Researchers have found that raising fish using water from underground desert springs has advantages besides saving water.

These efforts are becoming increasingly important in helping countries around the world provide food for their growing populations even as supplies of fresh water are tapped dry.

Appelbaum, the head of Israel's Bengis Center for Desert Aquaculture in the Negev Desert, estimates more than 30 million tons of shrimp and fish are raised from desert fish farms each year worldwide, producing an industry worth more than $40 billion. In Israel, most of the fish are raised in the Negev Desert, where temperatures average about 97.5 degrees Fahrenheit in August and annual rainfall is close to zero.

The Bengis Center is part of the Jacob Blaustein Institute for Desert Research, which itself is part of Ben-Gurion University of the Negev of Beersheva, Israel.

"People thought we were lunatics at first," Appelbaum said. "But we know there is a need and this can answer that need. Much of the world has arid land that is rich in sun and cheap labor - for aquaculture you don't need much else to be successful."

To host fish and shrimp in the desert, Israeli farmers draw water from deep underground aquifers that exist under many arid regions of the world. The water is contained in prehistoric caverns 50 to 150 feet beneath the desert surface.

To access the salty water supply, the farmers drill through the desert floor using equipment similar to oil drilling machinery and collect it in aboveground pools, creating comfortable living quarters for edible creatures.

In 10 years of experimentation, the farmers found that some species, including shrimp, catfish, tilapia (a fish that has become more popular on U.S. dinner tables in recent years) and striped bass thrive in the warm, slightly salty water. In fact, the warm water appears to accelerate the breeding rate of many species.

Keeping fish and shrimp in enclosed farms in the desert actually holds a key advantage over coastal fish farms that are open to the ocean - the fish remain protected from diseases that are often spread between seaside farms through ocean waters.

Shrimp are not in great demand in Israel since the crustacean is considered a non-kosher food, but, as Appelbaum points out, the London market is a mere three-and-one-half hour plane trip away. The shrimp's quick maturation rate (about five to six months) also makes it a more desirable crop, since aqua farmers can harvest at least two crops a year.

Inland fish farms have also been installed recently in Alabama, Georgia, Florida and west Texas. U.S. researchers are now visiting regions in central China where it's believed farmers are using brackish water to raise shrimp and fish. Appelbaum is encouraging development in Central Asian countries by recruiting students from the regions to his desert aquaculture program.

Although the underground brackish aquifers are not an endless water resource - Appelbaum estimates most contain about 200 years worth of water - he argues using the salty resources can help buy time until the day when scientists find a cheap way to desalinate ocean water.

As he says, "In the desert, and maybe in the future, we've got to use every liter of water we've got."