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Okinawa Churashima RESEARCH CENTER

Research on marine organisms

Research staff profile

Shinichiro Oka

Shin-ichiro Oka, Ph.D.

(Chief Research Scientist, Zoological Laboratory)

Area of expertise Life history of fishes and crustaceans
Research content Fish ecology and morphology of early life stages
Life history of fishes and crustaceans


  • 1998 - Bachelor of Marine Science, University of the Ryukyus, Japan
  • 2000 - Master of the Faculty of Science, University of the Ryukyus, Japan
  • 2000 - Employed by Nishinihon Institute of Technology
  • 2010 - Current post at the Okinawa Churashima Foundation Research Center
  • 2017 - Ph.D. at Ryukyu University, Japan

Essays, Reports

  • Oka, S. & K. Tachihara. 2001. Estimation of spawning sites in the spotted flagtail, Kuhlia marginata, based on sperm motility. Ichthyological Research, 48: 425-427.
  • Oka, S. & K. Tachihara. 2008. Migratory history of the spotted flagtail, Kuhlia marginata. Environmental Biology of Fishes, 81(3):321-327.
  • Oka, S. & T. Higashiji. 2012. Early ontogeny of the big roughy Gephyroberyx japonicus (Beryciformes: Trachichthyidae) in captivity. Ichthyological Research, 59: 282-285.
  • Kawazu, I, K. Maeda, M. Kino & S. Oka. 2013. Structure of the Loggerhead Turtle Assemblage in Okinawan Waters Estimated from Variation in Body Size and Blood Profile. Current Herpetology, 32: 190-196.
  • Oka, S, S. Matsuzaki & M. Toda. 2013. Identification of individual coconut crabs, Birgus latro, on the basis of the pattern of grooves on the carapace. Crustacean Research, 42: 17-23.
  • S. Oka, S. Matsuzaki, K. Miyamoto. 2014. Current status of the coconut crab, Birgus latro (Anomura: Coenobitidae) in Ocean Expo Park, Okinawa-jima Island, southwestern Japan., Biological Magazine Okinawa 52: 11-19.
  • Oka, S, & S. Odoriba. 2014. Morphological development of larval and juvenile Alectis indica (Perciformes: Carangidae) reared in captivity. Ichthyological Research, 61: 298-302.
  • S. Oka, K. Miyamoto. 2014. Larvae and juvenile fishes collected by light-trap sampling at Shinzato Port, Okinawa Island southern Japan, Fauna Ryukyuana, 16: 1-11
  • K. Miyamoto, S. Oka. 2014. Occurrence of Gerres macracanthus (Perciformes: Gerreidae) from Okinawa Island, Ryukyu Archipelago, Japan. Fauna Ryukyuana, 17: 1-6
  • Oka, S., K. Miyamoto, S. Matsuzaki & T. Sato. 2015. Growth of the coconut crab, Birgus latro, at its northernmost range estimated from mark-recapture using individual identification based on carapace grooving patterns. Zoological Science, 32: 260-265.
  • Oka, S. & K. Miyamoto. 2015. Reproductive biology and growth of bluestripe herring Herklotsichthys quadrimaculatus (Rüppell, 1837) in the northernmost waters. Journal of Applied Ichthyology, 31: 709-713,
  • Oka S. & Miyamoto K. 2015. Pelagic juvenile of Plectroglyphidodon johnstonianus Flower & Ball, 1924 (Perciformes, Pomacentridae, Stegastinae) identified from morphometric and genetic evidence. Fauna Ryukyuana, 20:1-6.
  • Miyamoto, K., A. Nonaka & S. Oka. 2015. Northernmost record of a poorly known tuskfish, Choerodon margaritiferus (Perciformes: Labridae), from southern Japan, and first description of a female. Zootaxa, 4007 (1): 82-90.
  • Tomita T, Murakumo K, Miyamoto K, Sato K, Oka S, Kamisako H, Toda M. 2015. Eye retraction in the giant guitarfish, Rhynchobatus djiddensis (Elasmobranchii: Batoidea): a novel mechanism for eye protection in batoid fishes. Zoology, doi:10.1016/j.zool.2015.09.004
  • Tomita S, Matsuzaki S, Oka S, Toda M, Imai H. 2016. High level of genetic diversity and gene flows in an endangered population of Hypseleotris cyprinoides on Okinawajima Island, Ishigakijima Island and Luzon Island. Japanese Journal of Ichthyology, 63: 27-32.
  • Oka S, Miyamoto K, Tokutake K, Nagata S, Yamazaki K. 2016. The nature outreach using the wild coconut crab resource in Ocean Expo Park, Okinawa, Japan. Environmental Education, 26:78-84.
  • Oka S, Miyamoto K, Matsuzaki S. 2016. Long-term sedentary behavior of coconut crab in their northernmost range. International Journal of Pure and Applied Zoology, 4: 174-178.
  • Oka S, Tomita T, Miyamoto K. 2016. A mighty claw: Pinching force of the coconut crab, the largest terrestrial crustacean. PLOS ONE, 11(11): e0166108. doi: 10.1371/journal.pone.0166108.
  • Miya M, Minamoto T, Yamanaka H, Oka S, Sato K, Yamamoto S, Sado T, Doi H. 2016. Use of a filter cartridge for filtration of water samples and extraction of environmental DNA. Journal of Visualized Experiments, e54741. doi:10.3791/54741.
  • Tomita, T. Miyamoto, K., Kawaguchi, A., Toda, M., Oka, S., Nozu, R., Sato, K. 2016. Dental ontogeny of a white shark embryo. Journal of Morphology. doi: 10.1002/jmor.20630.
  • Miyamoto, K., Oka, S., Yonamine, H., Agarie, S., Genba, H., Hanahara, N. 2017. A high-density habitat and genetic characteristics of the Oriental weatherfish, Misgurnus anguillicaudatus, and the Asian swamp eel, Monopterus albus, found in Nago City, Okinawa-jima Island, southwestern Japan. Fauna Ryukyuana, 34: 15-20.
  • Tomita, T., Toda, M., Miyamoto, K., Oka, S., Ueda, K., and Sato, K. 2018 Development of the lunate-shaped caudal fin in white shark embryos. The Anatomical Record.
  • Oka S, Hanahara N, Shintani T. 2018. First Japanese record of the Mindoro snake eel Lamnostoma mindorum (Actinopterygii: Anguilliformes: Ophichthidae) from the Ryukyu Islands. Fauna Ryukyuana, 42: 5-8.
  • Tomita T, Toma H, Murakumo K, Yanagisawa M, Yano N, Oka S, Miyamoto K, Hanahara N, Sato K. 2018. Captive Birth of Tiger Shark (Galeocerdo cuvier) Revealed the Shift of Respiratory Mode Across Parturition. Copeia, in press.
  • Tokutake K, Yamasaki K, Oka S. 2018. Individual identification for wild Kuroiwa's ground gecko, Goniurosaurus kuroiwae kuroiwae, on the basis of the natural marks, 2018: 48-51.


  • River Ecology and Conservation in the Ryukyus, edited by S. Shokita, K. Tachihara, Ryukyu-ayu Restorative Association, joint authorship
  • An Atlas of Early Stage Fishes in Japan Second Edition, edited by M. Okiyama, Tokai University Press, joint authorship

Affiliated academic society

  • The Ichthyological Society of Japan
  • Research Society of Fish Larva
  • The Carcinological Society of Japan