168 



Illinois Natural History Survey Bullltin 



Vol. 27, Art. 2 



Two members of the staflr of the Illinois State Laborator\' of Natural History making obser- 

 vations ofi the breeding habits of fish near Havana, 1910 or 1911. The box at the stern of the 

 boat was used by observers in watching the movements of fish and in searching for fish nests 

 and fry. 



new species, and one with a new genus 

 of plankton (Kofoid 1897, 1898, 1899). 

 Two longer papers on plankton (Kofoid 

 1903, 1908), one on quantitative inves- 

 tigations and the other on constituent or- 

 ganisms and their seasonal distribution, 

 he wrote in California. Kofoid remained 

 on the st.'iff at Herkelc\ until his retire- 

 ment in 1936. 



BOTTOM FAUNA 



I\. K. Richardson's classic studies of 

 the bottom fauna of the Illinois River 

 covered a period that coincided with se- 

 vere changes in the biologv of the river 

 (Forbes & Richardson 1913, 1919; Rich- 

 ardson 1921, 1925./, 1925/., 1928). Be- 

 fore 1900 the Illinois was a reasonably 

 clean river receiving very limited organic 

 pollution from a small number of towns 

 along its banks. H\ 1900 Chicago had 

 become an important trading center and 

 was growing rapidl\'. In order to get rid 

 of the sewage and the organic waste from 



a number of meat packing plants of Chi- 

 cago, a diversion channel was opened be- 

 tween Lake Michigan and the Des 

 Plaines River, one of the headwater 

 streams which united with the Kankakee 

 to form the Illinois. Forbes and Rich- 

 ardson had collected bottoin fauna in the 

 Illinois prior to 1900, and Richardson 

 had continued to do so after the diver- 

 sion of Lake Michigan water had begun. 

 At first the organic pollutants created a 

 nuisance only in the upper part of the 

 river, at Morris, Marseilles, and Starved 

 Rock. Richardson studied the bottom 

 fauna throughout the length of the upper 

 part of the river in 1909, 1910, and 1911 

 and found that the river was nearly nor- 

 mal at Chillicothe and Hennepin. Above 

 these towns it became progressively more 

 polluted. 



During the period 1900-1908 the or- 

 ganic pollutants acted as fertilizer, and 

 the annual fish yield of the lower part of 

 the Illinois increased from 11.5 million 

 to 24 million pounds. Gradually, after 



