Do you know where your fish comes from? Chances are it’s from a farm somewhere, most likely in Asia or Latin America—80 percent of U.S. seafood is now imported. But what of these farms?

Olivia Wu investigates the question of farmed fish in an article in the San Francisco Chronicle. With many fish species on the brink of extinction, she asks, “What are we to do for safe, sustainable and affordable seafood?”

The solution: fish farms, otherwise known as aquaculture.

Many experts say that aquaculture must be part of the answer. While freshwater fish have long been farmed in the United States, the domestic offshore aquaculture industry is still in its infancy, and governmental regulation in a formative stage.

Of course, it’s not that easy. Fish raised in offshore open pens create waste that decimates the environment. These fish can escape and breed with the wild fish, introducing disease and impacting the wild breed’s ability to reproduce. Much like feedlots, fish farms use cramped pens and require high levels of antibiotic use. Farmed salmon is even fed red dye to mimic the rosy hues found in healthy wild fish.

The question of salmon and tuna is particularly challenging. These are carnivorous fish—it takes 10 to 25 pounds of wild-caught fish to feed and raise 1 pound of farmed tuna. “There’s a net loss of protein every time you eat a piece of farmed salmon,” Wu writes. “It takes away food from the wild fish trying to survive in the ocean.”

With the high levels of imported seafood, the National Oceanic and Atmospheric Administration is behind the 2007 National Offshore Aquaculture Act (HR 2010), which will provide for more aquaculture off American coasts—with the potential to “damage ecology and deplete the oceans of wild fish.”

Those wanting to be conscientious consumers can take a look at the Seafood Watch put out by the Monterey Bay Aquarium, which gives a breakdown of which fish to choose and which to avoid.

I don’t know about you, but suddenly that tuna sandwich doesn’t look quite so appealing.

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