Report on the survey of freshwater planarians and the water analysis in the Suyoshi River,

The Suyoshi River is a first-class river running from Suyoshi, the eastern hill side of Nagaoka city through the central aerea of the city to join the Shinano-gawa River. The creature having correlationship with the emvironmental factor such as water qualities are known as indicator organizms. Planarian is one of the indicator organisms in freshwater emvironment. This paper reports the survey about the distribution of aquatic indicator organizms, mainly planarians and the water qualities in the Suyoshi River. Cl-, Na+, K+ and Ca2+ at downstream sampling sites were higher than at upstream sites. NO3 -N was 0.19mg/L at sampling site No.4. Three spieces of freshwater planarians; Phagocata vivida, Dugesia japonica and Girardia tigrina were found in the Suyoshi River by different distribution. G. tigrina is the first foreign planarian spieces reported in Niigata Prefecture. This survey was conducted with pre-laboratorial (Prelab) students during May to October in 2016