Female sharks gather under sea to … sleep?

The video footage above, captured from a remotely operated underwater vehicle, shows the Fort Jackson sharks. Scientists spied thousands of them resting on the seafloor.

• Thousands of sharks were spotted sleeping on the seafloor off the coast of southern Australia.
• All the sharks were female; the scientists don’t know why.
• An underwater robot vehicle spotted the sharks, using cameras that help scientists see what’s happening on the ocean floor.

Thousands of sharks spotted resting on seafloor

On August 13, 2024, while wrapping up a two-week expedition off the southern Australia coast, scientists using a remotely operated underwater vehicle stumbled upon thousands of sharks asleep on the seafloor. Notably, the Port Jackson sharks all appeared to be female. It was the second time in six years that scientists at Australia’s Beagle Marine Park have seen and documented them in the midst of an all-girl shark slumber party.

The scientists announced their extraordinary find in an August 14 statement. Expedition leader, Jacquomo Monk, of the University of Tasmania, said:

We had been hoping to see the sharks again on this survey. Coming upon them twice in a 3,000-square-kilometer [1,158 square miles] park is like finding a needle in a haystack.

It was very exciting when we managed to traverse over a rise in the reef to get a glimpse of the sharks snoozing 65 meters [213 feet] below the vessel in almost the same location as they were six years ago.

These scientists were conducting a survey of undersea life at the Beagle Marine Park in Australia, located in the central Bass Strait, between Tasmania and Victoria.

They were using a remotely operated vehicle, an underwater robot equipped with seven cameras, to image the seafloor.

What are they doing?!

This gathering of sharks was, as mentioned before, observed at Beagle Marine Park in southern Australia waters. It is a rocky reef habitat with sponge gardens. Islands in the park are also important breeding grounds for seabirds. So what are the sharks doing, sleeping under the sea in that area? Monk commented about an important clue:

One of the interesting things we discovered this time is that the Beagle gathering appears to be only for females.

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.

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.

Seeing them again does tell us that the area is important to them.

An interview (3 min 12 s) with expedition leader Jacquomo Monk about the Port Jackson sharks seen at Beagle Marine Park.

More about Port Jackson sharks

Port Jackson sharks are found in coastal waters off southern Australia. These strikingly patterned bottom-dwelling sharks, that grow to about 5.5 feet (1.7 meters) in length, are primarily active at night. They feed on octopuses, squid, mollusks and crustaceans, and are usually found at depths of about 330 feet (100 meters).

Also, they breed in shallow waters off the coast of New South Wales and Victoria in late winter (late August to mid-November), where they’re often spotted by divers. There, the female sharks attach intricate spiral-shaped egg cases to the reef. It takes about 10 to 11 months for hatchlings to emerge.

Bottom line: Scientists recently observed thousands of Port Jackson sharks, all female, sleeping on the seafloor off south Australia.

Via Australian National Environmental Science Program

Read more: 12 shark facts that might surprise you