East of Lake Tahoe, an organic farmer and his son are putting the finishing touches on what is perhaps a counterintuitive approach to water conservation in a dry climate: a 32,000-sq ft greenhouse that will grow tomatoes, peppers and fish in the heart of the Nevada desert.

Mark O’Farrell, the owner of Hungry Mother Organics in Minden, Nevada, plans to have his desert fish farm operational by August, when he’ll begin to produce an estimated 36,000 to 50,000 tilapia per year.

Reeling it in: global sustainable seafood market hits $11.5bn Read more

O’Farrell is one of a growing group of aquaculturists in the American Southwest turning a harsh, dry climate to their advantage by growing fresh food in areas where it has traditionally been difficult to farm. Although fish require copious amounts of water, the same water can be used multiple times to irrigate crops and in some cases, even improve soil quality with the addition of nitrogen and potassium from fish waste.

In O’Farrell’s case, he’s combining aquaculture with hydroponics in an operation that allows him to grow plants directly above his fish tanks. After tinkering with a series of fish tanks and worm digesters to extract the fish waste solids and make them available to fertilize his young plants, O’Farrell realized his setup was saving him $12,000 a year and cutting his water use by 80%.

Kevin Fitzsimmons, a professor at the University of Arizona, has been leading a similar push across Arizona to draw conventional farmers into aquaculture, either to raise fish on their own or to partner with fish farmers and share water. The number of farms producing fish in Arizona nearly doubled between 2005 and 2013, according to the 2013 Census of Aquaculture.

“My hope is that people recognize that integrating aquaculture and agriculture would really encourage everybody to use water twice and be super efficient with it,” says Fitzsimmons. Desert Springs Tilapia, a Dateland, Arizona-based operation managed by one of Fitzsimmons’s former students, uses water once for raising tilapia and again to grow alfalfa, Bermuda grass, hay, barley, oats and olive trees.

“A drier climate is going to make irrigated farming that much more difficult,” Fitzsimmons said. For O’Farrell, the move to fish farming came after years of trying other approaches. “I’ve tried everything you can to grow crops [in Nevada] and you can’t do it profitably,” he says.

It would seem that finding more efficient uses of water in the Southwest could not come at a better time. The number of dry, hot days in the region is believed to be increasing in frequency. A recent study in Geophysical Research Letters found the Southwest, including parts of California, has entered a “drier climate state”, and is not just experiencing isolated, temporary periods of drought.

Fitzsimmons says the silver lining is a forced shift towards practices such as aquaculture that address two significant regional and national problems at the same time: limited water and an intense domestic dependence on imported fish.

Although data collection on US fish production is often sparse and out of date, Monterey Bay Aquarium’s Seafood Watch estimated in 2012 that 95% of tilapia consumed in the US is imported. The National Marine Fisheries Service says the US is the largest global importer of fish, half of which is raised through aquaculture practices in other countries. In 2015 alone, the US imported approximately 500m lbs of tilapia from China, Indonesia, and Central and South America, according to data from the United States Department of Agriculture.

Until recently, growing tilapia in the Southwest has largely been a business for Arizona, southern California and parts of Texas. In fact, the New Mexico Department of Fish and Game only began issuing permits for would-be aquaculturists in October of last year.

Most aquaculturists do not raise other livestock. Fitzsimmons initially tried to encourage traditional ranchers to set up fish farms, but has found it easier to get people interested in aquaculture to team up with and lease land from traditional farmers and share water pumping costs. “We kind of hoped that we could get farmers who had cows, horses, goats, sheep, whatever, to think of fish as another livestock. It’s more complicated than keeping horses or cows,” Fitzsimmons says.

Off the hook: can a new study in the Pacific reel in unsustainable fishing? Read more

One thriving aquaculture operation is Sterling Caviar, which has been growing sturgeon and selling caviar since 1993 around Sacramento, California. The company maintains 30 to 40 employees and produces 10-12 tons of caviar and 300 tons of meat each year, according to managing director Shaoching Bishop. The company’s deputy general manager, Bobby Renschler, is also a fish biologist, who says the company’s four farm sites recirculate their water as many as six times.

Sterling’s largest farm is in Elverta. It discharges 3.7m gallons of water each day, flowing first to artificial wetlands at the Natomas Basin Conservancy, and then into an irrigation canal, where the water flows mostly to local rice farmers. In the case of Sterling, the water released has been filtered of all fish waste and the company simply disposes of it. Sterling’s other sites release water to cattle farms, wetlands and other agricultural land.

Israeli company Microdel, which recently built its AquaTech Fisheries in Israel’s Negev Desert, is currently in negotiations to secure $65m for a similar project in Nevada. It hopes to begin construction in the first quarter of 2017, according to Microdel CEO Gabi Wolkinson.

Randy Lovell, state aquaculture coordinator at the California Department of Fish and Wildlife, says he would like aquaculture in the US to go one step further – to the coast. According to the National Oceanic and Atmospheric Administration (NOAA), marine aquaculture around the US is currently limited to around 11 types of seafood including oysters, clams, salmon and cod. NOAA is currently offering grants and other funding programs to encourage the expansion of marine aquaculture. “I would submit that there’s a whole other realm of food production that we have not fully supported in the US that has tremendous potential,” Lovell says.