Occurrence of Toxic Alexandrium and Intoxification of Two Mollusk Species by Paralytic Shellfish Poisoning Toxins on the Southeastern Coast of Korea

摘要

We analyzed the paralytic shellfish poisoning (PSP) toxins of the toxic marine dinoflagellate Alexandrium tamarense collected from Dadaepo and Gaduck-do in Busan and from Sujeong-ri in Jinhae Bay, Korea, in April 2003. We also analyzed the PSP toxin of mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) collected around Busan and Jinhae Bay. PSP toxin analyses were conducted by high performance liquid chromatography (HPLC). Fifteen cultured A. tamarense isolates contained 2.78 to 57.47 fmol/cell, with nearly identical toxin profiles: major components C2, GTX4; minor components Cl, GTX1, NEO; and trace components GTX2, GTX3, STX. PSP toxin contents were 0 to 492 ug STXeq/100 g in mussels and 0 to 48 ug STXeq/100 g in oysters. Musselsat Gijang and Sujeong-ri contained the most PSP toxin contents (492 ug STXeq/100 g and 252 ug STXeq/100 g, respectively), exceeding the quarantine level (80 ug STXeq/100 g). Their dominant toxin components were C2, Cl, GTX2, and GTX3; the minor components GTX1, GTX4, GTX5, and NEO were sporadically detected. Phytoplankton contained 0.774 fmol/L seawater and 1.228 fmol/L seawater at Gijang and Sujeong-ri in April. At that time, Alexandrium cells were present in the water column at Gijang at 2,577 cells/mL and at Sujeong-ri at 6,750 cells/mL. Overall, we found the high and similar PSP toxin contents in Alexandrium isolates and mussels, and a correlation between occurrence of toxic Alexandrium cells in the water column and mussel intoxification. High densities of toxic Alexandrium cells in the water column immediately preceded shellfish intoxification at Gijang and Sujeong-ri in April.