Third of US Fish Mislabeled ... Often Dangerously Seafood fraud has health implications, researchers warn By Rob Quinn, Newser Staff Posted Dec 11, 2012 2:31 AM CST Updated Dec 11, 2012 6:09 AM CST 16 comments Comments Supermarket fish counters were generally more reliable than restaurants, the study found. (AP Photo/Rick Bowmer) (Newser) – DNA testing has revealed that there is something extremely fishy going on with seafood labeling in the country's biggest city. The testing found that a startling 39% of seafood samples collected from stores and restaurants in New York City had been mislabeled, usually as fish that was either more expensive or more sustainable, the New York Times reports. Even the most expensive restaurants and retailers were rife with mislabeled fish. Similar studies in other cities also found large proportions of mislabeled fish—55% in Los Angeles. Researchers warn that the problem is a health issue as well as a consumer issue. One of the 13 kinds of fish found mislabeled as snapper was tilefish, which has such high levels of mercury that children and pregnant women are advised to avoid it. Sushi menu item "white tuna" was usually not tuna but snake mackerel, which can cause severe diarrhea and has been banned from restaurants in countries including Japan. "There are a lot of flummoxed people out there who are trying to buy fish carefully and trying to shop their conscience, but they can’t if this kind of fraud is happening," says a scientist at conservation group Oceana, which led the study.