At the risk of sounding like a paranoid schitzo, I personally, and I'm not alone, think you should steer clear of the farmed salmon when your perusing the seafood section at the supermarket.
The feed used by the farmers to raise the salmon you see, contains large amounts of PCB's (toxins) which is ingested by the salmon. And being raised on a farm or in a farm in a salmon's case, means there is not as much room to swim around making for a nice fatty salmon. Well, guess where the salmon likes to store the PCB's when he eats them. That's right. In his fat.
I'm not writing an essay on PCB's, so if you're wondering what they are exactly, google it.
Also, I'm a purist. If I'm given the choice between wild or farmed, you bet I'm grabbin' the wild one.
"Farmed". It just seems so manufactured. So artificial.
Cin Cin (Italian)