Here's an earlier story, with similar conclusions:

http://www.nytimes.com/2008/08/22/science/22fish.html

And here's a reference to an even earlier story from 2005, in which farmed salmon are substituted for wild (not DNA-checkable):

http://vitalchoice.com/shop/pc/articlesView.asp?id=95

So, 6 years later, we still don't know what we're eating.