抄録
The paper is the summary of the investigation studies that author examined for about twenty years in Uranouchi
bay where fish culture has been carried out. In the paper environmental characteristics and phenomenon are
explained, such as the season of stratification and convection, the intrusion caused by density difference of water
between inside of bay and outside of bay, internal tidal wave and estuarine circulation. Finally both environment
al improvement methods such as tide dam and enhancing estuarine circulation are proposed.