IO2 Salmonidae 



Cutthroat or Red-throated Trout. This species has much 

 smaller scales than the rainbow trout or steelhead, the usual 

 number in a longitudinal series being 160 to 170. Its head is 

 longer (about four times in length to base of caudal). Its 

 mouth is proportionately larger, and there is always a narrow 

 band of small teeth on the hyoid bone at the base of the tongue. 

 These teeth are always wanting in Salmo irideus and rivularis 

 in which species the rim of the tongue only has teeth. The 

 color in Salmo darkii is, as in other species, exceedingly variable. 

 In life there is always a deep-red blotch on the throat, between 

 the branches of the lower jaw and the membrane connecting 

 them. This is not found in other species, or is reduced to a 

 narrow strip or pinkish shade. It seems to be constant in 

 all varieties of Salmo darkii, at all ages, thus furnishing a good 

 distinctive character. It is the sign manual of the Sioux Indians, 

 and the anglers have already accepted from this mark the name 

 of cutthroat-trout. The cutthroat-trout of some species is 

 found in every suitable river and lake in the great basin of 

 Utah, in the streams of Colorado, Wyoming, and Montana, on 

 both sides of the Rocky Mountains. It is also found throughout 

 Oregon, Washington, Idaho, British Columbia, the coastwise 

 islands of southeastern Alaska (Baranof, etc.), to Kadiak and 

 Bristol Bay, probably no stream or lake suitable for trout-life 

 being without it. In California the species seems to be com- 

 paratively rare, and its range rarely extending south of Cape 

 Mendocino. Large sea-run individuals analogous to the steelheads 

 are sometimes found in the mouth of the Sacramento. In Wash- 

 ington and Alaska this species regularly enters the sea. In Puget 

 Sound it is a common fish. These sea-run individuals are more 

 silvery and less spotted than those found in the mountain streams 

 and lakes. The size of Salmo darkii is subject to much variation. 

 Ordinarily four to six pounds is a large size; but in certain 

 favored waters, as Lake Tahoe, and the fjords of southeastern 

 Alaska, specimens from twenty to thirty pounds are occasionally 

 taken. 



Those species or individuals dwelling in lakes of considerable 

 size, where the water is of such temperature and depth as in- 

 sures an ample food-supply, will reach a large size, while those 

 in a restricted environment, where both the water and food are 



