You know how nice salmon look when they are sitting on the slab in Sainsburys or Waitrose ... they are the farmed variety.
The pictures below are of a 45lb fish caught at Kercock on the Tay in Scotland last Friday. The weight is a good estimate as the fish went back and it was probably 50lb+ when it entered the river a few months back, however, note the dark colouring of one ready to spawn.
Looks a little different ...