DEFINITE RESULTS OF SURVEY WORK ON 

 THE ILLINOIS RIVER 



By Stephen A. Forbes 



My excuse for appearing before you is that I am con- 

 ducting a Natural History Survey of Illinois, under au- 

 thority of the State Legislature and by virtue of appropria- 

 tions from the state, with instructions to give especial atten- 

 tion to subjects of educational and economic importance. 

 In this survey work, we have been, during the past year, 

 giving particular attention to the aquatic life of the slate, 

 and especially to that of the Illinois River; and we have 

 brought out some rather definite results which have such a 

 general and important bearing upon the whole science of 

 fish culture and the conservation of the resources represented 

 in the principal rivers of the country, that I think it worth 

 while to call your attention to them. 



One of the things we have undertaken to do is to learn 

 as much as possible of the breeding grounds and habits of 

 some of the more important fishes. For that purpose I have 

 had upon the breeding grounds of the fishes of the central 

 part of the Illinois River, during the breeding seasons of the 

 last two years, two men — Mr. R. E. Richardson, with Air. 

 H. C. Allen as his assistant — who have fairly lived in a 

 boat, going over the grounds where fishes were depositing 

 their eggs, where the fry were hatched, and from which 

 the fry must escape if they were to survive. Their object 

 was to learn everything possible with regard to the whole 

 process, and also to determine what was the fate of the eggs 

 and what was the fate of the fry. I cannot give you full 

 details, but will mention two facts. 



The carp is the most abundant fish in the Illinois River, 

 giving us $412,000 of income in 1908, while all the other 

 fishes together gave us only $309,000. The most important 

 breeding ground for the carp which we have found on the 

 Illinois River is an overflowed field which was commonly in 



