Identified 7 species of the genus Prorocentrum which have been obtained from the southern coast area for 4 years from 1990 to 1994 can be summarized as followed. P.balticum is rare species, causing a red tide, and P.dentatum, P.micans, P.minimum, P.triestinum are cosmopolitan species often causing a red tide in the study area. P.gracile and P.lima are very rarely showed up, the former is recorded at first in domestic and later is benthic attached species which has diarrheic shellfish poison.