Low navigation dams (1871-1899) 



Forbes, in describing the man-made changes which affected "the 

 biological system of the river" (in Richardson, 1928) does not mention 

 the construction of low navigation dams at Marseilles, Henry, Copperas 

 Creek, LaGrange, and Kampsville. He does mention the introduction of 

 the carp, Cyprinus carpio , the opening of the Chicago Sanitary and Ship 

 Canal, and draining and leveeing of bottomlands and bottomland lakes. 



Nelson (1878) was of the opinion that a dam at Seneca (mile 252.5) 

 hindered the upstream movement of fishes. 

 European carp (1885) 



The European carp was introduced to the Illinois River in 1885, 

 from stock brought to the United States a few years earlier (Forbes 

 and Richardson, 1908). By 1889, the carp catch exceeded the total 

 value of all other commercial fishes from the Illinois River (Thompson, 

 1928) . Forbes and Richardson (1908) reported fishery statistics in- 

 dicating that increased carp populations did not adversely affect the 

 populations of other species. Forbes and Richardson (1908) did feel 

 that carp might compete with the native drum and buffalo fishes, which 

 have the same food preferences as carp. Competition for food does not 

 appear to have markedly affected populations of bigmouth buffalo — 

 bigmouth buffalo and carp comprise the bulk of the commercial catch 

 from the Illinois River and both species are abundant in the electro- 

 fishing collections from Peoria and LaGrange Pools. Bigmouth buffalo 

 are not abundant in the other pools of the river, probably because of 

 poor water quality in the upper pools, and the relative paucity of back- 

 waters in the Alton Pool, rather than because of competition from carp. 

 Forbes and Richardson (1908) did not feel that carp, by their rooting 

 habit of bottom feeding, had increased the turbidity of the water in 

 the Illinois River. In contrast, Jackson and Starrett (1959) observed 

 local areas of heavy turbidity produced by schools of carp in Lake 

 Chautauqua, a bottomland lake along the middle section of the river. 

 They felt that some instances of carp activity may have been stimulated 

 by low oxygen levels. More recently, carp activities may have had a 

 greater effect on turbidity because of the increased presence of 



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