New Scientist magazine is carrying the story of two classmates from New York's Trinity School who collected 60 fish samples from fish stores and restaurants around New York. They then sent their samples off to the University of Guelph in Canada for DNA testing. Of 56 samples that could be identified by the DNA barcoding identification technique, 14 were mislabeled as an entirely different species.
"We never expected these results. People should get what they pay for," said Kate Stoeckle, 18, of the project with Louisa Strauss, 17.In all cases, the fish was labelled as a more costly type, ruling out simple chance. In the worst cases, two samples of filleted fish sold as red snapper, caught mostly off the southeast United States and in the Caribbean, were instead the endangered Acadian redfish from the North Atlantic. The DNA of fish from a sushi restaurant called "white tuna" revealed the fish to actually to be Mozambique tilapia, a type of cichlid often raised on fish farms. One restaurant offered "Mediterranean red mullet" but the DNA matched spotted goatfish from the Caribbean.
I have highlighted this issue in previous posts here and here, but this is the first time I have seen such an excellent study showing what a widespread problem this is.