New research finds that Americans have been buying mislabeled seafood.

An international ocean advocacy group, Oceana conducted a DNA testing from 2010 to 2012 of 1,215 fish samples from 674 retail outlets in 21 states. The result is very disturbing which found that one-third of seafood is mislabeled. The study was restricted to retail outlets that include restaurants, sushi outlets and grocery stores.

From the 1,215 samples purchased by the organization that were tested revealed 401 samples to have been mislabeled.

"We looked all over the country, and we found mislabeling all over the place," said Kimberly Warner, a senior scientist at Oceana.

"It not only hurts consumers in the pocketbook, but this illegal activity provides lots of opportunities for what we call pirate fishing to occur," Warner said.

Oceana during the two-year study discovered Southern California was rating the highest with 52 percent. Here is a chart that displays the full results.

Generally cheaper species seem to have been mislabeled more than expensive types such as red snapper and tuna to boost profits, according to Oceana officials. Based on the study nationwide two most mislabeled fish were 87 percent of red snapper and 59 percent of tuna.

Below is the chart for more results.

The Oceana study reveals a big concern in seafood retailing, said Derek Figueroa, chief operating officer at Seattle Fish Co.

"Economic fraud is wrong, and it's illegal," he said. "Ultimately it erodes consumer confidence. It's in the interest of both consumers and the industry to be confident in the products being offered."

Although US is the second largest seafood-consuming country worldwide followed by China with more than 90 percent of them being imported, the Food and Drug Administration tests less than 1 percent seafood sold in the U.S., according to a 2009 Government Accountability Office report.

For concerned customers there are left with only few options, they can stand up to increase DNA testing and full traceability across the fish supply chain.

Here is the link of the full report [pdf].