To investigate the spatiotemporal distribution and vertical distribution characteristics of the growth-reduction process of Noctiluca scintillans in Liushui Bay, Pingtan Island, four stations were established between March and November 2020, along with seven ecological investigation voyages. The underwater imager was used to tow to obtain the image information of N. scintillans in the vertical direction, combined with the data collected from the N. scintillans, to study the spatiotemporal distribution and vertical distribution characteristics of the growth-reduction process of N. scintillans in Liushui Bay, Pingtan Island, and comprehensive environment factors and plankton data to discuss the occurrence mechanism and limiting factors of N. scintillans.The main conclusions are as follows:The abundance of N. scintillans population in Liushuiwan of Pingtan Island is higher in spring than in autumn than in summer; in the period of high abundance, the nearshore side is higher than the far shore in the horizontal distribution, and the N. scintillans in the vertical distribution migrates to the surface layer.During low abundance in summer, N. scintillans mainly concentrates on the bottom of the water.Water temperature, salinity and diatom feed abundance are important limiting factors for the dynamic changes of N. scintillans populations abundance.It can multiply in a water temperature of 18-19℃ and a salinity of 29.6-30.6. When the water temperature reaches 24℃ and the salinity is higher than 35, it has a significant inhibitory effect on its growth;There is a significant positive correlation between the abundance of N. scintillans and the abundance of phytoplankton and the abundance of diatoms, It shows that in phytoplankton, diatoms are the main feeding objects and nutrient sources of N. scintillans.

Noctiluca scintillans, phytoplankton, spatiotemporal distribution, vertical distribution