Seasonal change of PSP in Daya Bay

61 samples were selected from 2005 to 2006 in Daya Bay.Firstly,the samples were detected by the bioassay method,then,the several samples of them were determined by HPLC.The goal is to understand the patterns of PSP.The conclusions can be drawn as follows: firstly,the concentrations of PSP in Daya Bay were generally low.There is only one sample is detected and its concentration is 163Mu/100g.The seasonal change of PSP was quite obvious,and the positive rate mainly presented in spring,and other seasons scarcely.Secondly,the results of examination from HPLC showed 12 kind of PSP main toxin are discovered in this sea area.The results showed that the toxic value of oyster's four seasons is in 2005 spring 2006 year spring.But in 2005: Summer autumn winter spring.