Last Year, Oceana collected 119 seafood samples from grocery stores, restaurants and sushi venues in Los Angeles and Orange counties. In nearly nine out of 10 samples, the sushi was mislabeled.
Sometimes, a cheaper type of fish was being sold as a more expensive one. Other times, a fish with a health warning was sold as a different type of fish.
In eight out of nine sushi samples labeled as white tuna, the fish was actually escolar, a snake mackerel species that carries a health warning in the U.S. Escolar has toxins and a strong oil that acts as a "purgative" or laxative and can cause diarrhea, according to the FDA.
In 34 samples of so-called snapper, every fish was mislabeled, according to the Oceana report. Half of it was actually tilapia. And yellowtail was often replaced with Japanese amberjack.
Earlier this year, state Sen. Ted Lieu, D-Torrance, introduced legislation that would require large restaurant chains to accurately label seafood by species. The legislation is sponsored by Oceana.
The FDA is also conducting a yearlong DNA test of 800 fish collected nationwide as seafood fraud complaints are occurring at many levels from processing, distribution to the final point of sale.
While Oceana wouldn't release the names of the places where they obtained their sample, your best bet is to buy from long-standing reputable establishments.
The Associated Press contributed to this report.