158 The Pacific Salmons 



outlines are rather less graceful than those of the 



Atlantic salmon. Its flesh is of a uniform rich 



orange-red color, becoming paler and streaked as 



the spawning season approaches. 



According to the observations of the fishermen, 



salmon appear to pass from the mouth of the 



Columbia to the Cascades, about one hundred 



and forty miles, in ten or twelve days. In the 



rapid upper waters they doubtless travel more 



slowly. 



Sexual Differences 



External sexual differences are scarcely dis- 

 cernible when the salmon first come in from the 

 ocean, but as the time for spawning advances the 

 sexes become more and more dissimilar in ap- 

 pearance. The developing ova give to the 

 female a plump aspect, while the male grows 

 gaunt and thin, and the shape of his head is 

 strongly modified ; the jaws become curved and 

 hooked, the eyes are sunken, large teeth appear 

 in both jaws, and his general appearance is savage 



and repelling. 



Spawning 



Spawning begins shortly after the upper waters 

 are reached. The fish, in pairs, usually occupy a 

 position at the upper end of a rifile, where the 



