SALMON AND TROUT IN ALASKA. 105 



When the sockeyes emerge from the lake en route to the spawning 

 beds the change has become complete. The entire fish, except the 

 head and fins, has changed from its original green and silver to a bril- 

 liant vermilion or maroon. The head retains its bright green color 

 and the fins become variously dark. At this time the sockeye rivals 

 the tropical fishes in beauty of coloration. The elongation of jaws 

 and development of depth are extreme in large males; the females 

 show little of it and acquire less brilliance of color, in some cases 

 scarcely any. 



The grilse (Arctic salmon) exhibit less change than the large fish, 

 but show all the characters to a degree. 



The dwarf sockeye exhibits very little change ; sex of ripe fish taken 

 in Wallowa Lake can not be distinguished by external appearance. 

 At the time of entering streams for spawning they are thus described 

 by Kendall: 



Back olive green, more or less spotted with black; dorsal and caudal somewhat 

 spotted; sides dusky metallic blue or smoky with faint marks like parr marks; belly 

 white or slightly dusky. Pectorals, ventrals, and anal black, tipped with white; 

 outer ray of pectorals white; a general brassy luster after the fish has been out of 

 water some time. 



Colors, spotting, etc., vary in different individuals, but there is never 

 any red. In Alturas Lake in larger examples of the dwarf the red 

 is sometimes present and the other changes are somewhat more 

 marked. 



The coho shows more change in the female than any other species, 

 and the jaw develops more knob, as in the trout. It is sometimes 

 difficult to distinguish the sexes among spawning fishes in the Naha. 

 Both may acquire a red almost as brilliant as the sockeye' s, so that 

 in the water it is easy to mistake either species for the other. 



The extreme height of the back in the male of the humpback and 

 the characteristic color blotching of it and of the dog salmon are well 

 known. The females of the two species, particularly the latter, 

 retain silvery colors and neat forms more fully than other species. 



The useful purpose, if any, which these changes subserve, is difficult 

 to surmise. It may easily be believed that the development of teeth, 

 and of jaws to render them effective, is a matter of defense with the 

 male. It does not hesitate to make use of the weapon to drive away 

 intruders, but its awkward and slow movements render its armature 

 of no avail so far as trout and other egg-eating fish are concerned. 

 The only service is in preventing other males of the same species 

 from mating with the female, and even in this the ability is not always 

 equal to the emergency. A small active male has been seen to slip 

 alongside a spa^vning female during the absence of her consort in pur- 

 suit of another interloper and administer all the attention shown by 

 her regular attendant. In general it may be assumed that in this man- 



