Okay, how about one more website, obviously in support of farmed salmon.
This site has answers to all your questions, but from a farm point of view.
So who do you believe?
http://www.salmonoftheamericas.com/index.html

The one thing that stands out in all the hyperbole is the difference
between EPA and FDA safe levels of pcb's. About a 10x difference.

So who do you trust? Beats me.
Gordon