Study on a fishway design suitable for the upstream migration for reproduction of the endangered loach (Parabotia curtus) in paddy field areas

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K06300
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 41030:Rural environmental engineering and planning-related
• Research Institution: Kagawa National College of Technology
• Principal Investigator: Takahashi Naoki 香川高等専門学校, 建設環境工学科, 准教授 (70706580)
• Co-Investigator(Kenkyū-buntansha): 中田 和義 岡山大学, 環境生命科学研究科, 准教授 (70431343) ; 金尾 滋史 滋賀県立琵琶湖博物館, 研究部, 主任学芸員 (70618321)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 環境保全 / 水田生態系 / 農業水路ネットワーク / 遡上阻害 / 魚道 / アユモドキ

Outline of Final Research Achievements

In this study, we tried to develop effective fishway systems for the conservation of an endangered loach (Parabotia curtus). In the study area, relatively small drop of about 30 cm and large drop of over 200 cm exist and obstruct the upstream migration of the target species. We have developed portable fishway systems that can be transported to and applied to the migration obstruction points easily. We confirmed that the target species can swim upstream in the developed portable fishway in a laboratory experiment and clarified the characteristics of the water depth and flow velocity in the fishway. Using the developed portable fishway, we were able to reproduce the flow conditions in which the target species swam upstream in the laboratory experiment at a migration obstruction point with a drop of about 200 cm.

Free Research Field

水工学，生態工学

Academic Significance and Societal Importance of the Research Achievements

アユモドキが利用可能な魚道構造について検討された事例は少なく，本研究にて開発した魚道を対象種が遡上した際の魚道内水深・流速特性を解明できたことは，対象種に関する保全技術の発展に寄与すると考えられる．また本研究で開発した低コストな可搬魚道システムは，専門知識・技術を持たない市民でも使用することができるため，国の天然記念物である本種の保全において河川・水路管理者と市民との連携を促進するツールとしての活用が期待される。