Author(s): Shigeo Morita; Makoto Kuwahara; Shoji Yamashita; Hiroshi Mayama
Linked Author(s):
Keywords: Masu salmon; Descending environment; Fall velocity; Pool depth
Abstract: In mountain rivers, if the dam structure was installed, the majority of masu salmon are discharged from the overflow section. However, measures for descending fish have not been considered in the designs of fishways installed alomg with dam structures. In this study, the influence of the differences in pool depth and fall velocity on the ecology of the masu salmon was examined in an on-site experiment. As a result, in the case that the fall velocity is larger than 15 m/s, the value of the survival rate of the experimental fish differed considerably comparing a pool depth of 1.0 m and a pool depth of 0.7 m. Also, in the case that a pool depth is 1.0 m, there is no significant difference if the falling fish is compared with the survival rate of non-falling fish.
Year: 2009