The monitoring program of current and water quality at the mouth of Ise Bay has been conducted since Mar. 2008. The obtained water quality data is compared with datasets of freshwater discharge, meteorological parameters and tide. 1) At the mouth of Ise Bay, the velocity of tidal current is larger than 1m/s at the spring tide. The largest velocity is observed at Irago strait. 2) The residual current in shallow layer is larger at the spring tide rather than at the neap tide.3) Because the shallow water and deep water are mixed by the high speed tidal current at the Irago strait, salinity at the Irago strait is larger than that of the other area.4) The salinity becomes lower several days after the fresh water runoff from rivers. Even if there is little fresh water discharge, salinity becomes higher at the spring tide because the water column is well mixed at the spring tide.
