Author(s): Yasuharu Watanabe; Kazuhiro Takahashi; Gen Saito; Takafumi Nakasato; Norito Makiguchi
Linked Author(s): Yasuharu Watanabe
Keywords: No Keywords
Abstract: The cherry salmon (Oncorhynchus masou) is an anadromous fish that spends its first year in rivers, and the river environment is very important to its growth. River freezing is the most difficult challenge for overwintering cherry salmon. Indeed, it is the main factor determining their survival. We conducted onsite surveys on the overwintering locations of cherry salmon and the riverbed conditions of such locations to identify a correlation between them. The surveys were conducted at the upper reaches of rivers, where successions of riffles and pools were present. It was found that the population of overwintering cherry salmon in pools and riffles can be determined by the local Froude number. Where the overwintering environment of fish had been understood only qualitatively, our findings have enabled some quantitative understanding of the overwintering environment of fish.
Year: 2004