LELAND, Miss. — Catfish farmers across the South, unable to cope with the soaring cost of corn and soybean feed, are draining their ponds.

"It's a dead business," said John Dillard, who pioneered the commercial farming of catfish in the late 1960s. Last year Dillard & Co. raised 11 million fish. Next year it will raise none. People can eat imported fish, Dillard said, just as they use imported oil.

James Patterson/The New York Times (ENLARGE)

Alex Hunter waits to load harvested catfish into a truck for processing in Leland, Miss.

James Patterson/The New York Times (ENLARGE)

Keith King, president of Dillard & Company, kneels in an abandoned catfish pond that will be planted with crops in Leland, Miss.

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As for his 55 employees? "Those jobs are gone."

Corn and soybeans have nearly tripled in price in the last two years, for many reasons: harvest shortfalls, increasing demand by the Asian middle class, government mandates for corn to produce ethanol and, most recently, the flooding in the Midwest.

This is creating a bonanza for corn and soybean farmers but is wreaking havoc on consumers, who are seeing price spikes in the grocery store and in restaurants. Hog and chicken producers as well as cattle ranchers, all of whom depend on grain for feed, are being severely squeezed.

Perhaps nowhere has the rise in crop prices caused more convulsions than in the Mississippi Delta, the hub of the nation's catfish industry. This is a hard-luck, poverty-plagued region, and raising catfish in artificial ponds was one of the few mainstays.

Then the economics went awry. Feed is now more than half the total cost of raising catfish, compared with a third of the cost of beef and pork production, according to a Mississippi state analysis. That makes catfish more vulnerable. But if the commodities continue to rocket up — and some analysts believe they will — other industries will fall victim as well.

Keith King, the president of Dillard & Co., calculates that for every dollar the company spends raising its fish, it gets back only 75 cents when they go to market.

"What's happening to this industry is sad, but being sentimental won't pay the light bill," Mr. King said.

Dillard and other growers take their fish, still squirming, to Consolidated Catfish Producers in the hamlet of Isola, where workers run the machinery that slices them into filets. With fewer fish coming in, Consolidated Catfish is resorting to layoffs.

One hundred employees were let go in the last month, and an additional 200 will be cut soon. President Dick Stevens predicts that by the end of the year the company will have jobs for only 450, about half the number at its peak. That might not be enough to keep the plant open.

"The industry is going to implode," Mr. Stevens said. He blamed the government's ethanol mandates for making fuel compete with food for the harvest of the nation's farmland. "Politicians were in a rush to do something, and it became a terrible snowball."

Across the highway, one of the local feed mills, Producers Feed Company, has already shut down. The ripple effects have begun: between the grain mill and the fish plant was Peter Bo's Restaurant, locally celebrated for, naturally, its catfish. Hanging on the door is a "for rent" sign.

Some catfish producers recently switched to a feed based on gluten, a cheaper derivative of corn, to reduce their costs. But corn gluten transportation and prices were particularly hard hit by the Midwest floods.

"As sick as we were over what happened to the Iowa farmers, we were also sick over what was going to happen to us," Mr. Stevens said.

It is a feeling echoed by others who depend on corn and soybeans.

In the spring, hog farmers thought they were past the worst. Export sales to China were strong. Corn appeared to level off. Some farmers sought an edge by reformulating pigs' diets and reducing the weight at which they sent the animals to the packer.

"And then corn goes up another buck, and you're back where you were," said Dave Uttecht, a producer in Alpena, S.D., who raises 70,000 pigs a year.

"I'm a farmer. I'm used to peaks and valleys." Mr. Uttecht said. "But this is like falling into the Grand Canyon."