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FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Table 5. — Parr marks in young North American Salmonidae 



1 Chamberlain, (1907). 



' Foerster and Pritchard, (1936b). 



3 Chamberlain (1907) says fry indistinguishable from S. darki. 



The young of *S'. salar and trutta are difficult to 

 distinguish, as are those of *S'. gairdneri and clarhi. 

 The former agree in tlie small red blotches between 

 the parr marks, while the latter two have no col- 

 ored spots but agree in the light lateral band, 

 which is less conspicuous in darki. The hybridiza- 

 tion experiments also show tndta closer to salar 

 than to gairdneri. 



The aforementioned relation of parr marks to 

 anadromy is indicated by the retention of parr 

 marks throughout life in some landlocked strains 

 of anadromous species. Thus Sahno gairdneri 

 agua-honita, the golden trout, and Sahno clarhi 

 seleniris, the piute trout, retain their parr marks. 



There are a few other color patterns which have 

 from time to time been used to distinguish between 

 certain species or groups. Because information on 

 these color characteristics is lacking for all of the 

 Salmonidae we shall merely mention the char- 

 acteristic for the groups with such information. 



' Bacon (1954, text and plate). 



s Counts include the incomplete bars: Vladykov (1954) . 



Color of the mouth is used to distinguisli On- 

 corhynchus (mouth black) from Salmo gairdneri 

 and cl.arki, whose mouths are white (Snyder, 1940 ; 

 Shapovalov, 1947). 



Color of the roof of the mouth is given by 

 Vladykov (1954) as black for Salvelinus fontina- 

 lis, blackish for /iV. aureolus, and white for S. 

 oquassa, S. marstoni, S. alpinus, and Cristivomer 

 namaycush. 



ANADROMY 



The degree of anadromy exhibited by various 

 taxonomic groups (see Rounse fell, 1958) may well 

 be of phylogenetic significance. Thus, when the 

 degree of anadromy was scored for each species of 

 Salmonidae according to a subjective rating of 

 several criteria it was found that the most anadro- 

 mous species belonged to Oncorhynchus. The next 

 highest rating for anadromy belonged to Salmo. 

 Only slight anadromy characterized Salvelinus, 

 while Cristivomer was lacustrine. The ratings for 

 anadromy are listed in the following table: 



1 Degree of anadromy (Rounsefell, 1958: p. 180); the rating of a species 1 

 different habitat. 



partly dependent on the existence of subspecies, which In some cases occupy a 



