March, 1963 



Larimore & Smith: Fishes of Champaign County 



351 



Table 27. — Number of species of fish collected at several stations above and below the 

 sewage disposal plant on the West Branch of the Salt Fork. The two pools immediately above 

 and below the mouth of the Boneyard were one-half mile above the disposal plant. 



*Heavy oil film on banks and part of water surface. tWater level too high to permit collecting. 



hornyhead chub, creek chub, and redfin 

 shiner. 



Three quantitative samples from Sec- 

 tion 1, taken at points 4 miles, 1 mile, and 

 one-half mile above the sewage treatment 

 plant, table 25, indicate that several spe- 

 cies have been able to tolerate the amount 

 of pollution present during the past 30 

 years, but in 1959 the weight of fish per 

 100 square yards of water varied from 0.4 

 to 1.1 pounds, a capacity considerably be- 

 low that of streams of this class (32-64 

 square miles of drainage) for the rest of 

 the county, table 14. 



Section 2, below the disposal plant, was 

 already polluted at the time of the first 

 survey. Pollution apparently had not 

 greatly reduced the number of species 

 present, inasmuch as Forbes & Richardson 

 reported 33 species in the area. Soon after, 

 however, water conditions became intol- 

 erable to most fishes (Baker 1922:117). 

 When Thompson & Hunt collected in 

 this 9-mile stretch, they found seven spe- 

 cies, most of which were tolerant of mod- 

 erate pollution. Only a few individuals of 

 each species were taken, and most of these 

 were found near outlets of drain tiles that 

 supplied clean water. On the initial visit 

 of the 1959 survey, the four stations that 

 had been sampled by Thompson k Hunt 

 produced only three species, table 24, and 

 a total of 10 individuals. However, nu- 

 merous revisits to these stations during 

 the following spring and early summer 

 enabled us to collect a few individuals of 

 12 other species. 



The list of species disappearing from 

 Section 2 is much longer than the list 

 of species extirpated from Section 1. Spe- 

 cies appearing for the first time in Section 

 2 after the advent of pollution include 

 the carp and redfin shiner. 



The drastic reduction in the number of 

 species, in total fish weight, and in num- 

 ber of individuals for Section 2 in 1959 

 may be seen if figures in table 26 (pol- 

 luted area) are compared with county- 

 wide averages for streams having similar 

 drainage areas (6-1—128 square miles), 

 table 14. Drastic reduction in the fish pop- 

 ulation was observed in the stream just be- 

 low the disposal plant, tables 25 and 27. 



Section 3 (actually the Salt Fork), a 

 4-mile stretch directly below the con- 

 fluence of the East and West branches, 

 receives the benefit of dilution from the 

 cleaner East Branch. Twenty species of 

 fish were collected in this section during 

 the first survey, 19 in the second, and 14 

 in the third. The average number of fish 

 per 100 square yards taken in the third 

 survey was very low for streams of this 

 size, 128-256 square miles of drainage 

 area, table 26, but the poundage (3 

 pounds per 100 square yards) was about 

 average for the county. However, the 

 quantitative data were based on a single 

 sample that contained 14 large carp. Spe- 

 cies other than carp were present in very 

 low numbers, only nine fish per 100 square 

 yards. Signs of pollution were apparent 

 in this section, especially at times of low 

 water. 



