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If you go to the supermarket, you can usually find fish that's labeled wild caught. But you're never going to see wild caught pork or chicken. It's because practically all of our food comes from farms. In fact, more and more seafood now comes from farms, too. There's not nearly enough fish growing wild to meet demand, and the seafood Americans eat most - think shrimp, tilapia, salmon - mostly comes from fish farms overseas. NPR's Dan Charles reports.
DAN CHARLES, BYLINE: The shrimp and tilapia grow in warm water ponds in Southeast Asia and Latin America. The salmon comes from big nets in the ocean, off the coast of Norway and Chile.
MICHAEL RUBINO: About 90 percent of the seafood that we eat, by value, is imported.
CHARLES: That's Michael Rubino, director of aquaculture for the National Oceanic and Atmospheric Administration. We could do that here, Rubino says. It wouldn't take that much space.
RUBINO: The entire Norwegian production of salmon, which is about a million tons a year, can be grown on the size of the runways at JFK airport in New York.
CHARLES: In fact, the UN recently did a study. It asked, what countries in the world could grow the most fish in those nets in the ocean?
RUBINO: And the U.S. came out number one in terms of potential. You know, so one question is, why don't we do more of it?
CHARLES: One reason is there's been a lot of opposition. Environmentalists have been deeply suspicious of large-scale aquaculture. When millions of fish are crowded together, they generate a lot of waste. Fish farms can also be breeding grounds for diseases that can infect wild fish nearby. And then there's the feed. It usually contains lots of fish meal and fish oil, which mainly come from processed wild fish, small ones that are getting sucked out of the ocean by the shipload to support the growth of fish farms.
It's all given aquaculture a bad name. But there are people trying to create fish farms that are totally clean and green. They're trying to overcome two different kinds of barriers: technological and economic. The cutting edge of technology is Yoni Zohar's laboratory at the Institute of Marine and Environmental Technology.
YONI ZOHAR: So here you go. It's a basement. We are located right on the inner harbor of Baltimore, right on the water. But we don't take a drop of water from the inner harbor, and we don't drain a drop of water back to the harbor.
CHARLES: I can see a whole array of plastic tanks. The biggest ones are a dozen feet across. They're filled with artificial seawater and hundreds of fish. Some of these are hard to find in the wild. If you find them on a restaurant menu, they're usually pretty expensive, like the sea bream, which lives in the Mediterranean.
ZOHAR: And those fish are now spawning. This is the sea bream, another high-value marine fish, which is called the Italian orata or the French dorade royale.
CHARLES: Fish like these won't normally spawn in captivity. But Zohar has figured out ways to make the female fish think that they're in their natural spawning grounds.
ZOHAR: The idea is to have the entire cycle, life cycle, in completely clean and controlled conditions that are disease free so you don't introduce anything from the outside.
CHARLES: So no antibiotics ever?
ZOHAR: No antibiotics ever. No nothing.
CHARLES: The whole place is self-contained, so no pollution, no disease. And they're starting to use a new kind of feed with no fish meal in it, just common grains and algae. It seems to solve all of aquaculture's environmental problems. But remember, just in a laboratory. This will only replace traditional fish farming if you can make money at it. So I went to visit Bill Martin and his tilapia factory in southern Virginia.
BILL MARTIN: If these were cattle, it'd be called a feedlot. If it were chicken, it'd be a broiler house.
CHARLES: We're in the main fish-growing room at Bill Martin's company, Blue Ridge Aquaculture, in the town of Martinsville. It's a huge space. Warm and so humid, the mist hangs in the air.
MARTIN: There are 42 tanks in this building, about two and a half million gallons of water.
CHARLES: Every day, trucks haul away 10 or 20,000 pounds of live tilapia. They go to markets from Baltimore to Toronto. It's big enough to make indoor aquaculture a real business. Like Yoni Zohar's laboratory in Baltimore, this factory is self-contained, free of disease. Martin says it's just practical.
MARTIN: I'm not a tree-hugger or an environmentalist by nature. I am one because it makes this capitalism that you see here work so much better.
CHARLES: The technology here isn't quite as cutting edge as what I saw in Baltimore. Tilapia are a lot easier to grow than ocean fish. They aren't picky about where they spawn. But in a way, that makes Bill Martin's job that much harder, because he's competing with tilapia growers in Vietnam, China, and Latin America. He sells his fish to just a small segment of the market, people who want to buy their fish live and will pay extra for them. He still cannot really compete with the imported tilapia filets that you see in the store.
MARTIN: We can't pay people a dollar a week or whatever they pay them to hand cut these fish. So we had to wait until machinery was available.
CHARLES: I think we've now found some machines that will cut tilapia into filets, he says. We're about to test them. If they work, they'll make our tilapia almost as cheap as the imports. He'd like to grow other kinds of fish, too, and shrimp. Indoor fish farms, he says, can be the clean and green future of aquaculture. Dan Charles, NPR News.