Limited oversight

But the FDA only inspects about 2 percent of imports.

Ken Albala is a food historian at University of the Pacific in Stockton, California. He teaches about food policy and environmental issues. He says, while the cattle industry has been tightly regulated, that's not the case with the fishing industry.

"And when you're talking about a several thousand pound cow versus a bass, let alone a shrimp," says Albala. "I don't see how they could ever begin to inspect consistently what's coming in from abroad. Definitely not."

Right now, Congress is considering a bill that would give the FDA increased authority over imported seafood. So far, the bill has passed the house and is waiting to be picked up in the Senate.

So consumers who want to eat shrimp are faced with two choices: trust that random spot checks find any problems with seafood imports or pay more for domestic, wild harvested shrimp.

And that price could go even higher if the oil spill in the gulf contaminates a good part of the domestic supply.

(Support for The Environment Report comes from the Park Foundation, the Gaylord and Dorothy Donnelly Foundation, and the Great Lakes Fishery Trust. You can find more stories - and post your comments - at environment-report.org.)