The Guardian recently conducted an investigation of slavery in the shrimp farming industry in Thailand, finding that “Slaves forced to work for no pay for years at a time under threat of extreme violence are being used in Asia in the production of seafood sold by major US, British and other European retailers.” http://www.theguardian.com/global-development/2014/jun/10/supermarket-prawns-thailand-produced-slave-labour.
Now there is a lawsuit seeking to require Costco to disclose alleged slavery in its shrimp supply chain. Here is a copy of the detailed complaint.