Press Release
September 11, 2009
Incorporated Administrative Agency, Fisheries Research Agency
Early predictions of red tide by monitoring the cyst dynamics of Chattonella
– Success in taking a video on the germination process of the cyst –
The Fisheries Research Agency has confirmed that noxious red tide organism Chattonella spp., which have
caused serious fishery damages in the Ariake and Yatsushiro Sea in the summer of 2009, have left a large number
of cysts (dormant cells of the species) in the bottom sediments of the sea.
Cysts of Chattonella spp. remain dormant over the winter in the bottom sediment of the sea. The vegetative cells
germinate in early summer when the water temperature rises, divide, proliferate and cause red tides.
Abundance of the cyst was examined in June 2009 before the occurrence of the red tide at 25 points in the Ariake
and Yatsushiro Sea. The largest number of cysts found in 1 g of the sediment was 45. On the other hand, on
August 20, after the outbreak of the red tide, as many as 2,193 cysts/g were found at 3 points in the northern part
of the Yatsushiro Sea, showing that the red tide had supplied a large number of newly-formed cysts onto the
bottom sediment.
Cysts of Chattonella, which can survive dormant for several years, germinate in the next summer if the
environmental conditions are favorable. Therefore it is quite important to understand the entire life cycle of the
organism in order to control or mitigate the fishery damages caused by Chattonella red tides. The cysts of
Chattonella were incubated under optimum conditions for the germination. We found the cysts germinated on
the 6th day after incubation and succeeded in taking a video on the whole process of the germination of the cysts
for the first time. The germination of cysts concluded within 5 minutes.
Prediction of red tides has been conducted mainly by monitoring the number of the vegetative cells in seawater.
On the basis of the present findings, the number of cysts in the sediment and environmental conditions for the
germination will become useful indexes for the early prediction of the red tides.
For more information, call the Fisheries Research Agency at:
TEL: 045-227-2621
Public Relations Section, General Planning and Coordination Department, Headquarters
Mineo Yamaguchi TEL: 0829-55-3695 (Chief, Section)
Harmful Phytoplankton Section, Harmful Algal Bloom Division, National Research Institute
of Fisheries and Environment of Inland Sea
15F Queen’s Tower B, 2-3-3 Minato Mirai, Nishi-ku, Yokohama 220-6115
TEL: 045-227-2600
FAX: 045-227-2700
http://www.fra.affrc.go.jp/