Illegal, unreported or unregulated (IUU) fishing remains important challenges to the sustainability of a number of fish stocks, including cod, crabs and shrimp. The strongest initiative to combat such practices was recently taken by the U.S. in requiring chain-of-custody documentation of 17 species if they are to be imported to the U.S., showing these species to not be IUU. The fact that the U.S. is the world´s largest seafood importer makes it possible that this will provide incentives to improve management. However, there is a global market for many species, and as improved management is costly, it is not obvious that the incentives will be strong enough to foster any real change on the water. If the U.S. does not have market power, one are likely to observe a change in trade patterns, and costs associated with the documentation being transferred to U.S. consumers. In this paper, a residual supply approach will be used to investigate whether the U.S. has buyer power for the species where the U.S. market is the largest.