10 SALMON AND TKOUT IN ALASKA. 



case of the Pacific salmon in some instances mature perfect sperma- 

 tozoa, but whether they spawn and die immediately afterwards is not 

 known, nor is it known definitely whether fingerling parrs may develop 

 the sex product. 



The terms "smolt" (frequently still spelled and pronounced 

 "smelt") and "kelt" as used for stages of the Atlantic salmon 

 hardly have parallels in the case of the Pacific salmon. If any 

 of the genus Oncorhynclius return to sea as kelts, it has not yet 

 been fully demonstrated, and almost the entire weight of evidence 

 is against the belief that it ever occurs. The term "smolt" (French 

 "tacon") is applied, in contradistinction to parr, to that stage of 

 Salmo solar when, in fresh water, the parr marks are lost and the 

 young fish assumes its livery of silver in preparation for its descent 

 to the sea.'* It might be used with some propriety of the yearling 

 migrating sockeye, but it seems undesirable to confuse further the 

 meaning of words which have their proper use only with the eastern 

 species. 



HYBRIDIZATION. 



The question of natural hybridization has never been investigated, 

 though it has long been well known that trout may be artificially 

 crossed and fertile hybrids produced.^ That the species of salmon 

 may be variously crossed with success has also been demonstrated, but 

 owing to the difficulty of retaining them in fresh water until of breed- 

 ing age the fertility of salmon hybrids has not been proved. Rarely 

 adult salmon are taken which seem to possess characters of two spe- 

 cies, but on the basis of predoroinating characters they have been 

 assigned to one or the other of the species and the possibility of a 

 hybrid ignored. The differences in time and place selected by the 

 different species of salmon for spawning minimizes the possibility 

 of natural hybridization; and the deficient vitality of crossed eggs 

 and hybrid fry is, perhaps, sufficient to account for the failure of 

 most if not all such accidental product when natural vicissitudes 

 must be overcome. Moreover, the young of the different species of 

 salmon are distinct and show characteristically distinct habits. This 

 is not so evident, however, in Alaskan trout. Rainbows and steelheads 

 spawn together in the Naha. Spawning cutthroats have not been noted 

 there because they do not happen to inhabit that portion of the Naha 

 which was under observation; but their segregation is inconstant. 

 One species or the other may be most numerous in the lower or upper 

 reaches of a stream. In the Naha basin cutthroats are more numerous 



a Day, op. cit., p. 90. 



?> For a full discussion of hybridization of trout, see " British and Irish Salmonidse'' 

 by Francis Day, p. 47-50, 254r-270, pi. x and xi, 1887, and Paul Vogel, op. cit., p. 

 308, 311. 



