カテゴリ

論文発表

発表または掲載年月日

2026.06.03

発表学会／学会誌名

一般社団法人　日本魚類学会

発表題目

環境DNAにより明らかになった琵琶湖南湖の魚類相 ―在来種の回復に着目して―

発表者

伊藤 玄1, 2・倉本真央3・近藤昭宏3・中村昌文3・石崎大介4・田口 貴史4・川瀬 成吾5・朝見 麻希1・後藤 祐子1・山中 裕樹1, 2

発表者所属

1龍谷大学 生物多様性科学研究センター　2龍谷大学大学院 先端理工学研究科 環境科学コース　3株式会社日吉　4滋賀県水産試験場　5滋賀県立琵琶湖博物館

概要

The South Basin of Lake Biwa, Japan, has undergone significant changes in fish fauna due to the introduction of invasive species and habitat alterations. This study assessed the current status of native fish species recovery through environmental DNA (eDNA) metabarcoding and capture surveys conducted in 2008 and 2021. The eDNA survey detected 40 fish taxa, including 31 native and nine non-native taxa, while capture surveys identified 18 taxa. Notably, ten native taxa absent from the 2008 survey were detected in both the 2021 capture and eDNA surveys, indicating their potential recolonization. Among these, eight taxa not subject to fisheries stocking suggest natural population recovery. The decline in invasive largemouth bass (Micropterus nigricans) and bluegill (Lepomis macrochirus) populations may have contributed to this resurgence. Additionally, eDNA surveys detected several benthic and elusive species, highlighting their effectiveness over traditional capture methods. A novel detection of Gobio gobio, a Eurasian cyprinid with no prior records in Japan, suggests possible human-mediated introduction. Conversely, nine native species previously recorded in the South Basin were not detected, warranting conservation attention. The study underscores the utility of eDNA metabarcoding for biodiversity monitoring and conservation, providing a non-invasive and comprehensive approach to assessing fish community dynamics in high-diversity lake ecosystems