Dugong numbers rise in Queensland but calf count raises recovery concerns

An increase in dugong numbers spotted in key coastal areas in south-east Queensland has researchers feeling cautiously optimistic.

James Cook University (JCU) researchers conducted their second round of aerial surveys in Hervey Bay and Great Sandy Strait in 2024 to analyse how the vulnerable species was recovering after major flooding decimated seagrass meadows in 2022.

The joint study with TropWATER released last month reported positive population growth and wider geographic spread due to the revival of seagrass habitats in key zones.

But the low number of calves has raised concerns about whether the local population is truly on the path to recovery.

Australian Marine Conservation Society's Great Barrier Reef campaign manager Simon Miller said the report was an "important" measure for the local dugong population.

"Typically these surveys tend to happen every five years, so it was great to see the [federal] government provide funding to do another survey so soon," he said.

Two data-collection methods were used to calculate the dugong population: raw counts and abundance estimation.

The first technique involved observers in the aircraft taking note of the number of dugongs spotted, while the second procedure applied cross-correction factors to the raw data to gain an approximate population size.

These correction factors are applied because "there's a good chance if they're feeding at the bottom, or if the water is too deep and murky, you'll miss them," JCU's principal research officer Christophe Cleguer said.

According to the report, researchers initially counted about 109 dugongs in 2024 — a slight increase on the 103 dugongs noted in 2022.

The population change also aligned with the distribution of dugongs: in 2022, the marine mammals were mainly spotted in the central portion off Hervey Bay but had spread south towards the Great Sandy Strait in 2024.

"It is likely the result of seagrass on its way to recovery in these inshore areas," Dr Cleguer said.

JCU-TropWATER consulted with the Butchulla people, the traditional owners of the land from Burrum Heads to Rainbow Beach.

Butchulla Native Title Aboriginal Corporation chair Shawn Wondunna-Foley said the importance of protecting seagrass and yuangan –the Butchulla word for dugong — was clearly highlighted in the report.

"When we look after the seagrass, we look after the yuangan, and we look after sea country," Mr Wondunna-Foley said.

Calf concerns

Worries were raised about the small number of young dugongs counted during observations.

Only three calves were tallied in 2024, a decrease from the nine spotted in 2022.

But Dr Cleguer said there were biological reasons behind the low numbers.

"There is a time lag for dugongs; they need to recover and get healthy enough to reproduce calves," he said.

The researcher said further monitoring was needed to determine how nutritional stress was impacting their reproductive responses.

Mr Miller said the few calves were a "negative indication" for the dugong population.

"We're not seeing any evidence a lot of dugongs are coming back," he said.

Although Dr Cleguer maintained the belief that the new report showed the population was on the slow path towards recovery, he urged the public to remain cautious.

Future cross-collaboration 'beneficial'

JCU hopes to secure funding to conduct a third aerial survey into the dugong population stretching from the southern Great Barrier Reef to Moreton Bay next year.

But monetary constraints and unexpected weather events could cause significant time delays between studies being undertaken.

To avoid these potential gaps, Dr Cleguer said collaborating with local organisations would be "beneficial".

"They could survey using drones or vessels to give us some indication of dugong presence and movement on the local scale that can fit into the bigger picture," he said.

Mr Wondunna-Foley said the opportunity to work with researchers on improving water quality monitoring efforts and building the resilience of seagrass meadows "in a proactive and positive way" would be welcomed.

For people hoping to make a difference on a small scale, Mr Miller said reducing their boat's speed in areas populated by dugongs can have a big impact.

"It's important for people to respect slow zones, paying attention to their surroundings and really keeping an eye out for the incredible wildlife out there," Mr Miller said.