米代川におけるアユの産卵床と河道特性の関係
キーワード:
sweetfish,
spawn bed,
formation factors,
gravel size of bed material,
penetration depth,
multivariate analysis,
monitoring method
2006 年 12 巻 p. 359-364
詳細
2006 年 12 巻 p. 359-364
This paper reports the results of field observations about sweetfish's spawn bed. The field observations were carried out from 2001 to 2005 in the Yoneshiro River. The distribution of the spawn bed in the river was observed, and the characteristics of flow and gravel were measured.
The sweetfish generally spawns at floating gravel, and the spawn beds were found at relatively stable rapids on sandbars which locate between lower and middle reachs of the Segment 2-1 every year. It was remarkable that the gravel size of bed material and the states in riverbed such as penetration depth are important factors for spawn beds.
Based on a statistical analysis, a simple method was proposed to monitor the potential of each point to be a spawn bed.
