On the Red Color of the Flesh in the Salmons and Trouts

Edward E. Prince
1916 Transactions of the American Fisheries Society  
Various theories have been expounded to explain the characteristic red color of the flesh of salmon and •trout, and as all these seem to involve difficulties, in my opinion fatal difficulties, it seems to me that some explanation must be sought to which less objection can be raised. Is Color Due to Food ? The common view is that the food upon which the fish feed giv, es the characteristic tint to the flesh. The late Dr. Giinther, of the British Museum, emphatically held this view and pointed
more » ... that the coloring matter in shrimps and other crustaceans (which turns red when subjected to the digestive fluids, or boiled, or treated with alcohol) is chemically the same as that present in the flesh of salmon and trout. Many authorities could be quoted in favor of this theory, even Dr. Francis Day, in his well-known work on the "British Salmonidle," refers'to it several times; but rather cautiously adds, that it may not be the correct explanation. It is the popular and most widespread view; yet it is almost certainly erroneous. The cases are rare in which the color of the food of any animal directly appears in the muscular tissues. Moose meat is not green though green lily-pads and leafy birch-twigs form so large a par• of its food, nor is cariboo meat colored by the pale green moss, which largely furnishes it with nutriment. The ruffed grouse has very white breast-muscles, while in the spruce par•ridge the color is dark, though both birds live under very similar conditions and are found in the same localities. Prince.--The Red Flesh of the Salmons Is Color Due to Vaseularity? A second view is that the vascularity of the muscles, the rich blood-supply, explains the color. Pale flesh would mean that the blood vessels were fewer or smaller. Certainly in such Scomberoids as the Tuna (Thynnus) the rich provision of blood vessels gives a dark red color to the meat, and accounts too for the high temperature of these fish. Does Color Signify Health-energy? Again, the red color it is claimed is a sign of the healthy condition of the fish. Just as a pale complexion may be a sign of ill-health in the human subject, whereas rosy cheeks imply a robust state of health, so a trout or salmon, showing pale-tinted or whitish flesh, is thought to be out of condition. Many anglers and epicures reject such as sick fish. White flesh is regarded as having a pathological significance. A slightly different view is that taken by those who do not regard the pale color as due to sickness or ill-health in the fish; but to poor feed. A well-fed fish in prime condition should, it is claimed by those 'who adopt this theory, have flesh of a rich red salmon color. Apart from conditions of health, a poorlyfed, starved fish would, according to this view, be lacking in color and wanting in flavor. Many people regard the color as intimately related to flavor and a highly-colored salmon or trout must, in their opinion, have a superior flavor. Is Color Due to Sexual Ripeness ? Again, the color is associated by many authorities with the ripeness of the fish; that is to say, their reproductive condition. Up to the commencement of spawning it is asserted, salmon and trout accumulate fat, especially the red, oily matter, which during the breeding season is transferred from the muscles to the ovaries and spermaries. There is, no doubt, much ground for holding the view that the red lipochrome is stored up in the muscular tissues. It occurs, indeed, as minute shining bodies 52 Ameriean Fisheries Society in the small fibrill•e of the muscle fibres, and the same bright-tinted matter occurs, later, in the eggs contained in the ripe female; but a transference of stored materials must also take place in the male salmon, the destination being the spermaries. In the spermaries the red color, however, is lacking, the organs are white, and the ripe contents appear of an opaque, white, creamy color• Tl•e purpose of the richly-colored, oily matter in the muscles of the male would not appear, therefore, to be the building up of the white testes, though such might be the explanation of the brilliant red contents of the ovaries. Other explanations, modifications of the foregoing, have been propounded by various authorities, but all may be summarized under the headings just set forth, viz:
doi:10.1577/1548-8659(1916)46[50:otrcot]2.0.co;2 fatcat:a4yzijd745aofabqxhlqk6j2cq