76 Salmonidas 



tooth mountains of Idaho, and their extreme limit is not known. 

 This is a distance of nearly a thousand miles. In the Yukon 

 a few ascend to Caribou Crossing and Lake Bennett, 2250 miles. 

 At these great distances, when the fish have reached the spawn- 

 ing grounds, besides the usual changes of the breeding season 

 their bodies are covered with bruises, on which patches of white 

 fungus (Saprolegnia) develop. The fins become mutilated, 

 their eyes are often injured or destroyed, parasitic worms gather 

 in their gills, they become extremely emaciated, their flesh 

 becomes white from the loss of oil ; and as soon as the spawning 

 act is accomplished, and sometimes before, all of them die. 

 The ascent of the Cascades and the Dalles of the Columbia 

 causes the injury or death of a great many salmon. 



When the salmon enter the river they refuse to take bait, 

 and their stomachs are always found empty and contracted. 



FIG. 58. Red Salmon (mutilated dwarf male, after spawning), Oncorhynchus 

 nerka (Walbaum). Alturas Lake, Idaho 



In the rivers they do not feed ; and when they reach the spawn- 

 ing grounds their stomachs, pyloric coeca and all, are said to 

 be no larger than one's finger. They will sometimes take the 

 fly, or a hook baited with salmon-roe, in the clear waters of the 

 upper tributaries, but this is apparently solely out of annoyance, 

 snapping at the meddling line. Only the quinnat and blue -back 

 (there called redfish) have been found at any great distance 

 from the sea, and these (as adult fishes) only in late summer 

 and fall. 



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 



