Bait and Switch: UCLA Study Finds Fish Fraud Runs Rampant

By ALISON HEWITT

Next time you go out for sushi in Los Angeles, don’t bother ordering halibut. Chances are it’s not halibut at all.

A new study from researchers at UCLA and Loyola Marymount University checked the DNA of fish ordered at 26 Los Angeles sushi restaurants from 2012 through 2015, and found that 47 percent of sushi was mislabeled.

The good news is that sushi represented as tuna was almost always tuna. Salmon was mislabeled only about one in 10 times.

But out of 43 orders of halibut and 32 orders of red snapper, DNA tests showed the researchers were always served a different kind of fish. A one-year sampling of high-end grocery stores found similar mislabeling rates, suggesting the bait-and-switch may occur earlier in the supply chain than the point of sale to consumers.

“Half of what we’re buying isn’t what we think it is,” said Paul Barber, a UCLA professor of ecology and evolutionary biology and senior author of the study that appeared Jan. 11 in the journal Conservation Biology. “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. I suspected we would find some mislabeling, but I didn’t think it would be as high as we found in some species.”

It’s not just a question of being miffed that the wrong fish is on your plate — the fraud undermines environmental regulations limiting overfishing, introduces unexpected health risks and interferes with consumers’ decisions, the researchers noted.

Over the four-year study, only bluefin tuna was always exactly as advertised. While only one of 48 tuna samples was not tuna, different kinds of tuna occasionally swapped places, including two samples that turned out to be Atlantic bluefin tuna and southern bluefin tuna, species classified as endangered and critically endangered.

Out of nine orders of yellowfin tuna, seven were a different kind of tuna, usually bigeye — a vulnerable and overexploited species, the researchers said.

Salmon remained a largely safe bet, with only six of 47 orders going awry. However, all halibut and red snapper orders failed the DNA test, and in nine out of 10 cases, diners ordering halibut were served flounder. About four in 10 halibut orders were species of flounder considered overfished or near threatened.

Although some short-term studies have suggested that fish fraud is declining due in part to stricter regulations, this study uncovered consistent mislabeling year over year, indicating seafood misidentification is not improving. While the current study took place in Los Angeles, previous studies detected similar problems nationwide, suggesting that the UCLA findings are widely applicable, said Barber, who worked with lead author Demian Willette and researchers from UC Santa Cruz and UC Santa Barbar