Monitoring and trends in harmful algal blooms and red tides in Korean coastal waters, with emphasis on Cochlodinium polykrikoides

•The first red tide event in Korea was reported in AD 161.•Since 1972, a total of 71 species have been responsible for red tide events in Korea.•Cochlodinium polykrikoides blooms have become regular and annual events since 1993 in Korea.•The earliest bloom by C. polykrikoides was associated with continuous cell accumulation by lateral mixing of waters and wind shift.