Author(s): Naoki Takahashi; Yuki Misawa; Kento Kinoshita; Ryoichi Yanagawa; Tadashi Tagawa
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Keywords: No Keywords
Abstract: The installation of portable fishways is one of the effective solutions to support the upstream migration of aquatic animals at such drop structures where fishways are not functioning well. As the method of quickly producing the migration route of aquatic animals, a V-shaped portable fishway for volunteer activities has been produced by the authors. Local residents can handle this fishway even if they don’t have the expertise. This study presents the flow characteristics of the portable fishway with improved partition walls, and the status of utilization of small aquatic animals. In the laboratory experiment, water depth in the migration route of the fishway was measured. The flow velocities and directions were measured in the fishway pools and the partition walls. Improved partition walls gathered the overflow at the both ends of them and expanded the migration area at the sides of fishway. It was clarified that the improved partition walls increased the water depth of the migration route and reduce the flow velocity of the middle layer of the pools where aquatic animals take a rest. In the field experiment, the installation of the improved fishway enabled the upstream migration of small aquatic animals such as Goby and juvenile Ayu fish.
Year: 2018