.SALMON AND TROUT IN ALASKA. 11 



in the upper sections of the system; at Yes Bay the case is reversed. 

 If the fry and fingerhngs of the three recognized species possess any 

 distinctive marks or habits these have so far escaped detection. 



RESEMBLANCE OF THE YOUNG. 



By one who knows the adult salmon, the young of the salmon are 

 not apt to be confused ^vith any fishes except trout. Of the fishes 

 having an adipose dorsal they are readily distinguishable from the 

 capelin, smelt, and eulachon by the siphon-shaped stomach and numer- 

 ous ccecal appendages; the grayling is known by its high dorsal fin; 

 the whitefish by its comparatively small mouth. 



The young of the true trout very greatly resemble the spotted 

 species of salmon, and are distinguishable mainly by the short 

 anal fin. The salmons usually show at least 14 fully developed — 

 that is, full length — rays, exclusive of the 3 to 5 short, simple (un- 

 branched) rays in the front of the fin. Sometimes there are but 13, 

 and in rare instances only 12, while the number ma}- be increased to 

 17 in the sockeye, which normally has 14, and in the king salmon, 

 with 16 as a 'normal, the extreme will doubtless be still greater. The 

 trout have normally 10 to 12 developed rays in the anal, but wliile 

 this seems little separated from the number given for the salmon, as a 

 rule the extra length of the fin in the latter may be noted by even a 

 casual comparison. When spread the fin of the trout fingerling 

 shows a rounded outline, the front rays somewhat more evenly 

 graduated than in the salmon and the hinder rays much higher in 

 proportion, causing it to resemble the dorsal in general outline. The 

 anal of the salmon fingerling usually has a slightly concave outer 

 margin, the hinder rays being shortened. The charr (Dolly Varden, 

 or ''salmon trout"), in addition to the characters of the anal as just 

 described for the true trout, is distinguishable by the peculiarly 

 mottled coloration, and in the advanced stages also by the less com- 

 pressed body. 



The different species of salmon (OncorJiyncTius) are not usually 

 difficult to distinguish from one another, yet individual variations 

 sometimes confuse the determination. Wliile in adults the sum of 

 various differentiating characters makes it possible to decide the 

 species, the late development of some characters greatly increases the 

 problem in immature examples. It is possible that some local variations 

 obtain; for example, sockeye fingerhngs from Wood River seem to 

 have a much smaller eye than fingerhngs of the same size and species 

 in Southeast Alaska. There is also much variation in the length and 

 number of gillrakers in the young of this species and perhaps also in 

 those of the humpback salmon. From the number of specimens at 

 present available for study it can not be determined whether or not 

 this variation is of geographical origin. 



