A two-year(2020–2021)observation of marine phycotoxins in phytoplankton in typical mariculture areas of East China Sea

To learn the marine phycotoxins(MPTs)contamination status in mariculture areas in the East China Sea(ECS),from May 2020 to October 2021,80 net-concentrated phytoplankton samples were collected from 12 stations in three typical areas with high incidence of red tides,namely,Gouqi Island,Sandu’ao-Lianjiang,and Zhangzhou-Dongshan Island in ECS,and MPTs of the samples were detected.Six types of toxins were detected in 24 samples from 9 stations.Lipophilic marine toxins(LMTs)were more common and diverse in these areas.Pectenotoxin 2(PTX2)was the main lipophilic marine toxin(LMT)in the concentrated phytoplankton samples and the occurrence showed seasonal differences from north to south.According to the potential risks of pectenotoxin(PTXs)to seafood safety,it is suggested to execute regular monitoring on PTXs in ECS and a mandatory standard should be formulated based on the comprehensive analysis of in-situ monitoring and lab research.Meanwhile,contamination risks of cyclic imine toxins in the north and domoic acid(DA)in the south of ECS should also be paid with attention to.Only 2 paralytic shellfish toxins(PSTs),N-sulfocarbamoyl toxin C2(C2),and decarbamoyl gonyatoxin 3(dcGTX3),were found from spring samples in the north of ECS.As the biggest mussel culture county of China,Gouqi Island showed higher toxin diversity and the toxin detection rate was higher than the other two areas.In Gouqi Island area,PSTs were a serious potential threat in spring,and LMTs instead of PSTs became the main risk in summer-autumn seasons.To ensure the safety of seafood and marine environmental health,it is recommended to conduct long-term targeted tracking and monitoring of MPTs in this and similar mariculture areas.