2025.10.01

news

Kaiyukan welcomes its 90 millionth visitor

On Wednesday, October 1, 2025, we welcomed our 90 millionth visitor. We would like to express our sincere gratitude to everyone who has visited us so far. We will continue to try new things to convey the wonder and beauty of the natural environment and life to visitors from all over the world and to inspire them. ▼Scenes from the commemorative ceremony▼Scenes from the special guide by the museum director

2025.09.29

news

The Osaka Aquarium Kaiyukan Co.,Ltd page has been published

2025.09.18

Living creature information

A baby tufted Tufted puffin , an endangered seabird, is born. A special experience event will also be held where you can see the aquarium keeper' perspective.

2025.08.04

Living creature information

[Exhibition closed] After a three-year hiatus, the large Ariake Bizen Kurage (Japanese Name) is now on display!

The Ariake Bizen Kurage (Japanese Name), a large jellyfish native to the Ariake Sea, has been exhibited for a limited period of approximately one month. This marks the first time a large specimen of this species has been exhibited at Kaiyukan in three years, since 2022. Kaiyukan has been conducting research on the Ariake Bizen Kurage (Japanese Name) in the Ariake Sea since 2001, and in 2002 successfully transported and reared a large specimen for the first time. This year, we once again collected a Risen jellyfish for research and display, coinciding with the start of jellyfish fishing in the Ariake Sea. Through this exhibit, Kaiyukan hopes to provide an opportunity for visitors to develop an interest in living creatures and the natural environment. Exhibit location: "Jellyfish"*Exhibit has closed. Exhibits: 3 (umbrella diameter approximately 50 cm) *Exhibit period and number of specimens may change without notice depending on the condition of the creatures. About the Ariake Bizen Kurage (Japanese Name) Scientific name: Rhopilema esculentum It lives in coastal waters of tropical, subtropical, and warm temperate zones, and is found in the Seto Inland Sea and Ariake Sea in the waters around Japan. It is a large jellyfish that grows to an umbrella diameter of 60 cm and weighs about 20 kg, and is known in English as "edible jellyfish" because it is edible. It is caught in gillnet fishing off the coast of the Ariake Sea from July to October. In recent years, the name was changed from a type of Rhopilema esculentum to "Ariake Bizen Kurage (Japanese Name)" to avoid confusion with similar species.

2025.07.10

Sales/Shop

Original goods commemorating the 35th anniversary of Kaiyukan now available at the official shop

To commemorate the 35th anniversary of the opening of Kaiyukan on Sunday, July 20, 2025, original 35th anniversary merchandise (three types) will be available from July 20, and a 35th anniversary version of the medal leaf will be available from July 18. The original merchandise will include a 35mm-wide masking tape commemorating the 35th anniversary, as well as a collaboration with INTERACTIVE AQUAZOO「NIFREL」 produced by Kaiyukan that will celebrate its 10th anniversary on November 19, 2025. Both merchandise features designs of Kaiyukan's creatures and landmarks. We aimed to create a festive atmosphere so that visitors to Kaiyukan can celebrate this milestone. We hope that these items, which can be used in everyday moments, will bring Kaiyukan closer to you in your daily life. Drawstring Bag: This drawstring bag features designs of Kaiyukan's creatures and landmarks on the front and the opening date of Kaiyukan printed on the back. It also comes with a keychain featuring the 35th anniversary symbol. Product Name: Drawstring bag with 35th acrylic keychain Price: 1,200 yen (tax included) Sold at: Official Shop, 3rd floor, Kaiyukan Entrance Building Release Date: July 20, 2025 Masking Tape: This masking tape features designs of Kaiyukan's creatures and landmarks and is stamped with gold foil. The tape is 35mm wide to commemorate the 35th anniversary. Product Name: 35th Masking Tape Price: 700 yen (tax included) Sold at: Official Shop, 3rd floor, Kaiyukan Entrance Building Release Date: July 20, 2025 Cleaning Cloth: This is a collaboration product with INTERACTIVE AQUAZOO「NIFREL」 that will celebrate its 10th anniversary on Wednesday, November 19, 2025. Designs commemorating Kaiyukan's 35th anniversary and NIFREL 10th anniversary are printed on both sides of the cloth. Product name: Cleaning Cloth 35th, 10th Price: 600 yen (tax included) Sold at: Kaiyukan Entrance Building 3F "Official Shop", NIFREL 1F Museum Shop "NIFREL x NIFREL" Release date: From July 20, 2025 Medal Leaf sold near the exit of Kaiyukan will feature a 35th anniversary design for a limited time. Sales period: July 18, 2025 - February 27, 2026 Price: 200 yen (tax included) Sold at: Kaiyukan Entrance Building 3F, near the exit

2025.06.18

Living creature information

[They are growing rapidly] Three Southern rockhopper penguin chicks born

You can see the raising of the chicks in the exhibition tank . On May 29th (Thursday), June 7th (Saturday), and June 9th (Monday), 2025, three Southern rockhopper penguin chicks were born in the "Falkland Islands(Malvinas)" tank . The Southern rockhopper penguin kept in the "Falkland Islands(Malvinas)" tank entered their breeding season in late April, and three pairs were formed, one chick each, for a total of three chicks. Currently, the parents are raising the chicks in their own nests, and you can see them occasionally feeding the chicks by mouth. The chicks born earlier are also growing well, with the chick born on May 29th weighing over 1kg and the chick born on June 7th weighing over 500g. aquarium keeper are watching over the raising of the chicks, checking their health by weighing and observing them every morning. A parent and child of the Southern rockhopper penguin(photographed on June 11th) [About the Southern rockhopper penguin chicks] [1st chick] Hatching date: Thursday, May 29th, 2025 Gender: Unknown Weight: 75.3g (immediately after hatching) 1.1kg (as of June 18th) [2nd chick] Hatching date: Saturday, June 7th, 2025 Gender: Unknown Weight: 64.1g (immediately after hatching) 556.2g (as of June 18th) [3rd chick] Hatching date: Monday, June 9th, 2025 Gender: Unknown Weight: 49.7g (immediately after hatching) 235.8g (as of June 18th)

2025.06.13

Living creature information

California sea lion baby born

On Thursday, June 12, 2025, a baby California sea lion was born in the "Monterey Bay" tank . This is the 19th birth of a California sea lion at Kaiyukan . From Wednesday, June 11, 2025, the female "Asuka (15 years old)" living in the "Monterey Bay" tank was found to be showing signs of giving birth, and the aquarium keeper were observing her 24 hours a day. At 8:00 a.m. on Thursday, June 12, the baby was safely born. Both mother and child are healthy, and you can see the nursing and other child-rearing activities in the "Monterey Bay" tank. We would like to watch the baby grow up so that it will grow up healthily. Please note that the baby may be moved to the back yard depending on the situation, and you may not be able to see it. Thank you for your understanding. Appearance of parent and child (photographed on 6/12) About the newborn baby (as of June 12, 2025) (photographed on 6/12) ・Date of birth: Thursday, June 12, 2020 ・Display tank : "Monterey Bay" tank on the 7th floor of Kaiyukan・Body length: 60 cm (estimated) ・Weight: 9.4 kg (actual measurement) ・Gender: Male ・Parents: Mother Asuka (15 years old), father unknown About California sea lion English name: California sea lion Scientific name: Zalophus californianus They live only on the eastern coast of the North Pacific Ocean Ocean. When fully grown, males reach a body length of about 200 cm and a weight of about 300 kg, while females reach a body length of about 170 cm and a weight of about 100 kg. Males are dark brown all over, while females are a slightly lighter dark brown. Their limbs are well developed, which is useful not only for swimming underwater but also for walking on land. They are polygamous, with one male leading about 30 females and their children in groups called "harems." The gestation period is about one year. Usually, one child is born at a time, and the baby continues to be nursed for about one year after birth. Comments from the California sea lion aquarium keeper California sea lion breed seasonally, and the fertilization period is limited to a very short period of the year. It is very difficult to determine the date of birth by observing the behavior seen during the breeding season, such as mating. This time, the aquarium keeper and veterinarians worked closely together to determine the date of birth by regular ultrasound examinations and weight measurements, so that the mother could give birth with even more peace of mind. Because of this, on the day of birth, many aquarium keeper watched over the birth, and all the aquarium keeper were filled with joy. All the aquarium keeper in charge will continue to work together to provide care so that Asuka can raise her children with peace of mind and that the baby will grow up healthy and strong.

2025.06.12

Research and studies

Research into artificial breeding of Southern rockhopper penguin wins the Koga Award, the highest award from the Japanese Association of Zoos and Aquariums

The artificial breeding research of the Southern rockhopper penguin, which is being conducted jointly with Kasai Rinkai Aquarium, has been awarded the Koga Award, the highest award of the Japan Association of Zoos and Aquariums (JAZA), to which both zoos and aquariums belong, and was presented at the association's general meeting held on Thursday, May 22, 2025. In 2011, Kaiyukan began research aimed at elucidating the breeding ecology of this species, which is at risk of extinction in the wild and whose captive population in Japan is also declining, and establishing artificial breeding techniques. In 2016, in collaboration with Kasai Rinkai Aquarium, the world's first artificial insemination using liquid preserved semen was successfully performed on this species in the same year. In 2017, the two zoos and aquariums signed a joint research agreement and began artificial breeding using frozen preserved semen with the aim of further developing the research. In 2022, a chick born at Kasai Rinkai Aquarium was found to have been artificially inseminated using frozen semen, marking the first successful breeding of this species in the world, and in 2024, a chick born at Kaiyukan became the second successful breeding case in the world. Award ceremony at the General Assembly of the Japanese Association of Zoos and Aquariums (JAZA) (provided by Toyohashi Zoo and Botanical Gardens) In recognition of 14 years of research achievements, the Koga Award was awarded by the Japanese Association of Zoos and Aquariums. The Koga Award is the highest award given by the Japanese Association of Zoos and Aquariums to zoos and aquariums that have made outstanding contributions to the breeding of rare animals (species that are difficult to breed and are globally important). Since its establishment in 1986, 37 awards have been given, making this the 38th. Kaiyukan and Kasai Rinkai Aquarium hope to use the technology developed in this research to continue breeding the Japanese Southern rockhopper penguin through in-Aquarium breeding and, in the future, to contribute to the conservation of penguins in the wild. We will continue to work on this issue to advance research. For more information about artificial breeding research, click here. A chick born through artificial insemination using frozen preserved semen at the Kaiyukan in 2024. Artificial insemination in progress.

2025.06.04

Research and studies

Report on Kaiyukan Crowdfunding

Since its opening in 1990, Kaiyukan has been communicating the natural environment and the ecology of the creatures that live there through the display of the "Great Barrier Reef" tank , which reproduces the Great Barrier Reef , the world's largest Great Barrier Reef that spreads across northeastern Australia. After undergoing on-site diving surveys in preparation for the renovation of the tank , which was reopened on November 28 last year, we once again felt a strong desire to let more people know about the beauty of the Great Barrier Reef and the wonderful life there. As an effort to protect the future of the Great Great Barrier Reef and coral reefs, we conducted crowdfunding from June 3, 2024 to July 31, 2024, and received approximately 5.46 million yen in support. Once again, we felt the passion and warmth of our supporters through crowdfunding. We would like to express our sincere gratitude. Your donations, together with the contribution from Kaiyukan, have been combined to donate 10 million yen to the local NPO "Great Barrier Reef Legacy," which works to conserve the Great Barrier Reef. In addition, Kaiyukan has set up a "coral biobank" since last year and is working on breeding and researching coral. We look forward to your continued support.

2025.05.29

Living creature information

A first for the Kaiyukan! A large shark called the Sand tiger Shark is now on display

Kaiyukan has begun exhibiting the "Sand tiger Shark." This is the first time this species has been exhibited at Kaiyukan. Left: Male Right: Sand tiger Shark are a large shark species that can grow to over 3m in length. Contrary to their fearsome appearance with their large, bared teeth, they have a docile personality and live in coral reefs, shallow offshore waters, and underwater caves. Two sharks, a 2.7m female and a 2.5m male, were brought to the "Pacific Ocean" tank from the Tokai University Marine Science Museum. They have now gotten used to their new environment, swimming leisurely in the tank and eating food provided by the aquarium keeper during " Feeding Time " twice a day. Exhibit location: "Pacific Ocean" tank . Individuals exhibited: Female: 2.7m in length, delivered on Monday, May 12, 2025. Male: 2.5m in length, delivered on Thursday, May 15, 2025. About the Sand Tiger Shark: English name: Sand tiger shark. Scientific name: Carcharias taurus. A large shark with a total length of over 3m. It inhabits warm seas such as coral reefs and shallow offshore waters, and is currently said to only inhabit the Ogasawara Islands (Mukojima Islands, Chichijima Islands, and Hahajima Islands) in Japan. It hides in underwater caves during the day and is nocturnal, active at night, feeding mainly on other fish. Contrary to its fearsome appearance, it has a docile personality. It is viviparous, has two uteruses, and produces up to two young with a total length of about 1m per breeding. The fetuses are known to grow by eating other eggs and siblings in the uterus.