Spatial Distribution of Resting Cysts and Vegetative Cells of PSP Toxigenic Alexandrium spp. in Jinhae Bay, Korea

Abstract

Outbreaks of paralytic shellfish poisoning (PSP) and red tide caused by Alexandrium spp. have frequently been reported around Jinhae Bay in the southeastern coastal areas of Korea. The present paper deals with the seasonal occurrence of motile cells and monthly alternation of the resting cysts of Alexandrium spp. and the phytoplankton population in Jinhae Bay from January to May 2014. The standing crop of phytoplankton population varied significantly with month; it ranged from 6,576 to 79,865 cells/mL and had the reach the maximum crop in January 2014. Alexandrium motile cells in Jinhae Bay that had been known to produce PSP toxin appeared mostly in January when the temperature in low, and reached to high densities from March to May 2014. Alexandrium spp. resting cysts were distributed at seven stations in Jinhae Bay, but it showed a significant variation among stations, ranging from 17 to 117 cysts/cm³ in the sediment samples. Vegetative cells frequent in the cold season could result from cysts germination which had controlled mainly by environmental factors and biological endogenous clock. Considering PSP outbreaks with the same season as cysts germinated, it is suggested the monitoring for the prediction on prevailing regions should be undertaken based on the life cycle strategies of the causative organisms.