b U. S. BUREAU OF FISHERIES, 



about 1^ inches and the maximum size of the large smelt 4 inches, 

 while in another the minimum size of the small form at maturity is 

 about 4 inches and the maximum size of the large form 15| inches. 

 We have to do, it seems, either with different species or with distinct 

 races; that is to be determined later. 



DETERMINATION OF SPECIES AND RELATIONSHIPS IN THE SALMON 



FAMILY. 



One of the obstacles to the best success in fish-cultural work is the 

 great difficulty of distinguishing positively the species of trouts and 

 salmon. To obtain the desired results in propagation and distribu- 

 tion of fish, it is necessary to know beyond a doubt what species is 

 being propagated and planted, as well as what kinds are native to 

 certain waters, and what have previously been introduced. Never- 

 theless there still exist among sportsmen, fish-culturists, and scientists 

 varying and conflicting opinions regarding the identity and relation- 

 ships of the species of Salmonidse, notably in the case of the steel- 

 head and rainbow, fish which are extensively propagated by Federal 

 and State hatcheries. 



The difficulty lies solely in the fact that sufficient technical work 

 has not been done upon the structural examination and comparison 

 of such fish in numbers and from varying localities. The bureau 

 has, therefore, encouraged the prosecution of a thorough and critical 

 study of the structure and relationships of the members of the im- 

 portant salmon family. 



Dr. W. C. Kendall, scientific assistant and ichthyologist, has given 

 much attention to the osteology (bony structure) of salmon, trout, 

 and related fishes, which, with studies of scales, proves of much value 

 in the determination of families, genera, and species. T\Tiile verify- 

 ing many of the statements of others, some new facts have been 

 discovered." 



A paper which is in preparation, based upon a study of trout from 

 various regions of the West and upon geological considerations, pre- 

 sents a scheme of origin and distribution of the trouts which offers a 

 plausible explanation of their present distribution and throws light 

 upon hitherto obscure problems of classification. 



Another report nearing completion is believed to settle the much- 

 discussed question of the specific identity or distinctness of the rain- 

 bow and steelheacl trouts.^ 



"It appears that the salmons, trouts, and chars form a family (Salmonidfe) distinct 

 from the whiteflshes and ciscoes (Coregonidii?), the latter being based upon the characters 

 enunciated by Cope and given by later writers as the characters of a subfamily. It has not 

 yet been decided whether or not the grayling should be regarded as a family (Thymal- 

 lidae, Gill), distinct from the whiteflshes (Coregonida;), in which Regan includes them. 

 The separation of the Pacific coast salmons (Oncorhynchus) from the genus which 

 embraces the Atlantic salmon and rainbow and steelhead trouts is definitely confirmed. 

 The lake trout (Cristivomer) is found to be notably different from the brook trout 

 (Salvelinus). The smelt family (Osmeridie. Regan) should also stand as distinct from the 

 Argentinida\ The pelvic bones of Argentina sUus are widely different from any other 

 isospondylous fish examined. 



" After a ca'-efnl study of the fish from taxonomical, anatomical, and distributional 

 evidence the conclusion is reached that there are at least two wild forms which have been 

 confused under the names of rainbow and steelhead trouts. One is predominantly migra- 

 tory (ascending fresh waters from the sea), the other predominantly a permanent resh- 

 water inhabitant. The name Snhno irideiis was originally bestowed upon a small steel- 

 head form, as was also Salmo riviilaris. There is absolutely no doubt concerning the 

 proper application of Salmo gairdncrii to the steelhead. as Richardson's description is 

 that of a large Columbia River fish and not a small blueback salmon {Om-orhiinchus 

 nerka), as one writer has stated. Contrary to current descriptions, the steelhead has 



