Think what you have in your sushi roll is tuna? Think again.

A new report reveals that seafood fraud is rampant in the United States. Fish substitution happens for a range of reasons from downright fraud to a chef's ignorance, the Boston Globe reported in a YouTube video posted below.

The Inquisitr reported that nearly one-third of fish is being mislabeled in the U.S., according to a new study from the advocacy group Oceana, that was conducted between 2010 and 2012.

Oceana is a non-profit organization that is dedicated to ocean conservation and their research was focused on exposing seafood fraud and to discourage overfishing.

The group collected 1,215 seafood samples from 674 restaurants, fish markets, grocery stores and sushi vendors from across the nation.

Since some of types of fish are so similar in the way they look, taste and cook, the samples were submitted for DNA testing to determine if the fish matched the labels on the packaging.

Researchers found that seafood fraud is widespread, with 33 percent of the samples being mislabeled. They concluded that packages that were labeled “red snapper” or “tuna” were most often marked incorrectly, with New York City being the biggest offender. Out of the 142 fish samples that were taken there, 39 percent were not labeled correctly, the study said.

Tuna fraud specifically was found to be the worst, the study said, with 94 percent of the tuna tested being mislabeled. Red snapper came in second.

According to CBS' 1010 WINS, it can be really dangerous if the wrong fish is being served to consumers.

“We found tilefish, which is on the FDA’s ‘Do Not Eat List’ because of its high mercury content for women of child-bearing age and children, was found in New York City sold as both red snapper and Alaskan halibut,” Oceana Campaign Director Beth Lowell told 1010 WINS.

Even though the results from Oceana’s study were released in December, seafood fraud continues to be a problem in the Big Apple.

“It’s not allowed to mislabel seafood sold in the U.S. and we want to, at Oceana, want to require to track the fish from boat to plate,” Lowell said.

The organization said diners are most often being deceived at sushi bars, whereas their safest bet on getting the real deal is at supermarkets.

Lowell provided some questions for consumers to ask while buying seafood to protect themselves from purchasing fraudulent seafood:

“If the person you’re buying the fish from doesn’t have the answers, then you may want to buy something else. Also, if the price is too good to be true, you might want to avoid that one as well,” she said. “Finally, purchase the whole fish or as close to the whole fish as you can. The more hands your fish passed through on the way to your plate, the more opportunity for seafood fraud.”