Koeda Keita

写真a

Title

Assistant Professor
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Current Affiliation Organization 【 display / non-display 】

  • Duty   University of the Ryukyus   Faculty of Science   Assistant Professor  

  • Concurrently   University of the Ryukyus   Graduate School of Engineering and Science   Chemistry, Biology and Marine Science   Assistant Professor  

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External Career 【 display / non-display 】

  • 2014.04
    -
    2017.03

    Kagoshima University  

  • 2015.05
    　
    　

    Tokyo Metropolitan University  

  • 2017.04
    -
    2019.03

     

  • 2019.04
    　
    　

     

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Research Interests 【 display / non-display 】

  • 魚類学

  • Fish fauna

  • Ichthyology

  • Biogeography

  • Life cycle

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Research Areas 【 display / non-display 】

  • Life Science / Ecology and environment

  • Life Science / Biodiversity and systematics

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Published Papers 【 display / non-display 】

  • First Japanese Record of the Deep-sea Scorpionfish Phenacoscorpius megalops (Teleostei: Scorpaenidae) from Minamidaito Island

    Sato M.

    Species Diversity ( 日本動物分類学会 )  31 ( 1 ) 63 - 69   2026.04

    Type of publication: Research paper (scientific journal)

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    <p>A single specimen (45.9 mm standard length) of the deep-sea scorpionfish <i>Phenacoscorpius</i> <i>megalops</i> Fowler, 1938 (Teleostei: Scorpaenidae) was collected by ROV (remotely operated vehicle) from within an unidentified colonial sun coral [Dendrophylliidae gen. sp. (Scleractinia)] on a steep sea floor off Minamidaito Island, southern Japan. <i>Phenacoscorpius</i> <i>megalops</i>, characterized by the absence of palatine teeth, an incomplete lateral line, and a dark blotch on the dorsal fin, has been previously recorded from the western and central Pacific, including Vietnam, the South China Sea, Taiwan, the Philippines, Indonesia, Vanuatu, the Emperor Seamounts, and the Hawaiian Islands. This is the first record from Japanese waters.</p>

  • Absence of the luciferase gene in the genome of the kleptoprotein bioluminescent fish Parapriacanthus ransonneti.

    Bessho-Uehara M, Yamaguchi K, Koeda K, Matsuzaki S, Maeda T, Shigenobu S

    Scientific reports ( Scientific Reports )  16 ( 1 )   2026.04 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    The metabolic and physiological functions of the living organisms are primarily governed by enzymes encoded within their own genomes. An exception to this doctrine is the phenomenon of kleptobiology, where individuals sequester and use functional modules from their prey. The fish Parapriacanthus ransonneti possesses a luciferase that catalyzes a light-emitting reaction in its light organs. Intriguingly, the protein sequence of this luciferase is identical to that of the ostracod-derived luciferase. We recently demonstrated that the fish sequesters and retains the luciferase from the luminous prey, leading to the hypothesis that the fish does not have a gene encoding the luciferase. To test this hypothesis, here, we produced a high-quality draft genome of P. ransonneti. The assembled size of 625 Mbp closely matches the experimentally estimated genome size of 613 Mbp, and we constructed a gene model with a high BUSCO score. Our search within this gene model did not detect any ostracod-type luciferase genes. Expanding our search to include the entire assembled genome, raw reads, and the transcriptome also supported the absence of the luciferase genes. These results suggest that P. ransonneti lacks the luciferase gene, supporting our previous discovery that it utilizes stolen proteins for bioluminescence.

  • <i>Vanderhorstia supersaiyan</i> sp. nov. (Perciformes: Gobiidae) collected from the twilight zone off Ishigaki-jima Island, Okinawa, Japan

    Koeda, K; Hirasaka, H; Sato, M

    ICHTHYOLOGICAL RESEARCH ( Ichthyological Research )  73 ( 3 ) 322 - 328   2025.11 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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  • Records of the Hawaiian Flagtail <i>Kuhlia sandvicensis</i> (Centrarchiformes: Kuhliidae) from the oceanic islands of Japan

    Sasaki Daichi, Abe Kimiya, Koeda Keita, Kimura Seishi

    Japanese Journal of Ichthyology ( The Ichthyological Society of Japan )  72 ( 2 ) 243 - 249   2025.11 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    <p>Two specimens of <i>Kuhlia sandvicensis</i> (Steindachner, 1876), previously reported in Japanese waters only from Minamitori-shima Island, were recently collected from Minamidaito-jima Island, Japan. In Japanese waters, <i>K. sandvicensis</i> is most similar to <i>Kuhlia munda</i> (De Vis, 1884), but differs from the latter in having a greater number of lower gill rakers (25–30 vs. 21–26), smaller eyes (eye diameter 2.88–3.45 in head length vs. 2.30–2.80), and no dark markings on the body and fins (except black caudal-fin margins in juveniles) (vs. a black spot on the caudal-fin base and dark diagonal bands on both caudal-fin lobes). The new standard Japanese name “Saihate-yugoi" is proposed for the species.</p>

  • Environmental DNA analysis at multiple taxonomic levels highlights geographic variation in subtropical coastal marine communities

    Gibu, K; Hamamoto, K; Koeda, K; Nishijima, M; Kise, H; Mizuyama, M; Suzuki, A; Aoki, N; Yasuda, N; Iguchi, A

    SCIENTIFIC REPORTS ( Scientific Reports )  15 ( 1 ) 20791 - 20791   2025.07 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    In this study, environmental DNA was used to assess marine diversity across the southern part of Okinawa Island, Japan, located in the subtropics. Diversity analysis was performed for prokaryotes and eukaryotes. Differences in diversity were detected between the west side of Okinawa (an area exposed to groundwater influenced by land-derived loads) and the east side (an area where coral reefs, beaches, and seagrass beds coexist). In particular, the community composition of prokaryotes, for which 16S rRNA metabarcoding analysis was performed, differed markedly between the east and west sides of the island. Differences in the composition of eukaryotic communities between the east and west coasts are relatively unclear, likely due to the fact that 18S rRNA metabarcoding targets a wide range of species (including almost all eukaryotic taxonomic groups), making it difficult to identify differences. On the other hand, MiFish analysis indicated that distributions of various fish species differed markedly between the east and west coasts of the island, suggesting a close relationship between differences in the coastal environment and the habitat selection by fish. We show that prokaryotic communities can be evaluated using eDNA analysis in order to monitor extensive geographic environments via water cycles. This can then be used to promote understanding of geographic variations of marine community structures of eukaryotes, including fish.

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Books 【 display / non-display 】

  • Identification guide to fishes of the Amami Islands in the Ryukyu Archipelago, Japan

    Keita Koeda ( Part: Single Author )

    Minaminippon Shinbun Kaihatsu Center, Kagoshima  2019.02

  • Identification guide to fishes of the Amami Islands, Japan

    Keita Koeda ( Part: Single Author )

    The Kagoshima University Museum, Kagoshima  2018.04

  • Field guide to fishes landed at Uchinoura Fishing Port, Kagoshima, Japan.

    Keita Koeda ( Part: Editing and Writing )

    The Kagoshima University Museum, Kagoshima  2018.03

  • Field guide to fishes of Kuchinoerabu-jima Island in the Osumi Group, Kagoshima, southern Japan

    Keita Koeda ( Part: Joint Editing and Writing )

    The Kagoshima University Museum, Kagoshima  2017.12

  • Commercial and Bycatch Market Fishes of Panay Island, Republic of the Philippines

    Keita Koeda ( Part: Single Author )

    2017.01

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Other Papers 【 display / non-display 】

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SDGs 【 display / non-display 】

  • 1)琉球列島における魚類の生態学的研究
    2)琉球列島における魚類の多様性形成機構の解明
    3)黒潮流域の海産魚類相の時空間的変移

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