Something fishy might be going on in the sushi supply chain.

The 26 L.A. restaurants that a recent UCLA study found had incorrectly identified almost half of their sushi could be the victims of fish fraud rather than the perpetrators, according to one of the report’s authors.

Paul Barber, professor of ecology and evolutionary biology at the university, said the problem could lie with suppliers, as both restaurants and grocery stores were found to be selling mislabeled fish.

“The take-home message is that it’s not about pointing fingers at anyone, or saying that purveyors of sushi are being deceptive intentionally, or that people shouldn’t eat sushi,” Barber said last week. “It really is highlighting the issue that if we, as consumers, want to exercise choices, to be able to choose what kind of food we want to eat or the kind of fisheries we want to support, we can only do that with accurate information.”

California Restaurant Association, an industry advocacy group, said in an emailed statement that it hoped federal legislation that went into effect on Jan. 9 requiring fish importers to document their product’s chain of custody would shed some light on the problem.

“UCLA’s study openly acknowledges that it is difficult to determine the point at which fish mislabeling happens in the supply chain,” the statement said.

The study, published Jan. 11 in journal Conservation Biology, tested DNA of raw fish specimens taken from about 10 percent of L.A.’s sushi restaurants from 2012 to 2015. Its authors found the restaurants served a different fish than was listed on the menu about 47 percent of the time. Restaurants weren’t identified in the study.

The researchers, who haven’t yet notified the affected restaurants, hadn’t heard any response from the restaurant industry by late last week.

Other studies in Los Angeles and other cities have come to similar conclusions as UCLA’s. The UCLA study was unique in that it spanned more than a year, reducing probability that the results are an aberration, said Demian Willette, a researcher at the university and the lead author.

Barber said the findings have broader business and environmental implications for the rest of the country, which imports almost 90 percent of its fish. The global export market was worth $148 billion in 2014, according to a United Nations report.

Transparency in the food chain would allow consumers to make better educated decisions, he said.

“In the end, it’s a win for businesses because they have a sustainable supply of seafood to continue a culinary tradition, and there’s an environmental benefit because there’s sustainable fish stock in the ocean,” said Barber.

Almost one-third of commercial fish stocks are overharvested at unsustainable levels, the U.N. report says.

Deceptive labeling might also make it harder for those selling fish harvested in an environmentally friendly way to compete with others economically, he said, comparing the scenario to someone selling traditionally grown produce marketed as organic and charging a higher price.

Barber and Willette plan to reach out to the restaurants, which were all given good ratings on Yelp and Zagat, to see if they’d be interested in allowing the researchers to test their supply in order to determine the source of the mislabeling. Having a certification of the food’s provenance could even be an attractive marketing pitch, especially in Los Angeles, Barber said.

Staff reporter Caroline Anderson covers restaurants, retail, and hospitality. She can be reached at canderson@labusinessjournal.com.