A red tide occurred in waters near Pingtan, an island county in Southeast China's Fujian, but lasted only one day, according to the local marine monitoring authorities Tuesday.

The red tide started to form and spread across roughly 20 square kilometers in waters near Longfengtou Bathing Beach in Pingtan on May 9, according to a monitoring station of the Xiamen Marine Environment Monitoring Center.

Red tide is a common name for a phenomenon known as an algal bloom (large concentrations of aquatic microorganisms) caused by a few species of dinoflagellates that take on a red or brown color. It is usually found in coastal areas. It is sometimes toxic to fish life and, through accumulation in shellfish, to humans.

But the harmful algae blooms disintegrated according to data from the Pingtan aquatic product technology promotion department over the next three days.

No deaths to farmed marine species due to the red tide have been reported, said the department. But it warned that the risk of red tide reoccurrence still exists in the next few days.

Fishery farmers should stay informed of red tide updates and take preventive measures, as the active red tide season comes in April, May and June to Fujian province, said experts.

Edited by Chen Zhilin and Michael Thai