356 



Ii.i.iNOis Natlrai. History StRxi;^- Hui.letin 



Vol. 28. Art. 2 



enrichment of stream water by the do- 

 mestic sewage of Raiitoul. At that time, 

 Rantoul did not treat sewage hut allowed 

 it to run throuj^h an open ditch where, 

 durinji warm weather, it was well di- 

 gested before entering the East Branch. 

 On revisiting the station iluring a cooler 

 part of the year, Thompson ^ Hunt 

 found that the raw sewage was not di- 

 gested in the open ditch but that it en- 

 tered the Kast Branch as to.xic material 

 that eliminated fish for se\eral miles 

 downstream. 



At present, there is evidence of enrich- 

 ment of the East Branch by domestic 

 sewage from Rantoul ami Chanute Air 

 Force Base. For several miles below the 

 outlets, this sewage is toxic to fish most 

 of the time. Farther downstream, large 

 populations of a wide variety of fishes 

 benefit from the end-products of the 

 sewage that has been digested upstream. 

 At one station with 41 square miles of 

 drainage, 7.2 miles below the Rantoul dis- 

 posal plant and approximately 2 miles be- 

 low the entrance of the badly polluted 

 stream from Chanute, the collection per 

 100 square yards amounted to 1,337 fish 

 weighing more than 9 pounds. At an- 

 other station with 73 square miles of 

 drainage, 4.5 miles farther downstream, 

 the collection per 100 square yards 

 amounted to 1,331 fish weighing more 

 than 10.5 pounds. These figures, three to 

 four times the county averages, table 14, 

 represented an area a few miles below 

 the badly polluted area in which very few 

 fish Avere found. 



A fish population possibly benefiting 

 from stream enrichment was taken in the 

 upper Sangamon River about a mile be- 

 low the mouth of Drummer Creek, 

 which receives pollution from several 

 sources in Gibson City. In this popula- 

 tion, the numbers of individuals of the 22 

 species represented were low, but their 

 sizes were sufficiently large to make the 

 collection average 5.6 pounds per 100 

 square yards, a weight nearly twice that 

 for most other streams of this size (193 

 square miles of drainage) in the countv, 

 table 14. 



An instance that ma\' be considered 

 partial enrichment was found west of 

 Champaign on Phinney Branch at the 

 junction of Copper Slough. The upper 



regions of both Phinney Branch and Cop- 

 per Slough were polluted, but where they 

 converge 20 species were taken ; the col- 

 lection averaged 2.6 pounds per 100 

 square yards of drainage. Although 20 is 

 an unusually high number of species for 

 streams of this class (16 square miles of 

 drainage) in the county, the weight was 

 not much ahoxe average, table 14. 



The Salt Fork from St. Joseph to the 

 county line was the longest stretch of 

 stream in the county enriched by up- 

 stream sewage. However, our collections 

 failed to indicate any desirable efiects of 

 the enrichment. 



Where fishes are benefiting from enrich- 

 ment of the water, they may be existing 

 under conditions that with very slight 

 changes in chemical balance and concen- 

 tration can quickly become toxic to them. 

 Our data show that when desirable en- 

 richment changes to undesirable pollution 

 the effects on a fish population are hrst a 

 reduction in the number of species, then a 

 reduction in the total weight, and finally 

 a reduction in the number of individ- 

 uals. 



FISHERIES 



The network of streams and a scatter- 

 ing of artificial ponds and lakes provide 

 a considerable amount of fishing water in 

 Champaign County. All of the streams, 

 except the Little Vermilion and Embar- 

 rass, are listed in the Game and Fish 

 Codes as fish preserves; that is, fishing is 

 lestricted to hook-and-line methods, or to 

 minnow seining and spearing as provided 

 by the Game and Fish Codes. Public ac- 

 cess to most of the streams is provided by 

 the system of section-line roads, and fish- 

 ing is generally heaviest near bridges. 

 All the waters as well as the stream banks 

 are privately owned; fishermen must ob- 

 tain landowners' consent to enter the 

 property. 



Sport Fishing 



Approximately 20 of the 90 species in 

 the annotated list of the fishes of Cham- 

 paign County are commonly taken by 

 hook-and-line fishing. However, Dr. Mar- 

 cus S. Goldman has caught 38 species. 

 The 189 miles we have classed as Rivulets 

 and Small Creeks provide satisfactory 

 angling only for small boys in quest of 



