Observational data on the features of the water temperature continuous change were analysed and compared with the synchronous change of the tidal. level. The results showed that the water temperature underwent frequently rapid changes between 0 - 10m depth, and that the diurnal change of the water temperature and the tidal level were basically indentical. Frequency spectrum analyses of the water temperature time series showed that the wavy variation of the water temperature had the distinct features of the tidal period.

This study revéaled high scallop mortality in the off western Haiyang Is land upper to middle layer waters with frequently rapid wavy variation of temperature.