The fish harvesters.

Farm-Raising Salmon and Shrimp Makes Millionaires, and Also Creates Dead Seas

As yet another snowstorm was burying Minnesota and the rest of the Midwest last winter, traders in the "futures pit" of the Minneapolis Grain Exchange were shouting and signaling bids and offers for spring wheat, white wheat, white shrimp and black tiger shrimp. The trading in shrimp was closely followed by the staff of the local Thai Trade Office.

Wait a minute. Shrimp on the Minneapolis Grain Exchange? A Thai Trade Office in Minnesota? It's all part of the incredible rise of "aquaculture," or fish farming, a science that goes back 5,000 years to the ancient Egyptians, but has exploded in popularity since the 1960s. The 1993 launch of shrimp futures trading, which involves the buying and selling of contracts to purchase lots at set prices, completes the transition of shrimp from delicacy to international commodity.

Aquaculture is an all-inclusive term that covers the captive raising of fish, shellfish and plants in either fresh or salt water. According to the United Nations Food and Agriculture Organization (FAO), by the year 2000 aquaculture will supply up to 20 percent of the world's fish consumption (98.1 million tons in 1992). Aquaculture fish production doubled between 1984 and 1992, when it reached 9.4 million tons, while farmed mollusks and crustaceans accounted for another 4.5 million tons that year.

Scientists predict a bright future for aquaculture because human per capita fish consumption - currently at 13 kilograms per person - is unlikely to be met by wild harvesting alone. The UN estimates that aquaculture production will have to double by 2100 to meet increased population demands. In the U.S., it is one of the fastest-growing segments of the economy, increasing at 15 percent a year since 1980.

Common farmed species include shrimp, catfish, crayfish, salmon, mollusks of various kinds, seaweed, eels, trout and carp. Salmon aquaculture is a $1 billion industry (with output growing 150 percent from 1987 to 1995). There are thriving processors in Norway, Great Britain, the U.S. (specifically Maine and Washington State), Canada and the Far East.

Just as fast-growing is the production of shrimp, involving about 12 different species around the world. The largest "farms" are in Latin America and in Asia, where aquaculture grew by 40 percent a year between 1983 and 1988. But shrimp farming is both risky and environmentally disastrous. In 1989, for instance, 80 percent of the shrimp farms near Bangkok, Thailand went bankrupt, victims of a drop in world prices, reduced profits and, especially, the results of poor harvests caused by polluted water. But hard-luck stories didn't stem the flood of new aquaculture enterprises, usually based in ponds dug out of mangrove forests, marshes and other tropical coastal areas. Within a year, investors in shrimp ponds could recover their investments.

Farmed shrimp began flooding markets in developed countries between 1982 and 1994, when tropical shrimp farms increased their production from about 220 million pounds to 1.6 billion pounds. Of the roughly 850 million pounds of shrimp consumed in the United States in 1994, about 750 million pounds were imported.

While shrimp farming has brought millions of dollars of hard currency to some 50 countries, it's extremely destructive to the environment. Farms have often annihilated broad areas of mangrove forests and other coastal habitats, polluted rivers and coastal waters, eliminated wild fisheries and fishing communities, and fallen victim to ravaging diseases.

Alfredo Quarto, co-director of the Seat-tle-based conservationist Mangrove Action Project, says that would-be farmers choose to clear mangrove forests (which provide coastal stability, protection from storms and nurseries for juvenile fish) because they're usually government-owned, under-populated and in poor areas. "It's a slash-and-burn industry," Quarto says. "And everywhere it's boomed, it's also busted, after destroying coastal land. And millions of people who were already poor have become impoverished by this industry." Carl Safina, director of the Living Oceans Campaign of the National Audubon Society, adds that the process of making shrimp ponds "affects the ecosystem in the same way the corn belt affected the tall grass prairie - it obliterates it."

Although farmed salmon has yet to make it onto the Minneapolis Grain Exchange, international trade in farmed salmon has boomed as well. Between 1981 and 1991, production of Atlantic salmon in floating cages off Norway, Canada and several other countries leapt from 22 million pounds to nearly 530 million pounds, or about one quarter of all salmon consumed around the world, while farms off British Columbia, Chile and Japan produced millions of pounds of Pacific salmon.

Salmon farms don't chew up coastal lands as shrimp farms do, but they can cause their own kind of environmental problems. Large amounts of uneaten salmon feed has polluted waters near some farms with nutrients, fostering blooms of algae that rob waters of oxygen. Each year, thousands of salmon escape from pens and compete or breed with native salmon, threatening the diversity of wild salmon.

Like shrimp farming, salmon farming in many areas has developed with little attention to environmental effects or to long-term economics. As prices have collapsed due to a glut of farmed and wild salmon in major markets, the dramatic expansion of salmon farms has slowed. In the meantime, consumers in the United States might ask about the origins of the shrimp and salmon they buy. They will probably find themselves more closely linked to distant parts of the world than they had imagined.

CONTACT: The Mangrove Action Project, 4649 Sunnyside Avenue N., #321, Seattle, WA 98103/[phone]; Penbur Farms, 1235 South Loop 4, Buda, TX 78610/[phone].