Beauty fish, hope I'm that lucky next week. The meat coloration has little to do with genetics, more to do with diet. Krill and shrimp eaters have red flesh when their primary diet is crustaceans. Kings that eat primarily fish will be whiter. My guess is fraser fish feed on more fish to attain the size they do by staying out at sea longer which makes them whiter. More pelagic fish like Coho are redder as they are somewhat smaller, schooling fish and can feed more on the krill than larger Chinook can.