Dinophysis spp. recorded in the coastal waters of northern Vietnam during 2002-2003
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概要
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A monitoring on toxins responsible for Diarrhetic Shellfish Poisoning (DSP) was carried out at several culture areas of hard clam (Meretrix meretrix) in the northern coast of Vietnam during May 2002 and December 2003. Quantitative observation of Dinophysis spp. was made one to four times every month and DSP toxins in the hard clam grown in the area was analyzed monthly using the HPLC method. Six species of Dinophysis were recorded, including D. caudata, D. fortii, D. miles, D. rotundata, D. mitra and D. hastata. Among them, D. caudata was the most common species. Others were not common and their densities were ignorable. D. caudata appeared almost all around the year at all sampling sites with density ranged from 0 to more than 3000 cells/l. However, it was more abundant during the warm period, i.e. from late February to late November. For the rest of a year, cells were rarely found. D. caudata was recorded in a wide range of temperature (15-34.3℃), but its significant density (over 100 cells/l) was only observed when water temperature exceeded 20℃. D. caudata appeared and could reach high density at all salinity in the range of 8-34 PSU. The highest recorded density was 3128 cells/l at 22℃ and 8.2 PSU in Thanh Hoa area in February 2003. "Blooms" of D. caudata, together with other dominant dinoflagellates, usually coincided with the vanishing period of diatoms. Okadaic acid (OA) was detected in edible part of clams but at low concentration in all samples. Maximal level was 80ng OA/100g, encountered in Thanh Hoa transect during August 2002 and April 2003. DTX 1-4 were not detected in all samples. No significant correlation between OA concentration in clam and the density of D. caudata in the water sample was observed, although toxins sometimes peaked the same time with D. caudata density. Low concentration of toxins implicates low risk of DSP and explains the absence of poisoning cases in the area so far. However, other shellfishes in the area should also be subjected to toxin monitoring.
- 東京大学の論文
- 2006-04-28
著者
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HA Dao
National Institute of Oceanography
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Ha Dao
National Inst. Oceanography Nha Trang Vnm
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NGUYEN Nguyen
Research Institute for Marine Fisheries
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HA Dao
Institute of Oceanography
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TUNG Le
Research Institute for Marine Fisheries
関連論文
- Occurrence of domoic acid in tropical bivalves
- Domoic acid in a bivalve Spondylus cruentus in Nha Trang Bay, Khanh Hoa Province, Vietnam
- Dinophysis spp. recorded in the coastal waters of northern Vietnam during 2002-2003