Foreign producers of pond-raised shrimp have powerful economic incentives to use banned substances, such as antibiotics and pesticides, to increase production yields in crowded shrimp ponds and to reduce the risk of total crop failure. Use of these banned substances and various subsidies encourage overproduction and below fair market pricing.
The European Union (EU), Canada, and Japan, have strict food safety regimes that have repeatedly found banned substances in farm-raised shrimp imports. Every major shrimp importing country, except the United States, has taken action to prevent contaminated shrimp from entering their markets. Foreign pond-raised shrimp that is or may be contaminated is diverted to the U.S. market because of the relatively lax U.S. testing of imports. For example, the massive surge of U.S. imports from China in 2002-2004 was due in substantial part to the closure of the EU market to Chinese imports after banned antibiotics were detected.