Author(s): Yoshiki Shiraishi; Takayuki Nagaya; Kouki Onitsuka; Makoto Higashino; Tohru Takami; Shinji Matoba; Juichiro Akiyama

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Keywords: Plecoglossus altivelis altivelis; Habitat; PHABSIM; Spawning

Abstract: The Osegawa River is located in Kyushu Island, Japan. A lot of floods have been occurred in this river, so that the great deal of damage has been done. The shape of the cross section of the Osegawa River is compound. Therefore, it is quite easy to decrease the flood damage, because much discharge may flows if the flood plain is eliminated. In contrast, a lot of ayu, Plecoglossus altivelis altivelis, inhabits in this river. One of the highest haul of inland fish in Japan is ayu, so that it is necessary to consider whether the ayu can inhabit or not when a river improvement plan will be conducted. Recently, Onitsuka et al. (2005) pointed out that to preserve the spawning bed of the ayu is quite important for preservation of the ayu’s living environment. This is because the ayu can inhabit both in pools and rapid, but ayu can spawn only in the rapids. In this study, a river improvement method, in which the ayu can spawns, will be proposed by making use of a 2-D numerical method and also PHABSIM. Such a proposal is firstly proposed in Japan.

DOI:

Year: 2007