In a world hungry for cheap shrimp, migrants labor overtime in Thai sheds Thanks to a bottomless appetite for cheap shrimp in the West, Burmese migrants such as Mon are the backbone of a Thai shrimp industry that is the world's third largest. The United States is Thailand's top customer, accounting for a third of the country's annual shrimp exports. Rights groups say that overseas demand for shrimp products in greater volume has fueled a culture of exploitation in the Thai industry. They insist the failure of foreign companies to sufficiently verify the origin of the shrimp they import allows abuses to persist. "If you look at the cost of shrimp overseas, it's very, very cheap, and that comes from the exploitation inherent in the shrimp industry," says Andy Hall, an expert on migration at Mahidol University who tracks Burmese labor in the Thai seafood industry. Brisk business with major U.S. retailers such as Wal-Mart, Costco, Sam's Club and Red Lobster pumps more than a billion dollars in revenue each year into the Thai economy, the second largest in Southeast Asia. As Thai living standards have risen, a shortage of unskilled labor has attracted tens of thousands of Burmese migrants looking to escape the poverty and job scarcity that has gripped their homeland for decades. Most head to Samut Sakhon province, the heart of the processing industry just south of the capital, Bangkok, where modern facilities line the highway alongside fast-food chains and car dealerships. The more prominent factories are the size of football fields, with neon signage and billboards that feature smiling children. But there's a darker side behind the scenes, activists say. Of an estimated 400,000 migrants at work in the province, only about 70,000 are legally registered. The rest are employed illegally in anonymous peeling sheds that supply the larger companies that must fill massive orders from abroad. At this lower end of the supply chain, according to migrant activists, crooked brokers and employers trap scores of Burmese in abusive conditions tantamount to slavery, particularly in the shrimp industry. "The small factory owners know that most of their workers are undocumented, so they can control the workforce however they want - such as locking workers in until they finish their work," says Sompong Sakaew, a labor activist based in Mahachai, the provincial capital. There are also teenagers between 12 and 17 years old in the workforce. Sold into a waking nightmare Problems for Burmese migrants typically start as soon as they link up with brokers who promise steady work and a decent salary, only to sell them into a nearly inescapable cycle of debt bondage.