As one of the important microzooplankton in marine pelagic habitats,tintinnids are classified as neritic genera,oceanic genera and cosmopolitan genera.Until now,we know little about the interaction between neritic and oceanic genera in continental shelves.Low species richness area was found in the mixing area between neritic and oceanic genera in the East China Sea.In this study,we investigated the spatial distribution of tintinnid community throughout the entire Bohai Sea in May (spring) of 2014 to find out: (1) whether the tintinnid assembalges differed in the three major bays bordering this shallow inland sea; (2) whether there was low species richness area in the Bohai Sea.Three genera and 11 species attributed to neritic and cosmopolitan taxa were reported from this region.Tintinnid abundance averaged (81±216) ind./L (0–1234 ind./L).Tintinnid community differed within the three major bays,with each characterized by different tintinnid taxa.Referring to the average abundance of three bays,tintinnids were most abundant in the Laizhou Bay ((328±445) ind./L),and least abundant in the Liaodong Bay ((34±57) ind./L).A low species richness area occurred in the central Bohai Sea (20–40 m isobaths),in some stations of which no tintinnid was recorded.Our study demonstrates that tintinnid community varied greatly over small spatial scales,and low species richness area was found in the mixing area between neritic and oceanic genera within this inland sea.