“Hi David, I suggest you only eat Wild Salmon, have a look at this site. Also this you tube. 

"Marine Harvest's operations have been severely affected in the south of Chile, where millions of fish have died by the disease infectious salmon anemia salmon contains the highest level of cancer causing toxin PCB as well as other contaminants. Read more about the toxins found in farmed salmon and the health implications.”

David Fuller's view

Thanks for your email and the two links provided, which are enough to worry anyone.  I am wary of unknown (to me) online sites, including those with a doctor recommending the products.  However, I hope the one above is fine but I cannot confirm that.  Living in London, the salmon I eat is farmed in Scotland, and I only buy it from Waitrose and Marks & Spencer.  They also sell wild salmon but it has been frozen too long and I do not like it.  The best wild salmon I have ever had was in Vancouver.  It came in several varieties, a couple of which were fantastic.