A Beautiful Wavy Pattern Like a "Mermaid's Purse"? Or a Washboard?! First Exhibit at Aqua World Oarai! Australian Swellshark Egg
Aqua World Oarai has begun exhibiting the egg of an 'Australian Swellshark' for the first time in Japan. The egg, characterized by its wavy pattern and also known as a 'mermaid's purse,' allows visitors to observe the baby shark growing inside. This marks a new challenge in shark breeding for the aquarium.
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- 📰 Published: May 14, 2026 at 22:00
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Aqua World Ibaraki Prefectural Oarai Aquarium (Aqua World Oarai), which boasts the 'largest number of shark species under human care in Japan (*),' began exhibiting the egg of an Australian Swellshark for the first time at the facility on Thursday, May 14, 2026.
*Based on a survey of member facilities of domestic aquarium associations (our research/as of December 2025)
Australian Swellshark egg (approx. 12 cm)
Aqua World Oarai, which prides itself on having the 'largest number of shark species under human care in Japan (*),' currently keeps 55 species of sharks. On Thursday, May 14, 2026, we began exhibiting the egg of the 'Australian Swellshark' for the first time.
The Australian Swellshark inhabits shallow seas to depths of 60m along the southern coast of Australia in the southwestern Pacific, and can grow to a maximum length of about 150cm. It is a species of shark closely related to the Draughtsboard shark that lives in the waters near Japan. When threatened, it has a habit of swallowing seawater to inflate its stomach to protect itself, and its English name 'swell' means to inflate. The eggs of the Draughtsboard shark's relatives are also called 'mermaid's purses' because of their shape and size. While the egg case surface of the Japanese Draughtsboard shark is smooth, the surface of this species' egg case has beautiful curved ridges, featuring a distinctive wavy pattern. The meaning of the pattern is not well understood. The egg currently on display is developing well, and you can see the baby shark growing inside the egg.
Australian Swellshark
Scientific Name: Cephaloscyllium laticeps Carcharhiniformes Scyliorhinidae
Total Length: approx. 150cm Habitat: Southwestern Pacific to Southern Australia
Inside the egg
Our aquarium obtained the egg of this species in early May, and as stable keeping became possible, we began exhibiting the egg only. The Australian Swellshark has no prior breeding record at our facility, making it a shark with many unknown aspects. For our shark keepers, this is their first experience seeing not only the egg but also the hatched fry. The keepers are looking forward to the birth of this new life growing inside the egg. Please observe the egg and imagine what kind of baby shark will be born.
Exhibit Location: 5th Floor, Nagomi no Umi Zone, Samekko Room
Exhibit Start Date: Thursday, May 14, 2026
*This is an exhibit of the egg only. Adult sharks are not on display.
*Contents may change depending on the condition of the living creature.
View Details
Samekko Room
'Samekko Room' introduces Aqua World Oarai's shark breeding research
Our aquarium is also focusing on breeding to elucidate the ecology of sharks. In the 'Samekko Room' on the 5th floor, we exhibit baby sharks born at our facility and introduce the latest information on our shark breeding research. Along with this egg exhibit, we hope you will take this opportunity to pay attention to our efforts.
*All images in this release are for illustrative purposes only.
Operated by: Ibaraki Cultural Promotion Foundation
*Based on a survey of member facilities of domestic aquarium associations (our research/as of December 2025)
Australian Swellshark egg (approx. 12 cm)
Aqua World Oarai, which prides itself on having the 'largest number of shark species under human care in Japan (*),' currently keeps 55 species of sharks. On Thursday, May 14, 2026, we began exhibiting the egg of the 'Australian Swellshark' for the first time.
The Australian Swellshark inhabits shallow seas to depths of 60m along the southern coast of Australia in the southwestern Pacific, and can grow to a maximum length of about 150cm. It is a species of shark closely related to the Draughtsboard shark that lives in the waters near Japan. When threatened, it has a habit of swallowing seawater to inflate its stomach to protect itself, and its English name 'swell' means to inflate. The eggs of the Draughtsboard shark's relatives are also called 'mermaid's purses' because of their shape and size. While the egg case surface of the Japanese Draughtsboard shark is smooth, the surface of this species' egg case has beautiful curved ridges, featuring a distinctive wavy pattern. The meaning of the pattern is not well understood. The egg currently on display is developing well, and you can see the baby shark growing inside the egg.
Australian Swellshark
Scientific Name: Cephaloscyllium laticeps Carcharhiniformes Scyliorhinidae
Total Length: approx. 150cm Habitat: Southwestern Pacific to Southern Australia
Inside the egg
Our aquarium obtained the egg of this species in early May, and as stable keeping became possible, we began exhibiting the egg only. The Australian Swellshark has no prior breeding record at our facility, making it a shark with many unknown aspects. For our shark keepers, this is their first experience seeing not only the egg but also the hatched fry. The keepers are looking forward to the birth of this new life growing inside the egg. Please observe the egg and imagine what kind of baby shark will be born.
Exhibit Location: 5th Floor, Nagomi no Umi Zone, Samekko Room
Exhibit Start Date: Thursday, May 14, 2026
*This is an exhibit of the egg only. Adult sharks are not on display.
*Contents may change depending on the condition of the living creature.
View Details
Samekko Room
'Samekko Room' introduces Aqua World Oarai's shark breeding research
Our aquarium is also focusing on breeding to elucidate the ecology of sharks. In the 'Samekko Room' on the 5th floor, we exhibit baby sharks born at our facility and introduce the latest information on our shark breeding research. Along with this egg exhibit, we hope you will take this opportunity to pay attention to our efforts.
*All images in this release are for illustrative purposes only.
Operated by: Ibaraki Cultural Promotion Foundation