After recent reports that hot dogs contain disturbing ingredients, processed meat is carcinogenic and sugar is toxic, researchers now turn to fish. A new study says that salmon fraud is happening in almost half of the restaurants tested, particularly during winter.

Advocacy group Oceana released a report Wednesday about salmon fraud or mislabeling wherein American restaurants put "wild," "Pacific" or "Alaskan" salmon on the menu but actually serve the less expensive farmed salmon. Researchers took salmon samples from both restaurants and grocery stores and used DNA testing to determine if they were labeled properly.

Out of 82 salmon samples tested, 43 percent were found to be mislabeled. Sixty-nine percent of the mislabeled salmon were farmed salmon marketed as wild. In other cases, the salmon were labeled as a specific type but were actually a cheaper species. Salmon fraud in restaurants was observed in 48 percent of samples in Virginia, 45 percent in Washington, 38 percent in Chicago and 37 percent in New York.

"Americans might love salmon, but as our study reveals, they may be falling victim to a bait and switch," Oceana Senior Campaign Director Beth Lowell said in a press release. "When consumers opt for wild-caught U.S. salmon, they don't expect to get a farmed or lower-value product of questionable origins."

She said salmon fraud "can have serious ecological and economic consequences" and affects not just the consumers but also the hardworking fishermen whose catch would have to compete with the prices of "fraudulent products."

"While U.S. fishermen catch enough salmon to satisfy 80 percent of our domestic demand, 70 percent of that catch is then exported instead of going directly to American grocery stores and restaurants," lead researcher Kimberly Warner said in the press release. "What we end up eating is mostly cheaper, imported farmed salmon, sometimes masquerading as U.S. wild-caught fish."

Additionally, the report says consumers are more likely to buy mislabeled salmon at restaurants than in grocery stores, where only 20 percent of the salmon samples tested were mislabeled. And there are better chances of buying properly labeled salmon in bigger grocery store chains because these are required to supply additional information about their seafood products.

Warner advises consumers to eat salmon in season, specifically from May to September.

"Time of year makes such a big difference on whether salmon mislabeling is high or low," Warner told USA Today.

"The federal government should provide consumers with assurances that the seafood they purchase is safe, legally caught and honestly labeled," Lowell said.