How Much of US Tuna Is Fake?

In 2013, a sampling of the fish sold and used across the United States was genetically tested to determine what percentage of the "fish" was actually fish. The test was done by the nonprofit ocean protection group Oceana. Out of the 1,215 samples, Oceana found that roughly three-fifths of tuna sold in US grocery stores and restaurants was not actually tuna. Oceana also found that sushi restaurants were more likely to mislabel their fish than restaurants or grocery stores. A shocking 74 percent of fish at sushi restaurants was mislabeled, compared to 18 percent at grocery stores and 38 percent at other restaurants.

More about the Oceana study on the labeling of fish in the US:

• 674 retail outlets in 21 states were sampled.
• Snapper, at a whopping 87 percent, was the most commonly mislabeled.
• Tilapia, a less expensive fish, was substituted (although not labeled as such) in place of red snapper nationwide.