Fish farming in the desert may at first sound like an anomaly, but in Israel over the last decade a scientific hunch has turned into a bustling business. Scientists here say they realized they were no to something when they found that brackish water drilled from underground desert aquifers (含土水层) hundreds of feet deep could be used to raise warm-water fish. The geothermal water, less than one-tenth as saline as sea water, free of pollutants and a toasty 98 degrees on average, proved an ideal match. 'It was not simple to convince people that growing fish in the desert makes sense,' said Samuel Appelbaum, a professor and fish biologist at the Jacob Blaustein Institutes for Desert Research at the Sede Boqer campus of Ben-Gurion University of the Negev. 'It is important to stop with the reputation that arid land is nonfertile, useless land,' said Professor Appelbaum, who pioneered the concept of desert aquaculture in Israel in the late 1980s. 'We should consider arid land where subsurface water exists as land that has great opportunities, especially in food production because of the low level of competition on the land itself and because it gives opportunities to its inhabitants.' The next step in this country, where water is scarce and expensive, was to show farmers that they could later use the water in which the fish are raised to irrigate their crops in a system called double usage. The organic waste produced by the cultured fish makes the water especially useful, because it acts as fertilizer for the crops. Fields watered by brackish water dot Israel's Negev and Arava Deserts in the south of the country, where they spread out like green blankets against a landscape of sand dunes and rocky outcrops. At Kibbutz Mashabbe Sade in the Negev, the recycled water from the fish ponds is used to irrigate acres of olive and jojoba groves. Elsewhere it is also used for irrigating date palms and alfalfa. The chain of multiple users for the water is potentially a model that can be copied, especially in arid third world countries where farmers struggle to produce crops, and Israeli scientists have recently been peddling their ideas abroad. Dry lands cover about 40 percent of the planet, and the people who live on them are often among the poorest in the world. Scientists are working to share the desert aquaculture technology they fine-turned here with Tanzania, India, Australia and China, among others. (Similar methods offish farming are being used in the Sonoran Desert of Arizona.) 'Each farm could run itself, which is important in the developing world,' said Alon Tal, a leading Israeli environmental activist who recently organized a conference on desertification, with the United Nations Convention to Combat Desertification and Ben-Gurion University, that brought policy makers and scientists from 30 countries to Israel. 'A whole village could adopt such a system,' Dr. Tal added. At the conference, Gregoire de Kalbermatten, deputy secretary general of the antidesertification group at the United Nations, said, 'We need to learn from the resilience of Israel in developing dry lands.' Israel, long heralded for its agricultural success in the desert through innovative technologies like drip irrigation, has found ways to use low-quality water and what is considered terrible soil to grow produce like sweet cherry tomatoes, people, asparagus and melon, marketing much of it abroad to Europe, especially during winter. The history of fish-farming in nondesert areas here, mostly in the Galilee region near the sea, dates back to the late 1920s, before Israel was established as a state. At the time, the country was extremely poor and meat was considered a luxury. But fish was a cheap food source, so fish farms were set up on several kibbutzim in the Galilee. The early Jewish farmers were mostly Eastern Europeans, and Prof