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  5. Isao Kawazu
Okinawa Churashima Foundation RESEARCH INSTITUTE

Research on marine organisms

Research staff profile

Isao Kawazu

Isao Kawazu, Ph.D.

Area of
expertise		 Reproductive biology and ecology of sea turtles
Research
content		 Reproductive biology and research on artificial insemination of sea turtles
Reproductive ecology of sea turtles

Background

  • 2024-present: “Senior researcher, Zoological Laboratory, Okinawa Churashima Research Institute” and “Manager, Fish section, Okinawa Churaumi Aquarium”
  • 2015: Ph.D. in Fishery Science at Graduate School of Science and Technology, Nagasaki University, Japan. “Reproductive Biology of Captive Hawksbill Turtles and the Development of a Technique for Artificial Insemination”
  • 2003: M.Sc. in Fisheries Science at Graduate School of Science and Technology, Nagasaki University, Japan.
  • 2001: B. Sc. in Fisheries Science, Nagasaki University, Japan.

Committee Career

  • 2017-present: IUCN Species Survival Commission Marine Turtle Specialist Group
  • 2015-present: Board member, Sea Turtle Association of Japan
  • 2014-present: Editorial board member, Umigame Newsletter of Japan

Research papers, publications

  • Higa, S., Omata, M., Nakamura, M., Kobayashi, N., Ueda, K., Kawazu, I. Long-term monitoring of semen quality and serum testosterone concentration in a captive male false killer whale. Mammal Study. (in press)
  • Ikeshima, S., Higa, S., Ueda, K., Kawazu, I. Observation of abnormal nursing behavior in a captive Pantropical spotted dolphin. Journal of Japanese Association of Zoos and Aquariums. (in Japanese with English abstract)
  • Higa, S., Mitani, Y., Ikeshima, S., Kobayashi, N., Ueda, K., Kawazu, I. 2023. Parturition and Nursing Events in a Cephalic Birth of a False Killer Whale (Pseudorca crassidens) in Managed Care. Aquatic Mammals 49: 217–222.
  • Kawazu, I, Maeda, K, Kobuchi, T, Sasai, T, Mizuochi, K, Yamazaki, K, Maeda, K, Kino, M, Fukada, S. 2023. Age and body characteristics of captive green turtles at the onset of vitellogenesis. Journal of Japanese Association of Zoos and Aquariums 65: 31–36. (in Japanese with English abstract)
  • Kiyomura, K., Kawazu, I. 2023. First observation of mating behavior involving one female and two male green turtles in Tarama Island. Umigame Newsletter of Japan 112: 3–4. (in Japanese with English abstract)
  • Kiyomura, K., Kawazu, I. 2023. Large amounts of green turtle feces washed ashore on the sandy beaches of Tarama Island, Japan. Umigame Newsletter of Japan 112: 7–8. (in Japanese with English abstract)
  • Kobuchi, T., Makabe, M., Maeda, K., Fukada, S., Ueda, K., Kawazu, I. 2023. Successful retrieval of a fishhook from a rescued olive ridley turtle. Umigame Newsletter of Japan 112: 12–13. (in Japanese with English abstract)
  • Kohama, S., Matsuzaki, S, Kawazu, I. 2023. First record of a lost-aged green turtle in northern waters of Minamidaito Island. Umigame Newsletter of Japan 112: 5–6. (in Japanese with English abstract)
  • Mukouda., K., Fukamachi., M., Mizuochi., K., Kawazu., I. 2023. First record of a lost-aged hawksbill turtle in the coastal waters of Okinawajima Island. Umigame Newsletter of Japan 112: 14–15. (in Japanese with English abstract)
  • Fukada S, Kawazu I, Maeda K, Kobuchi T, Makabe M, Kino M, Maeda K, Omata M, Sasai T. 2022. Breeding success of captive F2 generation of loggerhead turtle in Okinawa Churaumi Aquarium. Herpetological Review: 246–249.
  • Kawazu I, Suzuki M, Maeda K. 2022. Rock installation reduces aggressive behavior in captive hawksbill turtles. Current Herpetology 41: 1–7.
  • Sasai T, Kino M, Miyamoto K, Okabe H, Maeda K, Fukada S, Maeda K, Kobayashi N, Kobuchi T, Makabe M, Kawazu I. Evaluation of marine debris ingestion in sea turtles around Okinawa Island, Japan. Marine Turtle Newsletter 163: 21–24.
  • Kawazu I, Komesu K, Kayo M, Inoue N, Kino M, Maeda K, Fukada S. 2021. Nesting and reproductive ecology of hawksbill turtles on Okinawajima Island, Japan. The Biological Magazine Okinawa 59: 45–50.
  • Ikeshima S, Higa S, Mitani Y, Omata M, Kobayashi N, Ueda K, Kawazu I. 2021. First observation of pregnancy and parturition in a captive pantropical spotted dolphin (Stenella attenuate). Mammal Study 46: 1–6.
  • Seto S, Higa S, Kawazu I. 2021. Suppression of aggressive behavior in a captive pygmy killer whale using behavior modification. Journal of Japanese Association of Zoos and Aquariums 63: 42–50. (in Japanese with English abstract)
  • Kayou M, Maeda K, Kawazu I. 2021. Hawksbill turtle nesting on northernmost beach of Okinawajima Island, Japan. Umigame Newsletter of Japan 109: 12–13. (in Japanese with English abstract)
  • Kobayashi N, Tokutake K, Yoshida H, Okabe H, Miyamoto K, Ito H, Higashi N, Fukada S, Yamazaki K, Higa S, Kawazu I, Ueda K. 2021. The first stranding record of Longman’s beaked whale (Indopacetus pacificus) in Okinawa, Japan. Aquatic Mammals 47: 153–174.
  • Hatanaka T, Miyake, Takada K, Sasai T, Fukada S, Kayou M, Kobuchi T, Maeda K, Makabe M Kawazu I, Saito T. 2021. Influence of retention conditions and duration on the swim frenzy in green sea turtle hatchlings. Kuroshio Science 14: 103–112. (in Japanese with English abstract)
  • Hamabata T, Matsuo A, Sato P. M, Kondo S, Kameda K, Kawazu I, Fukuoka T, Sato K, Suyama Y. Kawata M. 2020. Natal origin identification of green turtles in the North Pacific by genome-wide population analysis with limited DNA samples. Frontiers in Marine Science 7: 658. doi: 10.3389/fmars.2020.00658
  • Koga S, Yanagisawa M, Koga H, Ueda K, Kawazu I, Tokutake K, Funasaka N, Yoshioka M, Miyahara. 2019. Reproductive ability of elderly male Indo-Pacific bottlenose dolphins (Tursiops aduncus) in captivity. Mammal Study 44: 135–139.
  • Kawazu I, Fukada S, Okabe H, Maeda K, Kino M, Maeda K, Miyamoto K, Omata M, Kobuchi T, Makabe M. 2019. Comparison of the emergence success between wild and captive loggerhead turtles. Umigame Newsletter of Japan 108: 2–5. (in Japanese with English abstract)
  • Kawazu I, Okabe H, Kobayashi N. 2019. Observation of a Loggerhead Turtle with a Shark Bite Injury. Umigame Newsletter of Japan 108: 6–7. (in Japanese with English abstract)
  • Kayou M, Kawazu I. Unusual timing of a loggerhead turtle nesting on Kunigami, Okinawajima Island, Japan. Umigame Newsletter of Japan 108: 8–11. (in Japanese with English abstract)
  • Kayou M, Kawazu I. 2019. Loggerhead sea turtle hatchlings misoriented and run over by a vehicle at Kunigami, Okinawa Island, Japan. Umigame Newsletter of Japan 108: 11–13. (in Japanese with English abstract)
  • Kawazu I, Fukada S, Maeda K, Maeda Ko, Kino M, Omata M, Makabe M, Kobuchi T. 2018. Reproductive Parameters of Captive Sea Turtles in Okinawa Churaumi Aquarium. Proceedings of 10th International Aquarium Conference Fukushima 2018. 74–79.
  • Kawazu I, Maeda K, Fukada S, Omata M, Kobuchi T, Makabe M. 2018. Breeding success of captive Black turtles in an aquarium. Current Herpetology 37: 180–186.
  • Kawazu I, Inoguchi E, Maeda K, Fukada S, Omata M. 2018. Long-distance movement of a tag-released hawksbill turtle from Japan to Yapen Island, Papua Province, Indonesia. Fauna Ryukyuana 45: 1–3.
  • Kawazu I, Ueda K, Hirai S, Maeda K, Yanagisawa M, Miyaraha H. 2018. Captive loggerhead turtle hatchlings infected by parasitic cardiovascular blood flukes. Marine Turtle Newsletter 155: 20–21.
  • Hamabata T, Nishizawa H, Kawazu I, Kameda K, Kamezaki N, Hikida T. 2018. Stock composition of green turtles Chelonia mydas foraging in the Ryukyu Archipelago differs with size class. Marine Ecology Progress Series 600: 151–163.
  • Kawazu I, Okabe H, Kobayashi N. 2017. Direct observation of mating behavior between one female and two male loggerhead turtles in the wild. Current Herpetology 35: 69–72.
  • Kobayashi N, Okabe H, Kawazu I, Higashi N, Kato K, Miyahara H, Nakamura G, Kato H, Uchida S. 2017. Distribution and local movement of humpback whales in Okinawan waters depend on their sex and reproductive status. Zoological Science 34: 58–63.
  • Shimura A, Maeda K, Inoue N, Kawazu I. 2017. Observation of a stranded pelagic-stage juvenile olive ridley turtle with a missing right front flipper on Okinawa Island, Japan. Umigame Newsletter of Japan 105: 11–15. (in Japanese with English abstract)
  • Kawazu I, Nakada K, Maeda K, Sawamukai Y. 2016. Daily Changes in the Blood Levels of Two Steroids and Other Biochemicals Related to Vitellogenesis and Eggshell Formation during Internesting Intervals in a Captive Female Loggerhead Turtle Caretta caretta. Current Herpetology 35: 14–21.
  • Kawazu I, Komesu K, Kayo M. 2016. Hatching of eggs rescued from a green turtle involved in an automobile collision. Marine Turtle Newsletter 151: 24–26.
  • Funasaka N, Okabe H, Oki K, Tokutake K, Kawazu I, Yoshioka M. 2016. The occurrence and individual identification study of indo-pacific bottlenose dolphins Tursiops aduncus in the waters around Amami Oshima Island, Southern Japan: a preliminary report. Mammal Study　41: 163–169.
  • Hamabata T, Hikida T, Ishihara T, Kawazu I, Nashiki Y, Oki K, Tanaka T, Ui K, Kamezaki N.　2016. MtDNA analysis suggests local origin for pelagic stage juvenile green turtles collected in Japanese coastal waters. Pacific Science 70: 45–54.
  • Kobayashi N, Okabe H, Kawazu I, Higashi N, Miyahara H, Kato H, Uchida S. 2016. Peak mating and breeding period of Humpback Whales (Megaptera novaeangliae) in Okinawa Island Region in Japan. Open Journal of Animal Sciences 6: 169–179.
  • Kobayashi N, Okabe H, Kawazu I, Higashi N, Miyahara H, Kato H, Uchida S. 2016. Spatial distribution and habitat use patterns of humpback whales in Okinawa, Japan. Mammal Study 41: 207–214.
  • Matsuzawa Y, Kamezaki N, Ishihara T, Omuta K, Takeshita H, Goto K, Arata T, Honda H, Kameda K, Kashima Y, Kayo M, Kawazu I, Kumazawa Y, Kuroyanagi K, Mizobuchi K, Mizuno K, Oki K, Watanabe K, Yamamoto A, Yamashita Y, Yamato T, Hamabata T, Ishizaki A, Dutton PH. 2016. Fine scale genetic population structure of loggerhead turtles in the Northwest Pacific. Endangered Species Research 30: 83–93.
  • Yoshikawa N, Kamezaki N, Kawazu I, Hirai S, Taguchi S. 2016. Stock origin of the leatherback Turtles (Dermochelys coriacea) found in the vicinity of Japan revealed by mtDNA haplotypes. Current Herpetology 35: 115–121.
  • Kino M, Kawazu I, Maeda K. 2016. Preliminary examination on identification of appropriate coral fishes for cleaning shells of captive hawksbill turtle. Umigame Newsletter of Japan 104: 11–15. (in Japanese with English abstract)
  • Komesu K, Kogachi M, Kayo M, Kawazu I. 2016. Record of a hawksbill turtle with regular reproductive cycle in Ogimi of Okinawa Island, Japan. Umigame Newsletter of Japan 103: 6–10. (in Japanese with English abstract)
  • Takahashi Y, Furuzutsumi K, Nakanishi Y, Kawazu I. 2016. Repeated recapture as an indicator of the mating area of loggerhead turtles-Case study in the set-net of western waters of Okinawa Island, Japan-. Umigame Newsletter of Japan 103: 10–12. (in Japanese with English abstract)
  • Yamazaki K, Maeda K, Wakai M, Kawazu I. 2016. Dermatosis in captive green turtle hatchlings: Suspected herpes virus infection. Umigame Newsletter of Japan 104: 11–15. (in Japanese with English abstract)
  • Kawazu I, Kino M, Maeda K. 2015. Relationship between the water temperature experienced by captive loggerhead turtles (Caretta caretta) and eggshell formation. Herpetological Review 46: 364–368.
  • Kawazu I, Kino M, Yanagisawa M, Maeda K, Nakada K, Yamaguchi Y, Sawamukai Y. 2015. Signals of vitellogenesis and estrus in female hawksbill turtles. Zoological Science 32: 114–118.
  • Kawazu I, Kino M, Maeda K, Teruya H. 2015. Age and body size of captive hawksbill turtles at the onset of follicular development. Zoo Biology 34: 178–182.
  • Kawazu I, Maeda K, Kino M, Koyago M, Sawamukai Y. 2015. Optimal intervals for semen collection by electro-ejaculation in hawksbill turtles. Journal of Japanese Association of Zoos and Aquariums 56: 9–14. (in Japanese with English abstract)
  • Kawazu I, Maeda K, Sawamukai Y. 2015. Electroejaculation of Hawksbill Turtles: Assessment of Muscle Damage Caused by Electrostimulation. Umigame Newsletter of Japan 102: 10–15. (in Japanese with English abstract)
  • Kawazu I, Watanabe S, Maeda K, Ueda K, Miyahara H. 2015. Bacterial Flora in Abscess of Captive Loggerhead Turtle Hatchlings. Umigame Newsletter of Japan 102: 6–10. (in Japanese with English abstract)
  • Nakashima T, Kobayashi N, Yamada H, Katsumata T, Yoshida R, Kato H, Okabe H, Kawazu I, Yanase Y, Omine M, Terada M, Sugioka H, Kyo M. 2015. Repellence Effect of the New Sound for Underwater Speaker of Hydrofoil. TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation 9: 207–211.
  • Kino M, Maeda K, Kawazu I. 2015. Gastrointestinal contents of a Black turtle (Chelonia mydas agassizii) stranded at Okinawa Island, Japan. Umigame Newsletter of Japan 101: 8–10. (in Japanese with English abstract)
  • Matsumoto K, Suzuki M, Kawazu I. 2015. A stranding report of leatherback turtle at Okinawajima Island. Umigame Newsletter of Japan 101: 4–7. (in Japanese with English abstract)
  • Miyazato S, Umemoto H, Fukugawa Y, Miyamoto K, Kawazu I. 2015. Confirmation of loggerhead turtles (Caretta caretta) ingesting porcupine fish (Diodon sp.). Umigame Newsletter of Japan 101: 2–4. (in Japanese with English abstract)
  • Kawazu I, Maeda K, Koyago M, Nakada K, Sawamukai Y. 2014. Semen evaluation　of captive hawksbill turtles. Chelonian Conservation and Biology 13: 271–278.
  • Kawazu I, Kino M, Maeda K, Yamaguchi, Y, Sawamukai Y. 2014. Induction of oviposition by the administration of oxytocin in hawksbill turtles. Zoological Science 31: 831–835.
  • Kawazu I, Suzuki M, Maeda K, Kino M, Koyago M, Moriyoshi M, Nakada K, Sawamukai Y. 2014. Ovulation induction with follicle-stimulating hormone administration in Hawksbill turtles Eretmochelys imbricata. Current Herpetology 33: 88–93.
  • Kawazu I, Okabe H. 2014. Mating Season of Loggerhead Turtles in Western Waters of Okinawa Island. Umigame Newsletter of Japan 100: 2–7. (in Japanese with English abstract)
  • Kawazu I, Kayo M, Maeda K. 2014. A loggerhead turtle with a remigration interval of one year: first record from Jashiki Kunigami of Okinawa Island, Japan. Umigame Newsletter of Japan 100: 17–21. (in Japanese with English abstract)
  • Kayou M, Kawazu I. 2014. Observation of a nesting loggerhead turtle with a missing rear flipper. Umigame Newsletter of Japan 100: 21–25. (in Japanese with English abstract)
  • Kino M, Kawazu I. 2014. A stranding report of a young juvenile Olive ridley turtle (Lepidochelys olivacea) at Yagajijima Island, Okinawa. Umigame Newsletter of Japan 100: 7–11. (in Japanese with English abstract)
  • Kawazu I, Maeda K, Kino M, Oka S. 2013. Structure of the loggerhead turtle assemblage in okinawan waters estimated from variation in body size and blood profile. Current Herpetology 32: 190–196.
  • Suzuki K, Noda J, Yanagisawa M, Kawazu I, Sera K, Fukui D, Asakawa M, and Yokota H. 2012. Relationships between Curved Carapace Sizes and Plasma Major and Trace Element Status in Captive Hawksbill Sea Turtles (Eretmochelys imbricata). The Journal of Veterinary Medical Science 74: 1677–1680.
  • Suzuki K, Noda J, Yanagisawa M, Kawazu I, Sera K, Fukui D, Asakawa M, and Yokota H. 2012. Particle-Induced X-ray Emission Analysis of Elements　in Plasma from Wild and Captive Sea Turtles　(Eretmochelys imbricata, Chelonia mydas, and Caretta caretta) in Okinawa, Japan. Biological Trace Element Research 148: 302–308.
  • Yamaguchi Y, Kawazu I. 2002. Preliminary studies on catch forecast of yellowtail (Seriola quinqueradiata) caught by a set net off Nomozaki, Nagasaki Japan. p. 1980–1983. In The Japanese Society of Fisheries Science (ed.). Proceedings of International Commemorative Symposium 70th Anniversary of the Japanese Society of Fisheries Science. The Japanese Society of Fisheries Science, Tokyo.
  • Yamaguchi Y, Kawazu I, Samson R. 2001. Effect of current direction on an approaching process to a bated fish pot for mantis shrimp Oratosquilla oratoria. UPV Journal of Natural Science 6: 24–33.

Books

  • Omata M, Ueda K, Kawazu I. 2020. Disease of reptiles. p.102–104. Handbook of captive animals (aquarium 1). Japanese Association of Zoos and Aquariums (ed.), Tokyo. (in Japanese)
  • Hirate K, Kawazu I. 2017. Loggerhead turtles. p.188–190. Threatened Wildlife in Okinawa, Third Edition (Animals) – Red Data Okinawa. Okinawa Prefecture (ed.), Okinawa. (in Japanese)
  • Hirate K, Kawazu I. 2017. Green turtle. p.199–202. Threatened Wildlife in Okinawa, Third Edition (Animals) – Red Data Okinawa. Okinawa Prefecture (ed.), Okinawa. (in Japanese)
  • Hirate K, Kawazu I. 2017. Hawksbill turtles. p.182–183. Threatened Wildlife in Okinawa, Third Edition (Animals) – Red Data Okinawa. Okinawa Prefecture (ed.), Okinawa. (in Japanese)

Grants and Awards

  • 2024: Award for best technique and research at the Journal of Japanese Association of Zoos and Aquariums in 2024 on “Age and body characteristics of captive green turtles at the onset of
  • 2023: 37th Koga Award at Japanese Association of Zoos and Aquariums on “Ecological and conservation research through captive breeding of sea turtles”
  • 2022: 37th Koga Award at Japanese Association of Zoos and Aquariums on “Ecological and conservation research through captive breeding of sea turtles”
  • 2022: Award for best technique and research at the Journal of Japanese Association of Zoos and Aquariums in 2022 on “Suppression of aggressive behavior in a captive pygmy killer whale using behavior modification”
  • 2017: Award for best presentation at the 62th Aquarium Specialist Conference on “Breeding success of captive Black turtles”
  • 2017: Prize of Best Paper Award of Mammal study on “Spatial distribution and habitat use patterns of humpback whales in Okinawa, Japan.”

Affiliated academic society

  • The Zoological Society of Japan
  • Herpetological Society of Japan
  • Sea Turtle Association of Japan

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