A decades-long study has found endangered whales are having fewer babies. 

The Australian population of southern right whales is calving less frequently and fewer whales visited coastlines this whale season than expected, putting further pressure on the already endangered species, according to research. 

Using drones, researchers captured unique encounters that the team had never observed before including two calves suckling from one female, as well as interactions between whales and sharks, playful sea lions and dolphins.

For more than 30 years, Curtin University researchers have conducted annual surveys of southern right whales in the coastal waters off southern Australia.

Researcher Dr Claire Charlton says that although the number of southern right whales has risen from just 300 in the Southern Hemisphere to almost 3,000 in the Australian population, the lower-than-expected counts in recent years and increased calving intervals is a cause for concern.

“Instead of having a calf every three years – on average, the majority of whales are now only having a calf every four or five years,” Dr Charlton said.

“In other parts of the southern right whale species range in Argentina, Brazil and South Africa, increased calving intervals has been linked to climate change and slower recovery rates, so it’s vital we understand how climate change and human activities may impact their ongoing recovery.

“We know the key threats to whale populations are habitat disruption, underwater noise strikes from marine vessels and entanglement, so we must do everything we can - including legislative protection - to ensure their expansion into new habitats and continued recovery over time.

“The commitment of South Australia’s Labor Government to fully supporting the World Heritage status of the Great Australian Bight so that the whales are protected forever, and to explore establishing Whale Nursery Protection Areas where whales come close to shore with their young, are essential steps in supporting this recovery.”

Curtin University recently teamed up with mining magnate Andrew ‘Twiggy’ Forrest’s philanthropic investment company Minderoo Foundation, and the Yalata Anangu Aboriginal Corporation, which has offered access to the Head of Bight area and accommodation for staff for a period of two months each year in-kind.

Project founder Dr Steve Burnell, who began the research in 1991, said the research team was grateful to Minderoo Foundation for providing funding to ensure the continuation of one of the very few, long-term population studies of large marine mammals in the world.

“The long-term Southern Right Whale Study is unique and irreplaceable, with the national and international value of the unbroken 30-plus year dataset growing each year. It is vital for informing conservation management of this endangered species across the Australian Marine Park Networks, and for understanding the marine ecosystems, right whales rely on,” Dr Burnell said.

Yalata Aboriginal Community chief David White says the southern right whales live in the coastal waters off the land of the Far West Coast Aboriginal People.

“The shallow, sandy and protected bays along this stretch of coast provide ideal habitat for the southern right whales that migrate to Australian waters between May and November each year, to mate, calve, nurse their young, rest and socialise,” Mr White said.

Dr Charlton said that whales are an indicator species for the health of our marine environment, so the Southern Right Whale Study can provide insights into the effects that climate change is having on threatened marine species and the Southern Ocean.

“As the southern right whale population recovers from near extinction due to commercial whaling, the numbers along our coasts are increasing. Numbers have increased from as few as 300 in the Southern Hemisphere to almost 3,000 in the Australian population,” Dr Charlton said.

“Studies show that major calving grounds like the Head of the Great Australian Bight are reaching saturation capacity, and numbers are increasing elsewhere with biologically important areas emerging and becoming increasingly important along the southern coasts, such as Encounter Bay and Sleaford Bay in South Australia, Geographe Bay in Western Australia and Portland in Victoria.”