84 REPOET OF THE COMMISSIONEE OF FISHEEIES. 



A further investigation of the migrations of the Pacific salmon has 

 been undertaken with the most competent assistance, having special 

 reference to the salmon of Alaska and the problems of governmental 

 and private artificial propagation. 



INVESTIGATIONS PERTAINING TO FRESH-WATER FISHES. 



The Bureau has continued actively the several investigations 

 relating to the food of fresh-water fishes, both as independent studies 

 and as phases of the. experiments in the rearing of fishes in ponds. 

 The results of more -than two years of study of the habits and food of 

 the yellow perch have been prepared for publication. A report on the 

 pikes, comprising most of the known data regarding the habits, 

 artificial propagation, and commercial importance of this weU- 

 defined family of fishes, has been issued and will prove useful to those 

 who are interested in the cultivation of the pike, pickerel, and mus- 

 kellunge, and to whom it is of importance to understand the relations 

 of these predatory fishes with their less vigorous associates in natural 

 or artificial bodies of water. 



The serious decline in important fisheries of the Great Lakes, due 

 to excessive and sometimes unrestricted fisliing, long ago showed the 

 necessity for a thorough knowledge of the habits and migrations of the 

 principal fishes of the Lakes, in order that the regulation of the fishery 

 and the artificial propagation of the fishes might be founded upon such 

 a clear understanding of the habits and movements of the fishes that 

 the maximum in practical results would be attained. It has not yet 

 been possible to give to this field attention commensurate with the 

 importance of the fisheries and the difficulties of the problems. A 

 beginning was made during the fiscal year in the inauguration of a 

 new study of the systematic relations, habits, and migrations of the 

 fishes of the subfamily Coregoninse, including the whitefishes and 

 ciscoes or lake herring. 



The experiments and investigations in the rearing of fishes in ponds, 

 which have been pursued in connection with the fisheries biological 

 station at Fairport, Iowa, have continued to yield gratifying results. 

 Wliile the artificial propagation of the buff alofish had previously been 

 shown to be entirely feasible as regards the fertilization and subse- 

 quent handling of eggs and the rearing of young to a fairly advanced 

 stage, the effort to have buff alofish spawn naturally in artificial ponds 

 had not, until the spring of 1917, met with success. The conditions 

 were varied last season by keeping the experimental pond about half 

 full of water in the early part ot the season and allowing it to fill 



fraduaUy early in May. A few days after the pond was filled, a few 

 uff alofish were observed to be "splasliing" along the margin of the 

 pond. Abundant buffalofish fry were observed soon afterwards, 

 when specimens were collected and identified. Without additional 

 experimentation it can not be definitely determined if the manner 

 of manipulation of the pond practiced this season was the particular 

 effective factor in bringing success. 



In the last annual report it was mentioned that, in spite of many 

 failures in earlier trials, a successful attempt at the propagation of 

 the channel catfish, or spotted catfish, in ponds was in progress as the 

 fiscal year closed. As the channel catfish at Fairport have again 

 spawned under observation in the ponds of Fairport, it seems alto- 



