12th International Conference on Harmful Algae

INTERNATIONAL SOCIETY FOR THE STUDY OF HARMFUL ALGAE12 th <strong>International</strong> <strong>Conference</strong> on Harmful Algae, Copenhagen, Denmark, 4-8 September 2006circularisquama is a temporarystage rather than a resting stage.Heterocapsa circularisquama grewwell at ca.17.5 °C, poorly at 15 °Cand 12.5 °C, and it died at 10 °C.Two weeks after inoculation, theratio of pellicle cyst/total cells at12.5 °C was 57.5±1.4 %,significantly higher than at the othertemperatures. After 60 days and 90days of incubation at 10 °C undercontinuous darkness, viabilitypercentage of the pellicle cyst was0.9% and 0.8 %, respectively. Thus,the pellicle cyst designated astemporally cyst in the otherdinoflagellates is not always in atemporary stage in H.circularisquama, part of a H.circularisquama population mightoverwinter as pellicle cysts formedat low temperature.PO.13-25Long-term variation ofphytoplankton in Harimanada,Seto Inland Sea, JapanSession: PO.13 - Regional eventsSadaaki YoshimatsuAkashiwo Res. Inst. of Kagawa Pref.,TAKAMATSU, JapanChattonella antiqua wasresponsible, in the 1970-1980s, forlarge fishery damages inHarimanada, Seto Inland Sea,Japan. PSP toxicity is also aproblem in this region. Thisresearch was carried out to clarifythe appearance of phytoplankton,including harmful and toxic species.Long-term variations inphytoplankton a point inHarimanada were investigated fromApr. 1983 to Dec. 2005, three to fivetimes a month during summer, andone to three times a month at otherseasons. A litre of seawater wascollected from 8 layers at 5-mintervals, filtered and concentratedto 50 mL. The number ofphytoplankton species in theunfixed samples was counted.Among the species observed in thisstudy, harmful and toxic speciesfound were: Chattonella antiqua, C.marina, C. ovara, C. verruculosa,Heterosigma akashiwo, Kareniamikimotoi, Cochlodiniumpolykrikoides, Heterocapsacircularisquama, Alexandriumcatenella, A. tamarense,A.tamiyavanichii, Gymnodiniumcatenatum and Dinophysis fortii.PO.05-20Preparation of toxin standardsfor use in monitoring diarrheticshellfish toxins by LC-MSSession: PO.05 - Toxin analysisA YoshinoTropical Technology Center Ltd., URUMA-CITY, JapanIn determining marine toxins inseafood, LC-MS is the mostpowerful tool with its high sensitivity,specificity, and accuracy. Topromote wide use of the method,however, an adequate supply ofstandard toxins is imperative.Though highly or moderatelycontaminated shellfish have beenunavailable for years in Japan, wesucceeded in preparing DSP-toxinstandards by taking differentapproaches. First, we obtainedokadaic acid (OA) anddinophysistoxin-1 (DTX1) byculturing Prorocentrum lima.Second, OA and DTX1 wereextracted from the black sponge,Halichondria okadai. Third, in orderto secure DTX1, which was of lowoccurrence in the preceding twosources, we improved purificationprocedures to enable purification ofDTX1 from scallop extracts of very309