An unexpected poisonous algae bloom, also known as red tide, has dealt a fatal blow to the shellfish industry in Lianjiang County in Fuzhou, the capital of East China's Fujian Province.

Local authorities estimated the loss at around 3 million yuan (US$362,000) yesterday, but a Xinhua report said total loss could reach over 10 million yuan (US$1.2 million).

A red tide is an explosive propagation of algae caused by excessively accumulated nutrients in sea waters. The algae either consume too much oxygen in the water or release poisonous substances that kill sea life.

The red tide was caused by the area's over-dense aquatic farming, authorities said.

"We have been trying to reduce the density of aquatic animals in the area. But it is hard to convince people to give up profits," said an unnamed official with the Lianjiang County Fishery Bureau, who would only give his surname Li.

Although the area has been affected by red tides before, previously deadly algae only came in after they floated from neigh-bouring areas. In the past they were never hard to clean up, authorities said.

This most recent red tide will greatly affect the long-term development of the county's aquatic farming industry, they added.

"Many local farmers have voluntarily worked to reduce their farming density for the first time in decades," he said.

However, Li dismissed the reported loss of over 10 million (US$1.2 million).

"That is drastically different from our estimation and sounds too big. The red tide does not affect a wide area and almost all fish, apart from the shellfish, have survived," he said.

No sea products from the area will be allowed to be sold until they have passed a series of strict examinations ensuring their safety.

Ji Weidong, a red-tide expert with the State Oceanographic Administration, said it was unfortunate that the red tide was not detected sooner.

"Although the county authority moved quickly to control the damage after the red tide broke out, the loss would not have been as great if a red tide monitoring station had been set up in the area," said Ji. "In view of China's present marine environment, it is a pressing task for all aquatic farming areas to have monitoring stations."

(China Daily November 20, 2002)