10 



INTRODUCTION 



tion of the family as a whole ( C. Tate Kegan, 

 Ann. Mag. Nat. Hist., 13, p. 405, 1914) 

 giving no extension of this range. They 

 breed in fresh water streams or lakes and 

 may or may not migrate to the sea, even in 

 the one species. 



The family is typified by the genus 

 Salmo and the species 8. solar, the Atlantic 

 salmon. It includes a larger or smaller 

 number of genera depending upon the 

 classification adopted. American ichthy- 

 ologists place the whitefishes and the gray- 

 lings in separate families, the Coregonidae 

 and the Thymallidae. Similarly for the 

 arrangement of the species in genera, the 

 American ichthyologists, following the 

 classical works of Dr. David Starr Jordan 

 and his collaborators, place the Great Lake 

 trout, a former member of the genus Sal- 

 velinus, in a separate genus Cristivomer, 

 and separate the Pacific salmons from 

 Salmo to form the genus Oncorhynchus. 

 There are also the North Asian genera, 

 Hucho, Brachymystax, Phylogephyra, and 

 Stenodus, the last alone ranging into North 

 America in its very northwestern part. 

 Apart from the extent of the subdivision 

 into genera, there are divergent views as to 

 the relationships of particular species. 

 Some of those occurring in western North 

 America, e.g., the Rainbow trout or Steel- 

 head salmon, are placed in the genus Salmo 

 by American ichthyologists, but are consid- 

 ered by Regan as more nearly related to the 

 species included in the genus Oncorhynchus 

 than to the Atlantic salmon. 



It is not perhaps surprising that the 

 common names of these fishes should be 

 in a somewhat confused state. The term 

 "char," used in Great Britain for species 

 of the genus Salvelinus, has little vogue in 

 North America, where * * trout ' ' is the usual 

 name, and even "salmon" is used. Some 

 species of the genus Salmo are called, not 

 "salmon" but "trout," both in North 

 America and in Great Britain. The term 

 "salmon" used in the title of this sym- 

 posium, does not correspond with any taxo- 

 nomic group. From the scientific stand- 

 point, it is somewhat unfortunate that this 

 name, given originally to the Atlantic sal- 



mon, has been extended to include five 

 species of Pacific fishes, those in the genus 

 Oncorhynchus, which, unlike the Atlantic 

 salmon, die after first spawning, a pecu- 

 liarity of very general interest. The be- 

 havior of migrating between fresh and salt 

 water is, however, fairly general through 

 the family and not in correspondence with 

 any classification. 



The Atlantic salmon {Salmo solar) oc- 

 curs on both sides of the Atlantic and is the 

 typical and best known member of the fam- 

 ily. The individuals of this species charac- 

 teristically migrate to and from the sea, 

 although some, thought to constitute a sub- 

 species or variety, fail to leave the lakes in 

 which they occur. 



In this symposium, three out of the five 

 species of salmon on the Pacific coast of 

 North America have been considered, as 

 well as the Atlantic salmon. The principal 

 one of these is Oncorhynchus nerka, vari- 

 ously known as the red, sockeye or blueback 

 salmon. Some individuals of this species 

 are non-migratory, not leaving the lakes in, 

 or above, which they spawn and never be- 

 coming large. W. E. Ricker (J. Fish. Res. 

 Board Can. 4, p. 192, 1938) has recently 

 distinguished among these individuals those 

 which seem to form a separate sub-species 

 (0. n. kennerlyi), known as the kokanee, 

 and those for which he proposes the name 

 "residual" sockeye "because the evidence 

 shows that they are, at least in large part, 

 the progeny of anadromous parents," that 

 is parents that have been to sea. The other 

 two species are Oncorhynchus tschowytscha, 

 the Chinook, spring or quinnat salmon, and 

 Oncorhynchus gorbuscha, the pink or hump- 

 back salmon. The former spawns in the 

 upper waters of large streams, sometimes 

 as much as a thousand miles from the sea, 

 grows to a large size, and may travel very 

 long distances in the ocean. The latter does 

 not go far upstream to spawn, and matures 

 at the end of its second year, being then 

 only from three to six pounds in weight. It 

 should be noted that the Pacific salmon die 

 after the first spawning, while the Atlantic 

 species may spawn as many as five times. 



