A new approach to mangrove estuary conservation based on fish distribution and migration ecology

2017 Fiscal Year Final Research Report

• Project/Area Number: 26252027
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: The University of Tokyo
• Principal Investigator: SANO Mitsuhiko 東京大学, 大学院農学生命科学研究科(農学部), 教授 (50178810)
• Co-Investigator(Kenkyū-buntansha): 渡邊 良朗 東京大学, 大気海洋研究所, 教授 (90280958) ; 河野 裕美 東海大学, 付置研究所, 教授 (30439682) ; 岡本 研 東京大学, 大学院農学生命科学研究科(農学部), 准教授 (20160715) ; 菊池 潔 東京大学, 大学院農学生命科学研究科(農学部), 准教授 (20292790) ; 中村 洋平 高知大学, 教育研究部総合科学系黒潮圏科学部門, 准教授 (60530483) ; 白井 厚太朗 東京大学, 大気海洋研究所, 助教 (70463908) ; 細谷 将 東京大学, 大学院農学生命科学研究科(農学部), 助教 (60526466) ; 南條 楠土 国立研究開発法人水産研究・教育機構, 水産大学校, 助教 (70725126)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: マングローブ水域 / 非回遊魚 / 耳石 / 微量元素組成分析 / 酸素同位体比分析 / 遺伝的な分化 / DNA分析 / 琉球諸島

Outline of Final Research Achievements

To establish conservation areas in mangrove estuaries, fish distribution and migratory ecology were examined in the Ryukyu Islands, Japan. Otolish oxygen isotopic or microchemisry analyses indicated that three dominant mangrove fishes (Zenarchopterus dunckeri, Fibramia amboinensis and Neopomacentrus taeniurus) were not marine migrant species that spawn at sea and enter estuaries as juveniles, but rather estuarine resident species that complete their entire life cycle within the estuarine environment. Moreover, in Z. dunckeri, the genetic divergence was detected not only between islands (e.g. Ishigaki Island and Miyako Island), but also between rivers within an island (Ishigaki Island), suggesting the occurrence of several different populations within a single island due to restricted movements. These results showed that small spatial scale conservation, such as for each river or an area where some neighboring rivers within an island were combined, is needed in mangrove estuaries.

Free Research Field

水域保全学