Chinook or 'King' Salmon isn't always RED!
The term 'Marbled Salmon' is used to describe Chinook salmon that exhibits flesh pigmentation that is not either the characteristic red/orange coloration or the somewhat similarly common white. Instead it exhibits a combination of the two colors, varying in depth of color and amount "marbled" throughout the flesh of the fish.
Marbled salmon occurs only in the troll fisheries of Washington and Southern BC Canada, and is a result of a recessive genetic feature and diet intake of the fish.
Some Additional Info and Links:
Marbled Salmon - Unique to the Northwest