The Small Bottom and Shore Fauna of the Middle and Lower Illinois River and Its Connecting Lakes, Chillicothe to Grafton: Its Valuation; Its Sources of Food Supply; and Its Relation to the Fishery

Abstract

The present paper, so far as it relates particularly to the valuation of the bottom and shore animals, brings together the results of three summer-autumn seasons of dredging operations in the Illinois River and its connecting backwaters, July, 1913, to October, 1915. The work in the river proper and in the wide expansion of its waters known as Peoria Lake included forty cross-sections at intervals ranging from one to about eleven miles, covering the lower one hundred and eighty miles of the river, or about 80 per cent. of the total distance between the mouth and head of navigation at La Salle ; and embraced a total of three hundred and eighty-seven dredge and dipper collections. The dredging operations in the more inclosed bottom-land lakes were mainly confined to those in the middle Illinois valley district of about fifty-nine miles river length between the Copperas Creek and Lagrange dams, in the lakes and other backwaters of which region three hundred and eighty-five dredge and dipper hauls were taken during the three working seasons.