2025.10.31

Research and studies

Physical measurements of a Whale shark were taken

Ahead of Measurement Day on Saturday, November 1st, we measured the total length and girth of the Whale shark currently on display in the "Pacific Ocean" tank on Friday, October 31st. The results are as follows: Total Length Girth Estimated Weight Estimated Age Kai (Male) 5m 30cm Last year (4m 70cm) 2m 60cm Last year (2m 30cm) 1,100kg Last year (700kg) 8-9 years old Yu (Female) 6m 20cm Last year (6m 20cm) 2m 70cm Last year (2m 60cm) 1,800kg Last year (1,800kg) 18-19 years old Umi has grown 60cm in total length and estimated weight 400kg since being brought in on October 2nd of last year. While Yu's overall length has not changed, his girth has grown by 10 cm. Because weight is estimated from his overall length, his estimated weight is the same as last year's, but it is highly likely that he has gained weight. At Kaiyukan, we regularly measure Whale shark sharks, whose detailed ecology is still unknown, as part of our Whale shark research and health management. A aquarium keeper took a tape measure to measure the whale shark's overall length and girth while it was in the tank eating, and calculated its estimated weight. Through the Weighing Day, we hope to showcase the healthy growth of these creatures and to raise awareness of Kaiyukan's health management efforts and the natural environment.

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.

2024.11.01

Research and studies

The total length and girth of the Whale shark were measured.

On Friday, November 1st, the "Weight Anniversary", we measured the overall length and girth of the Whale shark currently being kept and exhibited in the "Pacific Ocean" tank in the Aquarium . The results are as follows. Overall length Girth Estimated weight Estimated age Yu 6 m 20 cm Last year (6 m 10 cm) 2 m 60 cm Last year (2 m 62 cm) 1,800 kg (1,700 kg) 17-18 years old Umi 4 m 70 cm 2 m 30 cm 700 kg 7-8 years old Since the year before last, we have also been measuring the girth of the whale sharks in order to improve the accuracy of health management. "Umi" was measured when it was brought in on October 2nd, 2024, so it was not measured on "Weight Anniversary". At Kaiyukan , we measure the overall length of Whale shark as part of ecological research and health management of Whale shark , whose ecology is still unknown. The total length was measured using a tape measure, which was achieved by training participants to touch the Whale shark's body while it was being fed. Through the Measurement Day, we hope to show how the creatures grow healthily and introduce the health management efforts at Kaiyukan, and to encourage interest in the natural environment.

2024.07.25

Research and studies

Artificial insemination using frozen sperm of Southern rockhopper penguin was successful

Following the first success in 2022, this is the second such achievement in the world! In a joint research project on artificial breeding of Southern rockhopper penguin conducted by Kaiyukan and Tokyo Rinkai Aquarium, Kaiyukan has successfully performed artificial insemination using frozen sperm. This is the second artificial insemination using frozen sperm in this species, following the world's first success achieved by both zoos in 2022, and the first success at Kaiyukan. A Southern rockhopper penguin chick that was found to have been artificially inseminated using frozen sperm (center photo: taken on July 20th) The chicks are currently being raised by their parents in the "Falkland Islands(Malvinas)" tank at Kaiyukan , and you can see them occasionally feeding the chicks by mouth. The chicks are growing well, and the aquarium keeper are watching over them while checking their health by weighing and observing them every morning. Results of the artificial insemination carried out this time Parent bird: female from Kaiyukan Father: male from Kasai Rinkai Aquarium Sperm processing: frozen storage Artificial insemination carried out on: April 19, 22, 24 Egg laying date: May 3 Hatching date: June 4 DNA test results: confirmed to be chicks produced by artificial insemination *Second case in the world Research on artificial breeding of the Southern rockhopper penguin Since 2011, Kaiyukan has been conducting 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. Since 2016, the company has collaborated with Kasai Rinkai Aquarium, and in the same year, it succeeded in artificial insemination using liquid-preserved sperm, the first in the world. In 2017, the two zoos and aquariums signed a joint research agreement and have been working on freezing and preserving sperm in order to further advance research. It was revealed that a chick born at Kasai Rinkai Aquarium in 2022 was the result of artificial insemination using frozen sperm, the first successful case of this species in the world. This year, sperm was collected from a male kept at Kasai Rinkai Aquarium, frozen and stored, then transported and artificially inseminated a female at Kaiyukan. The eggs laid by the female who had been artificially inseminated hatched on June 4th (announced on June 10th, 2024), and a blood parentage test was performed, confirming the DNA of the male at Kasai Rinkai Aquarium and revealing that artificial insemination using frozen storage was successful. Kaiyukan and Kasai Rinkai Aquarium will further deepen their cooperative relationship and establish the technology for artificial insemination of this species. In addition, by spreading this technology to aquariums and zoos both in Japan and abroad, we hope to promote breeding and contribute to the preservation of the endangered wild species of the southern Southern rockhopper penguin. About the Southern Rockhopper Penguin English name: Southern Rockhopper Penguin Scientific name: Eudyptes chrysocome Classification: Order Sphenisciformes, Family Spheniscidae (IUCN Red List: VU (Endangered)) Distribution: Falkland Islands(Malvinas) and other islands around Antarctica Mature individuals are 45-58cm long and weigh 2.2-4.2kg. This is a small species of penguin, and it is said that it got its name from the fact that it moves by hopping between the rocks. They are characterized by their yellow crest feathers above their eyes, and build nests out of pebbles and weeds on coastal rocks. Females usually lay two eggs per breeding. They have a somewhat feisty temperament compared to other penguins, and feed on small fish and krill.

2024.05.30

Research and studies

~Conservation project for the Great Barrier Reef, the world's largest coral reef~ We are taking on the challenge of crowdfunding

~An effort to protect the world's largest coral reef~We are taking on crowdfunding for the "Great Barrier Reef Conservation Project Connected to Kaiyukan". Since its opening in 1990, Kaiyukan has been conveying the natural environment and the ecology of the creatures living there through the display of the "Great Barrier Reef" tank, which reproduces the Great Barrier Reef, the world's largest coral reef that spreads across northeastern Australia. The tank is currently undergoing renovation work with the theme of "the vitality of coral" (scheduled to open in autumn 2024). After conducting on-site diving surveys in preparation for the tank renovation, we have once again felt a strong desire to let more people know about the beauty of the Great Barrier Reef and the wonder of life, and have decided to take on crowdfunding. The donations you have made, along with a contribution from Kaiyukan, will be donated to local NPOs working to conserve the Great Barrier Reef environment. Through this initiative, we hope to not only convey information about the Great Barrier Reef and coral reefs, but also that Kaiyukan will act as a bridge to connect the thoughts of each supporter to a future of rich oceans. About this crowdfunding campaign Use of funds Donated to the NPO "Great Barrier Reef Legacy" to support Great Barrier Reef conservation activities Implementation period Monday, June 3, 2024 to Wednesday, July 31, 2024 Target amount 10 million yen Format All-in format (will be carried out even if the target amount is not reached) Platform READYFOR About "Great Barrier Reef Legacy" An NPO established for the purpose of environmental conservation of the Great Barrier Reef. Based in Queensland, Australia, it has been conducting research and education on coral reefs for over 35 years, and in recent years has also been working on a "biobank" project aimed at protecting coral. Introducing some of the return gifts We plan to prepare various return gifts related to Kaiyukan. ▲Colorful coral eco keychain ▲Ocean-friendly flat pouch ▲ Whale shark feeding experience ▲Coral aquarium keeper experience *Content may change or be canceled without notice. Message from the Director of Kaiyukan The Earth, the Sea, the Sun, and Coral In September 2019, while moving forward with plans to renovate the exhibition tank, I had the opportunity to participate in a diving survey of the Great Barrier Reef. I thought I had a good understanding of the local nature and coral reefs from books, photos, and videos. The underwater experience of the Great Barrier Reef was filled with sunlight, and I was overwhelmed by the magnificent scenery of huge coral reefs towering from the white sand. The curtains of light created by the waves flickered, illuminating the corals. I truly hope to experience the magnificent sea, the presence of the sun... and the Earth, known as the miracle star and water planet, and pass on this nature to future generations. Director of Kaiyukan Murakami Hiroyuki

2024.03.11

Research and studies

Announcement of ArCSⅡ Coastal Environmental Issues Joint Lecture "Understanding the Present of the Arctic Region and Linking it to the Future - What We Can Learn from Seals"

Kaiyukan x ArCSⅡ joint event "Knowing the Arctic Region today and connecting it to the future - What we can learn from seals" "ArCSⅡ (Arctic Research Acceleration Project)" is a project launched by three organizations, the National Institute of Polar Research, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), and Hokkaido University, with the aim of studying the Arctic region, where the effects of global warming are most evident, and covers a wide range of research fields, including marine issues and coastal environmental issues. In 2018, Kaiyukan accompanied the first Arctic voyage survey on Hokkaido University's training ship "Oshoromaru," which was carried out as a project of "ArCS (Arctic Research Promotion Project)," the predecessor of ArCSⅡ, and conducted a collection survey, and also accompanied the "Oshoromaru" Arctic voyage survey, which was carried out again as an ArCSⅡ project in 2023. In the "Arctic Region" tank in the Aquarium , explanatory panels about the collected Arctic Region creatures and Arctic surveys are displayed. This event will focus on the theme of " Arctic Region seals," which are kept or studied by Kaiyukan and ArCSⅡ, and the aquarium keeper and researchers will talk about the ecology of the seals they have kept, and the current state of wild seals and the natural environment as revealed through research. Lecture summary Date and time: Sunday, March 24, 2024 13:30-16:30 Location: Kaiyukan Hall, 2nd floor of the Kaiyukan Entrance Building Participation application: 150 people (first come, first served, free of charge) will be recruited. *There is no age limit, but the lecture is intended for junior high school students and above. Content: aquarium keeper and researchers will talk about "Arctic Region seals" from various perspectives. 〇 Introduction to seals living in the Northern Hemisphere Yoko Mitani (Kyoto University) 〇 Seal research in Greenland Yuta Sakuragi (Hokkaido University) 〇 Seal food and Inuit use of fur Ryo Kusaka (Hokkaido University) 〇 Arctic Region seals kept at Kaiyukan Kei Takeuchi ( Kaiyukan) 〇 About Arctic Region research and collection on the Oshoro Maru Mikito Murata (Kaiyukan) Others: 〇 There is a possibility that media will cover the event. Please note. Click here to apply [About the joint event] This event will be jointly held by Kaiyukan and ArCSⅡ Coastal Environment Issues. ArCSⅡ (Arctic Research Acceleration Project)

2023.11.01

Research and studies

We measured the overall length of the Whale shark and publicly weighed the King penguin chicks!

On November 1st (Wednesday), which is "Weighting Day", we measured the total length and girth of the Whale shark that are being kept and exhibited in the "Pacific Ocean" tank in the Aquarium . The results are as follows. Total length Girth Estimated weight Estimated age Yu: 6m 10cm Last year (6m 00cm) 2m 62cm Last year (2m 35cm) 1,700kg (1,650kg) 16-17 years old Umi: 5m 40cm Last year (5m 25cm) 2m 34cm Last year (2m 20cm) 1,150kg (1,050kg) 8-9 years old *Since last year, we have also been measuring girth to improve the accuracy of health management. At Kaiyukan , we measure the total length of Whale shark as part of ecological research and health management of Whale shark , whose ecology is still unknown. The total length was measured using a tape measure, and this method was achieved by training the participants to touch the bodies of whale Whale shark while they were being fed. In addition, we conducted public weight measurements of the king King penguin chicks born in August and September of this year. We weigh the chicks every morning to observe their growth and understand their health, but in order to share the growth of the chicks, we conducted the weight measurements in front of the guests while explaining about King penguin and chicks. The results of the weight measurements are as follows. Weight immediately after birth Weight on November 1st Chicks hatched on August 11, 2023 171.9g 11.04kg Chicks hatched on September 3, 2023 210.0g 6.90kg *The weight of the chicks hatched on September 3, 2023 was measured on the morning of November 1st. Through the Weighing Day, we hope to introduce the healthy growth of creatures and the health management efforts of Kaiyukan, and to encourage interest in the natural environment.

2023.10.24

Research and studies

~ November 1st is "Measurement Day" ~ Divers measure the total length of Whale shark

On November 1, 2023 (Sunday), which is "Weighting Day", the total length of the Whale shark will be measured. At Kaiyukan, we measure the total length of whale sharks as part of ecological research and health management of Whale shark, whose ecology is still unknown. The total length is measured with a tape measure, which was achieved by training to touch the Whale shark's body while it is being fed. Since last year, in order to improve the accuracy of health management, we have been measuring the girth in addition to the total length. In addition, on the same day, we will measure the Kaiyukan and provide an explanation of two King penguin chicks living in the "Antarctica" tank , in order to let people know about the health management efforts that Whale shark is working on on a daily basis. About the measurement of whale sharks Date and time: Wednesday, November 1, 2023 10:30-10:40 Location: "Pacific Ocean" tank Individual measured: Yu (female), estimated age 16-17 years old *Measurements may be canceled without notice depending on the condition of the creatures. ※Last year's measurement results are here. About the Whale shark: ■English name: Whale shark ■Scientific name: Rhincodon typus A large shark that lives in temperate to tropical coasts and the open ocean, it appears in the waters off Japan from spring to autumn on the King penguin chicks Date and time: Wednesday, November 1, 2023, 11:25 to 11:30 Location: "Antarctica" tank measured: ①Chicks hatched on August 11, 2023 ②Chicks hatched on September 3, 2023 Total of 2 Note: During the measurement, the tank aquarium keeper will provide an explanation to the customers. *Depending on the situation, the content may be changed or canceled without notice. About Metrology Memorial Day: Metrology systems are the most fundamental systems of the economy and society, and are fundamental to all areas of people's lives. Setting standards for measurements and ensuring proper measurements is extremely important for protecting daily life, as well as for economic development and cultural improvement. The Ministry of Economy, Trade and Industry has designated November 1st as "Metrology Memorial Day" and November as "Metrology Emphasis Month" in commemoration of November 1st, 1993, when the current Measurement Act came into effect, with the aim of popularizing the metrology system and raising metrology awareness throughout society. (From the website of the Japan Metrology Promotion Association)

2023.10.20

Research and studies

We have begun our second Whale shark survey since crowdfunding.

On Thursday, September 28, 2023, a recording device was attached to the Whale shark kept at the Osaka Kaiyukan Biological Research Institute Iburi Center (Tosashimizu City, Kochi Prefecture, commonly known as the Iburi Center), a research institute of the Kaiyukan Kaiyukan Kaiyukan, and an investigation was started to clarify the ecology of the Whale shark, such as their migration routes. Since 2011, the Osaka Aquarium Kaiyukan has been working with Hokkaido University on "biologging," a migration route survey using recording devices, in order to clarify the ecology of whale sharks. From December 2022 to February 2023, we conducted crowdfunding for three months to further develop this survey, and received support of over 10 million yen. In the first survey after crowdfunding, conducted in July, new discoveries were made, such as the confirmation of behavior different from that of individuals surveyed in the past. →We have started a Whale shark survey. This survey is the second survey following that one. In addition to the conventional recording device (data logger) that can record the coordinates, water depth, and environment of the Whale shark, we attached a "camera logger" that can record video as part of a joint research with Kobe University and released it. The camera logger is designed to detach from the Whale shark and rise to the surface in a short time, and was successfully retrieved on the day of release. When we checked the video, we were able to confirm the swimming of "yellowfin tuna (a type of tuna)". We are currently proceeding with more detailed video analysis. The recording device, which can record the coordinates, water depth, and environment, is detached from the survey subject when the set period is reached, and rises to the surface to transmit the collected data. By receiving and analyzing data via satellite, we can learn about the Whale shark's migration information. The survey results will be posted on the Kaiyukan website.