Fishes of the IVestern North Atlantic 



519 



Finally, Yessipov's report {^y()'- 69, 70) that the sea-run Arctic Charr of Novaya 

 Zemlya, where 75 "/o of their food consists of crustaceans and worms, eat the young 

 of the Atlantic cod (Gadus morrhuii) in greater amount than any other fish is especially 

 interesting, for young cod are not mentioned at all in any of the other diet lists that I 

 have seen. 



Parasites. Sea-run alpinus of northeastern Labrador have been reported as being 

 heavily parasitized by the tapeworm Eubothrium^ and lightly so by the round worm 

 Philomena (2: 858, 859). It seems astonishing that none of the accounts of this species 

 has mentioned any infestation by the so-called sea lice (parasitic copepods, genus 

 Lepeophtheirus) that are so often found clinging to the sides of Atlantic salmon (p. 484) 

 and sea-run brook trout (p. 537) when they re-enter fresh water. 



Variations. Variations have been reported in the colors of sea-run alpinus, the size 

 of the mouth, the length of the pectorals, the average number of vertebrae, the 

 number of fin rays, and dentition. However, the relative degree of "silveryness" of the 

 Arctic Charr caught during their marine sojourn together with the distinctness of their 

 color pattern seems clearly to be associated with the relative salinity of the water where 

 they are taken combined with the length of time since they last left fresh water. The 

 difference in the relative length of the pectoral fins between sexually mature freshwater 

 alpinus of Labrador (average 17-19 "/o of TL) and those taken in salt water (not in 

 breeding condition) does not bear directly on the racial problem of saltwater fish (j: 290). 



The south-to-north increase in the average number of both fin rays and verte- 

 brae that has been reported for the coast of northeastern Labrador (2: 854-856) 

 evidently is a function of latitude, a relationship paralleled among sundry other coastal 

 fishes of boreal-Arctic waters ; thus it is environmental, not genetic. The small-mouthed 

 fish reported by Weed for the vicinity of Nain, Labrador {^2: 131), doubtless rep- 

 resented the female portion of the pop- 

 ulation, the very large-mouthed ones 

 "with strongly hooked jaws" the ma- 

 ture males. While the sea-run Arctic 

 Charr from Collinson Point, Alaska 

 {jo: 258, fig. 14), included some that 

 had an upper pattern of dentition that 

 is generally characteristic of Salvelinus 

 (p. 527, Fig. 1 27 a), others had a pat- 

 tern characteristic of the genera Hucho 

 and Brachymystax (pp.458, 459, Fig. 1276,0); in this case there can be no question 

 of regional varieties, since both types were taken at the one locality. 



In short, the regional differences reported thus far for the populations of sea- 

 run alpinus do not seem either wide enough or consistent enough to justify their 

 formal recognition in systematic nomenclature for alpinus anywhere between Novaya 

 Zemlya in the east and northwestern Alaska in the west. Farther westward the typical 

 alpinus is replaced, at least predominantly, by the red-spotted form malma., which 



Figure 127. Salvelinus alfinus dentition. 



