Xli FISHES OF ILLINOIS 



Valuable collections have sometimes been obtained, especially 

 from western Illinois, by arrangement with high-school teachers, 

 who have fished the streams of their neighborhoods in accordance 

 with our instructions, and in consideration of our return of a named 

 series of specimens to their schools. 



Our field apparatus consisted mainly of seines of various size and 

 mesh, from the smallest and finest minnow seines to those long 

 enough and deep enough for use in our largest rivers. For collec- 

 tions from weedy ponds and from creeks, and especially from swift 

 waters or from streams where a shore landing was difficult, we have 

 depended largely on the so-called "Baird seine," a close-meshed min- 

 now seine of medium length with a wide-mouthed, deep, conical bag 

 of netting in its center. Trammel-nets have been very serviceable 

 in waters through which a seine could not be drawn, especially in 

 those encumbered by brush or filled with water-plants. Set-nets or 

 pound-nets of various size and mesh, both with and without wings, 

 have brought us much material, especially of the larger and more 

 abundant species. For our knowledge of these, however, we have 

 depended largely upon an inspection of fish markets and an exam- 

 ination of the catches of commercial fishermen, with whom we have, 

 indeed, made frequent trips to their fishing grounds. 



More than 200,000 specimens of our 150 species have been thus 

 collected and preserved, under about 1,800 accessions numbers rep- 

 resenting differences of date, location, or situation, and from more 

 than 450 localities, fairly well distributed through ninety-three of 

 the one hundred and two counties of the state. These collections 

 bore, as a rule, permanent labels showing the date, place, and body 

 of water from which they came, and, in the majority of cases, some 

 particulars concerning the apparatus used and the more notable fea- 

 tures of the situation. This has made possible a statistical analysis of 

 the data of relative abundance of the different species under varying 

 conditions, geographical, local, and ecological, and also of the fre- 

 quencies of joint or associate occurrence of the various species, one 

 with another, in each class of situation or in each place. The results 

 of statistical comparisons of this kind have been used to some extent 

 in this report, especially in the chapter on geographical and ecolog- 

 ical distribution, and in the detailed discussions of the leading fam- 

 ilies, genera, and species. 



A knowledge of the food and feeding activities of fishes is funda- 

 mental to any fair understanding of their place and function in the 

 general system of life, and especially to any just appreciation of their 

 importance to man. Unfortunately, our definite knowledge of this 



