`Harvesting' fish in China. Integrated pond system provides a model for alternative methods

WHEN his fish gasped at the surface for air, the Chinese peasant fish farmer confided to a visiting UN consulting team, he threw a dosage of salt into the fresh water. Some of the Western scientists laughed at this; the Chinese officials looked uncomfortable. But sure enough, later calculations showed that the salt did indeed help reoxygenate the water by acting on fish waste.

``Who knows how long they've been doing this?'' says Ron Zweig, an expert in the computer modeling of aquaculture systems and a member of the United Nations Food and Agriculture Organization (FAO) team. ``A thousand years? Two thousand years? Perhaps long enough to try everything else. The man couldn't read or understand why it worked, but he knew that it did.'' A centuries-old tradition

China presently accounts for 25 percent of world fish production, 60 percent of which is generated from their highly integrated freshwater pond system. Legend has it that China's tradition of fish farming dates back 3,000 years to Emperor Li's prohibition against consumption of a common carp, also called ``li.'' In urgent response, a refugee devised an economical method of farming several different species of carp in a single pond: Some were surface feeders of vegetable refuse; others fed on algae through the pond depths; and some species on nutrients from the pond bottom. Over time, the pond system was more tightly integrated with vegetable and livestock production, much in the way of natural ecosystems -- each component's waste revived as another's feed or fertilizer.

The tight integration of the system is what Zweig finds so interesting. ``You throw an atom of nitrogen into the pond as food, see it go through the fish, out into the water and over the vegetables when you irrigate, enriching the soil; then the vegetable waste goes back into the pond as food.''

``That's why I'm totally dedicated to these tightly integrated, resource-recovering structures,'' says Zweig. ``The notion of whole systems is critical to long-term sustainability.'' He has been studying such systems for the past 15 years, most recently at the New Alchemy Institute on Cape Cod, a facility specializing in research on alternative food and energy production. 18,000 acres of fish ponds

Zweig was one of the first Western scientists to visit China after Deng Xiaoping's rapprochement with the West began in the 1970s. It was here that Zweig saw aquaculture on a scale he had only imagined.

His second consulting trip to China took him to Guangdong, where the Chinese were planning 18,000 acres of fish farms, the largest such project of its kind, and the first to request international loans. The Chinese government sought tractors to expedite the installation, and Zweig was the UN-appointed economic analyst. Tens of thousands would be employed by the Guangdong farms; literally millions would be fed.

As proposed, however, the rate of return on the project was less than one percent -- too low to encourage the loan. For a time, Zweig was caught between the exigencies of Western finance and China's food and labor concerns. But after more analysis, Zweig found a modification that brought the loan return all the way up to 25-30 percent. If common grass, instead of sugarcane, were grown on the pond dikes, more fish feed in the form of grass and algae would be generated. The loan was approved.

Zweig is now on his third major FAO consultation to China, a site analysis of 23 counties for their aquaculture potential. Between trips abroad, he runs his own nonprofit group, Ecologic, in partnership with his wife, Christina Rawley, a Harvard doctoral student and longtime board member of the New Alchemy Institute.

``The focus on aquatic systems is a primary difference between East and West,'' observes Ms. Rawley. ``The West has not paid attention to water due to the abundance of land.'' Promoting aquaculture in the US

Ecologic attempts to promote on a small scale in the US the same efficient and ecologically sound production Zweig and Rawley have seen on so vast a scale in China. Zweig's data shows that pond fisheries and and hydroponics (plants grown in nutrient solution) are economically feasible, but establishing such concerns is difficult. The recent expiration of alternative energy tax credits, combined with the presently low price of oil, means that few farms or fisheries are presently looking to alternative methods.

On the educational front, however, Zweig has seen progress -- both for himself and in his field of endeavor. International loan agencies are gradually becoming more accustomed to indigenous, labor-intensive methods of production. A Carnegie Foundation report is recommending aquaculture as an important educational subject. And Zweig is scheduled to teach a course project at the Woods Hole Oceanographic Institution in 1987 to 30 policy analysts from around the world.

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