Why do some king salmon have an ivory color?
A rare variety of king salmon has highly prized ivory-colored flesh, and its color is due to genetics rather than diet.
“I used to be able to get white king for less than regular king. It must have caught on, because the cost has gone through the roof.”
When choosing fish, color plays a significant role in the decision. In the supermarket, pinkish fillets are generally preferred over pale ones, and in most cases, this is a good choice. Deep red salmon (sockeye) and king salmon are the most common, with the latter being much pinker.
However, there is a royal salmon with a much paler, ivory-like hue. In this case, the color is not as concerning as it might be in other varieties. It is a rare and highly prized variety, and its color is inherited and completely natural.
Most king salmon is the pink variety found in supermarkets, and much of it comes from the coasts of Alaska or California. Ivory king salmon makes up about 5% of the population and is found primarily in the Gulf of Alaska. It is difficult to find in the continental United States because it rarely ventures far from Alaska, and local restaurants buy it eagerly, so very little reaches retail outlets.
The color of salmon flesh comes from carotenoids. In the wild, salmon feed on plankton and crustaceans containing astaxanthin, a pigment responsible for the characteristic hue of their flesh. In aquaculture, astaxanthin is added to the feed to achieve the same effect. For a long time, it was believed that ivory salmon simply had a diet with less carotene pigment.
However, according to the Alaska Department of Fish and Game, the cause lies not in diet, but in genetics. King salmon possess a recessive gene that, when expressed, provides an enzyme that breaks down the pigment instead of allowing the flesh to absorb it. Ivory salmon is not a different species. It has an additional mechanism that prevents the color from fully developing.
The flavor has also changed its reputation. For a long time, it was considered inferior for lacking that intense color, much like lobster, which was once considered poor people's food before becoming the most expensive item on the menu. Alaskans who knew the secret of white king salmon could enjoy it, and it typically sold for around 60% of the price of common king salmon.
Chef David Moorehead, who worked in Juneau, told Alaska Fish & Wildlife News, “I used to be able to get white king salmon for less than regular king salmon. It must have become more popular, because the price has skyrocketed.” Those who have tried it describe it as butterier than the usual pink king salmon, with a more delicate flavor, similar to some white fish.