Updated

Here's some real news about a problem with fake fish.

Los Angeles diners chowing down on sushi may be surprised to learn that their yellowtail roll might not really have any yellowtail in it at all. A new study from the University California Los Angeles (UCLA) and Loyola Marymount University (LMU) found that 47 percent of sushi in L.A. eateries is mislabeled as the wrong fish.

The study, which examined 26 area restaurants from 2012 to 2015, discovered that while tuna was almost always tuna, and salmon was almost always salmon, plenty of fish were masquerading as something else.

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But out of 43 orders of halibut and 32 orders of red snapper, DNA testing showed a different kind of fish being used everytime -- in both cases flounder (some species of which are considered severely overfished by Seafood Watch) was the substitute.

“Fish fraud could be accidental, but I suspect that in some cases the mislabeling is very much intentional, though it’s hard to know where in the supply chain it begins," wrote Paul Barber, a UCLA professor of ecology and evolutionary biology and senior author of the study.

"I suspected we would find some mislabeling, but I didn’t think it would be as high as we found in some species."

But the consistent mislabeling of sushi fish may not just be tied Los Angeles-area restaurants. In a report published in September by seafood watchdog group Oceana, it was found that one in five seafood samples tested among purveyors selling to restaurants and other retail sectors worldwide were mislabeled, from restaurants passing off endangered whale as fatty tuna to caviar that wasn’t caviar at all.

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In December, the Obama administration implemented a program to help prevent illegal fishing and seafood fraud across the U.S. The National Oceanic and Atmospheric Administration will install a Seafood Import Monitoring Program to track about 25 percent of imported seafood from the fishing boat where the originates until it reaches U.S. borders.

Enforcement began Jan. 1, and those caught defrauding customers now face having their products seized or legal action taken.

“If we don’t have accurate information on what we’re buying, we can’t make informed choices,” Barber said. “The amount of mislabeling is so high and consistent; one has to think that even the restaurants are being duped.”