476 Bulletin 47, United States National Museum. 



and this is probably true, that salmon which would not have run till later are brought up by the 

 contact with the cold water. The cause of this effect of cold fresh water is not understood. 

 We may call it an instinct of the salmon, which is another way of expressing our ignorance. In 

 general, it seems to be true that in those rivers and during those years when the sprin g run is 

 greatest, the fall run is least to be depended upon. 



It varies for each of the different rivers, and for different parts of the same river. It doubt- 

 less extends from July to December. The manner of spawning is probably similar for all the 

 species, but we have no data for any except the Quinnat and the Kedfish. In these species 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 1 to 4 feet ; the female deposits her eggs in 

 it, and after the exclusion of the milt, they cover them with stones and gravel. They then 

 float down the stream tail foremost. As already stated, a great majority of them die. In the 

 head waters of the large streams, unquestionably all die ; in the small streams, and near the sea, 

 an unknown percentage probably survive. The young hatch in about sixty days. 



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 ot differ- 

 ent 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 a good many in the 

 fall. In Fraser River the fall run of the Quiunat is nearly worthless for canning purposes, 

 because so many are " white-meated." In the spring very few are " white-meated," but the 

 number increases toward 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 can not be distinguished externally, and the color is dependent upon neither age nor sex. 

 There is said to be no difference in the taste, but there is no market for canned salmon not of 

 the conventional orange color. 



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 can not 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 Oncorhynchus gorbuscha, 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 Blueback turns rosy 

 or brick-red, the Dog Salmon a dull blotchy red, and the Quinnat generally blackish. The dis- 

 torted 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. It is not positively known that any fully hook- 

 jawed old male survives the reproductive act. If any do, the jaws must resume the normal form. 



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. After- 

 wards 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 2 miles per day; on the Colum- 

 bia at about 3 miles per day. Those who 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. 



