Slave produce: Workers and children sold to Thai factories supplying peeled shrimps to Wal-Mart, Red Lobster, Fancy Feast and others

Poor migrant workers and children are being sold to factories in Thailand and forced to peel shrimp that ends up in global supply chains, including those of Wal-Mart and Red Lobster, the world's largest retailer and the world's largest seafood restaurant chain, an investigation found.

At the Gig Peeling Factory, nearly 100 Burmese labourers were trapped, most working for almost nothing. They spent 16 hours a day with their aching hands in ice water, ripping the guts, heads, tails and shells off shrimp. One girl was so tiny she had to stand on a stool to reach the peeling table. Some workers had been there for months, even years. Always, someone was watching.

“They didn't let us rest,” said Eae Hpaw, 16, her arms a patchwork of scars from shrimp-related infections and allergies. “We stopped working around seven in the evening. We would take a shower and sleep. Then we would start again around three in the morning.”

More than 2,000 trapped fishermen have been freed this year as a result of an ongoing Associated Press investigative series into slavery in the Thai seafood industry. The reports also have led to a dozen arrests, millions of dollars' worth of seizures and proposals for new federal laws.

Pervasive human trafficking has helped turn Thailand into one of the world's biggest shrimp providers. Despite repeated promises by businesses and government to clean up the country's US$7 billion seafood export industry, abuses persist, fuelled by corruption and complicity among police and authorities. Arrests and prosecutions are rare. Raids can end up sending migrants without proper paperwork to jail, while owners go unpunished.

“I was shocked after working there a while, and I realised there was no way out,” said Tin Nyo Win, 22, another former Gig factory worker, who routinely peeled 175 pounds of shrimp with his wife for just US$4 a day.