And here are the figure in the Sunday Times study of fat levels in farmed salmon versus wild salmon:
An analysis by the Sunday Times found a classic Pizza Express margherita contains 6.4g of fat per 100g while Sainsbury's Scottish oak smoked salmon made from farmed fish contains 14g of fat per 100g.
The wild equivalent, Sainsbury's wild Alaskan smoked salmon contains 3.2g of fat per 100g.
Tesco's farmed smoked salmon contains three times as much fat as the wild alternative with 9.9g of fat per 100g compared with 3.3g of fat, the newspaper found
In Waitrose, the Heston Blumenthal lapsang souchong tea smoked salmon contains 10.5g of fat per 100g while the wild Alaskan whisky oak smoked salmon contains just 2.7g per 100g.
The omega-3 fatty acids in fish are beneficial but United States Department of Agriculture data has shown that the fat in farmed salmon contains a smaller proportion of omega-3 fatty acids than in the wild fish.
The farmed salmon is, however, likely to contain more omega-3 overall because of the higher levels of fat.