The Guangdong provincial bureau of public health, concerned oover mass food poisonings, said no sea creatures killed by red tide should reach markets.

"Otherwise, they will have to bear responsibility for the results and will be severally punished," a bureau official told the China Daily.

"No such food poisonings have been reported in Guangdong so far but we have to enhance our vigilance."

The paper said the tide would hit areas around Shenzhen, which borders Hong Kong, hardest.

China's coastal regions have been ravaged by springtime red tides in recent years, especially in the northern Bohai Sea, the East China Sea and the South China Sea near the mouth of the Pearl River.

The tide is a densely populated algae bloom that breeds in abundance and can suffocate fish by sapping the water of oxygen or by producing toxins that paralyze fish and contaminate seafood.

The algae mainly feasts on urban pollution, industrial discharges, farming wastes and fertilizer run-off that are rich in nitrogen and phosphorus and which flow into coastal waters from rivers and streams.

Since it was first discovered off Guangdong in 1998, an average of 400 tons of fish have died each year, the paper said.

TERRA.WIRE