The report — by the research and advocacy group Oceana — studied 1,200 samples of seafood at grocers and restaurants taken in the U.S. between 2010 to 2012, reports The Los Angeles Times.
DNA testing showed that about 33% of the seafood wasn’t from the species advertised. Tuna was mislabeled 59% of the time and an astounding 87% of snapper samples were some other type of fish. The most common substitutes for snapper were rockfish and tilapia, but more than 30 species were among the counterfeits.
Sometimes the switch can be hazardous. Tilefish, which is swapped for snapper, is on a watch list by the federal government concerning high mercury levels. Escolar, which is a common substitute for tuna, contains a toxin called gempylotoxin which causes gastrointestinal issues.
“Our findings demonstrate that a comprehensive and transparent traceability system — one that tracks fish from boat to plate — must be established at the national level,” Oceana says in the report.