A beautiful, wavy pattern resembling a "mermaid's purse"? Or perhaps a washboard?! These are Australian swell shark eggs (all hatched on July 16, 2026!).
Aqua World Oarai began exhibiting Australian swell shark eggs for the first time on Thursday, May 14, 2026. Furthermore, on Friday, June 19, a baby shark successfully hatched from the egg and is now on display in the same tank.

The Australian swell shark inhabits the shallow waters to depths of up to 60 meters off the southwestern Pacific Ocean and the southern coast of Australia, and can grow up to 150 cm in length. It is a species closely related to the Japanese swell shark found in Japanese waters. The eggs of the Japanese swell shark and its relatives are sometimes called "mermaid's purses" due to their shape and size. While the eggshells of the Japanese swell shark have a smooth surface, the eggs of this species have a beautiful curved, uneven surface with a distinctive wavy pattern. The meaning of this pattern is not yet fully understood. The eggs on display are developing well, and visitors can observe the baby sharks growing inside the eggs.

Australian swell sharks are a species that we have never kept in captivity before, and there are many unknowns about them. For our shark keepers, this is the first time they have seen these eggs, and the first time they have seen hatched baby sharks. The keepers are looking forward to the birth of the new life that will develop inside the eggs.

On Friday, June 19th, the baby sharks successfully hatched from their eggs. They are currently on display in the same tank as the eggs.Please be aware that once all the eggs have hatched, we will switch to exhibiting only the juvenile fish.
| Exhibition place | 5th Floor, Nagomi no Umi Zone Samekko Room |
|---|
*Please note that the exhibition may be canceled depending on the condition of the animals.
"Samekko Room" introduces shark breeding research at Aqua World Oarai.

At Aqua World Oarai, we are also focusing on breeding sharks to unravel the mysteries of their ecology. On the 5th floor, in the "Shark Room," we exhibit baby sharks born at our facility and introduce the latest information on shark breeding research conducted at our aquarium.
