A new study has found one-third of all seafood samples taken across the United States are fraudulently labeled. In some places, roughly half of samples were found to be a different type of fish than customers thought they were buying, according to the group Oceana, which tested more than 1,200 seafood samples. Certain types of fish were more commonly mislabeled than others. Out of 120 samples of red snapper, for example, only seven were labeled correctly. The group found fish species that are considered potentially risky for pregnant women and children because of their high mercury content were being sold to customers who ordered safer types of fish. Report author Kimberly Warner described the findings.

Kimberly Warner: “Some of the most troubling substitutions we found were for species that can really cause health problems. Our prime example was we found escolar substituted for something called white tuna, sold in sushi venues. Eighty-four percent of the white tuna was actually escolar, which is something that can cause acute and serious digestive effects if you eat more than just a couple of ounces.”