Abstract: Economic shellfish resources in shallow sea, intertidal zone and seawater ponds before and after flood discharge were investigated and analyzed after typhoon “Doksuri” in order to understand the impact of flood on economic shellfish in Tianjin sea area. The results showed that, the salinity in the mouth of Duliujian River and Ziyaxin River has decreased more than 60%, almost all economic shellfish such as Scapharca subcrenata, Crassostrea gigas, Ruditapes philippinarum, and Rapana venosa died except for Sinonovacula constricta and Cyclina sinensis, and the seawater salinity rose above 20 beyond 11.5 km offshore; The mortality rates of Rapana venosa, Ruditapes philippinarum and Scapharca subcrenata in Liyumen mudflat were 42.5%, 62.6% and 100% respectively, and the biomass decreased by 87.8%; The salinity in Dashentang shallow sea and the Lvjuhe intertidal zone decreased by 30%-40%, the mortality rate of economic shellfish were less than 10%, and the biomass increased by 0.6% and 25.9% respectively; The salinity of seawater ponds has decreased by about 30%, and the mortality rates of Ruditapes philippinarum and hard clams in aquaculture raised by 12.3% and 5.3%, respectively. Thus, it is suggested to conduct economic shellfish release, disaster warning and follow-up investigations.

Key words: flood discharge, economic shellfish, mortality rate, biomass