Fig. 59.—Young Male Quinnat Salmon, Oncorhynchus tschawytscha, dying after spawning. Sacramento River. (Photograph by Cloudsley Rutter.)
The spawning season is probably about the same for all the species. It varies for each of the different rivers, and for different parts of the same river. It doubtless extends from July to December, and takes place usually as soon as the temperature of the water falls to 54°. The manner of spawning is probably similar for all the species. In the quinnat the fishes pair off; the male, with tail and snout, excavates a broad, shallow "nest" in the gravelly bed of the stream, in rapid water, at a depth of one to four feet and the female deposits her eggs in it. They then float down the stream tail foremost, the only fashion in which salmon descend to the sea. As already stated, in the head-waters of the large streams, unquestionably, all die; it is the belief of the writer that none ever survive. The young hatch in sixty days, and most of them return to the ocean during the high water of the spring. They enter the river as adults at the age of about four years.
The salmon of all kinds in the spring are silvery, spotted or not according to the species, and with the mouth about equally symmetrical in both sexes. As the spawning season approaches the female loses her silvery color, becomes more slimy, the scales on the back partly sink into the skin, and the flesh changes from salmon-red and becomes variously paler, from the loss of oil; the degree of paleness varying much with individuals and with inhabitants of different rivers. In the Sacramento the flesh of the quinnat, in either spring or fall, is rarely pale. In the Columbia a few with pale flesh are sometimes taken in spring, and an increasing number from July on. In Frazer River the fall run of the quinnat is nearly worthless for canning purposes, because so many are "white-meated." In the spring very few are "white-meated"; but the number increases towards fall, when there is every variation, some having red streaks running through them, others being red toward the head and pale toward the tail. The red and pale ones cannot be distinguished externally, and the color is dependent on neither age nor sex. There is said to be no difference in the taste, but there is little market for canned salmon not of the conventional orange-color.
Fig. 60.—Quinnat Salmon, Oncorhynchus tschawytscha (Walbaum). Monterey Bay. (Photograph by C. Rutter.)
As the season advances the difference between the males and females becomes more and more marked, and keeps pace with the development of the milt, as is shown by dissection. The males have (1) the premaxillaries and the tip of the lower jaw more and more prolonged, both of the jaws becoming finally strongly and often extravagantly hooked, so that either they shut by the side of each other like shears, or else the mouth cannot be closed. (2) The front teeth become very long and canine-like, their growth proceeding very rapidly, until they are often half an inch long. (3) The teeth on the vomer and tongue often disappear. (4) The body grows more compressed and deeper at the shoulders, so that a very distinct hump is formed; this is more developed in the humpback salmon, but is found in all. (5) The scales disappear, especially on the back, by the growth of spongy skin. (6) The color changes from silvery to various shades of black and red, or blotchy, according to the species. The blue-back turns rosy-red, the head bright olive; the dog-salmon a dull red with blackish bars, and the quinnat generally blackish. The distorted males are commonly considered worthless, rejected by the canners and salmon-salters, but preserved by the Indians. These changes are due solely to influences connected with the growth of the reproductive organs. They are not in any way due to the action of fresh water. They take place at about the same time in the adult males of all species, whether in the ocean or in the rivers. At the time of the spring runs all are symmetrical. In the fall all males, of whatever species, are more or less distorted. Among the dog-salmon, which run only in the fall, the males are hook-jawed and red-blotched when they first enter the Strait of Fuca from the outside. The humpback, taken in salt water about Seattle, have the same peculiarities. The male is slab-sided, hook-billed, and distorted, and is rejected by the canners. No hook-jawed females of any species have been seen.
On first entering a stream the salmon swim about as if playing. They always head towards the current, and this appearance of playing may be simply due to facing the moving tide. Afterwards they enter the deepest parts of the stream and swim straight up, with few interruptions. Their rate of travel at Sacramento is estimated by Stone at about two miles per day; on the Columbia at about three miles per day. Those which enter the Columbia in the spring and ascend to the mountain rivers of Idaho must go at a more rapid rate than this, as they must make an average of nearly four miles per day.
As already stated, the economic value of any species depends in great part on its being a "spring salmon." It is not generally possible to capture salmon of any species in large numbers until they have entered the estuaries or rivers, and the spring salmon enter the large rivers long before the growth of the organs of reproduction has reduced the richness of the flesh. The fall salmon cannot be taken in quantity until their flesh has deteriorated; hence the dog-salmon is practically almost worthless except to the Indians, and the humpback salmon was regarded as little better until comparatively recently, when it has been placed on the market in cans as "Pink Salmon." It sells for about half the price of the red salmon and one-third that of the quinnat. The red salmon is smaller than the quinnat but, outside the Sacramento and the Columbia, far more abundant, and at present it exceeds the quinnat in economic value. The pack of red salmon in Alaska amounted in 1902 to over two million cases (48 pounds each), worth wholesale about $4.00 per case, or about $8,000,000. The other species in Alaska yield about one million cases, the total wholesale value of the pack for 1902 being $8,667,673. The aggregate value of the quinnat is considerably less, but either species far exceed in value all other fishes of the Pacific taken together. The silver salmon is found in the inland waters of Puget Sound for a considerable time before the fall rains cause the fall runs, and it may be taken in large numbers with seines before the season for entering the rivers.
The fall salmon of all species, but especially of the dog-salmon, ascend streams but a short distance before spawning. They seem to be in great anxiety to find fresh water, and many of them work their way up little brooks only a few inches deep, where they perish miserably, floundering about on the stones. Every stream of whatever kind, from San Francisco to Bering Sea, has more or less of these fall salmon.