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Ecological Study of the Indo-Pacific Bottlenose Dolphin in Mikura Island, Aimed at Wildlife Conservation

Research Project

Project/Area Number 21K12331
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 64040:Social-ecological systems-related
Research InstitutionTokai University

Principal Investigator

Kita Yuki  東海大学, 生物学部, 准教授 (30710917)

Project Period (FY) 2021-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2023: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2022: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2021: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Keywordsミナミハンドウイルカ / 摂餌生態 / 繁殖生態 / 保全 / 年齢推定
Outline of Research at the Start

御蔵島に生息するミナミハンドウイルカの繁殖生態ならびに摂餌生態を明らかにし、本種の適切な保全管理方法の提言を目的とする。申請者の研究により蓄積された長年のデータと、糞を用いる非侵襲的な分析方法を進めることによって、本研究計画最終年度には、学術的「問い」として示した、①繁殖成功率の高い個体の有無、②繁殖成功率と性成熟年齢との差異、③個体や季節による食性の違い、④2012年からの食物網構造の変化のみならず、御蔵島周辺海域における環境変化をも捉えることが可能となる。本研究成果は御蔵島地域個体群保全のみならず、小型鯨類全般の保全に向けた基礎生態解明のモデルケースになると期待される。

Outline of Final Research Achievements

In order to clarify the reproductive and feeding ecology of the Indo-Pacific bottlenose dolphin that inhabits Mikura Island. We conducted dietary, kinship, and age analyses using 652 fecal DNA samples obtained between 2015 and 2023.
In particular, dietary analysis suggested that the Indo-Pacific bottlenose dolphins that inhabit Mikura Island do not have individual food preferences, and that their main prey consists of four species of fish and two species of cephalopods. Canonical correpondence analysis (CCA) was also performed and differences were detected by month, sex, and maturity stage.
Furthermore, epigenetic analysis was attempted using fecal DNA, and age estimation was successful using degraded genes such as feces.

Academic Significance and Societal Importance of the Research Achievements

これまで御蔵島に生息するミナミハンドウイルカの摂餌生態は数個体の胃内容物や行動観察によるもののみで,その全容を捉えられていなかった.海洋生態系で高次捕食者に位置する彼らの摂餌生態を把握することは,彼らの生息する環境の豊かさを多角的に評価する上で重要であることから,本研究成果はその一助となると期待される.
また,糞という劣化した遺伝子からの年齢推定の成功は,目視観察が開始された1994年当初より既に成熟していたとみられる個体の年齢を推定する上で非常に有効であると考えられる.

Report

(4 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Research-status Report
  • 2021 Research-status Report
  • Research Products

    (5 results)

All 2023 2021

All Journal Article (3 results) (of which Peer Reviewed: 3 results,  Open Access: 2 results) Presentation (2 results) (of which Int'l Joint Research: 1 results)

  • [Journal Article] Non‐invasive age estimation based on faecal DNA using methylation‐sensitive high‐resolution melting for Indo‐Pacific bottlenose dolphins2023

    • Author(s)
      Genfu Yagi, Huiyuan Qi, Kana Arai, Yuki F. Kita, Kazunobu Kogi, Tadamichi Morisaka, Motoi Yoshioka, Miho Inoue‐Murayama
    • Journal Title

      Molecular Ecology Resources

      Volume: 24 Issue: 2 Pages: 1-12

    • DOI

      10.1111/1755-0998.13906

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] 定住海域以外に出現したミナミハンドウイルカ様個体の種判別および種間交雑の可能性2021

    • Author(s)
      北夕紀,佐々木萌美,立川利幸,十万仁志,寺沢文男,小木万布,酒井麻衣,村山美穂,森阪匡通,神田育子,吉岡基
    • Journal Title

      DNA多型

      Volume: 29 Pages: 5-11

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] External Morphological and Molecular Evidence of Natural Intrageneric Hybridization between Common and Indo-Pacific Bottlenose Dolphins (Tursiops truncatus × T. aduncus) from Japanese Waters2021

    • Author(s)
      Inamori D, Kita YF, Funasaka N.
    • Journal Title

      Mammal Study

      Volume: 47 Issue: 2 Pages: 1-8

    • DOI

      10.3106/ms2021-0039

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] Age estimation of Indo-Pacific bottlenose dolphins (Tursiops aduncus) based on DNA methylation from fecal samples2023

    • Author(s)
      Yagi G, Qi H, Arai K, Kita YF, Kogi K, Morisaka T, Yoshioka M, Inoue-Murayama M.
    • Organizer
      13TH INTERNATIONAL MAMMALOGICAL CONGRESS
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research
  • [Presentation] 糞由来DNA を用いた御蔵島ミナミハンドウイルカの食性解析2023

    • Author(s)
      北夕紀, 久野晃子, 小木万布, 村山美穂
    • Organizer
      令和5 年度日本水産学会春季大会
    • Related Report
      2022 Research-status Report

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Published: 2021-04-28   Modified: 2025-01-30  

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