Australia: Underwater robot crashes girls-only shark slumber party on ocean floor

An underwater robot has stumbled upon a surprising sight on the ocean floor: thousands of sharks having a slumber party.

This remotely operated rover spotted the Port Jackson sharks’ sleepover party off the coast of Australia.

This peculiar underwater scene unfolded in Beagle Marine Park —  a protected underwater region located in the Bass Strait, the passage between Australia and Tasmania.

A team of marine scientists from the University of Tasmania Institute for Marine and Antarctic Studies (IMAS) sent a remotely operated vehicle to capture underwater footage of this park.

This high-tech robot — equipped with seven cameras — discovered these sharks resting motionless, creating a carpet on the ocean floor.

“There were thousands of sharks tightly packed like a carpet spread across the seafloor,” said Jacquomo Monk, voyage leader, from IMAS.

The IMAS team is conducting a two-week survey mission of the park aboard the research vessel MRV Ngerin.

Mysterious gathering

The mysterious gathering only included female Port Jackson sharks, which are native to Australia’s southern coastline. These sharks have distinct features, including blunt noses and head ridges.

These marine creatures, which may reach up to 1.65 meters (5.5 feet) in length, are normally solitary hunters. They rest during the day and embrace the darkness to hunt squid, octopus, and crustaceans. Port Jackson sharks are not endangered species.

Interestingly, the team had seen a similar gathering before, but this time there were more sharks.

“Coming upon them twice in a 3000-square-kilometre park is like finding a needle in a haystack,” said Monk. “It was very exciting when we managed to traverse over a rise in the reef to get a glimpse of the sharks snoozing 65-metres below the vessel in almost the same location as they were six years ago.”

The scientists were stunned by the discovery that the entire group consisted solely of females. “One of the interesting things we discovered this time is that the Beagle gathering appears to be only for females,” Monk added.

“This poses more questions than answers for us, but we know that the males and females of this species often live apart, except when mating,” Monk explained in the press release.

The exact reason for the female sharks’ presence remains elusive. A plausible hypothesis is that they’re consuming abundant doughboy scallops as a nutritional preparation for their upcoming northward migration to reproduce.

Monk highlights that their presence in this region again indicates that this area’s importance to them.

Survey of underwater park

These sharks are visible to divers in the shallows of New South Wales and Victoria. This is where they engage in mating behavior during late winter, subsequently depositing their characteristic spiral egg cases on the reefs for protection.

They conducted the first survey of Beagle Marine Park some six years ago. This two-week expedition aims to identify potential changes within the park.

Beagle Marine Park is a treasure trove of marine life. This marine protected area conserves rocky reefs and stunning sponge gardens, and serves as a feeding ground for island-breeding seabirds. Protecting this unique ecosystem is crucial for the health of our oceans.

The expedition is funded by the Australian government and the Southern Australian Coastal Research Vessel Fleet.