26 College of Forestry 



Writing of investigations relating to fresh-water fishes, Com- 

 missioner Smith says : " The fishery problems of fresh- water 

 are undoubtedly simpler than those of the seas, but they are 

 certainly less directly approachable than the problems of agri- 

 culture which have met their solutions. It is not surprising, 

 therefore, that, throughout the country in matters of fish cul- 

 ture, there is yet too little serious endeavor to find real causes 

 or to apply appropriate remedies. Year by year the Bureau is 

 devoting more careful and fitting attention to the problems of 

 fresh-water fisheries, and some of its principal activities in this 

 field may be referred to. 



" The problem of fish culture, at least as referring to pond 

 fishes, is primarily one of food supply. Our knowledge of the 

 food of fishes is as yet seriously inadequate. The food taken 

 by fishes varies with the species, with sizes and age of the fish, 

 with the season of the year, and with the abundance of the 

 various kinds of food materials present in difi^erent bodies of 

 water. A few observations in one locality or at one season of 

 the year afford no criterion for the conclusions that we may 

 seek to draw, for an appraisal of the possibilities of fish pro- 

 duction in any body of water, for an understanding of the 

 variations in the sizes attained by a given species of fish in 

 different bodies of water, and for the direction of our efforts 

 to promote an abundant and reasonably constant supply of 

 food under all conditions subject to control." 



The favorable comments on the bulletin previously issued on 

 the " Relation of Mollusks to Fish in Oneida Lake " leads the 

 author to hope that the present bulletin may be found useful, 

 not only for the data which it contains but also in stimulatinc: 

 more students to enter this interesting and important field of 

 study and investigation. 



Syracuse, July 12, 1917. 

 Department of Forest Zoology. 



