Watch: Sleepy Joes Found Together Again in their Hundreds

Scientists have again found aggregations of hundreds of Port Jackson sharks – sometimes known as Sleepy Joes.

Scientists from the Institute for Marine and Antarctic Studies of the University of Tasmania found the sharks when they revisited the depths of Beagle Marine Park in Bass Strait using a custom-made Boxfish ROV.

Most were females. Males and females often live apart except when mating, but it’s unknown why they are gathering in such numbers.

Sleepy Joes usually lay their eggs in the coastal waters of Victoria and mid-to-southern NSW from late winter, so it might be a mating aggregation or simply a ‘buffet’ where the sharks fatten up before their long trip north to lay their eggs.

The same phenomenon was seen at the location last year, and it was first spotted there six years ago.

Sleepy Joes grow to 1.65 metres in length and are found across southern Australia.

They rest by day and feed by night on animals such as squids, octopuses, scallops, and crustaceans.