Permalink : http://hdl.handle.net/2115/49087

KEYWORDS : Chattonella globosa;Funka Bay;Red tide species;Seasonal distribution;Dictyocha fibula

Chattonella globosa is known as a red tide species in western Japan from Kyushu, the Seto Inland Sea to Tokyo Bay, but the existence has been unknown in the northern Japan.　This is the first report of the observation of occurrence of C. globosa from Funka Bay, in Hokkaido, Japan.　Cells were globular and 33-42 μm in diameter with single flagellum, and sometimes performed “Amoeba-like movement”.　We also studied the seasonal variation in density and distribution of C. globosa.　This species was first detected in July 2011 and reached at maximum cell density of 2.6×10^4 cells L^-1 at the same time in the inner part of the bay.　They widely distributed in the bay in August and decreased under detection level in November.　The water temperature range was 14.0-23.2°C in Funka Bay when they were detected, indicating that the same occurrence temperature range as in the western part of Japan, such as the Seto Inland Sea.　C. globosa is probably the important species as a primary producer as well as a possible red tide species in summer in Funka Bay, northern Japan.