Retrogression of dispersal ability in insular freshwater fish

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K06412
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: Niigata University
• Principal Investigator: IIDA Midori 新潟大学, 佐渡自然共生科学センター, 准教授 (30745328)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 島嶼 / 分散 / 淡水魚 / 通し回遊 / 河川 / 環境

Outline of Final Research Achievements

To understand dispersal ability of freshwater fish in islands, Gobioid, Cottidae, Plecoglossidae were examined in Sado Island. Comparable islands and areas were also selected. Field survey, microchemistry and isotopic analyses of otoliths showed that many of examined individuals had marine larval duration. In contrast, newly hatched larvae of Cottidae survived longer in freshwater than in seawater. Insular freshwater fish would be adapted to unique environments in the islands rather than having freshwater residency.

Free Research Field

水圏生物学・魚類生態学

Academic Significance and Societal Importance of the Research Achievements

本研究は，陸域の動植物にみられる，島嶼における分散能力の消失が，淡水域でもみられるのかを検証した。またこれまで知見のなかったヨシノボリ属など複数種の海洋生活期間を耳石の日齢査定により初めて明らかにした。これらの成果は，島嶼の生物学，魚類の生態学に重要な知見となった。また，主な調査地である佐渡島において，希少種であるカンキョウカジカやチチブについて，基本的な生態を明らかにし，これらの保全策に有用である。