田辺湾におけるGymnodinium mikimotoiの増殖域の環境特性と本種赤潮の発生環境 Environmental Features of the Area Where Gymnodinium mikimotoi Appeared and Conditions for Occurrences of the Red Tide in Tanabe Bay
Relationships between the occurrences of <i>Gymnodinium mikimotoi</i> red tide and the environmental factors in Tanabe Bay were studied on the basis of field observation during 1989-1994. <i>G. mikimotoi</i> red tide first appeared at the southern area and then spread over the whole bay. The southern area is topographically semi-closed and nutrient concentrations were higher than those in the other areas of this bay. It appears that these features of this area permit the high proliferation of the species. Nutrient concentrations of the southern area was kept at the levels which support the occurrences of <i>G. mikimotoi</i> red tide period. However, <i>G. mikimotoi</i> red tide was observed in 1990, 1991 and 1994. The rate of seawater exchange in these years was considered to be lower than that in the years when the red tide did not occur. It is highly considered that the occurrences of <i>G. mikimotoi</i> red tide in Tanabe bay depends on the rate of seawater exchange in the southern area.
日本水産学会誌 63(2), 184-193, 1997-03-15