A study on the prewarning value of Alexandrium tamarense PSP in an area with frequent outburst of red tide

Taking the blue mussel(Mytilus edulis) cultured in western Xiamen waers and Alex andrium tamarense(Lebour) Balech monospecies laboratory cultured as the experimental objects,the PSP toxicityof A.tamarense on blue mussel is studied following the standard method of PSP mouse bioassay developedby the Association of Official Analytical Chemists(AOAC).The results indicate that the mice survived when the density of A.tamarense cells was lower than 1×10⁵cells/dm³ and the mice died when the density was higher than 1×10⁵cells/dm³.The pastrecord of red tide evolution in western Xiamen watersshows a general trend of starting from the bloom of non toxic plankto nic diatoms in local waters and resulting in harmful red tide bloom due to the fade of planktonic diatom which f ailed in the survival competitionin the unfavor able and deteriorated ecoenvironment.On the basis of experiment al results and natural environment of Xiam en waters and by making reference to the critical criteria of shellfish toxins in variousstates,a prewarning value 1×10⁵cells/dm³ of A.tamarense PSP in Xiamen waters is proposed.