Studies on harmful phytoplanktons in South East Asia

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In 1989 the studies were developed to survey the distribution of Pyrodimium bahamense and toxic shellfish together with the chemical environmental research in Masinloc Bay, Zambales and the coastal water area of Remay, Bataan of Manila Bay.Surveys in Masinloc Bay were carried out at 4 stations on February 17-19, 1992. Salinities of the surface water were 33.6-35.4*. The water mass of slightly low salinity (33.6-34.6*) and high concentration of silicate (0.153-0.562 mg/l as SiO_2) were detected in middle and lower layer outside Bamban Bay where located at the southern part of Masinloc Bay. The concentration of suspended solid and total planktonic pigments were 1.2-4.7 mg/l and 1.1-5.7 mug/l respectively. Mass flux which was measured by using the sediment traps was 1.73 g/m^2/day at north-east region of Masinloc Bay. P. bahamense var. essum bloomed from April to June, 1991 and reached the maximum density of 189, 000 cells/l in May. The blooming, was terminated in early August, maybe, by … More the effect of the dense ash falls and changes in weather conditions of the area the eruption of Mt. Pinatubo. The bloom of the species started to recur again in December. In February when the Japanese team made a field survey, dense density of 21, 860 cells/l and 29, 220 cells/l were observed at 4m-depth inside and 10m-depth outside Bamban Bay, respectively. However. water discoloration was not prominent.The survey along the coast of Rimay, Bataan. Manila Bay was carried out on February 19-20. The salinities were 27.7-33.6 * in surface water and 23.03 * in bottom water. Silicate were in the high range of 0.38-0.72 mg/l as SiO_2. The concentrations of suspended solid and total planktonic pigments were 0.45-8.26mg/l and 1.0-9.5 mug/l respectively. Mass flux was 3.61 g/m^2/day. These values seemed to be derived from the eutrophication of the Bay. P. bahamense var. essum bloomed and appeared as red tide off Limay in June, 1991 and the cell density was counted as much as 7, 549, 000 cells/l. In February, 1992, the species appeared in quite low quantities, 80 cells/l off Limay, and 1, 360 cells/l off Orion.Cells of P. bahamense var. compressum were isolated and inoculated into enriched sea water medium Tl and then the most of them are still alive and under culture investigation. The analysis of Paralytic shellfish poison of the bivalves collected at Masinloc Bay is under progress.Totally four long cores were collected in Masinloc Bay and Manila Bay in order to clarify the succession of the dinoflagellate cyst assemblage since the last few decades.Cumulative results of the research will be printed and that should be expected as materials for the survey manual on red tide and shellfish poisoning in western pacific region. Less