River management implications to consider biological diversity of ecologically-vulnerable benthic fishes such as freshwater sculpins with low mobility

2015 Fiscal Year Final Research Report

• Project/Area Number: 25340063
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental impact assessment
• Research Institution: Ibaraki University
• Principal Investigator: NATSUMEDA TAKAHARU 茨城大学, 教育学部, 准教授 (00468993)
• Co-Investigator(Kenkyū-buntansha): IGUCHI Kei'ichiro 長崎大学大学院水産, 環境総合科学研究科, 教授 (00371865) ; TAKESHIMA Hirohiko 総合地球環境学研究所, 研究高度化支援センター, 特任助教 (50573086)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 底生魚 / カジカ / 河川工作物 / マイクロサテライト / 生物多様性 / 種間関係

Outline of Final Research Achievements

This study aims to evaluate the effects on instream obstructions on populations of ecologically-vulnerable benthic fishes (e.g., freshwater sculpins) with low mobility based on ecological and conservation genetic approaches, and to propose river management implications to consider their ecological features. Results of mark-and-recapture surveys revealed that a weir with 80 cm height prevented individual sculpins to ascend weir. Genetic population structure analysis, based on 15 microsatellite DNA markers, indicated a presence of wear, but statistically significant genetic population structure along a stream course. To conserve spatial connectivity along a stream course for such ecologically-vulnerable benthic fishes, setting a ramp to mitigate the height of instream obstructions, setting simple fishways to assist individual fish passing by instream obstructions, and enrichment of instream habitat quality divided by instream obstructions, are considered as valid management implications.

Free Research Field

魚類生態学