October 22, 2024

New research uncovers the mysteries of the elusive Bryde’s whales

Citizen scientists and whale watchers help researchers capture new images of large whales in NSW waters

A new study has for the first time revealed unique insights into the behaviour, movements, and feeding patterns of the elusive Bryde’s whale, a species that was previously thought to be found only in tropical waters.

Dr Katharina Peters, from the University of Wollongong’s (UOW) Marine Vertebrae Ecology Lab, was part of a team of scientists and citizen scientists who took part in the study, led by Dr Vanessa Pirotta of Macquarie University. The paper, which provides vital insights that can help inform policies to better protect these marine mammals in Australian waters, was published in The New Zealand Journal of Marine and Freshwater Research last week.

Bryde’s whales, pronounced ‘broodus’, are the least known species of larges whale typically found in warm coastal waters around the world.

A member of the baleen whale family, Bryde’s whales share similarities with blue whales and humpback whales and can reach up to 16 metres in length.

Dr Peters, whose research lies at the nexus of animal behaviour, evolutionary biology, and conservation, said Bryde’s whales have been a something of a mystery to marine scientists for many years.

“While they occur in New Zealand, South African and South American waters, there has been little evidence about where they go, how they behave, and how they forage for food in Australian waters,” she said.

“Although there are some old whaling records, rescue cases, and a few observations, we still know very little about Bryde’s whales.”

Using information gleaned from citizen scientists and whale-watching operators, including drone footage and photography, the scientists from Macquarie University, UOW, Southern Cross University, and New Zealand’s Massey University pieced together the puzzle of the Bryde’s whales, discovering they might stay in Australian waters all year round with parts of the east coast potentially a nursery for Bryde’s whale calves. 

The study observed Bryde’s whales hunting for food 27 times at seven locations in New South Wales and Queensland, in both deep and shallow waters. The furthest north sighting was at K'gari (Fraser Island) in Queensland, and the furthest south was at Tura Beach on the NSW South Coast.

These whales were seen feeding in groups around schools of fish, sometimes together with dolphins and sharks.

Drone footage captured Bryde’s whales appearing to ride the surf in waters less than 10 metres deep, using wave momentum to help them feed on schools of fish.

“We observed whales moving with the surf as they fed, sometimes holding their mouths open for extended periods while they were skimming the surface,” said Dr Pirotta.

“This ‘surfing’ behaviour hasn’t been documented before in Bryde’s whales and it shows just how adaptable they are in gathering coastal food sources.”

Dr Peters said the work of citizen scientists, including whale watching operations on the Far South Coast, was integral to the project.

“Marine scientists cannot be everywhere at once and there is so much marine activity and so much ocean to cover,” Dr Peters said. “Field work is fundamental to our research but so too is the work of citizen scientists and we encourage anyone who sights a Bryde’s whale in the wild to send us the information.”

 “This work is a great example of how we can harness citizen science to get valuable information on a very elusive species. It seems unbelievable that we still know so little about an animal this big, but the ocean is vast and whales are notoriously difficult to study.”

The Marine Vertebrate Ecology Lab was established last year in the School of Earth, Atmospheric and Life Sciences at UOW. The group studies the ecology of marine megafauna such as whales, dolphins, and seals in Australian waters and beyond.

About the research

‘Bryde’s whale (Balaenoptera edeni) occurrence and foraging behaviour along the east coast of Australia, New Zealand Journal of Marine and Freshwater Research’, by Vanessa Pirotta, Daniele Cagnazzi, Brett Dixon, Simon Millar, Jessica Millar, Greg Pickering, Paul A. Butcher, Karen A. Stockin & Katharina J. Peters, was published in The New Zealand Journal of Marine and Freshwater Research. DOI: 10.1080/00288330.2024.2409681 

Main photo: Bryde's whales feeding off the Sapphire Coast in NSW.