Spatial-temporal distribution of red tide in coastal China

Abstract

The frequent occurrence of red tides in China’s coastal areas has caused huge losses to society and economy, and seriously threatened the coastal marine environment and ecological security. Based on the data of 30 years from 1990 to 2019, this paper analyzes spatial-temporal distribution characteristics of red tide in China’s coastal areas. Our results show that 1557 red tides occurred in China’s coastal areas from 1990 to 2019. (1) There were 961 red tides from 2001 to 2012, which was the high red tide period in offshore China, accounting for 62.00% of the total number of red tides. The number of red tides in the Bohai Sea, Yellow Sea, East China Sea and South China Sea were 117, 103, 588 and 153, respectively. Seasonally, 536 red tides occurred from April to September, accounting for 87.00% of the total number of red tides. (2) In space, according to the kernel density estimation, red tides are mainly concentrated in Bohai Bay, Yangtze River Delta, Pearl River Delta and other regions with relatively dense population and relatively developed economy, especially in Zhejiang Province and the estuary of the Yangtze River. The research in this paper is of great significance to the monitoring and prevention of red tides and water environment management.