December, 1958 



BiiNNor: Aquatic Biology 



169 



1908, organic waste from Chicago in- 

 creased until the volume approached the 

 capacity of the river to oxidize it. Diver- 

 sion was increased, and the fish yield 

 dropped; a peak diversion occurred in 

 1927 with a flow of 10,245 cubic feet per 

 second (MulvihiU &: Cornish 1930:57). 

 The period of maximum pollution oc- 

 curred between 1915 and 1920. From his 

 studies of bottom fauna during this time, 

 Richardson calculated a reduction in the 

 total weight of bottom organisms in the 

 reach from Chillicothe to La Grange of 

 34.5 million pounds, representing a po- 

 tential loss of 7 million pounds of fish. 

 By 1921 the fish yield of the river had 

 hit an all-time low of 4 million pounds, 

 partly from pollution and partly from ex- 

 tensive bottomland lake drainage. Aiter 

 1922 there was some reduction of the raw 

 sewage going into the Illinois River, and 

 from 1924 to 1930 the yield of commer- 

 cial fish varied around 10 million pounds 

 per year. 



Between 1913 and 1928, Richardson 

 (with some assistance from Forbes on two 

 of the early papers) published six articles 

 in the Bulletin series. Because of the op- 

 portune timing of his studies in relation 

 to the pollution of the Illinois, Richard- 

 son was able to set up a classification of 

 seven degrees of pollution based on the 

 presence of certain groups of aquatic or- 

 ganisms. These groups were often better 

 indicators of the degree of pollution than 

 were oxygen analyses, because the animal 

 associations were sensitive to small in- 

 creases in pollution, or to fluctuations in 

 pollution that might be missed unless 

 oxygen analyses were made continuously. 



NEW LINES OF RESEARCH 



During the second decade of the twen- 

 tieth century, biologists became interested 

 in measuring the effects of physical and 

 chemical changes in the aquatic environ- 

 ment upon fish, and in the responses of 

 the fish to these changes. From 1914 to 

 1925, members of the staf¥ working in 

 aquatic biology published papers on the 

 suitability of bodies of water for fishes; 

 the poisoning of fishes by illuminating gas 

 wastes; the reaction of fishes to carbon di- 

 oxide and carbon monoxide ; a collecting 

 bottle for quantitative determination of 



dissolved gases; methods of measuring tlie 

 dangers of pollution to fisheries; and ob- 

 servations on the oxygen requirements of 

 fishes in the Illinois River. These publi- 

 cations were the work of V^ictor E. Shel- 

 ford (1917, 191 8«, 1918/;), Morris M. 

 Wells (1918), Edwin B. Powers 

 (1918), and David H. Thompson 

 (1925). They represent a new approach 

 to fisheries studies, e.g., the use of labora- 

 tory studies to explain and expand the 

 knowledge of the relationships of fishes 

 and other aquatic organisms to their en- 

 vironments. 



In the early 1920"s acjuatic investiga- 

 tions were continued on the Illinois River, 

 where the Natural History Survey main- 

 tained a houseboat laboratory and attend- 

 ing boats and equipment. At this time 

 studies were begun on the lakes of north- 

 eastern Illinois, studies that included the 

 taking of quantitative plankton and bot- 

 tom samples and collections of fishes and 

 higher aquatic plants. In 1923, an inves- 

 tigation was begun also on the Rock River 

 (Forbes 1928). 



Surveys on the Illinois River, made in 

 co-operation with the Illinois Water Sur- 

 vey in 1923 and 1924, showed that the 

 normal life of the river had been de- 

 stroved bv pollution as far down as Peoria 

 Lake. 



By 1927 the stafif had published in the 

 Bulletin 20 articles, comprising 1,856 

 printed pages, on Illinois River biology. 

 These articles apparently had had a pro- 

 found effect on aquatic biologists in many 

 parts of the United States; other states 

 were engaged in making their own lake 

 and stream surve\s, for the most part not 

 so comprehensive as those of the Illinois 

 River, but adequate to give some informa- 

 tion on physical and chemical conditions 

 and rough measurements of the fish food 

 resources, plus inventories of the kinds 

 and relative abundance of fishes present. 



At this time (1927) the Natural His- 

 tory Survey had expanded its own stream 

 survey program to include, besides the 

 Rock River, the Hennepin Canal, the 

 Sangamon and Kaskaskia rivers, and the 

 streams of Champaign County (Forbes 

 1928). The Rock River investigation 

 was operated from 1923 to 1927 with 

 David H. Thompson in charge of field 

 collecting and R. E. Richardson in charge 



