Scientists have been left scratching their heads, wondering why so many female sharks are gathered on the seafloor in southern Australia.

By Melissa Hobson

Published: Monday, 02 September 2024 at 10:08 AM


Researchers on an expedition to Beagle Marine Park, Australia, stumbled across a blanket of thousands of sleepy Port Jackson sharks snoozing on the seabed. 

The Port Jackson shark is a nocturnal bullhead shark found in the coastal waters of southern Australia. Credit: NESP-IMAS

Scientists from the University of Tasmania Institute for Marine and Antarctic Studies (IMAS) captured stunning footage of the dozing sharks from an underwater robot that had been deployed from the South Australian Research and Development Institute (SARDI) research vessel MRV Ngerin.

“There were thousands of sharks tightly packed like a carpet spread across the seafloor,” says voyage leader, Dr Jacquomo Monk of IMAS. Surprisingly, the sharks were all females. 

“One of the interesting things we discovered this time is that the Beagle gathering appears to be only for females,” Dr Monk says.

“We don’t know exactly why the females are here. Perhaps they are feasting on the local delicacy – doughboy scallops – before the long trip north to lay their eggs.”

Solving the sleeping shark mystery

Credit: NESP-IMAS. The survey was led by the University of Tasmania Institute for Marine and Antarctic Studies (IMAS) and supported by the Australian Government’s National Environmental Science Program (NESP), the Southern Australian Coastal Research Vessel Fleet and the National Collaborative Research Infrastructure Strategy.

More wild stories from around the world