Xiv FISHES OF ILLINOIS 



Valuable collections have sometimes been obtained, espe- 

 cially 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 

 collections 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 minnow seine of medium length with a 

 wide-mouthed, deep, conical bag of netting in its center. Tram- 

 mel-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 va- 

 rious 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 examination 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 num- 

 bers representing 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 features of the situation. This has 

 made possible a statistical analysis of the data of relative abun- 

 dance of the different species under varying conditions, geograph- 

 ical, local, and ecological, and also of the frequencies 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 ecological 

 distribution, and in the detailed discussions of the leading 

 families, genera, and species. 



A knowledge of the food and feeding activities of fishes is 

 fundamental to any fair understanding of their place and func- 



