Author(s): Takaya Higuchi; Shogo Sakamoto; Kazuhiro Azami; Tomonori Osugi; Katsuki Nakai; Hiroyuki Miura; Yuko Kikuchi
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Abstract: Invasive alien fish, Bluegill, Lepomis macrochirus, was introduced and its number increased in the Miharu Dam reservoir, located in Otakine River (a line of Abukuma River channel) in Fukushima Prefecture. Considering potential impacts on the native fish species, some control means against bluegill were expected to be organized. From the mid-June to the mid-July, it was observed that adult bluegills spawned in the shoreline areas within the depth of 80 cm[1]. In nearly the same period, the end-June to the early-October, Miharu Dam Administrative Office implemented “flushing discharge” to enhance the downstream river environment once in two weeks. It was considered that spawning beds of bluegills could be exposed out water by taking advantage of the water level drawdown induced by the flushing discharge. Here, we report the outcome of the flushing discharge application conducted from 2012 to 2016 and address the points that could maximize the control effects to invasive bluegills.
Year: 2018