138 Fish Stories 



the one called Salmo jordani being close to Salmo clarkii, 

 the other, Salmo declivifrons, resembling Salmo crescentis. 

 Doubtless other mountain lakes of the Olympic range will 

 yield still other species of trout, isolated from the body of 

 their kind, and at least on the road to becoming separate 

 species of trout. The origin of each of the different species 

 of trout is clearly to be traced to the condition of isolation. 



In the coastwise streams from Skagway, in Alaska, to 

 Santa Barbara, California, is found a fine large trout, 

 known as the steelhead, its scientific name being Salmo 

 rivularis. This name was given by Dr. W. O. Ayres to a 

 specimen taken in the Sacramento River, at Martinez. The 

 species was long known as Salmo gairdneri, but the speci- 

 men originally named by Dr. Richardson for Dr. Gairdner 

 was a young blue-back salmon, and not a trout. The steel- 

 head is sometimes called salmon trout, and this name is not 

 inappropriate. The salmon trout of England is, however, 

 merely a sea-run example of the European brook trout, or 

 brown trout, Salmo eriox, a species which is also called in 

 the books, Salmo fario and Salmo trutta. 



From the other trout, the steelhead is best known by its 

 short -head, the length of the head along the side being con- 

 tained four and one-half to five times in the length of the 

 body from the tip of the snout to the base of the caudal fin. 

 The scales in the steelhead are rather small, averaging about 

 one hundred and fifty in a lengthwise series from head to 

 tail. The dorsal fin is low, and it has usually but three or 

 four rows of dark spots. There are no teeth on the base of 

 the tongue, the usual series lying around the outer edge. 



The steelhead trout does not go very far from the sea, 

 except in the large rivers, its habits in this regard being 

 more like the salmon than those usual among trout. The 

 old fishes do not, however, die after spawning. When in 

 salt water the steelhead is very silvery, but in fresh water 

 the spots appear, and in the small streams it is almost as 

 much spotted as the rainbow trout. It reaches a weight of 



