Humpback whales dominated recordings between June and October, aligning with their migration and breeding activity, while dwarf minke whale calls were concentrated from May to August and were closely associated with ocean productivity.
Dolphins were heard year-round, particularly during daylight and twilight hours, suggesting the island plays an important role in their daily movement and feeding behaviour.
The study also found whale vocal activity declined when boats were present or wind noise increased, highlighting the sensitivity of whales to sound and the importance of protecting marine acoustic environments.
Professor Kathy Townsend and Dr Christine Dudgeon with the acoustic equipment used to record dwarf minke whales at southern Great Barrier Reef. Photo credit: Asia Armstrong
"Sound is the primary way whales and dolphins communicate and navigate," Ms Taylor said.
"Even relatively low levels of vessel noise can change how they use a habitat. Understanding this helps managers protect key migration corridors as tourism and ocean noise continue to grow."
"This technology means we can monitor biodiversity at scale and detect changes over time - a critical capability as the Great Barrier Reef faces increasing environmental pressures."
UniSC senior researcher Dr Dominique Potvin , who supervised the project, said passive acoustic monitoring offers a powerful, cost-effective way to fill knowledge gaps in Australia's offshore ecosystems.
"This technology means we can monitor biodiversity at scale and detect changes over time - a critical capability as the Great Barrier Reef faces increasing environmental pressures," Dr Potvin said.
"There's more research to do. Deploying the technology in deeper water on the eastern side of Lady Elliot Island would help researchers assess the presence of other species, including blue, fin and Bryde's whales, in the southern part of the reef," she said.
This research was made possible through funding from the Reef Trust Partnership between the Australian Government's Reef Trust and the Great Barrier Reef Foundation, the Queensland Government, Lendlease and the Fitzgerald Family Foundation.
