Fish vendors in south China's Guangdong Province are struggling to sell fresh-water fish to Hong Kong where authorities are concerned about malachite green, a synthetic dye used to treat fungal infections on fish eggs and which is considered dangerous for human health.
Statistics from Guangzhou Customs show that Guangdong, separated from Hong Kong by the Shenzhen River, shipped 1,752.6 tons of live fresh-water fish last month, down 13.9 percent on December 2005 and down a drastic 46.7 percent on last November.
Hong Kong has traditionally been a prime consumer of live fish raised in Guangdong. Guangdong exported US$62.28 million worth of fish to Hong Kong last year, three quarters of Guangdong's total fish exports.
However, since August of last year, Hong Kong media have carried reports about positive tests for malachite green in live fresh-water fish sourced from the mainland.
Hong Kong's Health, Welfare and Food Bureau subsequently established a list of registered freshwater fish farms authorized to supply fresh-water fish to Hong Kong.
But ongoing public concerns have affected supplies.
While low levels of malachite green are not considered to pose an immediate risk to human health, many countries ban the substance from fish farming.
Food safety is a high-profile issue in Hong Kong.
Guangdong's exports of live fresh-water fish to Hong Kong totaled 38,000 tons last year, down one percent on 2005.