Value Assessment of Eco-friendly Structures Based on Substrate Dynamics and Fish Food Distribution and Its Application to Adaptive Management

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H03095
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 41030:Rural environmental engineering and planning-related
• Research Institution: Ibaraki University
• Principal Investigator: Maeda Shigeya 茨城大学, 応用生物学野, 教授 (00346074)
• Co-Investigator(Kenkyū-buntansha): 皆川 明子 滋賀県立大学, 環境科学部, 准教授 (70603968)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 農業水路 / 魚類 / 土砂水理 / 環境DNA / 付着藻類 / 維持管理 / 数値計算

Outline of Final Research Achievements

A field survey was conducted on a section of agricultural drainage channel that included fish nests and a fish pool introduced for the purpose of fish conservation. The survey focused on (1) the fish species present, (2) the fish food resources such as algae and benthic organisms, and (3) the accumulation of sediment and filamentous algae in the fish nests. For (1) and (2), we utilized environmental DNA analysis, which provided insights into the spatiotemporal variations of fish species and the temporal trends of species and quantities of filamentous algae. Additionally, we developed analytical methods using numerical flow calculations and a driftwood behavior model to devise efficient management techniques for sediment within fish nests and to explore the better fish nest size that reduces filamentous algae accumulation.

Free Research Field

生態水理学

Academic Significance and Societal Importance of the Research Achievements

農業水路の魚類保全施設の価値を評価するには，魚類の生息環境としての良さだけでなく，施設の維持管理のしやすさの視点が不可欠である．本研究では，これまで不十分だった魚類の餌資源や魚種の時空間変動と共に，堆砂，剥離糸状藻類の挙動に注目した．本研究成果の学術的意義は，魚巣の価値を多面的かつ長期的に評価するための生態水理学的な解析例を示した点にある．この成果の社会的意義は，より価値の高い魚類保全施設の設計に有用な点にある．