The Study On Paralytic Shellfish Poisoning And Diarrhetic Shellfish Poisoning And Shellfish Poisoning Monitoring Program In The Coast Of Nanji Island, Zhejiang Province

In recent years, the frequent occurrences of harmful algae blooms (HABs) andpoisoning events in the coast of Nanji island have seriously restricted the developmentof aquiculture and tourism and threatened people's health. The sporadic and transitoryinvestigations for biotixons had been done in the area in the past years. In order tounderstanding the pattern and toxin profiles characteristic of paralytic shellfishpoisoning(PSP) and diarrhea shellfish poisoning(DSP) in the coast, the contents ofPSP and DSP in 60 samples collected monthly during April of 2006 to March of 2007from 6 sites were determined. The results could be drawn as follows: Firstly, theconcentrations of PSP were generally low, under the public healthy safety standardand the positive rate was 11.7ï¼…. Secondly, the seasonal change of PSP was quiteobvious, and PSP mainly presented in spring and winter. Thirdly, PSP chiefly existedin Da sha bay, Ma zu bay and Huo kun bay, and the holistic pattern was distinct andpresented the tendency of gradual decrease from both south to north and west to east.Fourthly, the dominating shellfish species contaminated by PSP were cultured Pctenyessoensis, Mytilus edulis and wild ostrea.sp. Fifthly, the primary toxin profiles ofPSP were GTX1,GTX4 and GTX5. Sixth, the positive rate and over-standard rate ofDSP were 63.3ï¼…and 56.7ï¼…, respectively. Seventh, the positive rate andover-standard rate of DSP showed the trait of gradual decline seasonally. Eighth, DSPcontaminated shellfish spread widely in the area and the toxin content showed thetrend of gradual increase from south to north. Lastly, the principal shellfish speciescontaining DSP were cultured Pecten yessoensis, Mytilus edulis, wild ostrea.sp,Sptifer virgatus and Mytilus coruscus. Moreover cultured shellfish had stronger abilityto accumulate DSP than wild shellfish.The biotoxin monitoring program in Nanji island was designed including how tocollect shellfish species, and how to determine the sites and frequency of shellfishsampling, methods of toxin analysis, threshold of public healthy safety and biotoxinmanagement on the basis of the study.The present provided theoretical reference to the policies about improving andintensifying management of shellfish, consequently, guaranteeing the safe consumption of shellfish and persistent development of aquiculture.