Review on the Annual Variation of Red Tides in China Sea

The annual variation of red tide(i.e.harmful algal bloom,HAB) in China coast was reviewed,and the occurrence trend of red tide in the 21st century became the main part.We hope this review would help the people to analyze and control the HAB in China.The data showed that the HAB in China was becoming a serious environmental problem,and it generally increased in its frequency and scale,and in number of HAB species.The frequency and scale of HAB in the first decade of the 21st century were almost two times of that in the second five decades last century.Among the four China seas,East Sea became the most serious zone beyond South Sea,which was different from the last century.And the scale of HAB increased obviously in Bohai Sea,too.Most HAB often occurred in May and June,and its occurrence months had an increasing trend.This trend demanded longer monitoring and increasing monitoring frequency.On the other hand,the decrease in frequency and scale of HAB in some years also gave us the confidence to control the HAB.