Oceana, an international ocean advocacy group, has released a report on national seafood fraud [PDF], and the results are disconcerting. The report, which is one of the largest on seafood fraud to date, found that one-third of fish was mislabeled. Oceana performed DNA testing from 2010 to 2012 on 1,215 fish samples from 674 retail outlets in 21 states. In this study, Oceana found seafood fraud everywhere it tested, with rates hitting as high as 52 percent in Southern California.
Here is the breakdown:
You really need to read the article. One thing I'm wondering is if this applies to both fresh and frozen seafood as it doesn't really specify in the article. The article does say that the number one offender is red snapper with tuna as the followup. Of note is that tuna is evidently be substituted by escolar which is known to contain neurotoxins.