Hainan activates Level III emergency as red tide spreads along western coast

Hainan province has activated a Level III emergency response after a red tide outbreak spread along its western coastline, affecting waters off Changjiang Li autonomous county, Danzhou, Lingao, and Chengmai.

Provincial authorities convened an emergency video conference on Sunday as monitoring showed the bloom had expanded to about 187 square kilometers. The Department of Agriculture and Rural Affairs said economic losses had exceeded 20 million yuan ($2.9 million), meeting the threshold for a Level III red tide disaster.

A research team led by Professor Lyu Songhui from Jinan University, based in Guangzhou, Guangdong province, said preliminary analysis suggests the dominant algae may belong to the Cochlodinium genus, a dinoflagellate in the same order as Pheopolykrikos hartmannii, which was initially identified by the Hainan Marine Monitoring and Forecasting Center. Electron microscopy and molecular analyses are underway to confirm the species.

Authorities have stepped up surveillance using satellite remote sensing, drones, offshore and coastal monitoring stations, and vessel-based sampling to track the bloom and forecast its movement. Fishing and harvesting have been temporarily suspended in affected waters, while technical teams have been sent to assist aquaculture operators and minimize losses.

Officials said toxins produced by the suspected species are highly poisonous to fish but do not accumulate in shellfish or pass through the food chain to humans. Seafood from affected waters remains safe for consumption after routine food safety inspections.

Experts believe the outbreak was likely triggered by a combination of natural factors, including prolonged high temperatures, fluctuations in sea surface temperatures, and reduced plankton biodiversity, which allowed a small number of algae species to dominate local waters.