The crop that's bringing prosperity to farmers is making it harder for commercial fishermen in Louisiana to make a living.

U.S. farmers this spring planted the most acreage with corn since 1944, after demand for ethanol pushed the grain's price to a 10-year high in February. Scientists blame farm waste flowing into the Mississippi River basin for creating a pocket along the Louisiana coast where shrimp and other sea life can't survive.

The Gulf of Mexico's so-called Dead Zone is expected to be a record 8,543 square miles (22,126 square kilometers) this year and stretch into waters off Texas, said Nancy Rabalais, chief scientist for a study team at the Louisiana Universities Marine Consortium. Researchers are measuring the zone this week from boats.

"This is an area the size of New Jersey or potentially bigger where nothing can live," said Matt Rota, a program director at the Gulf Restoration Network, a coalition of environmental and civic groups. "If this were happening in the middle of the country, people would be outraged."

Corn fuels the zone because it requires more nitrogen-based fertilizer than crops such as soybeans, said Eugene Turner, a Louisiana State University oceanographer. Nitrogen and other nutrients eventually reach the Gulf, feeding microscopic organisms that deplete oxygen levels as they die and decompose on the sea floor. Shrimp and fish suffocate unless they escape.

Ethanol, a form of alcohol made from vegetable matter, is distilled mostly from corn in the United States. Less polluting than gasoline, it's at the center of President Bush's plan to reduce reliance on imported oil.

The Dead Zone, also known as an hypoxia zone, is an annual phenomenon that lasts several months and usually peaks around late July. Discovered in the 1970s, it may have existed for a century. The area has about doubled in size since scientists began studying it in 1985.

The zone could be catastrophic for the northern Gulf of Mexico's $2.6 billion-a-year fishing industry, Rota said. At some point, he said, the zone might extend too far out for any shrimp or other creatures on the sea floor to escape.

Louisiana's fishing industry is the second-largest in the U.S., behind Alaska's. It has the largest catches of shrimp, oysters and crawfish, according to state figures. Louisiana is losing shrimpers, though. The number of shrimp fishermen licensed in the state has declined 40 percent since 2001.

Landings of brown shrimp in both Louisiana and Texas declined steadily after peaking at 103.4 million pounds (46.9 million kilograms) in 1990, sliding as the hypoxia zone expanded, according to a 2001 study by Roger Zimmerman and James Nance of the National Oceanic and Atmospheric Administration.