"In China, Farming Fish in Toxic Waters"

FUQING, China — Here in southern China, beneath the looming mountains of Fujian Province, lie dozens of enormous ponds filled with murky brown water and teeming with eels, shrimp and tilapia, much of it destined for markets in Japan and the West.

Fuqing is one of the centers of a booming industry that over two decades has transformed this country into the biggest producer and exporter of seafood in the world, and the fastest-growing supplier to the United States.

But that growth is threatened by the two most glaring environmental weaknesses in China: acute water shortages and water supplies contaminated by sewage, industrial waste and agricultural runoff that includes pesticides. The fish farms, in turn, are discharging wastewater that further pollutes the water supply.

“Our waters here are filthy,” said Ye Chao, an eel and shrimp farmer who has 20 giant ponds in western Fuqing. “There are simply too many aquaculture farms in this area. They’re all discharging water here, fouling up other farms.”

Farmers have coped with the toxic waters by mixing illegal veterinary drugs and pesticides into fish feed, which helps keep their stocks alive yet leaves poisonous and carcinogenic residues in seafood, posing health threats to consumers.

Environmental degradation, in other words, has become a food safety problem, and scientists say the long-term risks of consuming contaminated seafood could lead to higher rates of cancer and liver disease and other afflictions.

No one is more vulnerable to these health risks than the Chinese, because most of the seafood in China stays at home. But foreign importers are also worried. In recent years, the European Union and Japan have imposed temporary bans on Chinese seafood because of illegal drug residues. The United States blocked imports of several types of fish this year after inspectors detected traces of illegal drugs linked to cancer...

"For 50 years,” said Wang Wu, a professor at Shanghai Fisheries University, “we’ve blindly emphasized economic growth. The only pursuit has been G.D.P., and now we can see that the water turns dirty and the seafood gets dangerous. Every year, there are food safety and environmental pollution accidents.”

Environmental problems plaguing seafood would appear to be a bad omen for the industry. But with fish stocks in the oceans steadily declining and global demand for seafood soaring, farmed seafood, or aquaculture, is the future. And no country does more of it than China, which produced about 115 billion pounds of seafood last year.

China produces about 70 percent of the farmed fish in the world, harvested at thousands of giant factory-style farms that extend along the entire eastern seaboard of the country. Farmers mass-produce seafood just offshore, but mostly on land, and in lakes, ponds, rivers and reservoirs, or in huge rectangular fish ponds dug into the earth.

“They’ll be a major supplier not just to the U.S., but to the world,” said Richard Stavis, the chairman of Stavis Seafoods, an American company that imports Chinese catfish, tilapia and frog legs.

China began emerging as a seafood power in the 1990s as rapid economic growth became the top priority in the country. But environmental experts say that headlong pursuit of higher gross domestic product has devastated Chinese water quality and endangered the country’s food supply. In Guangdong Province in southern China, fish contaminated with toxic chemicals like DDT are already creating health problems...

A possible solution to the water woes is to move aquaculture well out to sea, specialists say, with new technology that allows for deepwater fish cages served by automatic feeding machines.

The United States is already considering such a plan, partly as a way to make it less dependent on imports, which now fill 80 percent of its seafood needs. China is also considering adopting what is now being called “open ocean” aquaculture.

Currently, China’s coastal fish farms face many of the same challenges as those on land. Waters there are heavily polluted by oil, lead, mercury, copper and other harsh substances. Veterinary drugs dropped in shoreline waters may easily spread to neighboring aquaculture farms and affect species outside the cages, and while coastal waters are less polluted than those on land, aquaculture farms, with their intensive production cycles, are prone to be polluters.

Still, said An Taicheng of the Chinese Academy of Sciences: “China has to go to the sea because it’s getting harder and harder to find clean water. Every year there are seafood safety problems. One day, no one will dare to eat fish from dirty water, and what will farmers do?”