Fishes of the Western North Atlantic 



461 



Young Atlantic salmon 



Body Usually thinly spotted. 



Caudal peduncle^ depth One-tenth of length of body. 



Operculum Rarely more than three spots. 



Maxilla, at length of: 



4 inches To center of pupil. 



6 inches To posterior edge of pupil. 



Dorsal fin Usually weakly spotted. 



Adipose fin Rarely edged with red. 



Paired fins Generally grey. 



Tail Deeply forked ; middle rays 



not more than 0.6 of length 

 of longest rays. 

 Parr marks Usually 1 1— 12. 



Young brown trout 

 Usually much spotted. 

 One-eighth of length of body. 

 Usually more than three spots. 



To posterior edge of pupil. 

 To posterior edge of iris. 

 Usually well-defined spots. 

 Usually edged with red. 

 Generally orange-yellow. 

 Shallowly forked; middle rays 



0.6 or more of length of 



longest rays. 

 Usually 9-10. 



It is possible that hybridization may occur between salar and trutta, in which 

 case the hybrids probably would not possess the distinguishing characters of either 

 parent. 



Description. The adult Atlantic Salmon is a graceful fish, deepening rearward from 

 a small pointed head to the deepest point under the dorsal fin, then tapering to a slender 

 caudal peduncle which supports a spreading and slightly emarginate caudal fin. The 

 mouth is moderately large, with the posterior end of the maxillary extending to, or 

 slightly beyond, a vertical through the posterior margin of the eye. 



Proportional dimensions in per cent of standard length (averages, followed by 

 ranges in parentheses) of the 10 fresh specimens listed in the Study Material, 28—35 

 inches {ca. 71— 90 cm). Note: Shape and length of head and depth of body varying 

 with stage of sexual maturity. 



Males 



Females 



Body : greatest depth 21 



greatest width 12.2 



Caudal peduncle: depth 7.9 



Head: length 23 



Snout: length 9.2 



Eye: diameter of eyeball 2.9 



Maxillary: length 12.5 



Dorsal fin: longest ray 1 1.7 



Anal fin: longest ray 10.6 



length of base 9.5 



Pelvic fin: length i i.o 



Pectoral fin : length 13.3 



