Our U\'ini; RfSdiiivf.'. — Aquatic Eciisvslems 



!.J9 



Horu. ME, I4S4, Polychloiiiulcd brphcnvis (PCBsl in 

 common carp (Cxpriiuis carpia) of the Upper 



Mississippi River Pages 231-239 in J.G. Wiener. R.V. 

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 the Upper Mississippi River Btitterworths. Stoneham. 

 MA. 



Korschgen. C.E. 1984. Riverine and deepwater habitats lor 

 diving ducks. Pages 157-180 in L.M. Smith, R.L. 

 Peterson, and R.M. Kaminski. eds. Habitat management 

 tor migrating and wintering waterfowl in North America. 

 Texas Tech University Press, Lubbock. 



Malhiak. H.A. 1979. A nver survey of the unionid mussels 

 of Wisconsin. 1973-1977. Sand Shell Press. Honcon. Wl, 

 75 pp. 



Perry, E.W. 1979. A survey of Upper Mississippi River nius- 

 ,sels. Pages 1 18-139 in J.L. Rasmussen. ed. A compendi- 

 um of n.shery information on the Upper Mississippi 

 River. 2nd ed. Upper Mississippi River Conservation 

 Committee, Rock Island. IL. 



Platonow, N.S., and L.H. Karstad. 1973. Dietai^ effect of 

 polychlorinated biphenyls on mink. Canadian Journal of 

 Comparative Medicine 37:391-400. 



Shimek, B. 1921. Mollusks of the McGregor. Iowa. Region 

 I. Iowa Conservationist 5:1. 



Steingraeber, M.T, T.R. Schwartz, J.G. Wiener, and J. A. 

 Lebo. 1994. Polychlorinated biphenyl congeners in 



emergent mayflies from the Upper Mississippi River. 

 Environmental Science and Technology 28:707-714. 



Thiel, P.A. 1981. Survey of unionid mussels in the Upper 

 Mississippi River (Pools 3-11). Tech. Bull. 124. 

 Wisconsin Department of Natural Resources, Madison. 

 24 pp. 



Thiel. RA., M. Talbot, and J. Hol/.er. 1979. Survey of mus- 

 sels in the Upper Mississippi River. Pools 3 through 8. 

 Pages 148-156 in J.L. Rasmussen. ed. Proceedings of the 

 UMRCC Symposium on Upper Mississippi River 

 Bivalve Mollusks. Upper Mississippi River Conservation 

 Committee, Rock Island, IL. 



Williams, J.D., M.L. WaiTen, Jr., K.S. Cummings, J.L. 

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 freshwater mussels of the United States and Canada. 

 Fisheries 18:6-22. 



Wilson, D.M.. T.J. Naimo, J.G. Wiener, R.V. Anderson, 

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For further information: 



James Wiener 



National Biological Service 



Upper Mississippi Science Center 



POBox 818 



La Crosse, WI 54602 



The Illinois River is formed by the conflu- 

 ence of the Des Plaines and Kanisakee 

 rivers, about 80 km (50 mi) southwest of 

 Chicago. IlHnois. It then flows 439 km (273 ini) 

 to join with the Mississippi River about 50 km 

 (31 mi) northwest of St. Louis, Missouri (Fig. 

 1 ). The Illinois River has been extensively mod- 

 ified and degraded by industrial and municipal 

 pollution for most of this century (Mills et al. 

 1966). The upper river reaches above the 

 Starved Rock Dam (Fig. 1 ) became the most 

 degraded because most of this pollution origi- 

 nated in the densely populated and heavily 

 industrialized Chicago metropolitan area. In 

 fact, by the late 1920"s. the upper river was 

 thought devoid offish (Thompson 1928), Soon 

 after this period, as pollution-control effoils 

 began to have an effect, fish gradually returned. 

 Changes in the composition of a fish com- 

 munity in a polluted environment can be a use- 

 ful index for assessing environmental health 

 and the effectiveness of pollution control 

 because different fish species vary in their abil- 

 ity to tolerate effects of pollution. In 1957 the 

 Illinois Natural History Survey (INHS) initiated 

 an annual electrofishing survey of the Illinois 

 River to monitor fish populations. A central pur- 

 pose of the survey was to relate changes in fish 

 populations to environmental conditions. This 

 article summarizes trends in fish populations of 

 the upper Illinois River as determined from 

 electrofishing catches from 1959 to 1993. 



Status and Trends 



Fish sampling was conducted at five stations 

 in the upper Illinois River and at two stations in 



the Des Plaines River (Fig. I ) from late August 

 through October. Data from these seven fixed 

 stations were combined for analyses. At each 

 station, fish were sampled by electrofishing for 

 1 hr; thus, catches are expressed as number of 



Brandon Roads 

 Dresden 



Marseilles 

 Starved Rock 



• Sampling station 

 / Lock and dam 



Fish 



Populations in 

 the lUinois 

 River 



by 



Thomas V. Lerczak 



Richard E. Sparks 



Illinois Natural History 



Sur\'ey 



Fig. 1. The Illinois River with 

 locations of navigation locks and 

 dams. Locations of the Illinois 

 Natural History Survey's upper 

 Illinois Waterway electrofishing 

 stations are also shown. 



