Hong Kong has suspended the sale of over 30 species of freshwater fish as its food safety authority detected a cancer-causing dye in a popular fish from the mainland, Oriental Morning Post reported today.

Hong Kong's Center of Food Safety found small amounts of malachite green, an industry-use dye, in 11 samples of freshwater fish in an inspection of birds' eggs and fish for sale in the city, according to the Guangzhou-based Nanfang Metropolises Daily.

Its fish vendors suspended the sale of more than 30 species of fish, including the popular mandarin fish, accounting for one third of the freshwater fish supply. They also banned sales of freshwater shrimps and crabs, with only the sale of carp remaining.

"The samples didn't contain harmful antibiotics, but we found 0.0022 to 2.3 milligrams of malachite green in every kilogram of the fish," said an official with the center, which appealed for the suspension of the fish.

The center conducted a second test on Saturday and found one fish sample out of the 10 bought from a local wholesale market containing small amounts of the dye. The fish were reportedly imported from a legal fishery in Shunde, Guangdong Province.

"The import of freshwater fish from the mainland has been cut by half since Saturday," chairman of the Hong Kong, Kowloon, New Territories and Overseas Fish Wholesalers Association Limited told the newspaper.

He estimated a 40 to 50 percent loss for the city's venders.

Shanghai's largest fishery wholesale market on Tongchuan Road told the Morning Post it hadn't received any report on unqualified mainland fish. The market sold around 10 tons of the mandarin fish every day, with a wholesale price of 24 yuan (US$3.1).

"The mandarin fish on the market are mainly from Guangdong, as native mandarin fish are only available through September to November." said an official with the market.

A fishery insider told the newspaper that domestic farmers formerly used malachite green dye on fish to maintain their freshness and shiny appearance. However, the Ministry of Agriculture has stipulated that malachite green dye cannot be used in edible aquatic animals as large quantities can cause cancer.

(Shanghai Daily November 27, 2006)