Mechanism of timing of downstream migration for Japanese eels

• Project/Area Number: 18K14510
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: The University of Tokyo (2021-2022); Kobe University (2018-2020)
• Principal Investigator: Itakura Hikaru 東京大学, 大気海洋研究所, 助教 (40749040)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 回遊開始機構 / ニホンウナギ / 春機発動 / 標識再捕 / 耳石成長解析 / 回遊意思決定 / 成長履歴解析 / 耳石分析 / 標識放流実験 / 銀ウナギ / 成長解析 / 成長履歴 / ウナギ属魚類 / 生息域利用 / 降河回遊開始 / 標識再捕実験 / 降河回遊開始機構

Outline of Final Research Achievements

The objective of this study was to establish a method to predict the onset of downstream migration of Japanese eels at the individual level in summer, and to clarify the process of decision-making mechanisms related to the onset of the migration of eels. Using mark-recapture experiment of female Japanese eels in an artificial pond, it was found that the diameter of egg of puberty individuals was significantly larger than that of non-puberty individuals in fall, indicating that the onset of migration of eels in fall is predictable at the individual level during summer. In addition, growth analysis of eels collected in Lake Jinzei, Shimane Prefecture, revealed that individuals having high growth pattern start their migration at younger age than low growth pattern individuals.

Academic Significance and Societal Importance of the Research Achievements

本研究の実施により、これまで困難であった秋季におけるウナギ属魚類の銀化/回遊開始予測について、夏季に卵径を測定して春機発動の有無を調べることで、秋季の銀化/回遊開始を事前に個体レベルで予測することが可能となった。これにより、黄ウナギをその年に銀化/回遊開始個体か残留個体かに判別することで両者の成長パターンなどの比較から、ウナギ属魚類の回遊開始に関わる意思決定機構の解明が可能となるため学術的意義は高い。また、事前の銀化/回遊開始の予測は銀ウナギの確保を可能とするため、社会的意義も高いものと判断できる。

Research Products

• [Int'l Joint Research] Institute of Fisheries Science/National Taiwan University(中国)
• [Journal Article] Tracking oxy-thermal habitat compression encountered by Chesapeake Bay striped bass through acoustic telemetry (2021)
  • Author(s): Itakura Hikaru、O’Brien Michael H P、Secor David
  • Journal Title: ICES Journal of Marine Science Volume: 78 Issue: 3 Pages: 1049-1062
  • DOI: 10.1093/icesjms/fsab009
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Large contribution of pulsed subsidies to a predatory fish inhabiting large stream channels (2021)
  • Author(s): Itakura Hikaru、Miyake Yoichi、Kitagawa Takashi、Sato Takuya、Kimura Shingo
  • Journal Title: Canadian Journal of Fisheries and Aquatic Sciences Volume: 78 Issue: 2 Pages: 144-153
  • DOI: 10.1139/cjfas-2020-0004
  • NAID: 120007017125
  • Peer Reviewed / Open Access
• [Journal Article] Habitat preference, movements and growth of giant mottled eels, Anguilla marmorata, in a small subtropical Amami-Oshima Island river (2020)
  • Author(s): Itakura Hikaru、Wakiya Ryoshiro
  • Journal Title: PeerJ Volume: 8 Pages: e10187-e10187
  • DOI: 10.7717/peerj.10187
  • NAID: 120006938917
  • Peer Reviewed / Open Access
• [Journal Article] Estimations of Riverine Distribution, Abundance, and Biomass of Anguillid Eels in Japan and Taiwan Using Environmental DNA Analysis (2020)
  • Author(s): Hikaru Itakura , Ryoshiro Wakiya , Masayuki K. Sakata , Hsiang-Yi Hsu , Shih-Chong Chen , Chih-shao Yang , Satoshi Yamamoto , Toshifiumi Minamoto
  • Journal Title: Zoological Studies Volume: －
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Anguillid eels as a surrogate species for conservation of freshwater biodiversity in Japan (2020)
  • Author(s): Itakura H, Wakiya R, Gollock M, Kaifu K
  • Journal Title: Scientific Reports Volume: 10 Issue: 1 Pages: 8790-8790
  • DOI: 10.1038/s41598-020-65883-4
  • NAID: 120006882493
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Past and Lost Influence of the Kuroshio on Estuarine Recruitment of Anguilla japonica Glass Eels (2020)
  • Author(s): Miyake Y, Tellier M, Takeshige A, Itakura H, Yoshida A, Kimura S
  • Journal Title: Journal of Oceanography Volume: － Issue: 4 Pages: 1-12
  • DOI: 10.1007/s10872-020-00543-9
  • NAID: 40022290842
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Use of rocks as refuges by Japanese eel, <i>Anguilla japonica</i>, in artificial pond, revealed by acoustic telemetry. (2019)
  • Author(s): 海部健三 , 竹野遼馬 , 市川光太郎 , 高木淳一 , 脇谷量子郎 , 板倉光 , 平江多績 , 猪狩忠光 , 三田村啓理 , 荒井修亮
  • Journal Title: Ecology and Civil Engineering Volume: 22 Issue: 1 Pages: 83-92
  • DOI: 10.3825/ece.22.83
  • NAID: 130007705207
  • ISSN: 1344-3755, 1882-5974
  • Year and Date: 2019-07-28
  • Peer Reviewed / Open Access
• [Journal Article] Habitat use of Japanese eel, <i>Anguilla japonica</i>, in brackish water lake, revealed by acoustic telemetry. (2019)
  • Author(s): 海部健三 , 竹野遼馬 , 市川光太郎 , 三田村啓理 , 高木淳一 , 脇谷量子郎 , 板倉光 , 石井潤 , 荒井修亮
  • Journal Title: Ecology and Civil Engineering Volume: 22 Issue: 1 Pages: 73-82
  • DOI: 10.3825/ece.22.73
  • NAID: 130007705216
  • ISSN: 1344-3755, 1882-5974
  • Year and Date: 2019-07-28
  • Peer Reviewed / Open Access
• [Journal Article] Distribution of naturally recruited wild Japanese eels in Japan revealed by otolith stable isotopic ratios and document investigation (2019)
  • Author(s): YONETA AKIHITO、ITAKURA HIKARU、ARAI KOHMA、KAIFU KENZO、YOSHINAGA TATSUKI、MIYAKE YOICHI、SHIRAI KOTARO、KIMURA SHINGO
  • Journal Title: NIPPON SUISAN GAKKAISHI Volume: 85 Issue: 2 Pages: 150-161
  • DOI: 10.2331/suisan.18-00038
  • NAID: 130007622909
  • ISSN: 0021-5392, 1349-998X
  • Year and Date: 2019-03-15
  • Peer Reviewed / Open Access
• [Journal Article] Anthropogenic impacts on the distribution of wild and cultured Japanese eels in the Tone River watershed, Japan, from otolith oxygen and carbon stable isotopic composition (2019)
  • Author(s): Arai K, Itakura H, Yoneta A, Kaifu K, Shirai K, Miyake Y, Kimura S
  • Journal Title: Environmental Biology of Fishes Volume: 102 Issue: 11 Pages: 1405-1420
  • DOI: 10.1007/s10641-019-00915-1
  • Peer Reviewed / Open Access
• [Journal Article] Age, growth, and sex ratios of the giant mottled eel, Anguilla marmorata, in freshwater habitats near its northern geographic limit: a comparison to tropical regions (2019)
  • Author(s): Wakiya R, Itakura H, Kaifu K
  • Journal Title: Zoological Studies Volume: 58
  • Peer Reviewed / Open Access
• [Journal Article] Environmental DNA analysis reveals the spatial distribution, abundance, and biomass of Japanese eels at the river‐basin scale (2019)
  • Author(s): Itakura Hikaru、Wakiya Ryoshiro、Yamamoto Satoshi、Kaifu Kenzo、Sato Takuya、Minamoto Toshifumi
  • Journal Title: Aquatic Conservation: Marine and Freshwater Ecosystems Volume: 29 Issue: 3 Pages: 361-373
  • DOI: 10.1002/aqc.3058
  • NAID: 120006599158
  • Peer Reviewed
• [Journal Article] Distribution of wild and stocked Japanese eels in the lower reaches of the Tone River catchment revealed by otolith stable-isotope ratios (2018)
  • Author(s): Itakura Hikaru、Arai Kohma、Kaifu Kenzo、Shirai Kotaro、Yoneta Akihito、Miyake Yoichi、Secor David H.、Kimura Shingo
  • Journal Title: Journal of Fish Biology Volume: 93 Issue: 5 Pages: 805-813
  • DOI: 10.1111/jfb.13782
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Multiple habitat use of Japanese sea bass Lateolabrax japonicus in the estuary region of the Tone River system, implied by stable isotope analysis (2018)
  • Author(s): Miyake Yoichi、Itakura Hikaru、Takeshige Aigo、Onda Hiroaki、Yamaguchi Akira、Yoneta Akihito、Arai Kohma、Hane Yulina V.、Kimura Shingo
  • Journal Title: Ichthyological Research Volume: 66 Issue: 1 Pages: 172-176
  • DOI: 10.1007/s10228-018-0655-2
  • NAID: 40021806379
  • Peer Reviewed
• [Journal Article] Correction to: Predation on glass eels of Japanese eel Anguilla japonica in the Tone River Estuary, Japan (2018)
  • Author(s): Miyake Yoichi、Takeshige Aigo、Itakura Hikaru、Itoh Hajime、Onda Hiroaki、Yamaguchi Akira、Yoneta Akihito、Arai Kohma、Hane Yulina V.、Kimura Shingo
  • Journal Title: Fisheries Science Volume: 84 Issue: 6 Pages: 1015-1016
  • DOI: 10.1007/s12562-018-1257-7
  • Peer Reviewed
• [Journal Article] Depletion of naturally recruited wild Japanese eels in Okayama, Japan, revealed by otolith stable isotope ratios and abundance indices (2018)
  • Author(s): Kaifu Kenzo、Yokouchi Kazuki、Higuchi Tomihiko、Itakura Hikaru、Shirai Kotaro
  • Journal Title: Fisheries Science Volume: 84 Issue: 5 Pages: 757-763
  • DOI: 10.1007/s12562-018-1225-2
  • NAID: 40021650810
  • Peer Reviewed
• [Presentation] 北西太平洋におけるオオウナギの幼生分散過程 (2022)
  • Author(s): 祝 倩怡・熊 觀梅・萩原聖士・脇谷量子郎・ 羽根由里奈・板倉 光・木村伸吾
  • Organizer: 令和4年度日本水産学会春季大会
• [Presentation] Tracking oxy-thermal habitat compression encountered by Chesapeake Bay striped bass through acoustic telemetry (2021)
  • Author(s): Itakura Hikaru、O’Brien Michael H P、Secor David
  • Organizer: 151st Annual Meeting American Fisheries Society
  • Int'l Joint Research
• [Presentation] 奄美大島におけるオオウナギの年齢と成長 (2019)
  • Author(s): 脇谷量子郎・板倉光・海部健三
  • Organizer: 東アジア鰻学会、第二回研究発表会
• [Presentation] 天然ニホンウナギの生殖腺の性分化 (2019)
  • Author(s): 堀内萌未・中司大智・長谷川祐也・萩原聖士・板倉光・山下洋・ 久米学・寺島佑樹・塚本勝巳・井尻成保・足立伸次
  • Organizer: 東アジア鰻学会、第二回研究発表会
• [Presentation] 奄美大島におけるオオウナギの年齢と成長 (2019)
  • Author(s): 脇谷量子郎・板倉光・海部健三
  • Organizer: 日本水産学会春季大会
• [Presentation] 天然ニホンウナギにおける形態的性分化開始時期 (2019)
  • Author(s): 堀内萌未・中司大智・長谷川祐也・萩原聖士・板倉光・山下洋・ 久米学・寺島佑樹・塚本勝巳・井尻成保・足立伸次
  • Organizer: 日本水産学会春季大会
• [Presentation] ウナギ属魚類は淡水域の生物多様性保全の指標種となる (2019)
  • Author(s): 板倉光・脇谷量子郎・海部健三
  • Organizer: 日本水産学会春季大会
• [Presentation] Distribution of naturally recruited Japanese eels in rivers as inferred from otolith stable isotope ratios (2018)
  • Author(s): Itakura H, Arai K, Yoneta A, Kaifu K, Shirai K, Kimura S
  • Organizer: 6th International Otolith Symposium
  • Int'l Joint Research
• [Book] ウナギの科学 (2019)
  • Author(s): 塚本 勝巳
  • Total Pages: 240
  • Publisher: 朝倉書店
  • ISBN: 9784254485028