Study on Characteristics of Harmful Algal Blooms in the South Sea of Korea by using Satellite and In-Situ Data

Harmful Algal Blooms (HABs), caused by Cochlodinium polykrikoides that causative fishery mortality, impact on aquaculture and economic loss appear particularly in summer and fall seasons in the Korean seas. It was studied on characteristics of HABs in the South Sea of Korea by using satellite and in-situ data. The in-situ data encompassed oceanic and meteorological data from July to October 2002−2008 and satellite data from July to October 2002−2006. Chlorophyll concentrations were calculated using Sea-viewing Wide Field-of-view Sensor images by an Ocean Color (OC4) algorithm, and HABs were estimated using the Red tide index Chlorophyll Algorithm (RCA). When HAB occurrences dominant when, water temperature was 22.6−28C in August. In the frequency of the individual numbers during 2002−2008, the HABs more than 1000 cells/ml (alert condition) were 73.57 % in the frequency. In meteorological data from July to September during 2002−2008, the average precipitation, the mean air temperature, the mean wind speed and direction, and the sunshine was 9.31 mm/day, 24.07oC, 2.34 m/s and easterly, and 1−11 h, respectively. Both of OC4 algorithm and RCA for satellite data showed in Southeastern Sea of Korea from July to September 2004 and during the August month, of all the years from 2002 to 2008 have potential of the occurrences of HABs. Our results suggests that the upwelling caused by southwesterly wind in summer season and the Tsushima Warm Current have influenced on the dispersion and moving of HAB(chlorophyll), also the fresh water from Nakdong River as the source of nutrients which influences the occurrence of HABs.