Here is a recipe to re-instate the once traditional Fourth of July salmon.
Harold McGee, in On Food and Cooking, offers some fascinating facts on this favorite fish. Salmon, one of the oldest fish, was apparently swimming around 100 million years ago. Carnivores born in fresh water, salmon head to the sea to mature, and return to freshwater to spawn. Trout, in the same family as salmon, evolved when groups of Atlantic and Pacific salmon couldn’t make it back to the sea, and became landlocked.
Salmon is orange, according to McGee, “due to astaxanthin, a chemical relative of the carotene pigment that colors carrots.” In salmon’s case, astaxanthin comes from tiny crustaceans meals. Most fish have astaxanthin, but store it in their skin and ovaries. Salmon store it in their muscle. When heated, as in broiled, grilled or poached — all the delicious ways we cook salmon — astaxanthin produces volatile molecules that resemble those found in some fruits and flowers. This, apparently, is why we love the taste of salmon.
Although the image lingers, Fourth of July salmon and peas had only a brief run as a food tradition. For a short time after the American Revolution, harvest of the season’s first peas coincided with Atlantic salmon’s arrival at river mouths preparing to spawn. Yet, food historian Sandy Oliver claims that a cold spell gripped New England in the 18th century. Indeed, NASA scientists describe a Northern Hemisphere “Little Ice Age” beginning in 1550 and lasting until 1850, with three stages of cold spells in between. In 1816, Oliver says, Maine saw snow in June and a killing frost in July. July peas, she guesses, were rare in those years, making Fourth of July salmon and peas a treat only from mid-18th century to the mid-19th century, when Atlantic salmon stocks began their tragic decline. By the 1940s, Oliver says, Penobscot Bay salmon were just about gone.