460 Memoir Sears Foundation for Marine Research 



sistent; scales from adipose fin to lateral line, 12-16; maxillary extending to 

 below rear edge of eye at 150 mm, farther back in large specimens; caudal 

 truncate in adults; black spots on body large, many surrounded by halos. 



trutta Linnaeus 1758, p. 498. 

 lb. Anal with 10 or more fully developed rays; caudal spotted. 



gairdneri Richardson 1836, p. 499. 



Salmo salar Linnaeus 1758 



Atlantic Salmon, Sea Salmon 



Figures 120—123 



Study Material. Ten fresh specimens (7 males, 3 females), about 7 1 -90 cm or 

 28-35 inches SL, from the Matamek River, Saguenay County, Province of Quebec, 

 caught towards the end of July 1931 (not preserved); also 87 specimens, fry to 

 adult, from New Brunswick, Nova Scotia, Newfoundland, and Quebec (including 

 Ungava Bay). 



Distinctive Characters. Salmo salar is distinguished from all species of Oncorhyn- 

 chus of the Pacific in having fewer than 13 rays in the anal fin (13-19 in On- 

 corhynchus). 



It is readily distinguished from Salvelinus alpinus and fontinalis (Arctic charr 

 and brook trout) and from Cristivomer namaycush (lake trout) by its black spots (light- 

 colored in charrs) and by its larger scales (so small as to be readily overlooked in 

 charrs). 



It is separated from Salmo gairdneri (rainbow trout) by the absence of black 

 spots on its caudal fin (many spots on caudal oi gairdneri). 



Separation of Salmo salar from Salmo trutta (brown trout) is more difficult than 

 from the above species, for both salar and trutta lack spots on the caudal fin. How- 

 ever, in salar the tail is more constricted at the base of the caudal fin than in trutta, 

 so that in salar the anterior caudal rays form more of a shoulder; consequently, an 

 Atlantic Salmon does not slip through one's fingers when grasped round the caudal 

 peduncle as a brown trout usually does. This difterence is reflected in the number of 

 scales in an oblique row from the posterior edge of the adipose fin (downwards and 

 forwards) to the lateral line: 10-13 (usually 11) in salar, 13-16 (rarely 12) in trutta. 

 Other differences include: dorsal fin rays 10-13 (usually 11) in salar, 13-16 (usu- 

 ally 14, rarely 12) in trutta; pyloric caeca 50-80 in salar, 30-60 in trutta. The caudal 

 fin of salar is more widely spread and is more deeply emarginate than that of trutta. 

 Finally, salar has a smaller mouth, the maxillary in the adult extending scarcely, it 

 at all, beyond the eye (well beyond the eye in trutta). 



Jones {yy) has tabulated the differences between the young Atlantic Salmon and 

 brown trout as follows: 



