Longfengtou Bathing Beach in Pingtan, Fujian province, has been closed after a red tide was spotted nearby.

The 30-square-kilometer red tide stretches from the beach to waters near Xianshan Island in Aoqian town. Local people have been warned to stay out of the waters, a conference announced on May 15.

The conference also urged beefed-up monitoring efforts of the red tide as well as the seafood market.

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.

Edited by Chen Zhilin and Michael Thai